Hepatitis C
Hepatitis C is a bloodborne viral infection caused by the hepatitis C virus (HCV) that leads to chronic liver inflammation and can progress to cirrhosis and hepatocellular carcinoma.
Hepatitis C
Hepatitis C is a blood-borne infectious disease caused by the Hepatitis C virus (HCV), an enveloped, single-stranded RNA virus of the family Flaviviridae [1][2]. The name tells you a lot: "hepatitis" = hepar (Greek, liver) + -itis (inflammation); so this is literally "inflammation of the liver caused by the C virus."
The infection exists in two phases:
- Acute Hepatitis C: the initial 6 months after exposure. Most (≈80%) are asymptomatic/subclinical; only 10–20% develop symptomatic hepatitis with jaundice; fulminant hepatitis is rare [2][3].
- Chronic Hepatitis C: defined as persistence of HCV RNA ≥ 6 months after exposure [2][3]. Unlike HBV, where chronicity depends heavily on age at acquisition, HCV leads to chronic infection in 55–85% of infected individuals irrespective of age [2][3]. This is a critical distinction.
All viral hepatitis (A–E) are notifiable diseases in Hong Kong [2].
Why does HCV chronify so easily?
HCV is an RNA virus with an RNA-dependent RNA polymerase that lacks proofreading ability → extremely high mutation rate → generates "quasi-species" (swarms of closely related but genetically distinct variants) within a single host. These quasi-species continuously escape the host's neutralising antibody and cytotoxic T-cell responses. The hypervariable region 1 (HVR1) of the E2 envelope protein is the main target of neutralising antibodies, and its constant mutation means the immune system is perpetually "one step behind." This is also why there is no effective vaccine against HCV.
Epidemiology
- Global prevalence: approximately 0.7% (≈58 million chronically infected, WHO 2024 estimate) [2][3]. Older literature cited ~185 million (2.8%), but improved screening and direct-acting antiviral (DAA) treatment have reduced the global burden substantially.
- Highest prevalence in sub-Saharan Africa, the Middle East, Central Asia and Eastern Europe [3].
- Demographics: more common in males, IV drug users, and those with multiple sexual partners [3].
- < 0.5% of the general population are HCV carriers [2].
- Most common genotypes in HK: 1b and 6a (1 > 6 > 2 > 3) [2][3].
- HCV screening of blood products in HK started on 1 July 1991 [2]. Before this, transfusion was a major route.
- In the context of cirrhosis aetiology in HK: HBV dominates at ≈64–75%, while HCV accounts for ≈5–10% [4].
High Yield — HK Context
HCV is a relatively minor contributor to cirrhosis in Hong Kong compared to HBV. However, it remains critically important because: (1) it is curable with DAAs, (2) many cases are undiagnosed, and (3) co-infection with HBV or overlap with MASLD (metabolic-associated steatotic liver disease) is increasingly recognised.
Risk Factors
Understanding risk factors is really about understanding the routes of transmission. HCV is a blood-borne virus — its transmission requires direct percutaneous or mucosal exposure to infected blood [1][2][3].
| Route | Details | Why it works |
|---|---|---|
| Injection drug use (IVDU) | Most important cause globally and in HK [2][3] | Sharing needles/syringes → direct blood-to-blood inoculation; even microscopic amounts of residual blood suffice |
| Blood transfusion | Was ~50% of cases historically [5]; now risk < 1:5,000,000 in HK post-screening [3] | Large-volume parenteral blood exposure; pre-1991 blood products were not screened for anti-HCV |
| Healthcare-related | Needle-stick injuries, poor aseptic technique (especially dental extraction in mainland China), haemodialysis [3] | Percutaneous inoculation; dialysis patients have repeated vascular access |
| Sexual transmission | Risk relatively low compared to HBV and HIV; increased in MSM [2][3] | Mucosal micro-abrasions during intercourse allow blood-to-blood contact; risk amplified by HIV co-infection, multiple partners, and mucosal trauma |
| Perinatal (vertical) transmission | Occurs in ≈5% of anti-HCV-positive mothers, especially those with detectable HCV RNA [3] | Exposure to maternal blood during delivery; risk increases with higher maternal viral load and HIV co-infection |
| Tattooing, piercings, acupuncture | Especially with non-sterile equipment [2] | Percutaneous inoculation via contaminated instruments |
The three viruses well-known to be transmitted by blood products in hospital-acquired infections are HBV, HCV and HIV [6].
These determine how fast someone progresses from chronic hepatitis → fibrosis → cirrhosis → HCC:
| Factor | Mechanism/Explanation |
|---|---|
| Liver histology (most important predictor) [3] | Metavir score grading activity (A0–A3) and fibrosis (F0–F4); higher baseline fibrosis = faster progression |
| Male sex | Oestrogen may be hepatoprotective (anti-fibrotic effects via inhibition of hepatic stellate cell activation) |
| Older age at acquisition | Ageing immune system less effective at viral control; decreased hepatic regenerative capacity |
| Acquisition by blood transfusion | Historically higher viral inocula compared to other routes |
| Alcohol use | Synergistic hepatotoxicity — alcohol induces oxidative stress and CYP2E1 activity, amplifying HCV-mediated hepatocyte injury |
| HIV co-infection | Immunosuppression accelerates fibrosis; HIV promotes HCV replication |
| HBV co-infection | Dual viral hepatitis accelerates fibrogenesis |
| DM, obesity, MASLD | Insulin resistance promotes hepatic steatosis and stellate cell activation → fibrosis. Concept of concomitant liver disease is important in HK [4] |
| Genotype 1b and 3 | More rapid progression and higher risk of HCC [2] |
Anatomy & Function (Relevant Hepatic Anatomy)
To understand HCV pathophysiology, you need to know the liver's microanatomy:
- The functional unit is the hepatic lobule — a hexagonal structure with a central vein at the centre and portal triads (hepatic artery, portal vein, bile duct) at the periphery.
- Hepatocytes are arranged in plates radiating from central vein to periphery, bathed by sinusoidal blood flowing from portal triad → central vein.
- Hepatic sinusoids are lined by fenestrated endothelium, allowing plasma to enter the Space of Disse where hepatic stellate cells (Ito cells) reside.
- In health, stellate cells store vitamin A.
- In chronic injury, stellate cells activate → become myofibroblasts → secrete collagen (types I and III) → fibrosis.
- Kupffer cells (resident liver macrophages) line the sinusoids and are the liver's first-line innate immune defence. They clear pathogens, produce cytokines, and present antigens.
- Dual blood supply (hepatic artery + portal vein): The portal vein drains the GI tract, meaning the liver is exposed to a constant antigenic load. This creates a "tolerogenic" environment — the liver must avoid mounting excessive immune responses to food antigens. HCV exploits this immunological tolerance.
- Hepatotropism: HCV uses specific receptors on hepatocytes (see Pathophysiology below) to enter and replicate.
- Regenerative capacity: The liver can regenerate, but repeated cycles of injury → regeneration → fibrosis eventually distort architecture → cirrhosis with regenerative nodules surrounded by fibrous bands.
Virology of HCV
| Protein | Function | Clinical Relevance |
|---|---|---|
| Core | Nucleocapsid formation; modulates host lipid metabolism | Involved in steatosis; core antigen assay can be used diagnostically |
| E1, E2 | Envelope glycoproteins; viral entry via receptor binding | E2 contains HVR1 — target of neutralising antibodies but mutates rapidly → immune escape |
| NS3/4A | Serine protease — cleaves the polyprotein (replication) | Target of "-previr" drugs (e.g., glecaprevir, voxilaprevir) [2] |
| NS5A | Multifunctional phosphoprotein — involved in replication and assembly | Target of "-asvir" drugs (e.g., velpatasvir, pibrentasvir, ledipasvir) [2] |
| NS5B | RNA-dependent RNA polymerase — replicates viral RNA | Target of "-buvir" drugs (e.g., sofosbuvir) [2] |
Drug Name Roots — DAA Classes
Breaking down the drug names by suffix tells you their target:
- -previr = protease inhibitor (NS3/4A) — "pre" evokes "protease"
- -asvir = NS5A inhibitor
- -buvir = polymerase inhibitor (NS5B) — "b" for NS5B This is how you remember which class each DAA belongs to.
- 6 major genotypes (1–6) with multiple subtypes [2].
- In HK: genotype 1b (≈60%) and 6a (≈25–30%) are most common [2].
- Genotype 1b and 3: more rapid progression and higher risk of HCC [2].
- Genotyping matters because it historically determined the choice and duration of DAA therapy. Modern pan-genotypic regimens (e.g., sofosbuvir/velpatasvir, glecaprevir/pibrentasvir) have reduced this dependence, but genotyping is still performed routinely.
- Attachment & Entry: HCV binds hepatocyte surface receptors — CD81, SR-BI, claudin-1, occludin → receptor-mediated endocytosis.
- Uncoating & Translation: Positive-sense RNA is directly translated by host ribosomes at the rough ER → single polyprotein.
- Polyprotein Processing: Host signal peptidase and viral NS3/4A protease cleave the polyprotein into structural + NS proteins.
- Replication: NS5B (RNA-dependent RNA polymerase) replicates the RNA genome on a "membranous web" formed by NS4B. NS5A is essential for this replication complex.
- Assembly & Release: Core protein + new RNA assemble into nucleocapsid; envelope glycoproteins E1/E2 are added in the ER; virions are secreted via the VLDL secretory pathway (this is why HCV is associated with steatosis — it hijacks lipid metabolism).
Pathophysiology
A critical concept: HCV is not directly cytopathic (unlike, say, yellow fever virus). The liver damage in HCV infection is almost entirely immune-mediated.
-
Innate Immune Response:
- HCV RNA is detected by pattern recognition receptors (RIG-I, TLR3) in hepatocytes → triggers type I/III interferon production.
- However, HCV actively subverts innate immunity: NS3/4A protease cleaves MAVS (mitochondrial antiviral signalling protein) and TRIF, blocking interferon signalling. This is one reason why chronic infection is so common.
- Kupffer cells and NK cells are activated but often dysfunctional in chronic HCV.
-
Adaptive Immune Response:
- CD4+ T-helper cells: Coordinate the immune response. A strong, multi-specific CD4+ response is associated with viral clearance. Weak CD4+ response → chronicity.
- CD8+ cytotoxic T-lymphocytes (CTLs): Kill HCV-infected hepatocytes by recognising viral peptides on MHC class I. This is the main mechanism of hepatocyte injury.
- Paradox: The immune response damages the liver, but it also controls the virus. In chronic HCV, the CTL response is present but exhausted (expressing inhibitory receptors like PD-1, Tim-3) → insufficient to clear the virus but enough to cause ongoing low-grade hepatocyte destruction.
- Antibodies: Anti-HCV antibodies are produced but are mostly non-neutralising and do not confer protective immunity (unlike anti-HAV or anti-HBs). This is why re-infection is possible after viral clearance.
-
Fibrogenesis:
- Chronic hepatocyte injury → release of pro-fibrogenic cytokines (TGF-β, PDGF) → hepatic stellate cell activation → myofibroblast transformation → collagen deposition in the Space of Disse → progressive fibrosis.
- Over 20–30 years, fibrosis progresses through stages (Metavir F0–F4):
- F0 = no fibrosis
- F1 = portal fibrosis without septa
- F2 = portal fibrosis with few septa
- F3 = numerous septa without cirrhosis (bridging fibrosis)
- F4 = cirrhosis — diffuse distortion of liver architecture with regenerative nodules surrounded by fibrous bands [4].
-
Steatosis:
- HCV (especially genotype 3) directly causes hepatic steatosis by:
- Interfering with VLDL secretion (virus hijacks the lipid secretory pathway).
- Upregulating lipogenesis (SREBP pathway activation).
- Impairing mitochondrial fatty acid β-oxidation.
- This steatosis contributes to further oxidative stress and accelerates fibrosis.
- HCV (especially genotype 3) directly causes hepatic steatosis by:
-
Hepatocarcinogenesis:
- HCC in HCV almost exclusively occurs on a background of cirrhosis [3][5] — this is a key contrast with HBV, where HCC can occur without cirrhosis due to direct oncogenic effects of HBV DNA integration into the host genome.
- Mechanism: chronic inflammation → repeated cycles of hepatocyte death and regeneration → accumulation of somatic mutations → dysplastic nodules → HCC.
- Risk of HCC in HCV cirrhosis: 2–5% per year [3].
HBV vs HCV Carcinogenesis — A Key Exam Distinction
HCC that complicates hepatitis C usually presents on top of a cirrhotic liver. HCC that complicates hepatitis B usually presents on top of a non-cirrhotic liver since HBV has direct oncogenic effect (HBV DNA integration into host genome, HBx protein transactivation) [5]. This has practical implications: HCC surveillance in HCV is generally recommended only in those with cirrhosis, whereas in HBV, surveillance is recommended even without cirrhosis (males ≥40, females ≥50, family history of HCC) [7].
HCV doesn't just affect the liver. It can infect and/or stimulate lymphocytes (particularly B cells), leading to a range of extrahepatic manifestations through immune complex deposition and chronic B-cell stimulation:
- Cryoglobulinaemia: HCV chronically stimulates B cells → production of monoclonal/polyclonal immunoglobulins that precipitate at low temperatures (cryoglobulins) → immune complex deposition in small vessels → vasculitis, purpura, arthralgia, neuropathy, MPGN.
- MPGN (membranoproliferative glomerulonephritis): Immune complex (cryoglobulin) deposition in glomerular basement membrane → complement activation → glomerular inflammation.
- Lymphoproliferative disorders: Chronic B-cell stimulation → increased risk of B-cell non-Hodgkin lymphoma.
Classification
| Phase | Definition | Key Features |
|---|---|---|
| Acute HCV | First 6 months post-exposure | 80% asymptomatic; 15–45% spontaneously clear virus (usually within 12 weeks) [2] |
| Chronic HCV | HCV RNA detectable ≥ 6 months | 55–85% of infected; ongoing hepatocyte injury; risk of fibrosis, cirrhosis, HCC |
| Genotype | Geographic Distribution | HK Relevance | Clinical Significance |
|---|---|---|---|
| 1 (1a, 1b) | Global, most common | 1b most common in HK (≈60%) | 1b: more rapid progression, higher HCC risk |
| 2 | Global | Present in HK | Generally good response to DAAs |
| 3 | South Asia, Europe | Present in HK | Associated with hepatic steatosis, rapid progression, higher HCC risk |
| 4 | Middle East, Africa | Rare in HK | — |
| 5 | Southern Africa | Rare in HK | — |
| 6 (6a) | Southeast Asia | 6a ≈25–30% in HK | Associated with IVDU transmission |
| Stage | Description |
|---|---|
| F0 | No fibrosis |
| F1 | Portal fibrosis without septa |
| F2 | Portal fibrosis with few septa |
| F3 | Bridging fibrosis (numerous septa without cirrhosis) |
| F4 | Cirrhosis |
Clinical Features
Symptoms
- 80% asymptomatic/subclinical [2][3].
- When symptomatic (10–20%), the presentation is identical to other acute viral hepatitis — you cannot distinguish acute HCV from HAV, HBV, or HEV clinically [8]:
| Symptom | Pathophysiological Basis |
|---|---|
| Low-grade fever (usually < 39°C) | Cytokine release (IL-1, IL-6, TNF-α) from Kupffer cells and hepatocytes responding to viral infection → hypothalamic thermoregulatory set-point elevation [8] |
| Severe fatigue, malaise | Circulating pro-inflammatory cytokines (TNF-α, IL-1β) act on the CNS → "sickness behaviour"; also impaired hepatic metabolic function |
| Severe loss of appetite (anorexia) | TNF-α and IL-1 suppress appetite centrally; hepatic congestion → early satiety |
| Nausea and vomiting | Hepatocyte dysfunction → impaired bile acid metabolism → cholestasis → stimulation of chemoreceptor trigger zone; also direct vagal afferent stimulation from hepatic inflammation |
| Right upper quadrant dull ache | Distension of Glisson's capsule (liver capsule) — the liver parenchyma itself has no pain fibres; only when inflammation and swelling stretch the capsule do you get a dull ache [8]. This is why HCC can grow to massive size asymptomatically — slow expansion doesn't acutely stretch the capsule. |
| Dark urine (tea-coloured) | Intrahepatic cholestasis in early phase → conjugated bilirubin (water-soluble) spills into blood → filtered by kidneys → dark urine. Also inefficient hepatic clearance of reabsorbed urobilinogen → increased urinary excretion of urobilinogen [2] |
| Pale stools | Intrahepatic cholestasis → decreased delivery of conjugated bilirubin to gut → decreased deconjugation by bacterial β-glucuronidase → decreased urobilinogen (and its oxidised product urobilin, which gives stool its brown colour) [2] |
| Myalgia, arthralgia | Circulating immune complexes; pro-inflammatory cytokines acting on muscle and joint tissues |
| Transient pruritus | Cholestasis → bile salt retention → deposition in skin → stimulation of itch receptors (and possibly lysophosphatidic acid via autotaxin pathway) [8] |
Phases of symptomatic acute hepatitis [8]:
- Preicteric phase (1–2 weeks): Fever, anorexia, fatigue, myalgia, diarrhoea, RUQ ache, dark urine, pruritus.
- Icteric phase (1–2 weeks): Jaundice appears; paradoxically, all pre-icteric symptoms begin to subside (because the immune response is now controlling viral replication).
- Convalescent phase (4+ weeks): Gradual recovery.
-
Non-specific symptoms dominate [3]:
- Fatigue and malaise: Most common complaint; multifactorial — chronic cytokine elevation, altered serotonin metabolism, impaired hepatic energy metabolism.
- Anorexia and weight loss: Chronic inflammatory state; hepatic dysfunction impairing nutrient metabolism.
- Nausea, diarrhoea, abdominal pain: Mild, intermittent; related to portal hypertension and altered gut motility.
- Myalgia, arthralgia, weakness: Immune complex-mediated; also cryoglobulinaemia-related.
- Neuropsychiatric symptoms (depression, anxiety): HCV can cross the blood-brain barrier and infect microglia; also chronic inflammation → altered neurotransmitter metabolism [3].
-
When cirrhosis develops, patients present with complications:
- Ascites, peripheral oedema
- Variceal bleeding (haematemesis, melaena)
- Hepatic encephalopathy (confusion, asterixis)
- Jaundice
- Coagulopathy (easy bruising, bleeding tendency)
- Hepatorenal syndrome
- Spontaneous bacterial peritonitis
Signs
- Jaundice (scleral icterus): Inspect under natural light. Clinically detectable when serum bilirubin > 34 µmol/L (≈2 mg/dL).
- Tender hepatomegaly: Liver is enlarged and tender due to inflammatory swelling → capsular stretch.
- Low-grade fever.
- Usually no stigmata of chronic liver disease.
| Sign | Pathophysiological Basis |
|---|---|
| Spider naevi (upper body distribution — SVC territory) | Arteriolar dilatation due to hyperestrogenism (impaired hepatic oestrogen metabolism) → central arteriole with radiating vessels |
| Palmar erythema | Same mechanism — oestrogen-mediated arteriolar vasodilatation in thenar and hypothenar eminences |
| Gynaecomastia | Hyperestrogenism — impaired hepatic conjugation and clearance of oestrogen |
| Testicular atrophy | Hyperestrogenism + direct toxic effects on Leydig cells |
| Dupuytren's contracture | More associated with alcoholic liver disease, but can be seen; mechanism unclear, possibly related to palmar fibromatosis |
| Jaundice | Impaired hepatic bilirubin conjugation and excretion |
| Ascites | Portal hypertension (↑ hydrostatic pressure in splanchnic capillaries) + hypoalbuminaemia (↓ oncotic pressure) + splanchnic vasodilatation → effective hypovolaemia → RAAS activation → Na+/water retention |
| Caput medusae | Porto-systemic collaterals via recanalised umbilical vein (round ligament of liver) |
| Splenomegaly | Portal hypertension → congestion of splenic vein → passive splenic congestion |
| Asterixis (liver flap) | Hepatic encephalopathy — accumulation of ammonia and other neurotoxins → disruption of diencephalic motor centres controlling postural tone → negative myoclonus |
| Fetor hepaticus | Dimethyl sulphide and mercaptans in exhaled air due to portosystemic shunting (these are normally cleared by the liver) |
| Leukonychia / Muehrcke's lines | Hypoalbuminaemia → altered nail bed vascular pattern |
| Clubbing | Mechanism debated; possibly hepatopulmonary syndrome with intrapulmonary shunting → chronic hypoxia |
| Bruising / petechiae | Coagulopathy (↓ hepatic synthesis of clotting factors II, VII, IX, X) + thrombocytopenia (splenic sequestration from splenomegaly + ↓ thrombopoietin production) |
| Peripheral oedema | Hypoalbuminaemia + Na+/water retention |
| Scratch marks | Pruritus from cholestasis / bile salt deposition |
These are high-yield because they distinguish HCV from other chronic liver diseases and can be the presenting complaint:
| Category | Manifestation | Mechanism |
|---|---|---|
| Lymphoproliferative | Essential mixed cryoglobulinaemia (type II/III) | Chronic B-cell stimulation → production of cryoglobulins (immunoglobulins that precipitate at < 37°C) → immune complex vasculitis. Lab: ↓ C3/C4, RF+, cryoglobulin+ [2] |
| B-cell non-Hodgkin lymphoma | Chronic antigenic stimulation of B cells → clonal expansion → lymphomagenesis [2][3] | |
| Monoclonal gammopathy | Clonal B-cell proliferation → monoclonal immunoglobulin production [2] | |
| Dermatological | Porphyria cutanea tarda (PCT) | HCV-induced hepatic dysfunction → impaired uroporphyrinogen decarboxylase activity → accumulation of porphyrins → photosensitivity, skin fragility, blistering [2][3] |
| Lichen planus | T-cell mediated; cross-reactivity between HCV antigens and basal keratinocyte antigens [2][3] | |
| Leukocytoclastic vasculitis | Immune complex deposition in small dermal vessels [2] | |
| Autoimmune | Autoimmune thyroiditis | Molecular mimicry + immune dysregulation [2][3] |
| Autoimmune hepatitis | HCV-triggered loss of self-tolerance → autoimmune attack on hepatocytes [2] | |
| Sjögren's syndrome | Lymphocytic infiltration of exocrine glands; HCV may directly infect salivary gland epithelium [2][3] | |
| Renal | Membranoproliferative GN (MPGN) | Cryoglobulin immune complex deposition in glomeruli → complement activation → GBM thickening and mesangial proliferation [2][3] |
| Haematological | Immune thrombocytopenia (ITP) | Anti-platelet antibodies; also direct HCV infection of megakaryocytes; splenic sequestration from portal hypertension [2] |
| Aplastic anaemia | T-cell mediated destruction of haematopoietic stem cells (hepatitis-associated aplastic anaemia) [9] | |
| Metabolic | Insulin resistance / Type 2 DM | HCV core protein interferes with insulin signalling (IRS-1 degradation via SOCS pathway); hepatic steatosis worsens insulin resistance |
| Respiratory | Idiopathic pulmonary fibrosis (IPF) | Unclear mechanism; possible immune complex–mediated alveolar injury [2] |
Exam Pearl — Extrahepatic Manifestations
If an exam question describes a patient with purpura, arthralgia, weakness, proteinuria, and low complement with positive rheumatoid factor — think mixed cryoglobulinaemia secondary to chronic HCV. This is the classic extrahepatic manifestation and a favourite exam scenario.
Biochemical Features
- ALT is the most sensitive marker of hepatocyte injury and is typically elevated (often fluctuating in chronic HCV, ranging 100–500 U/L).
- In acute hepatitis, ALT can reach 200–2000 but is generally lower than in acute HBV or HAV [2].
- AST/ALT ratio:
- < 1 in early chronic hepatitis (ALT > AST because ALT is more liver-specific)
-
1 suggests cirrhosis (because AST is released from mitochondria in severe injury, and reduced hepatic clearance of AST by the cirrhotic liver)
- INR is the best marker for reflecting liver synthetic function (due to the short half-life of Factor VII ≈ 6 hours) [2][8].
- Falling ALT + improving INR → recovering.
- Falling ALT + worsening INR → consider fulminant hepatitis (AST/ALT falls because there are fewer hepatocytes left to release enzyme) [8].
- Bilirubin may remain elevated for a long time even after clinical recovery → cholestatic phase [8].
- GGT may be elevated, especially with alcohol co-use or cholestasis.
- ALP: Mild elevation possible; marked elevation suggests biliary obstruction (not typical of HCV alone).
| Marker | Interpretation | Timing |
|---|---|---|
| Anti-HCV IgG | Positive within 12 weeks after infection; remains positive after viral clearance [2][3] | Screening test; does NOT distinguish active from resolved infection |
| HCV RNA (by PCR) | Indicates active viraemia / active disease [2] | Gold standard for confirming active infection; indication for treatment |
| HCV genotype | Determines genotype/subtype | Guides DAA selection and duration (less critical with pan-genotypic regimens but still done) |
| HCV core antigen | Alternative to HCV RNA in resource-limited settings | Correlates with HCV RNA but less sensitive |
Anti-HCV Positive Does NOT Mean Active Infection
Anti-HCV may take up to 12 weeks to appear after infection [2] — this is the "window period." If clinical suspicion is high (e.g., known exposure), check HCV RNA directly rather than waiting for seroconversion.
| Feature | HCV | HBV |
|---|---|---|
| Virus family | Flaviviridae | Hepadnaviridae |
| Genome | ssRNA | dsDNA (partially) |
| Chronicity | 55–85% irrespective of age | Depends on age (90% neonates, < 5% adults) |
| Vaccine | No | Yes |
| Post-exposure prophylaxis | No (no immunoglobulin) | HBIG + vaccine |
| Main transmission | Blood (IVDU) | Blood, sexual, vertical |
| HCC mechanism | Almost exclusively on cirrhosis | Can occur without cirrhosis (DNA integration) |
| Cure | Yes — DAAs achieve SVR > 95% | Functional cure rare; lifelong nucleos(t)ide analogues |
| Extrahepatic manifestations | Very prominent (cryoglobulinaemia, MPGN, etc.) | Polyarteritis nodosa, MPGN |
High Yield Summary
- HCV = enveloped ssRNA virus (Flaviviridae), 6 genotypes; 1b and 6a most common in HK.
- Transmission: blood-borne — IVDU (most important), transfusion (pre-1991), healthcare-related, sexual (low risk, ↑MSM), perinatal (5%).
- Natural history: 80% acute infection asymptomatic → 55–85% become chronic (irrespective of age) → 15–30% develop cirrhosis over 20 years → HCC risk 2–5%/year in cirrhotics.
- HCC in HCV almost exclusively occurs on cirrhotic liver (vs HBV where it can occur without cirrhosis).
- Symptoms: Acute — mostly subclinical; Chronic — fatigue, malaise, non-specific; Late — cirrhosis complications.
- Extrahepatic manifestations: Mixed cryoglobulinaemia (↓C3/C4, RF+), MPGN, PCT, lichen planus, NHL, autoimmune thyroiditis, Sjögren's, ITP.
- Diagnosis: Anti-HCV (screening, +ve ≤12 weeks) → HCV RNA (confirms active infection) → genotyping.
- INR is the best marker for liver synthetic function (short t½ of Factor VII).
- All viral hepatitis are notifiable diseases in HK.
- HCV prevalence in HK < 0.5%; HBV dominates as the cause of cirrhosis (64–75%).
Active Recall - Hepatitis C (Definition to Clinical Features)
[1] Lecture slides: GC 239. Viral hepatitis HAV_HBV_HCV_HEV.pdf [2] Senior notes: Maksim Medicine Notes.pdf (Viral hepatitis, Chronic hepatitis C infection sections) [3] Senior notes: Ryan Ho GI.pdf (Hepatitis C Infection section) [4] Senior notes: Block A - Abdominal distension_ ascites and cirrhosis.pdf (Etiology of Cirrhosis) [5] Senior notes: MBBS Final MB (Surgery) (Felix PY Lai).pdf (Hepatitis C questions) [6] AOS material: AOS - Microbio.pdf (Question 14) [7] Senior notes: Block A - Gastroenterology Interactive Tutorial.pdf (HCC surveillance) [8] Senior notes: Block A - Jaundice after raw oysters_ acute hepatitis.pdf (Acute hepatitis features) [9] Senior notes: Block A - Hematology Data Interpretation.pdf (Hepatitis-associated aplastic anaemia)
Differential Diagnosis of Hepatitis C
The differential diagnosis of Hepatitis C depends entirely on the clinical scenario in which the patient presents. HCV is a chameleon — it can present as acute hepatitis, as an incidental finding of abnormal LFTs, as established cirrhosis, or even primarily with extrahepatic manifestations. Your differential therefore shifts depending on which "face" of HCV you are seeing.
Let me walk you through this systematically.
There are essentially four clinical presentations where HCV enters the differential:
- Acute hepatitis (elevated transaminases ± jaundice)
- Chronic hepatitis / persistently elevated liver enzymes (often asymptomatic, found on routine check)
- Established cirrhosis / decompensated liver disease
- Extrahepatic manifestations as the presenting complaint
A patient presents with fever, malaise, jaundice, dark urine, and markedly elevated ALT/AST (typically 200–2000+). You cannot clinically distinguish the cause — the presentation is identical across all aetiologies [8].
"Different liver diseases have different pattern of abnormalities of the liver function test... Determining the final diagnosis requires history (drug history), clinical presentation, other investigations. Liver biopsy may be required." [10]
Differential Diagnosis of Acute Hepatitis
| Category | Differential | Distinguishing Features / Why it's in the DDx |
|---|---|---|
| Viral hepatitis | Hepatitis A | Faecal-oral route (shellfish), anti-HAV IgM +ve; self-limiting, no chronicity [8] |
| Hepatitis B (acute) | Blood-borne/sexual/vertical; HBsAg +ve, anti-HBc IgM +ve; can cause fulminant hepatitis. In HK context, must always check [11] | |
| Hepatitis B reactivation | A known DDx of "acute hepatitis" picture — patient with known/occult HBV on immunosuppressants (especially anti-CD20, corticosteroids) [10][11] | |
| Hepatitis E | Faecal-oral/zoonotic (pork liver congee in HK), anti-HEV IgM +ve; high mortality in pregnancy (up to 20–25%); can chronify in transplant recipients [8][12] | |
| Hepatitis D (co/superinfection) | Only in HBV-positive patients (HDV is a defective virus requiring HBsAg); very rare in Chinese [11] | |
| EBV / CMV | Both can present with liver function abnormalities, fever, fatigue, and lymphadenopathy — the lymphadenopathy and atypical lymphocytes on blood film are the clue [13] | |
| HSV | Rare cause of hepatitis; occurs most commonly in immunocompromised patients; can cause fulminant hepatitis with very high transaminases [13] | |
| HIV (acute seroconversion) | Acute HIV infection can present with nausea, anorexia, diarrhoea and mildly deranged LFTs; think of this in the right risk factor setting [13] | |
| Adenovirus | Hepatitis can be a complication in immunocompromised hosts [13] | |
| Drug-induced | Drug-induced liver injury (DILI) | Recent drug history is essential — NSAIDs, antibiotics (amoxicillin-clavulanate, isoniazid), anticonvulsants, statins, TCM/herbal tea [10][13][14] |
| Paracetamol overdose | Less common nowadays as a form of suicide [15]; toxic dose > 150 mg/kg; characteristic time course (asymptomatic at 24–48h → fulminant hepatitis > 48h) [14] | |
| Ischaemic | Ischaemic hepatitis ("shock liver") | Brisk rise and rapid resolution of LDH; ALT/AST strikingly elevated, peak within 1–3 days then fall rapidly; ALT/LDH ratio < 1.5 early in course; other evidence of end-organ damage (e.g., acute renal failure). Dx based on clinical features [10][16]. No imaging needed — the speed of rise and fall is diagnostic. |
| Autoimmune | Autoimmune hepatitis (AIH) | Bimodal age distribution (young and middle-aged females); ↑total IgG; ANA, ASMA (type 1) or anti-LKM1 (type 2); associated autoimmune diseases (Graves', T1DM, UC) [14]. Can present as acute liver failure in 25%. |
| Metabolic | Wilson's disease | Young patients; can mimic Parkinson's (extrapyramidal signs); KF rings on slit lamp; low ceruloplasmin; fulminant hepatic failure in Wilson's has a specific feature: Coombs-negative haemolytic anaemia [17] |
| Vascular | Budd-Chiari syndrome | Hepatic venous outflow tract obstruction; presents with acute or subacute liver disease or acute liver failure; triad of abdominal pain, hepatomegaly, ascites [13] |
| Pregnancy-related | HELLP syndrome | Haemolysis, Elevated Liver enzymes, Low Platelets — occurs in pre-eclampsia context [15] |
| Acute fatty liver of pregnancy | 3rd trimester; microvesicular steatosis; rare [15] | |
| Other | Malaria | Presents with fever and jaundice due to haemolysis — travel history is key [13] |
| Alcoholic hepatitis | AST:ALT ratio typically > 2:1; AST usually does NOT exceed 500 [16]; history of heavy alcohol use; tender hepatomegaly, leucocytosis, fever |
High Yield — GC Lecture Slide DDx of Acute Hepatitis
The four major differentials for a "hepatitis pattern" LFT derangement highlighted in the GC Introduction to GI/Hepatology investigations lecture are:
- Acute viral hepatitis
- Ischaemic hepatitis
- Drug-induced hepatitis
- Hepatitis B reactivation [10]
These are the "big four" to always consider. The lecture emphasises that the final diagnosis requires history, clinical presentation, and other investigations — liver biopsy is only useful when all else fails [10].
This is the most common way HCV presents in clinical practice — an asymptomatic patient found to have persistently elevated ALT on routine health check. This is exactly the scenario in the GC Interactive Tutorial Case 2 [7].
The approach: Alcohol, drugs, fatty liver should be the first things you think about [7].
Differential Diagnosis
| Category | Differential | Key Distinguishing Points |
|---|---|---|
| Viral | Chronic HBV | HBsAg +ve; HBV DNA detectable; most common cause of cirrhosis in HK (64–75%) [4]. Concept of dual liver disease — many HBV patients also have MASLD [7] |
| Chronic HCV | Anti-HCV +ve, HCV RNA +ve; < 0.5% prevalence in HK | |
| Chronic HDV | Only if HBV co-infection; rare in Chinese | |
| Metabolic / Steatotic | MASLD (formerly NAFLD/NASH) | Obese/overweight patients; may have DM, dyslipidaemia; USG shows fatty liver; CAP score on elastography > 248 dB/m [7]. Classification: alcoholic fatty liver vs NASH/MAFLD [7] |
| Alcohol | Alcoholic liver disease | Isolated increase in GGT → inducible enzyme, alcohol [18]; AST:ALT > 2; social history is crucial. Anyone presenting with chronic liver disease and a history of alcoholism must exclude other causes — don't get fooled, find out if there are other things (e.g., this patient may also have HCV) [18] |
| Autoimmune | Autoimmune hepatitis | ↑IgG, ANA/ASMA/anti-LKM1; female predominance; associated autoimmune conditions [14] |
| Primary biliary cholangitis (PBC) | AMA M2 isoform highly specific; cholestatic pattern (↑ALP >> ALT); middle-aged female; pruritus [17][19] | |
| Primary sclerosing cholangitis (PSC) | Cholestatic pattern; associated with UC; "beading" on MRCP | |
| Drug-induced | DILI | Temporal relationship with drug exposure; supplements, drugs, TCM [7] |
| Metabolic-genetic | Haemochromatosis | Iron studies (↑ferritin, ↑transferrin saturation > 45%); HFE gene mutation; bronze diabetes; arthropathy |
| Wilson's disease | Young patients (< 40); low ceruloplasmin; ↑24h urinary copper; KF rings [17] | |
| α1-antitrypsin deficiency | Low α1-antitrypsin level; PiZZ phenotype; associated emphysema [13] |
The Data Interpretation Lesson
In the GI Data Interpretation case, a patient presenting with decompensated cirrhosis and alcohol history was found to also have positive anti-HCV and HCV RNA [18]. The teaching point: never accept a single diagnosis without screening for other causes. Always check viral hepatitis markers (HBsAg, anti-HCV) in ANY patient with chronic liver disease, regardless of alcohol history.
When a patient presents with signs of cirrhosis (ascites, variceal bleeding, encephalopathy, jaundice), you need to determine the underlying cause. This is essentially asking: "What is causing this patient's cirrhosis?"
Causes of cirrhosis (by prevalence in HK) [4]:
| Cause | HK Prevalence | Key Investigation |
|---|---|---|
| HBV | 64–75% | HBsAg, HBV DNA |
| HCV | 5–10% | Anti-HCV, HCV RNA |
| Alcohol | > 5% | History; AST:ALT > 2; GGT ↑ |
| MASLD | Increasing | BMI, metabolic syndrome, imaging |
| Autoimmune hepatitis | Rare | ANA, ASMA, ↑IgG |
| PBC | Rare | AMA M2, ↑ALP |
| Wilson's disease | Rare | Ceruloplasmin, urinary copper |
| Haemochromatosis | Rare | Iron studies, HFE genotyping |
| Drug-induced | Variable | Drug history |
| Budd-Chiari | Rare | Doppler USS, CT/MR venography |
| Cardiac (RHF, constrictive pericarditis) | — | Echo; JVP elevated; pulsatile hepatomegaly if TR |
"HCV cirrhosis — some is reversible, but not all" [4]. Unlike HBV where reversal with nucleoside analogues is well-established, HCV cirrhosis can reverse with successful DAA treatment achieving SVR, though advanced cirrhosis (Child C) shows less benefit.
Sometimes patients present to rheumatology, dermatology, or nephrology first, and HCV is the underlying cause. You must keep HCV in the DDx of:
| Presentation | DDx Beyond HCV |
|---|---|
| Cryoglobulinaemic vasculitis (purpura, arthralgia, neuropathy) | Other lymphoproliferative disorders; autoimmune diseases (SLE, RA); HBV-associated PAN |
| MPGN | Lupus nephritis, C3 glomerulopathy, monoclonal immunoglobulin deposition disease |
| Porphyria cutanea tarda | Hereditary PCT, alcohol, oestrogens, iron overload |
| Lichen planus | Idiopathic, drug-induced (beta-blockers, antimalarials) |
| B-cell NHL | Other causes of NHL (EBV, H. pylori MALT, idiopathic) |
| Mixed cryoglobulinaemia | Essential (idiopathic), other infections, autoimmune |
Key Exam Approach — Chronic Elevated LFTs
When faced with an exam question about a patient with persistently elevated liver enzymes, your approach should be:
- History: Alcohol, drugs/supplements/TCM, risk factors for viral hepatitis (transfusion, IVDU, sexual, travel), family history, metabolic syndrome components
- Baseline bloods: CBC, LRFT, INR, albumin
- Viral screen: HBsAg, anti-HCV (minimum); add anti-HAV IgM, anti-HEV IgM if acute
- Autoimmune screen: ANA, ASMA, anti-LKM1, IgG
- Metabolic screen: Ferritin + transferrin saturation, ceruloplasmin (if < 40 years)
- Imaging: USS liver (steatosis, masses, biliary dilatation), ± elastography (fibrosis, CAP score for steatosis)
- If all negative: Consider drug-induced, α1-antitrypsin deficiency, coeliac disease, thyroid disease
Distinguishing HCV from Key Mimics — Practical Tips
- Alcoholic hepatitis: AST usually does NOT exceed 500; AST:ALT ratio typically > 2:1 [16]
- Isolated GGT elevation → think alcohol (inducible enzyme) [18]
- HCV: ALT often > AST (until cirrhosis develops); ALT can be > 1000 in acute flares
- Critical point: they frequently co-exist. Always screen for HCV in "alcoholic" cirrhosis [18]
- AIH: female predominance, ↑IgG, ANA/ASMA positive, associated autoimmune diseases
- HCV: can trigger autoimmune phenomena (ANA may be mildly positive in up to 20% of HCV patients) — but IgG is not markedly elevated, and ASMA/anti-LKM1 are typically negative
- Must check HBV/HCV status before starting prednisolone for AIH (risk of viral reactivation) [14]
- MASLD: metabolic risk factors (obesity, DM, dyslipidaemia); USG shows diffuse hyperechoic texture [20]; anti-HCV negative
- HCV itself causes steatosis (especially genotype 3) — so a patient can have HCV + steatosis simultaneously (dual pathology)
When a patient with known HCV cirrhosis develops a liver mass:
| Feature | HCC | Metastasis | Haemangioma | Cholangiocarcinoma |
|---|---|---|---|---|
| Context | On cirrhotic liver [3][5] | Known primary elsewhere | Incidental | Can occur on non-cirrhotic liver |
| AFP | Elevated in ≈70–80% (but 20–30% non-secreting) [21] | Normal (unless gastric/germ cell primary) | Normal | Normal (CA 19.9 may ↑) |
| CT pattern | Arterial enhancement + portal venous washout [21] | Hypovascular (GI primary) or hypervascular (RCC, melanoma) | Peripheral nodular enhancement, centripetal fill-in | Delayed enhancement (fibrotic) |
| Hepatitis serology | HCV RNA +ve | Variable | Negative | May or may not have viral hepatitis |
"AFP is not always a tumour marker — high inflammation in the liver can also cause marked elevation of AFP sometimes. Key difference is to see whether it comes down after symptoms disappear" [11]. If AFP keeps rising despite resolving hepatitis, start worrying about cancer.
High Yield Summary
Differential diagnosis of Hepatitis C depends on the clinical scenario:
- Acute hepatitis DDx: Viral (HAV, HBV, HBV reactivation, HEV, EBV, CMV, HSV), drug-induced (DILI, paracetamol), ischaemic hepatitis, autoimmune hepatitis, Wilson's disease, Budd-Chiari [10][13]
- Chronic elevated LFTs DDx: HBV (most common in HK), alcohol, MASLD, autoimmune hepatitis, PBC, PSC, haemochromatosis, Wilson's, α1-antitrypsin deficiency, DILI [7][14][17]
- Cirrhosis aetiology DDx: HBV 64–75% in HK, HCV 5–10%, alcohol > 5%, MASLD increasing [4]
- Always screen for co-existing causes — dual liver disease (HBV + MASLD, alcohol + HCV) is common and clinically important [7][18]
- GC lecture "big four" for acute hepatitis LFT pattern: acute viral hepatitis, ischaemic hepatitis, drug-induced hepatitis, HBV reactivation [10]
- Ischaemic hepatitis: brisk rise/fall, ALT/LDH < 1.5, massive LDH, end-organ damage [10]
- Alcoholic hepatitis: AST usually < 500, AST:ALT > 2:1, isolated GGT rise [16][18]
- HCC in HCV occurs almost exclusively on cirrhosis (vs HBV which can cause HCC without cirrhosis) [3][5]
Active Recall - Hepatitis C Differential Diagnosis
References
[3] Senior notes: Ryan Ho GI.pdf (Hepatitis C Infection section) [4] Senior notes: Block A - Abdominal distension_ ascites and cirrhosis.pdf (Etiology of Cirrhosis) [5] Senior notes: MBBS Final MB (Surgery) (Felix PY Lai).pdf (Hepatitis C questions) [7] Senior notes: Block A - Gastroenterology Interactive Tutorial.pdf (Case 2) [8] Senior notes: Block A - Jaundice after raw oysters_ acute hepatitis.pdf [10] Lecture slides: Gastroenterology Hepatology Introduction to GI:Hepatology investigations from the abnormal.pdf [11] Senior notes: Block A - Gastrointestinal Data Interpretation.pdf [12] Senior notes: Ryan Ho GI.pdf (Hepatitis E section) [13] Senior notes: MBBS Final MB (Medicine) (Felix PY Lai).pdf (DDx of hepatitis sections) [14] Senior notes: Maksim Medicine Notes.pdf (AIH, DILI sections) [15] Senior notes: Block A - A jaundiced and incoherent patient_ liver failure.pdf [16] Senior notes: Block A - Introduction to GI_Hepatology investigations (LFT, Endoscopy).pdf (Cases 3-4) [17] Senior notes: Block A - Patients with non-viral chronic liver diseases.pdf [18] Senior notes: Block A - Gastrointestinal Data Interpretation.pdf (Case 2) [19] Senior notes: Ryan Ho GI.pdf (PBC section) [20] Senior notes: Ryan Ho GI.pdf (NAFLD diagnostic evaluation) [21] Senior notes: Ryan Ho GI.pdf (HCC supportive investigations)
Diagnostic Criteria, Algorithm and Investigations for Hepatitis C
Diagnostic Criteria
Unlike many conditions in medicine, Hepatitis C does not have a formal "diagnostic criteria" with a point-scoring system (contrast this with, say, the IAHG scoring system for autoimmune hepatitis, or the Jones criteria for rheumatic fever). Instead, the diagnosis is made through a two-step serological approach — screen, then confirm.
- Anti-HCV antibody (anti-HCV IgG) is the initial screening test [1][2][22].
- This is an enzyme immunoassay (EIA) that detects antibodies against HCV antigens.
- Positive within 12 weeks after infection; remains positive after viral clearance [2].
What does a positive anti-HCV mean? Three possibilities:
- Active chronic HCV infection (HCV RNA +ve)
- Resolved/cleared infection — spontaneous or post-treatment (HCV RNA –ve)
- False positive — particularly in low-prevalence populations
What does a negative anti-HCV mean? Two possibilities:
- No HCV infection (most likely)
- "Window period" — anti-HCV may take up to 12 weeks to appear [2]. This is the only situation where you might miss acute HCV on screening serology.
From the GC Data Interpretation lecture: "The reason why there are no brackets next to anti-HCV is because it's hard to catch the acute phase — UNLESS you have had a needlestick injury (this would be the only situation where you catch the Hep C early)" [11][22]. In other words, acute HCV is almost never diagnosed serologically because it is asymptomatic and patients don't present during the window period.
High Yield — GC Lecture Slide: Acute HCV Has No Acute Marker
From the GI DI lecture: for acute viral hepatitis serology, there is a specific IgM marker for HAV (anti-HAV IgM), HBV (anti-HBc IgM), and HEV (anti-HEV IgM), but for acute HCV — there is "no marker" [22]. You rely on:
- Anti-HCV seroconversion (negative → positive over weeks)
- Direct detection of HCV RNA (becomes positive within 1–2 weeks of infection, before antibodies)
- HCV RNA by PCR is the confirmatory test and the gold standard for active infection [2][3].
- HCV RNA indicates active disease and is the indication for antiviral treatment [2].
- Detectable as early as 1–2 weeks post-infection (much earlier than anti-HCV antibodies).
| Scenario | Anti-HCV | HCV RNA | Interpretation |
|---|---|---|---|
| Active HCV infection | +ve | +ve | Indication for treatment [2] |
| Resolved/cleared HCV | +ve | –ve | Prior HCV; no treatment needed [22] |
| Acute HCV (window period) | –ve | +ve | Very early infection; anti-HCV will seroconvert later |
| No HCV infection | –ve | –ve | Not infected |
| False positive screening | +ve | –ve | Confirm with repeat anti-HCV or recombinant immunoblot assay |
- Presence of HCV RNA ≥ 6 months after exposure [2].
- In practice, the "6 months" is often retrospective — most patients are diagnosed when already chronic because the acute phase is silent.
- SVR is defined as absent HCV RNA by PCR 12 weeks after stopping treatment [2].
- SVR is associated with a 99% chance of long-term HCV RNA negativity [2] — this is essentially considered a virological cure.
- Post-SVR monitoring: check ALT and HCV RNA at 48 weeks → consider cured if both normal [2].
SVR vs Cure
Why do we say "SVR" rather than "cure"? Because:
- Anti-HCV antibodies remain positive indefinitely after SVR (they don't clear — unlike anti-HBs which signifies immunity)
- HCV antibodies do not confer 100% immunity — re-infection is still possible [8]
- If the patient had cirrhosis at time of treatment, the cirrhosis-related complications (including HCC risk) persist even after SVR, though at a reduced rate So SVR = virological cure, but not necessarily clinical cure if end-organ damage has already occurred.
Here is the complete diagnostic approach, integrating the GC 239 Viral Hepatitis lecture slide investigation algorithm [1] with the clinical workflow:
This algorithm mirrors the GC 239 lecture slide [1] which shows a stepwise approach: start with the serological panel, then follow the positive result to its confirmatory test.
The GC 239 lecture slide explicitly shows this cascade: HBsAg → Anti-HAV IgM → Anti-HCV → Anti-HEV IgM → ANA/anti-smooth muscle/anti-LKM1 → Ultrasound → Toxicology screen. Each is checked; if all are negative, consider rarer causes [1].
Investigation Modalities — Detailed Interpretation
1. Serological / Virological Tests
| Feature | Detail |
|---|---|
| What it detects | IgG antibodies against HCV structural and non-structural proteins |
| When it becomes positive | Within 12 weeks of infection [2] |
| Sensitivity/Specificity | > 97% sensitive in chronic infection; lower in early acute infection (window period) and immunosuppressed patients |
| Remains positive after clearance | Yes [2][22] — this is critical to understand |
| Use | Screening only — cannot distinguish active from past infection |
From the DI lecture: "Prior HCV = Anti-HCV positive, HCV RNA negative" [22]. This single line is the key to interpreting anti-HCV.
| Feature | Detail |
|---|---|
| What it detects | Viral RNA in serum (qualitative or quantitative) |
| When it becomes positive | 1–2 weeks post-infection (earliest marker) |
| Use | Confirms active infection; is the indication for antiviral treatment [2] |
| Quantitative use | Baseline viral load before treatment; not used for treatment decisions with pan-genotypic DAAs but helps monitor response |
| Post-treatment | Absent HCV RNA at 12 weeks post-treatment = SVR [2] |
| Feature | Detail |
|---|---|
| What it determines | Viral genotype (1–6) and subtype |
| Clinical significance | Different disease course and DAA regimen selection [2] |
| Genotype 1b and 3: more rapid progression and higher risk of HCC [2] | |
| HK genotypes | 1b ≈ 60%, 6a ≈ 25–30% [2] |
| Current relevance | With pan-genotypic regimens (sofosbuvir/velpatasvir, glecaprevir/pibrentasvir) available, genotyping is less critical for treatment choice but still performed routinely for epidemiological and prognostic purposes |
- An alternative to HCV RNA in resource-limited settings.
- Correlates with HCV RNA levels but is less sensitive (detection limit ~500–3000 IU/mL vs ~10–15 IU/mL for PCR).
- Mainly used where PCR is unavailable.
2. Liver Function Tests (LFT) — Pattern and Interpretation
The approach to LFTs was heavily emphasised in the GC Introduction to GI/Hepatology investigations lecture [16][23]:
"Liver function tests assess three distinct aspects of hepatic function: cellular integrity through ALT and AST levels, synthetic capacity via albumin and prothrombin time, and excretory function using bilirubin, ALP and GGT" [23].
| Parameter | Expected Finding | Interpretation |
|---|---|---|
| ALT | Markedly elevated (200–2000+) [2] | Hepatocyte membrane damage releases cytoplasmic ALT; ALT is more liver-specific than AST |
| AST | Elevated, usually < ALT | In most primary liver diseases, ALT > AST [16] |
| INR | Normal in mild disease; prolonged if severe | Best marker for liver synthetic function due to short half-life of Factor VII (≈6 hours) [8][2] |
| Albumin | Usually normal in acute phase | Half-life ≈20 days → takes weeks to drop; a low albumin suggests chronic disease |
| Bilirubin | Elevated (conjugated > unconjugated) | Direct bilirubin elevation reflects intrahepatic cholestasis; bilirubin may remain elevated long after clinical recovery (cholestatic phase) [8] |
| ALP / GGT | Mildly elevated or normal | If markedly elevated → think biliary obstruction rather than hepatitis |
- ALT may be fluctuating (100–300 range) or even intermittently normal — this does NOT exclude significant fibrosis or cirrhosis.
- AST:ALT ratio: < 1 in non-cirrhotic disease; > 1 suggests cirrhosis (reversal of de Ritis ratio) [16].
- Why? In cirrhosis, there is mitochondrial damage releasing mitochondrial AST, plus reduced hepatic clearance of AST.
These are high-yield and repeatedly emphasised in the GC GI/Hepatology DI teaching [16]:
"4 liver pathologies cause AST elevation greater than ALT: (1) Alcoholic hepatitis (AST:ALT > 2:1, AST almost never > 500), (2) Hepatocellular carcinoma, (3) Congestive heart failure, (4) Ischaemic hepatitis" [16]
3. Liver Fibrosis Assessment
This is crucial because the fibrosis stage determines prognosis, surveillance strategy, and treatment urgency.
| Feature | Detail |
|---|---|
| Principle | Measures liver stiffness by tracking shear wave velocity through the liver; stiffer liver = faster wave propagation = higher kPa value |
| Interpretation | < 7.1 kPa = F0-F1 (minimal fibrosis); 7.1–9.5 = F2; 9.5–12 = F3; > 12 kPa = suggestive of cirrhosis (F4) [7] |
| CAP score | Controlled Attenuation Parameter — measures hepatic steatosis. 248–280 dB/m = mild-moderate steatosis; > 280 dB/m = severe steatosis [7] |
| Advantages | Non-invasive, reproducible, quick (~5 minutes), standard of care nowadays replacing liver biopsy [11] |
| Limitations | Unreliable in: obesity (BMI > 30 — use XL probe), ascites, acute hepatitis flare (inflammation falsely elevates stiffness), narrow intercostal spaces |
"Liver biopsy generally not done anymore, rarely performed due to invasiveness. Non-invasive measurements → FibroScan, standard of care nowadays" [11].
| Score | Components | Cut-offs |
|---|---|---|
| FIB-4 | Age, AST, ALT, platelet count | < 1.30 = low risk of advanced fibrosis; > 3.25 = high risk |
| APRI | AST, platelet count | < 0.5 = unlikely cirrhosis; > 1.5 = likely significant fibrosis |
These are calculated scores used as initial triage before elastography.
| Feature | Detail |
|---|---|
| Gold standard | For grading (inflammation activity) and staging (fibrosis) |
| Metavir scoring | Activity A0–A3; Fibrosis F0–F4 |
| When to perform | When diagnosis is uncertain despite imaging and blood tests; features of cirrhosis or increased risk of cirrhosis; to distinguish NAFL from NASH [20] |
| Risks | Pain, bleeding, pneumothorax, bile leak; sampling error (only assesses ~1/50,000th of the liver) |
| Current role | Rarely required for HCV diagnosis or staging with the availability of elastography and DAAs |
From the GC GI/Hepatology investigations lecture: "Determining the final diagnosis requires history, clinical presentation, other investigations. Liver biopsy may be required — ONLY USEFUL HERE" (referring to cases where all non-invasive tests are inconclusive) [10].
4. Imaging
| Feature | Detail |
|---|---|
| Role in HCV | Screen for complications: liver echotexture (coarsened in cirrhosis), portal hypertension (splenomegaly, ascites), hepatic masses (HCC surveillance) |
| Steatosis | Diffuse hyperechoic texture [20] |
| Cirrhosis | Coarsened echotexture, irregular/nodular liver surface, ascites, splenomegaly, reversed portal flow |
| HCC surveillance | 6-monthly USS ± AFP in cirrhotics [7] |
| From GC lecture | Ultrasound is part of the initial investigation panel for acute viral hepatitis — to exclude biliary obstruction and assess liver/spleen [1] |
This is the gold standard for HCC diagnosis [21][24]:
| Phase | Timing | HCC Appearance | Why |
|---|---|---|---|
| Late arterial | 35 seconds | Hyperdense (arterial enhancement) | HCC is supplied predominantly by hepatic artery (normal liver mainly by portal vein) |
| Portal venous | 70 seconds | Washout (hypodense) | Contrast leaves tumour faster than normal liver; best phase to see hypovascular lesions against enhancing liver |
| Delayed | 600 seconds | Iso/hypodense ± capsule enhancement | Fibrous capsule retains contrast |
"Arterial enhancement + portal venous washout = diagnostic hallmark of HCC on triphasic CT" [21][24].
- Used when CT is contraindicated or equivocal.
- Typical HCC features: high intensity on T2-weighted, low intensity on T1-weighted images [21].
- Primovist (gadoxetate) is taken up by functioning hepatocytes → HCC (which are non-functioning) appears hypointense on hepatobiliary phase.
The lecture slides specifically mention screening for complications in chronic HCV [2]:
| Investigation | Purpose | Rationale |
|---|---|---|
| Urinalysis | Screen for proteinuria/haematuria | MPGN from cryoglobulinaemia [2] |
| TFT + anti-thyroid antibodies | Screen for autoimmune thyroiditis | Extrahepatic manifestation of HCV [2] |
| ANA | Screen for autoimmune hepatitis overlap | HCV can trigger autoimmune phenomena |
| Cryoglobulins + complement (C3/C4) + RF | Screen for mixed cryoglobulinaemia | Type II/III cryoglobulinaemia: ↓C3/C4, RF+, cryoglobulin+ [2] |
| Serum AFP | HCC surveillance (if cirrhotic) | AFP > 400 ng/mL almost diagnostic of HCC [21]; but 20–30% of HCC is non-secreting [11] |
6. Severity and Prognostic Scoring
Once cirrhosis is established, these scores determine management and transplant candidacy:
| Parameter | 1 point | 2 points | 3 points |
|---|---|---|---|
| Bilirubin (µmol/L) | < 34 | 34–50 | > 50 |
| Albumin (g/L) | > 35 | 28–35 | < 28 |
| INR | < 1.7 | 1.7–2.3 | > 2.3 |
| Ascites | None | Mild (controlled) | Moderate-severe |
| Encephalopathy | None | Grade 1–2 | Grade 3–4 |
- Child A (5–6) = compensated; Child B (7–9) / C (10–15) = decompensated [18].
| Timing | Investigation | Purpose |
|---|---|---|
| Baseline (pre-treatment) | CBC, LRFT, INR, HCV RNA (quantitative), genotype, FibroScan, urinalysis, TFT | Baseline assessment |
| On treatment | CBC, LRFT q4 weeks | Drug toxicity monitoring |
| 12 weeks after stopping DAA | HCV RNA | Define SVR — absent HCV RNA = virological cure [2] |
| 48 weeks post-treatment | ALT + HCV RNA | If both normal → consider cured [2] |
| If SVR NOT achieved | HCV RNA, resistance testing | Continue treatment for another 12 weeks [2] |
| Cirrhotic patients post-SVR | 6-monthly USS ± AFP | HCC risk persists even after SVR (reduced but not eliminated) |
High Yield — Post-SVR HCC Surveillance
Even after achieving SVR, patients with cirrhosis at baseline must continue 6-monthly HCC surveillance indefinitely. This is because the accumulated genomic damage from years of chronic inflammation does not reverse with viral clearance. The annual HCC risk drops from ~2–5% to ~0.5–1% post-SVR, but this is still clinically significant.
The Felix Lai HCV case study [5][25] beautifully illustrates the investigation timeline for a typical HCV patient:
- 55-year-old male, ex-IVDU → found to have abnormal LFTs 10 years ago → chronic HCV diagnosed
- Treated with interferon + ribavirin (old regimen) → non-responder
- 5 years later → ascites → decompensated cirrhosis
- 10 months ago → AFP raised → USS suspicious → triphasic CT confirmed HCC
Investigations for this patient [5]:
- CBC — especially after each treatment course (pancytopenia if systemic chemo, rare if intra-arterial)
- HCV RNA — monitor continuing viraemia
- LFT — monitor hepatic function
- Serum AFP — follow tumour progression/regression
- Clotting profile (PT/INR) — monitor hepatic decompensation
- USS/CT liver — periodic tumour size assessment
High Yield Summary
Diagnosis of HCV is a two-step process:
- Screen with anti-HCV antibody (positive within 12 weeks, remains positive after clearance)
- Confirm with HCV RNA by PCR (gold standard for active infection; indication for treatment)
Key investigation pearls:
- Acute HCV has "no marker" for acute phase — unlike HAV/HBV/HEV which have IgM markers [22]
- Anti-HCV positive + HCV RNA negative = resolved/cleared infection (prior HCV) [22]
- SVR = absent HCV RNA 12 weeks after stopping treatment → 99% long-term cure [2]
- FibroScan is standard of care for fibrosis staging; liver biopsy is rarely needed [11]
- Liver stiffness > 12 kPa suggestive of cirrhosis; CAP > 280 dB/m suggestive of severe steatosis [7]
- Child-Pugh score: A = compensated; B/C = decompensated. MELD score: used for transplant prioritisation [18]
- HCC surveillance (6-monthly USS ± AFP) is mandatory for cirrhotic patients, even after SVR [7]
- AFP > 400 ng/mL almost diagnostic of HCC; but 20–30% of HCC is non-secreting [11][21]
- Four conditions where AST > ALT: alcoholic hepatitis, HCC, congestive heart failure, ischaemic hepatitis [16]
- INR is the best marker for liver synthetic function (short half-life of Factor VII) [2][8]
Active Recall - HCV Diagnostic Criteria, Algorithm and Investigations
References
[1] Lecture slides: GC 239. Viral hepatitis HAV_HBV_HCV_HEV.pdf (Investigation algorithm, slides 11, 20) [2] Senior notes: Maksim Medicine Notes.pdf (Chronic hepatitis C infection, Viral hepatitis overview) [3] Senior notes: Ryan Ho GI.pdf (Hepatitis C Infection section) [5] Senior notes: MBBS Final MB (Surgery) (Felix PY Lai).pdf (HCV case study, investigations) [7] Senior notes: Block A - Gastroenterology Interactive Tutorial.pdf (FibroScan values, HCC surveillance) [8] Senior notes: Block A - Jaundice after raw oysters_ acute hepatitis.pdf (INR, bilirubin interpretation) [10] Lecture slides: Gastroenterology Hepatology Introduction to GI:Hepatology investigations from the abnormal.pdf (Workshop conclusions) [11] Senior notes: Block A - Gastrointestinal Data Interpretation.pdf (FibroScan, AFP interpretation, anti-HCV window period) [16] Senior notes: Block A - Introduction to GI_Hepatology investigations (LFT, Endoscopy).pdf (AST/ALT patterns) [18] Senior notes: Block A - Gastrointestinal Data Interpretation.pdf (Child-Pugh, MELD, Case 2) [20] Senior notes: Ryan Ho GI.pdf (NAFLD diagnostic evaluation, liver biopsy indications) [21] Senior notes: Ryan Ho GI.pdf (HCC imaging, AFP interpretation) [22] Lecture slides: 1213_DI_GI_Prof_WK_Leung.ppt.pdf (Viral hepatitis markers interpretation) [23] Senior notes: Learning_Points_All_Lectures.txt (LFT learning points) [24] Senior notes: Maksim Surgery Notes.pdf (HCC investigations, triphasic CT) [25] Senior notes: MBBS Final MB (Medicine) (Felix PY Lai).pdf (HCV case study, AFP, HBV/HCV serology)
Management of Hepatitis C
The management of Hepatitis C has been revolutionised over the past decade. We have gone from a disease that was difficult to treat, required painful injections, had terrible side effects and low cure rates — to one that is essentially curable with 8–12 weeks of oral tablets in > 95% of patients. This is one of the great success stories of modern medicine.
Let me walk you through this systematically, from general principles to specific treatment modalities.
The management framework has four pillars:
- Antiviral treatment — the centrepiece; cure the infection with DAAs
- General/supportive measures — lifestyle, vaccination, monitoring
- Management of cirrhosis and its complications — if already present
- Prevention — primary and secondary
Pillar 1: Antiviral Treatment
"Indication: all patients with detectable HCV RNA" [2]
This is beautifully simple compared to the complex treatment algorithms for HBV. The principle: if HCV RNA is detectable, treat. There is no need to wait for elevated ALT or advanced fibrosis. The WHO and all major guidelines (AASLD/IDSA, EASL) now recommend treating everyone with active HCV infection.
From the Felix Lai notes, the indications for treatment were historically stated as [5]:
- Patients with elevated ALT levels (indicating active liver destruction)
- Patients with +ve HCV RNA (indicating continuing viraemia)
In current 2025/2026 practice, this has been simplified: detectable HCV RNA alone is sufficient indication — you don't need elevated ALT. The rationale: even patients with "normal" ALT can have progressive fibrosis, and treating early prevents complications.
From the GC 239 lecture — Hong Kong Viral Hepatitis Action Plan: "Expansion of access to direct-acting antivirals (DAA) for HCV — DAA is effective in curing HCV infection with minimal side effects. Expand the HA Drug Formulary indication for DAA therapy on all patients, regardless of their disease severity, in a stepwise manner" [1]
High Yield — GC Lecture: HK HCV Action Plan
The GC 239 lecture explicitly highlights the HK government strategy to expand DAA access to ALL HCV patients regardless of disease severity [1]. This reflects the WHO elimination goal of reducing new HCV infections by 90% and HCV-related mortality by 65% by 2030. Key strategies include:
Treatment Modalities: A Historical Perspective → Current Practice
Understanding the evolution helps you appreciate why DAAs are such a breakthrough and why older exam cases may reference interferon/ribavirin.
Historical Treatment (no longer first-line — but may appear in exam cases)
| Feature | Detail |
|---|---|
| Mechanism | Protein made by immune system to fight virus [25] — binds to IFN-α receptor → activates JAK-STAT pathway → induces antiviral genes (ISGs) that inhibit viral replication; also enhances NK cell and CTL activity |
| Route | SC injection [25] |
| Pegylated version | PEG = polyethylene glycol — no activity against virus itself but allows interferon to stay in body much longer → changed dosing from 3x/week to 1x/week [25] |
| Duration | 12 months for HCV [25] |
| SVR rates | ≈40–50% with peg-IFN + ribavirin (genotype-dependent; worse for genotype 1) |
| Side effects | Flu-like symptoms (fever, fatigue, myalgia, headache) [25] |
| Autoimmune reactivation (thyroiditis, autoimmune hepatitis) [25] | |
| Hepatic decompensation (killing virus-infected hepatocytes → further liver damage) [25] | |
| Neuropsychiatric symptoms (depression ± suicidal ideation, bipolar, schizophrenia) [25] | |
| Myelosuppression (anaemia, neutropenia, leukopenia) [25] | |
| Diarrhoea, alopecia [25] | |
| Contraindications | Pregnancy, children, liver cirrhosis, decompensated liver disease [25] |
| Current status | NOT used nowadays [25] — completely replaced by DAAs for HCV |
Exam Context — The Felix Lai Case Study
The classic HCV case study describes a 55-year-old ex-IVDU treated with interferon and ribavirin for 1 year — but was a non-responder [5][25]. Non-responders to interferon had higher risk of complications: his cirrhosis manifested > 15 years later and HCC > 20 years later [5]. This case was written in the interferon era — in 2025/2026, this patient would receive DAAs with > 95% chance of SVR.
| Feature | Detail |
|---|---|
| Mechanism | Inhibits replication of DNA and RNA virus [25] — multiple proposed mechanisms including lethal mutagenesis (incorporation into viral RNA causing errors), inosine monophosphate dehydrogenase (IMPDH) inhibition depleting GTP pools, and immunomodulation |
| Route | Oral [25] |
| Used as | Adjunct to interferon (historically) or adjunct to certain DAA regimens (in special situations like decompensated cirrhosis or treatment failures) |
| Side effects | Haemolysis (ribavirin accumulates in RBCs → oxidative damage → extravascular haemolysis; dose-dependent; the most clinically significant side effect) [25] |
| Pancytopenia [25] | |
| GI disturbance (abdominal pain, N&V, anorexia, weight loss) [25] | |
| Myalgia, arthralgia, alopecia, fatigue [25] | |
| Contraindications | Pregnancy (significant teratogenic and embryocidal effects) — both male and female patients must use effective contraception during and for 6 months after treatment [25] |
| Chronic renal failure (GFR < 60 mL/min/1.73m²) — renally cleared, accumulates [25] | |
| Hepatic decompensation (Child-Pugh B or C) [25] | |
| Autoimmune hepatitis [25] |
Current Standard of Care: Direct-Acting Antivirals (DAAs)
DAAs target specific viral proteins essential for HCV replication. They represent one of the most targeted therapies in all of medicine.
"DAA: inhibit replication, post-translational processing and assembly of HCV" [2]
| Drug Class | Target | Mechanism | Suffix | Examples |
|---|---|---|---|---|
| NS3/4A protease inhibitors | NS3/4A serine protease | ↓ replication (block polyprotein cleavage → cannot produce functional viral proteins) | -previr | glecaprevir, voxilaprevir, paritaprevir, grazoprevir [2] |
| NS5A inhibitors | NS5A phosphoprotein | ↓ replication (disrupt the membranous web replication complex and viral assembly) | -asvir | velpatasvir, pibrentasvir, ledipasvir, elbasvir [2] |
| NS5B polymerase inhibitors | NS5B RNA-dependent RNA polymerase | ↓ assembly, secretion (nucleotide/non-nucleotide analogues that directly block the viral polymerase) | -buvir | sofosbuvir (nucleotide analogue — pangenotypic, high barrier to resistance) [2] |
How to Remember DAA Classes by Suffix
- -previr → prevents protease cleavage (NS3/4A)
- -asvir → targets NS5A
- -buvir → targets NS5B (the polymerase, "b" for NS5B)
These suffixes are universally used and will help you identify drug class instantly in any exam question.
"Regimen: combination of drugs (↓ resistance)" [2]
HCV has an extremely high mutation rate (RNA-dependent RNA polymerase lacks proofreading). Using a single agent would quickly select for resistant variants. By combining drugs targeting different viral proteins (typically 2–3 classes), you dramatically reduce the chance of resistance — similar to the principle behind HIV antiretroviral therapy or TB multidrug treatment.
| Regimen | Components | Genotype Coverage | Duration | Notes |
|---|---|---|---|---|
| Sofosbuvir/Velpatasvir (SOF/VEL) (Epclusa) | NS5B + NS5A | Pan-genotypic (all genotypes 1–6) | 12 weeks | First-line pan-genotypic; well-tolerated |
| Glecaprevir/Pibrentasvir (GLE/PIB) (Maviret) | NS3/4A + NS5A | Pan-genotypic | 8 weeks (non-cirrhotic, treatment-naïve) or 12 weeks (cirrhotic) | Shortest duration available for non-cirrhotic patients; contains a protease inhibitor → contraindicated in decompensated cirrhosis |
| Sofosbuvir/Velpatasvir/Voxilaprevir (Vosevi) | NS5B + NS5A + NS3/4A | Pan-genotypic | 12 weeks | Mainly for DAA-experienced patients (retreatment after failure) |
| SOF/VEL + Ribavirin | NS5B + NS5A + ribavirin | Pan-genotypic | 12–24 weeks | For decompensated cirrhosis (where protease inhibitors are contraindicated) |
Key Point — Decompensated Cirrhosis
"PIs (protease inhibitors) must not be used in patients with Child-Pugh B or C decompensated cirrhosis or in patients with previous episodes of decompensation" [1]
Why? Protease inhibitors are hepatically metabolised and their levels increase dramatically in decompensated liver disease → risk of hepatotoxicity. So:
- Decompensated cirrhosis → use SOF/VEL ± ribavirin (no protease inhibitor)
- Compensated cirrhosis → either SOF/VEL or GLE/PIB is fine
| Patient Category | Recommended Regimen | Duration | Special Considerations |
|---|---|---|---|
| Non-cirrhotic, treatment-naïve | GLE/PIB or SOF/VEL | 8 weeks (GLE/PIB) or 12 weeks (SOF/VEL) | Simplest scenario |
| Compensated cirrhosis (Child A) | GLE/PIB or SOF/VEL | 12 weeks | Both regimens safe; IFN is contraindicated in cirrhosis [2] |
| Decompensated cirrhosis (Child B/C) | SOF/VEL ± ribavirin | 12–24 weeks | NO protease inhibitors; refer for transplant assessment; monitor closely |
| DAA-experienced (prior failure) | SOF/VEL/VOX ± ribavirin | 12 weeks | Resistance-guided if available |
| HBV co-infection | Same DAA regimens | Same | Screen HBsAg and anti-HBc before starting DAAs → risk of HBV reactivation (HCV suppresses HBV; when HCV is cleared, HBV can flare). Start prophylactic HBV antivirals if HBsAg +ve |
| HIV co-infection | Same DAA regimens | Same | Check drug-drug interactions with antiretrovirals carefully |
| Severe renal impairment (eGFR < 30) | GLE/PIB preferred | 8–12 weeks | SOF should only be used if no alternative approved for severe renal impairment is available [1] |
"There are few contraindications to treatment with DAAs" [1]
This is a key exam point — DAAs are remarkably safe. The main contraindications and precautions from the GC 239 lecture [1]:
| Contraindication/Precaution | Rationale |
|---|---|
| CYP/P-gp-inducing agents (e.g., carbamazepine, phenytoin) | Contraindicated with ALL regimens; risk of significantly reduced DAA concentrations [1] — these drugs induce hepatic enzymes that metabolise DAAs, leading to subtherapeutic levels and treatment failure |
| Protease inhibitors in Child-Pugh B/C decompensated cirrhosis | Must NOT be used [1] — hepatic metabolism impaired → drug accumulation → hepatotoxicity |
| SOF in eGFR < 30 mL/min/1.73m² | Should only be used if no alternative available [1] — sofosbuvir's active metabolite (GS-331007) is renally cleared and accumulates |
| Pregnancy | DAAs not recommended (limited safety data); ribavirin if used is absolutely contraindicated (teratogenic) |
| Drug-drug interactions | A thorough drug-drug interaction risk assessment is required → www.hep-druginteractions.org [1] |
"Educate patients on the importance of: (1) adherence to therapy, (2) following the dosing recommendations, (3) reporting the use of other medications and recreational drugs" [1]
These apply to all patients with chronic HCV, whether on treatment or not:
| Measure | Detail | Rationale |
|---|---|---|
| Alcohol abstinence | Complete abstinence recommended [3] | Alcohol synergistically accelerates fibrosis in HCV. "Small amount of alcohol is very dangerous in hepatitis C patient" (contrast with HBV where small amounts appear acceptable) [26] |
| Coffee | 2–3 cups daily [3] | Evidence that coffee consumption ↓ risk of fibrosis progression (likely via antioxidant and anti-inflammatory polyphenols) |
| Avoid hepatotoxic drugs | Avoid NSAIDs if advanced liver disease [3] | NSAIDs can be hepatotoxic; also impair renal function in cirrhosis (prostaglandin-dependent renal perfusion) |
| Vaccination | Hepatitis A and B vaccinations usually indicated; pneumococcal if cirrhotic [3] | Prevent superinfection with HAV/HBV which can cause severe acute-on-chronic liver failure; pneumococcal vaccine for immunocompromised cirrhotics |
| No dietary restriction needed for acute hepatitis | "No solid diet modifications needed — eat anything. Fatty diet is harmless. Glucose drip does not help" [8] | Rest and dietary restriction do not shorten disease course |
| No alcohol for 6 months (acute) / life (chronic) | Only dietary modification that matters [8] | |
| No drugs or herbs that hasten recovery | "No known drugs or herbs that hasten the recovery of acute hepatitis. Definitely do not try TCM" [8] | No evidence base; risk of DILI |
Pillar 3: Management of Cirrhosis and Complications
If the patient already has cirrhosis at the time of HCV diagnosis, you need to manage both the virus and the cirrhosis complications simultaneously.
- 6-monthly USS ± AFP [3][7]
- Mandatory for all cirrhotic patients, even after SVR — HCC risk is reduced but not eliminated
- For HCV, cirrhosis is the prerequisite for HCC surveillance (unlike HBV where surveillance is indicated even without cirrhosis in males ≥40, females ≥50, or family history of HCC) [7]
| Complication | Key Management |
|---|---|
| Ascites | Salt restriction (< 2g Na/day); diuretics (spironolactone ± furosemide); therapeutic paracentesis with albumin replacement |
| Variceal bleeding | OGD screening; band ligation for large varices; non-selective beta-blockers (propranolol/carvedilol) for primary prophylaxis |
| Hepatic encephalopathy | Lactulose (osmotic laxative, ↓ colonic pH → ↓ ammonia absorption); rifaximin (non-absorbable antibiotic reducing ammonia-producing gut bacteria) |
| SBP | Diagnostic paracentesis (neutrophils > 250/mm³); empirical ceftriaxone/cefotaxime; albumin replacement |
| Hepatorenal syndrome | Albumin + terlipressin (vasopressin analogue → splanchnic vasoconstriction → ↑ effective arterial blood volume) [27]; renal replacement therapy as bridge to transplant |
- The final line → after exhausting all other treatments [15]
- Indications for transplant in HCV:
- Post-transplant: DAA treatment can be given before or after transplant; recurrence rates are now negligible with DAA-era treatment
- HCV patients with cirrhosis who achieve SVR before transplant have improved post-transplant outcomes
Pillar 4: Prevention
"NO vaccine for hepatitis C is available" [26]
This is fundamentally different from HBV and HAV. The reason: HCV's hypervariable E2 envelope protein mutates too rapidly for a stable vaccine target. Research continues but no vaccine is expected in the near term.
Primary prevention measures [26]:
- Hand hygiene
- Safe and appropriate use of healthcare injections
- Safe handling and disposal of sharps and waste
- Provision of comprehensive harm-reduction service to people who inject drugs including sterile injecting equipment [1]
- Testing of donated blood for HBV, HCV, HIV and syphilis [1]
- Promotion of correct and consistent use of condoms [1]
| Prevention Type | HCV | HBV (for comparison) |
|---|---|---|
| Active prevention (vaccine) | No | Yes |
| Passive prevention (immunoglobulin) | No | Yes (HBIG) |
| Post-exposure prophylaxis | None available | HBIG + vaccine |
- Immunization with HAV and HBV to prevent coinfection (superinfection with HAV or HBV on chronic HCV → severe acute-on-chronic liver failure)
- Early and appropriate medical management including antiviral therapy
- Regular monitoring and early diagnosis of chronic liver disease
- Screen for alcohol use and counsel to reduce moderate and high levels of alcohol intake
- Education and counselling on options for care and treatment
Special Situations
A critically important consideration when treating HCV with DAAs:
- HCV and HBV can co-exist (especially in IVDU or endemic areas)
- HCV exerts a suppressive effect on HBV replication
- When DAAs rapidly clear HCV → HBV is "released" from suppression → HBV reactivation can occur
- Always screen HBsAg and anti-HBc before starting DAAs
- If HBsAg +ve: start prophylactic HBV antivirals (entecavir or TDF/TAF) concurrently with DAA treatment, and continue for ≥12 weeks after DAA completion
- If HBsAg –ve but anti-HBc +ve (occult HBV): monitor LFT and HBV DNA during/after DAA treatment; start HBV antivirals if reactivation occurs
- 15–45% spontaneously clear the virus within 6 months (usually within 12 weeks)
- Observation for 12 weeks is reasonable — if HCV RNA remains detectable at 12 weeks, treat with DAAs (same regimens as chronic HCV)
- If the patient develops severe hepatitis or has risk factors for chronicity → can treat immediately
- Patients on haemodialysis are a target for micro-elimination [1]
- GLE/PIB is preferred for eGFR < 30 (no renal dose adjustment needed)
- SOF should be avoided if possible in eGFR < 30 [1]
High Yield Summary
Treatment of HCV:
- Indication: ALL patients with detectable HCV RNA [2] — regardless of ALT level or fibrosis stage
- DAAs are the standard of care — oral tablets, 8–12 weeks, > 95% SVR rate
- Three DAA classes: NS3/4A protease inhibitors (-previr), NS5A inhibitors (-asvir), NS5B polymerase inhibitors (-buvir) [2]
- Pan-genotypic regimens: SOF/VEL (12 weeks) or GLE/PIB (8 weeks non-cirrhotic, 12 weeks cirrhotic)
- Protease inhibitors are contraindicated in decompensated cirrhosis (Child B/C) [1] → use SOF/VEL ± ribavirin
- CYP/P-gp inducers (carbamazepine, phenytoin) contraindicated with ALL DAA regimens [1]
- SOF should be avoided in eGFR < 30 if alternatives exist [1]
- SVR = absent HCV RNA 12 weeks post-treatment = 99% long-term cure [2]
- Post-SVR: check ALT + HCV RNA at 48 weeks. Cirrhotic patients continue 6-monthly HCC surveillance indefinitely
- No vaccine exists for HCV; prevention relies on harm reduction, blood screening, and safe injection practices [26]
- Always screen for HBV before DAA treatment — risk of HBV reactivation when HCV is cleared
- Interferon is NOT used nowadays [25] — but understand it for exam case interpretation
- Ribavirin side effects: haemolysis (most important), teratogenicity (absolute contraindication in pregnancy) [25]
- Alcohol: complete abstinence for chronic HCV (small amounts are very dangerous, unlike HBV) [26]
- Vaccinate all HCV patients against HAV and HBV to prevent superinfection [3][26]
Active Recall - Hepatitis C Management
References
[1] Lecture slides: GC 239. Viral hepatitis HAV_HBV_HCV_HEV.pdf (HK Action Plan, DAA contraindications, prevention strategies) [2] Senior notes: Maksim Medicine Notes.pdf (Chronic hepatitis C infection — DAA classes, SVR definition, indications) [3] Senior notes: Ryan Ho GI.pdf (Hepatitis C general management, surveillance, alcohol) [5] Senior notes: MBBS Final MB (Surgery) (Felix PY Lai).pdf (HCV case study, treatment response) [7] Senior notes: Block A - Gastroenterology Interactive Tutorial.pdf (HCC surveillance indications) [8] Senior notes: Block A - Jaundice after raw oysters_ acute hepatitis.pdf (Supportive management of acute hepatitis) [15] Senior notes: Block A - A jaundiced and incoherent patient_ liver failure.pdf (Liver transplantation as final line) [18] Senior notes: Block A - Gastrointestinal Data Interpretation.pdf (MELD score, SVR) [24] Senior notes: Maksim Surgery Notes.pdf (Liver transplant criteria, TACE, RFA) [25] Senior notes: MBBS Final MB (Medicine) (Felix PY Lai).pdf (IFN, peg-IFN, ribavirin — drug details, side effects, contraindications) [26] Senior notes: MBBS Final MB (Medicine) (Felix PY Lai).pdf (HCV prevention, alcohol in HCV) [27] Lecture slides: Handbook of Internal Medicine 2024.pdf (Hepatorenal syndrome management)
Complications of Hepatitis C
The complications of Hepatitis C are best understood as a cascade — each complication flows logically from the one before it, driven by the same fundamental process: chronic immune-mediated hepatocyte destruction leading to progressive fibrosis. Think of it as dominoes falling.
The complications can be divided into:
- Hepatic complications (the progressive liver damage pathway)
- Extrahepatic complications (immune-mediated systemic disease)
- Treatment-related complications (largely historical with interferon/ribavirin; minimal with DAAs)
1. Hepatic Complications
These follow a predictable timeline — and understanding this natural history is essential for exams.
"Presents with significant elevation of serum aminotransferase level over baseline level in the absence of other potential causes of acute hepatitis" [26].
- Occurs following immunocompromised state including prescription of immunosuppressive agents [26].
- This is the same concept as HBV reactivation, though less clinically prominent. In HCV, the exacerbation is less dramatic because HCV doesn't have an integrated DNA reservoir like HBV's cccDNA — but fluctuations in immune surveillance (e.g., during chemotherapy, post-transplant immunosuppression) can allow viral replication to surge, with a corresponding immune-mediated hepatitis flare when immunosuppression is reduced.
- Practically: always monitor LFT and HCV RNA in patients with chronic HCV receiving immunosuppressive agents.
- Risk of cirrhosis within 20 years = 15–30% [26][3].
- The mechanism is straightforward: chronic hepatocyte injury → inflammatory cytokines (TGF-β, PDGF) → hepatic stellate cell activation → collagen deposition in Space of Disse → architectural distortion → bridging fibrosis → regenerative nodules → cirrhosis (F4).
- Cirrhosis may be partially reversible with HCV eradication (DAA achieving SVR): "HCV cirrhosis — some is reversible, but not all" [4]. This depends on severity — Child A/B may regress, Child C less likely.
- Factors accelerating fibrosis progression (covered in Part 1): alcohol, HBV co-infection, HIV, obesity/MASLD, male sex, older age at acquisition, genotype 1b/3.
1c. Hepatic Decompensation
"Characterized by development of liver-related complications including ascites, variceal bleeding and encephalopathy" [26].
Once cirrhosis becomes decompensated (transition from Child A → Child B/C), the prognosis drops dramatically. "Poor survival once becomes decompensated" [18].
The six associated complications of liver failure (from the liver failure lecture) [15]:
Infections, variceal bleeding, ascites / spontaneous bacterial peritonitis, hepatorenal syndrome, hepatic encephalopathy, coagulopathy. And hepatocellular carcinoma — a complication you must ask for during history for any patient with cirrhosis [15].
Let me go through each in the context of HCV:
Why does this happen?
- Cirrhosis → architectural distortion with fibrous bands and regenerative nodules → increased intrahepatic vascular resistance → blood cannot flow freely through the liver → portal hypertension (portal pressure gradient > 5 mmHg; clinically significant at > 10 mmHg).
- The body compensates by opening porto-systemic collaterals — anastomotic channels that bypass the liver:
- Oesophageal/gastric varices (left gastric vein → oesophageal veins → azygos → SVC)
- Rectal varices (superior rectal → middle/inferior rectal veins)
- Caput medusae (paraumbilical veins → epigastric veins)
- These collateral vessels are thin-walled and not designed for high-pressure flow → prone to rupture and life-threatening haemorrhage.
- Variceal bleeding risk: 3.9% per year in cirrhotics [3].
Management:
- Screening OGD for varices (recommended Q2–3 years in compensated cirrhosis) [28]
- Primary prophylaxis: non-selective beta-blockers (propranolol, carvedilol — reduce portal pressure by ↓ cardiac output and ↓ splanchnic blood flow) or band ligation for large varices
- Acute variceal bleed: resuscitation → octreotide (splanchnic vasoconstriction) → urgent endoscopic band ligation → antibiotic prophylaxis (ceftriaxone — prevent SBP)
Why does this happen? Three mechanisms work together:
- Portal hypertension → ↑ hydrostatic pressure in splanchnic capillaries → fluid transudation into peritoneal cavity
- Hypoalbuminaemia → ↓ plasma oncotic pressure → fluid moves out of vessels
- Splanchnic vasodilatation (NO-mediated) → ↓ effective arterial blood volume → RAAS activation → Na+ and water retention → further fluid accumulation
Management:
- Salt restriction (< 2g Na/day)
- Diuretics: spironolactone (aldosterone antagonist — addresses the RAAS-driven Na retention) ± furosemide (loop diuretic for additional natriuresis)
- Therapeutic large-volume paracentesis with IV albumin replacement (6–8g per litre drained)
- Refractory ascites: TIPS (transjugular intrahepatic portosystemic shunt) or liver transplant
Why does this happen?
- Cirrhotic patients have impaired gut barrier function (portal hypertension → intestinal mucosal oedema → increased permeability → bacterial translocation from gut lumen into ascitic fluid).
- Combined with impaired immune function (reticuloendothelial dysfunction, reduced complement, reduced opsonisation) [15] → bacteria that reach the ascitic fluid are not efficiently cleared.
- Common organisms: especially from the respiratory and urinary tract — Staph, Strep, gram-negative rods. Bacteraemia in up to 25% of fulminant hepatic failure patients [15].
Diagnosis:
- Require high clinical suspicion — may actually not have a lot of abdominal signs since there is no perforation [18].
- Diagnostic paracentesis: ascitic fluid neutrophil count > 250/mm³ is diagnostic.
- Culture not useful, usually negative → defined by checking the neutrophils [18].
Management:
- Empirical IV ceftriaxone or cefotaxime
- IV albumin (1.5 g/kg at diagnosis, 1g/kg on day 3) — reduces hepatorenal syndrome and mortality
- Secondary prophylaxis: oral norfloxacin or co-trimoxazole
Why does this happen?
- The liver normally clears ammonia (from gut bacterial metabolism of proteins and amino acids) via the urea cycle.
- In cirrhosis: (1) hepatocyte loss → reduced urea cycle capacity; (2) porto-systemic shunting → ammonia bypasses the liver entirely.
- Ammonia crosses the blood-brain barrier → taken up by astrocytes → converted to glutamine by glutamine synthetase → osmotic swelling of astrocytes → cerebral oedema and altered neurotransmission (increased GABAergic tone, impaired glutamatergic signalling).
Clinical features: Asterixis (liver flap — negative myoclonus from disruption of diencephalic motor centres), confusion, disorientation, personality changes, somnolence → coma.
Diagnosis: Difficult — essentially a diagnosis by exclusion [15]. No one test is diagnostic; arterial ammonia is suggestive but not always raised and may not correlate with severity [15].
Common Mistake
"Confusion in cirrhosis does not mean hepatic encephalopathy. HE is actually a less common cause of confusion in cirrhosis. Confusion in cirrhosis is still most commonly caused by head injury and drug-related causes" [15]. Always order CT brain, electrolyte panel, and consider urine toxicology before attributing confusion to HE.
Management:
- Identify and treat precipitants (infection, GI bleeding, constipation, electrolyte disturbance, drugs)
- Lactulose (osmotic laxative → ↓ colonic pH → ionises NH₃ to NH₄⁺ which cannot be absorbed → ↓ ammonia absorption; also promotes bacterial fermentation reducing ammonia-producing bacteria)
- Rifaximin (non-absorbable antibiotic → reduces ammonia-producing gut bacteria)
- BCAA (branched-chain amino acids) — also used as supplementary treatment to increase ammonia removal [16]
Why does this happen?
- Severe portal hypertension → splanchnic vasodilatation (NO-mediated) → ↓ effective circulating volume → maximal activation of RAAS, sympathetic nervous system, and ADH → intense renal vasoconstriction → functional renal failure.
- The kidneys are structurally normal — if transplanted into a healthy recipient, they work perfectly. The problem is haemodynamic.
Management:
- Terlipressin (vasopressin analogue → splanchnic vasoconstriction → ↑ effective arterial blood volume → improves renal perfusion) + IV albumin [27]
- Renal replacement therapy only as bridge to transplant
- Definitive treatment: liver transplantation
Why does this happen?
- The liver synthesises all coagulation factors except vWF and Factor VIII (made by endothelium).
- Cirrhosis → ↓ production of Factors II, V, VII, IX, X → prolonged INR.
- Additionally: thrombocytopenia from (1) splenic sequestration (portal hypertension → congestive splenomegaly → hypersplenism → platelet destruction) and (2) ↓ thrombopoietin production (made by hepatocytes).
- This creates a "rebalanced" haemostasis — cirrhotic patients are both pro-bleed AND pro-clot (due to simultaneous ↓ anticoagulant proteins: protein C, protein S, antithrombin).
"Very common" in liver failure [15].
Why?
- Reticuloendothelial dysfunction and reduced opsonisation [15] — the liver's Kupffer cells are the body's main filter for gut-derived bacteria; in cirrhosis, they are dysfunctional, and porto-systemic shunting bypasses them entirely.
- Reduced production of complement, opsonins, and acute phase proteins [15].
- Fungal infection, especially Candida (but bacterial still most common) [15].
This is the most feared long-term complication and the one that makes lifelong surveillance mandatory.
"HCC occurs in patients with HCV exclusively in those with liver cirrhosis suggesting liver cirrhosis is the major risk factor" [26]. "In contrast, HCC occurs in patients with HBV on top of a non-cirrhotic liver since HBV has direct oncogenic effect" [26].
This distinction is hammered home repeatedly across lectures and is a guaranteed exam point.
Why does HCC develop in HCV cirrhosis?
- HCV is an RNA virus that does not integrate into the host genome → no direct oncogenic effect.
- Instead, carcinogenesis is driven by the cirrhotic microenvironment: chronic inflammation → repeated cycles of hepatocyte death and regeneration → accumulated somatic mutations → dysplastic nodules → HCC.
- Additionally: oxidative stress, epigenetic changes, and HCV core protein–mediated disruption of cell cycle control (p53 inactivation, NF-κB activation) contribute, but these only become oncogenic in the setting of cirrhosis.
Key statistics:
- HCC risk: 2–5% per year in HCV cirrhotics [3]
- 100% of HCV-related HCC has underlying cirrhosis (vs 80% for HBV) [29]
- HCC usually only causes symptoms when size exceeds ≈8 cm — hence the need for surveillance [5]
Why does HCC present late?
"4 reasons for poor prognosis in HCC" [29]:
- Present in the late stage — asymptomatic when tumour is < 8 cm; NO nerve fibres in the liver
- Presence of underlying liver disease (80–100% have cirrhosis)
- Early venous permeation — high recurrence rate due to circulating tumour cells
- Field cancerisation effect — whole liver is exposed to oncogenic influence of HCV or cirrhosis; presence of multiple small tumours in sites that are not identified
Surveillance:
- 6-monthly USS ± AFP [7][29]
- HCV patients: surveillance only when cirrhotic (unlike HBV where non-cirrhotic carriers also need surveillance in certain demographics) [7]
- Surveillance continues EVEN AFTER SVR in patients who had cirrhosis at baseline — the accumulated genomic damage does not fully reverse
Complications of HCC itself:
- Ruptured HCC → intraperitoneal haemorrhage → severe abdominal pain with peritoneal signs and shock → treatment: transarterial embolism (TAE); uncontrolled bleeding → laparotomy [29]
- Decompensation of cirrhosis (ascites, variceal bleeding, HE) [30]
- Metastasis: intrahepatic (via portal vein), lung (most common distant site), bone, brain, peritoneum, adrenals [30]
These were covered extensively in Part 1 (Clinical Features) but deserve emphasis here as complications of chronic HCV that can cause significant morbidity independent of liver disease.
| Complication | Mechanism | Clinical Significance |
|---|---|---|
| Type II/III mixed cryoglobulinaemia | Chronic B-cell stimulation → cryoglobulin production → immune complex deposition in small vessels | Vasculitis (purpura, arthralgia), neuropathy, MPGN. Lab: ↓C3/C4, RF+, cryoglobulin+ [2] |
| Membranoproliferative GN (MPGN) | Cryoglobulin immune complex deposition in glomeruli → complement activation | Proteinuria, haematuria, renal impairment. Screen with urinalysis [2] |
| B-cell non-Hodgkin lymphoma | Chronic antigenic stimulation of B cells → clonal expansion → malignant transformation | Increased lymphoma risk; resolves/regresses in some cases after HCV eradication with DAAs |
| Autoimmune thyroiditis | Molecular mimicry + immune dysregulation | Screen with TFT + anti-thyroid antibodies [2] |
| Porphyria cutanea tarda (PCT) | Impaired uroporphyrinogen decarboxylase → porphyrin accumulation | Photosensitive blistering, skin fragility, hypertrichosis |
| Lichen planus | T-cell cross-reactivity | Violaceous, pruritic, polygonal papules (skin) or white reticular pattern (oral) |
| Insulin resistance / Type 2 DM | HCV core protein → IRS-1 degradation via SOCS pathway | Accelerates fibrosis; increased cardiovascular risk |
| Aplastic anaemia | Hepatitis well known to precede aplastic anaemia — T-cell mediated destruction of haematopoietic stem cells [9] | Pancytopenia; an important association to remember |
Extrahepatic Manifestations Can Resolve with DAA Treatment
Many extrahepatic complications of HCV (cryoglobulinaemia, MPGN, PCT, insulin resistance) can improve or resolve after achieving SVR with DAAs. This is because removing the antigenic stimulus (HCV) allows the immune-mediated pathology to subside. This is an additional argument for treating ALL patients with detectable HCV RNA, even those without significant liver disease.
3. Treatment-Related Complications
These are largely historical but may appear in exam case studies:
| Drug | Key Complications | Mechanism |
|---|---|---|
| Interferon-α | Flu-like symptoms, neuropsychiatric (depression, suicidal ideation), myelosuppression, autoimmune reactivation (thyroiditis, AIH), hepatic decompensation [25] | Immune stimulation → excessive inflammation; direct bone marrow suppression |
| Ribavirin | Haemolytic anaemia (most clinically significant), teratogenicity, pancytopenia | Ribavirin accumulates in RBCs → oxidative damage → extravascular haemolysis |
DAAs have remarkably few complications:
- Generally well-tolerated; most common side effects are mild fatigue, headache, nausea
- HBV reactivation: the most important complication to be aware of in the DAA era. When DAAs rapidly clear HCV, the suppressive effect on HBV is removed → HBV reactivation can occur → hepatitis flare → potentially fulminant liver failure. "Treatment of HCV with DAAs may cause increased viral replication and flare of HBV and fulminant liver failure" [28].
- Prevention: screen HBsAg and anti-HBc before starting DAAs; start prophylactic HBV antivirals if HBsAg positive [28]
- Drug-drug interactions (especially with CYP/P-gp inducers like carbamazepine and phenytoin) [1]
- Protease inhibitor toxicity in decompensated cirrhosis (hepatotoxicity) — hence contraindicated in Child B/C [1]
"HCV antibodies do not confer 100% immunity — re-infection is still possible (given the multiple genotypes + antibodies don't last that long)" [8].
After SVR, patients are NOT immune to HCV. If ongoing risk factors persist (e.g., active IVDU), they can be re-infected with a new or even the same genotype. This is distinct from relapse (treatment failure) and requires re-treatment.
| Timeline | Complication | Frequency/Risk |
|---|---|---|
| Years 0–10 | Chronic hepatitis (fluctuating ALT) | 55–85% of infected |
| Extrahepatic manifestations (cryoglobulinaemia, MPGN, etc.) | ≈38% | |
| Acute exacerbation (if immunosuppressed) | Variable | |
| Years 10–20 | Progressive fibrosis (F2–F3) | Majority with ongoing infection |
| Steatosis (especially genotype 3) | Common | |
| Years 15–30 | Cirrhosis (F4) | 15–30% |
| Hepatic decompensation | 3.9%/year once cirrhotic | |
| HCC | 2–5%/year once cirrhotic | |
| Post-SVR | Residual HCC risk (if cirrhotic at baseline) | Reduced (~0.5–1%/year) but persists |
| Re-infection (if ongoing risk factors) | Variable |
High Yield Summary
Hepatic complications of chronic HCV follow a predictable cascade:
- Acute exacerbation of chronic HCV — elevation of transaminases over baseline; triggered by immunosuppression [26]
- Progressive fibrosis → Cirrhosis (15–30% within 20 years) — may be partially reversible with SVR [4]
- Hepatic decompensation (3.9%/year) — ascites, variceal bleeding, HE, SBP, HRS, coagulopathy, infections [15][26]
- HCC (2–5%/year in cirrhotics) — exclusively on cirrhotic liver in HCV (contrast with HBV) [26][29]
- Six complications of liver failure: infections, variceal bleeding, ascites/SBP, HRS, HE, coagulopathy (+HCC) [15]
- HE is a diagnosis by exclusion — confusion in cirrhosis is NOT always HE [15]
- SBP: may have minimal abdominal signs; diagnosed by ascitic fluid neutrophils > 250/mm³, not culture [18]
Extrahepatic complications: 8. Cryoglobulinaemia (↓C3/C4, RF+), MPGN, NHL, autoimmune thyroiditis, PCT, lichen planus, aplastic anaemia [2][9] 9. Many extrahepatic complications resolve after SVR
Treatment-related: 10. DAA era: HBV reactivation is the key complication to watch for — screen HBsAg/anti-HBc before treatment [28] 11. HCC surveillance continues indefinitely even after SVR if patient was cirrhotic at baseline [7] 12. Re-infection is possible after SVR — HCV antibodies do NOT confer protective immunity [8]
Active Recall - Hepatitis C Complications
References
[1] Lecture slides: GC 239. Viral hepatitis HAV_HBV_HCV_HEV.pdf (DAA contraindications, HK Action Plan) [2] Senior notes: Maksim Medicine Notes.pdf (Chronic HCV — extrahepatic manifestations, DAA treatment) [3] Senior notes: Ryan Ho GI.pdf (Hepatitis C clinical course, fibrosis progression, HCC risk) [4] Senior notes: Block A - Abdominal distension_ ascites and cirrhosis.pdf (Cirrhosis reversibility) [5] Senior notes: MBBS Final MB (Surgery) (Felix PY Lai).pdf (HCV case study — natural history) [7] Senior notes: Block A - Gastroenterology Interactive Tutorial.pdf (HCC surveillance indications) [8] Senior notes: Block A - Jaundice after raw oysters_ acute hepatitis.pdf (Antibody immunity, supportive management) [9] Senior notes: Block A - Hematology Data Interpretation.pdf (Hepatitis-associated aplastic anaemia) [15] Senior notes: Block A - A jaundiced and incoherent patient_ liver failure.pdf (6 complications, infections, HE) [16] Senior notes: Block A - Introduction to GI_Hepatology investigations (LFT, Endoscopy).pdf (BCAA, prognostic scoring) [18] Senior notes: Block A - Gastrointestinal Data Interpretation.pdf (SBP diagnosis, Child-Pugh, MELD, decompensation) [25] Senior notes: MBBS Final MB (Medicine) (Felix PY Lai).pdf (IFN/ribavirin side effects, HCV complications) [26] Senior notes: MBBS Final MB (Medicine) (Felix PY Lai).pdf (Complications of chronic HCV, prevention) [27] Lecture slides: Handbook of Internal Medicine 2024.pdf (Hepatorenal syndrome management) [28] Senior notes: Ryan Ho GI.pdf (Cirrhosis management principles, HBV co-infection) [29] Senior notes: MBBS Final MB (Surgery) (Felix PY Lai).pdf (HCC prognosis — 4 reasons, ruptured HCC) [30] Lecture slides: WCS 064 - A large liver - by Prof R Poon.pdf (HCC clinical presentation, metastasis)
High Yield Summary
- HCV = enveloped ssRNA virus (Flaviviridae), 6 genotypes; 1b and 6a most common in HK.
- Transmission: blood-borne — IVDU (most important), transfusion (pre-1991), healthcare-related, sexual (low risk, ↑MSM), perinatal (5%).
- Natural history: 80% acute infection asymptomatic → 55–85% become chronic (irrespective of age) → 15–30% develop cirrhosis over 20 years → HCC risk 2–5%/year in cirrhotics.
- HCC in HCV almost exclusively occurs on cirrhotic liver (vs HBV where it can occur without cirrhosis).
- Symptoms: Acute — mostly subclinical; Chronic — fatigue, malaise, non-specific; Late — cirrhosis complications.
- Extrahepatic manifestations: Mixed cryoglobulinaemia (↓C3/C4, RF+), MPGN, PCT, lichen planus, NHL, autoimmune thyroiditis, Sjögren's, ITP.
- Diagnosis: Anti-HCV (screening, +ve ≤12 weeks) → HCV RNA (confirms active infection) → genotyping.
- INR is the best marker for liver synthetic function (short t½ of Factor VII).
- All viral hepatitis are notifiable diseases in HK.
- HCV prevalence in HK < 0.5%; HBV dominates as the cause of cirrhosis (64–75%).
High Yield Summary
Differential diagnosis of Hepatitis C depends on the clinical scenario:
- Acute hepatitis DDx: Viral (HAV, HBV, HBV reactivation, HEV, EBV, CMV, HSV), drug-induced (DILI, paracetamol), ischaemic hepatitis, autoimmune hepatitis, Wilson's disease, Budd-Chiari [10][13]
- Chronic elevated LFTs DDx: HBV (most common in HK), alcohol, MASLD, autoimmune hepatitis, PBC, PSC, haemochromatosis, Wilson's, α1-antitrypsin deficiency, DILI [7][14][17]
- Cirrhosis aetiology DDx: HBV 64–75% in HK, HCV 5–10%, alcohol > 5%, MASLD increasing [4]
- Always screen for co-existing causes — dual liver disease (HBV + MASLD, alcohol + HCV) is common and clinically important [7][18]
- GC lecture "big four" for acute hepatitis LFT pattern: acute viral hepatitis, ischaemic hepatitis, drug-induced hepatitis, HBV reactivation [10]
- Ischaemic hepatitis: brisk rise/fall, ALT/LDH < 1.5, massive LDH, end-organ damage [10]
- Alcoholic hepatitis: AST usually < 500, AST:ALT > 2:1, isolated GGT rise [16][18]
- HCC in HCV occurs almost exclusively on cirrhosis (vs HBV which can cause HCC without cirrhosis) [3][5]
High Yield Summary
Diagnosis of HCV is a two-step process:
- Screen with anti-HCV antibody (positive within 12 weeks, remains positive after clearance)
- Confirm with HCV RNA by PCR (gold standard for active infection; indication for treatment)
Key investigation pearls:
- Acute HCV has "no marker" for acute phase — unlike HAV/HBV/HEV which have IgM markers [22]
- Anti-HCV positive + HCV RNA negative = resolved/cleared infection (prior HCV) [22]
- SVR = absent HCV RNA 12 weeks after stopping treatment → 99% long-term cure [2]
- FibroScan is standard of care for fibrosis staging; liver biopsy is rarely needed [11]
- Liver stiffness > 12 kPa suggestive of cirrhosis; CAP > 280 dB/m suggestive of severe steatosis [7]
- Child-Pugh score: A = compensated; B/C = decompensated. MELD score: used for transplant prioritisation [18]
- HCC surveillance (6-monthly USS ± AFP) is mandatory for cirrhotic patients, even after SVR [7]
- AFP > 400 ng/mL almost diagnostic of HCC; but 20–30% of HCC is non-secreting [11][21]
- Four conditions where AST > ALT: alcoholic hepatitis, HCC, congestive heart failure, ischaemic hepatitis [16]
- INR is the best marker for liver synthetic function (short half-life of Factor VII) [2][8]
High Yield Summary
Treatment of HCV:
- Indication: ALL patients with detectable HCV RNA [2] — regardless of ALT level or fibrosis stage
- DAAs are the standard of care — oral tablets, 8–12 weeks, > 95% SVR rate
- Three DAA classes: NS3/4A protease inhibitors (-previr), NS5A inhibitors (-asvir), NS5B polymerase inhibitors (-buvir) [2]
- Pan-genotypic regimens: SOF/VEL (12 weeks) or GLE/PIB (8 weeks non-cirrhotic, 12 weeks cirrhotic)
- Protease inhibitors are contraindicated in decompensated cirrhosis (Child B/C) [1] → use SOF/VEL ± ribavirin
- CYP/P-gp inducers (carbamazepine, phenytoin) contraindicated with ALL DAA regimens [1]
- SOF should be avoided in eGFR < 30 if alternatives exist [1]
- SVR = absent HCV RNA 12 weeks post-treatment = 99% long-term cure [2]
- Post-SVR: check ALT + HCV RNA at 48 weeks. Cirrhotic patients continue 6-monthly HCC surveillance indefinitely
- No vaccine exists for HCV; prevention relies on harm reduction, blood screening, and safe injection practices [26]
- Always screen for HBV before DAA treatment — risk of HBV reactivation when HCV is cleared
- Interferon is NOT used nowadays [25] — but understand it for exam case interpretation
- Ribavirin side effects: haemolysis (most important), teratogenicity (absolute contraindication in pregnancy) [25]
- Alcohol: complete abstinence for chronic HCV (small amounts are very dangerous, unlike HBV) [26]
- Vaccinate all HCV patients against HAV and HBV to prevent superinfection [3][26]
High Yield Summary
Hepatic complications of chronic HCV follow a predictable cascade:
- Acute exacerbation of chronic HCV — elevation of transaminases over baseline; triggered by immunosuppression [26]
- Progressive fibrosis → Cirrhosis (15–30% within 20 years) — may be partially reversible with SVR [4]
- Hepatic decompensation (3.9%/year) — ascites, variceal bleeding, HE, SBP, HRS, coagulopathy, infections [15][26]
- HCC (2–5%/year in cirrhotics) — exclusively on cirrhotic liver in HCV (contrast with HBV) [26][29]
- Six complications of liver failure: infections, variceal bleeding, ascites/SBP, HRS, HE, coagulopathy (+HCC) [15]
- HE is a diagnosis by exclusion — confusion in cirrhosis is NOT always HE [15]
- SBP: may have minimal abdominal signs; diagnosed by ascitic fluid neutrophils > 250/mm³, not culture [18]
Extrahepatic complications: 8. Cryoglobulinaemia (↓C3/C4, RF+), MPGN, NHL, autoimmune thyroiditis, PCT, lichen planus, aplastic anaemia [2][9] 9. Many extrahepatic complications resolve after SVR
Treatment-related: 10. DAA era: HBV reactivation is the key complication to watch for — screen HBsAg/anti-HBc before treatment [28] 11. HCC surveillance continues indefinitely even after SVR if patient was cirrhotic at baseline [7] 12. Re-infection is possible after SVR — HCV antibodies do NOT confer protective immunity [8]