Liver Cirrhosis

Liver cirrhosis is not just a disease, but the end-stage anatomical consequence of sustained, chronic liver injury. Think of it as the liver's "scar tissue response" gone too far. It's defined by three key, interconnected pathological hallmarks that you can see under the microscope:

1. Diffuse Hepatic Fibrosis: This isn't just a small scar. It's a widespread deposition of abnormal, dense collagen (predominantly Type I) that forms a spiderweb-like network throughout the liver. This replaces the normal, delicate extracellular matrix.
2. Nodular Regeneration: The surviving hepatocytes, trapped in this fibrous web, attempt to regenerate. However, because the normal scaffolding is destroyed, they form clumps called regenerative nodules. These nodules are not functional liver units (lobules) and lack a central vein and portal triads.
3. Architectural Distortion: The combination of fibrosis and nodules completely disrupts the liver's normal microscopic and macroscopic structure. The organized portal triads and central veins are lost. This is the key difference from simple hepatic fibrosis, where the architecture is preserved.

Reversibility: This is a critical concept. Early cirrhosis, often termed "compensated cirrhosis," may be reversible if the underlying cause is aggressively treated (e.g., curing Hepatitis C, abstinence in alcohol-related disease, chelation in hemochromatosis). However, advanced cirrhosis with extensive nodularity and portal hypertension becomes irreversible. At this stage, the only curative treatment is liver transplantation.

Globally, the leading causes of cirrhosis are Hepatitis B (HBV), Hepatitis C (HCV), and Alcohol-Related Liver Disease (ALD). However, the epidemiology in Hong Kong has its own distinct profile, largely driven by the high prevalence of HBV.

In Hong Kong, Chronic Hepatitis B is the overwhelming cause of liver cirrhosis. The carrier rate in the general population is approximately 7-8%, a legacy of pre-vaccination era vertical transmission. A significant proportion of these carriers progress to chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC).

Global and Local Risk Factors

• Viral Hepatitis: Hepatitis B virus (HBV) and Hepatitis C virus (HCV). Chronic infection leads to persistent immune-mediated inflammation, hepatocyte death, and eventually fibrosis. HBV also has direct oncogenic properties (via the HBx protein), which can promote carcinogenesis even before cirrhosis develops.
• Alcohol: Chronic, excessive alcohol consumption is a major cause. Risk is dose-dependent (typically >60-80g/day for men, >20g/day for women over 10+ years). Ethanol metabolism generates toxic metabolites (acetaldehyde) and causes oxidative stress, leading to steatosis, hepatitis, and fibrosis.
• Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): This is the new terminology (as of 2023) replacing NAFLD. It's tightly linked to insulin resistance, obesity, type 2 diabetes, and dyslipidemia. A subset progresses to MASH (metabolic dysfunction-associated steatohepatitis), which can lead to cirrhosis.
• Autoimmune & Biliary Diseases:
  • Autoimmune Hepatitis: Immune system attacks hepatocytes.
  • Primary Biliary Cholangitis (PBC): Immune-mediated destruction of small intrahepatic bile ducts, leading to cholestasis and cirrhosis. Strong female predominance (F:M ~9:1) and association with other autoimmune conditions like Sjögren's syndrome and thyroiditis.
  • Primary Sclerosing Cholangitis (PSC): Inflammation and fibrosis of both intra- and extra-hepatic bile ducts, creating a "beaded" appearance on imaging. Strongly associated with Inflammatory Bowel Disease (IBD), especially Ulcerative Colitis.
• Genetic/Metabolic Disorders:
  • Hemochromatosis (HFE gene): Autosomal recessive disorder of iron overload. Excess iron deposits in hepatocytes, catalyzing free radical formation and fibrosis.
  • Wilson's Disease (ATP7B gene): Autosomal recessive disorder of copper metabolism. Copper accumulation in the liver is directly toxic.
  • Alpha-1 Antitrypsin Deficiency: Mutant protein (PiZZ) polymerizes and gets trapped in hepatocytes, causing injury.
• Vascular: Chronic right-sided heart failure (e.g., severe tricuspid regurgitation, constrictive pericarditis) leads to congestive hepatopathy. Sustained high pressure in the hepatic veins backs up into the sinusoids, causing centrilobular congestion, atrophy, and fibrosis ("nutmeg liver").
• Drugs/Toxins: Certain medications are notorious for causing chronic liver injury that can progress to cirrhosis, e.g., methotrexate (cumulative dose-related), amiodarone (can cause a steatohepatitis-like picture), and high-dose vitamin A.

^[1] Senior notes: felixlai.md (Liver Cirrhosis - Overview, Etiology, Clinical manifestation, Pathogenesis, Diagnosis, Complication) ^[2] Senior notes: maxim.md (Hepatocellular carcinoma - Overview, Risk factors; Gynaecomastia) ^[3] Lecture slides: WCS 064 - A large liver - by Prof R Poon ^[20191108].doc.pdf (HCC Aetiology, Pathology, Clinical Presentation) ^[4] Lecture slides: HCC and Gallstone acute cholangitis_Prof TT Cheung.pdf (HCC Aetiology)

These conditions can produce portal hypertension, splenomegaly, and even variceal bleeding, but the liver architecture is preserved.

• Non-Cirrhotic Portal Hypertension (e.g., Idiopathic Portal Hypertension, Nodular Regenerative Hyperplasia): The liver develops regenerative nodules without significant fibrosis, leading to increased intrahepatic resistance. Patients present with varices and splenomegaly but have relatively preserved liver synthetic function. It is a key differential in patients with portal hypertension but near-normal liver enzymes and no obvious cause of cirrhosis ^[1].
• Pre-Sinusoidal Portal Hypertension:
  • Portal Vein Thrombosis (PVT): Blockage of the main portal vein increases pressure upstream without intrinsic liver disease. Common in hypercoagulable states, abdominal sepsis, or after umbilical vein catheterization. Presents with acute variceal bleeding in a patient with a normal-sized, smooth liver.
  • Schistosomiasis: A major global cause of non-cirrhotic portal fibrosis. Schistosoma eggs lodge in portal venules, triggering a granulomatous inflammatory reaction and presinusoidal fibrosis ("pipe-stem fibrosis"). Endemic in some regions but rare in Hong Kong.
• Post-Sinusoidal Portal Hypertension:
  • Budd-Chiari Syndrome: Thrombosis of the hepatic veins or Inferior Vena Cava (IVC). This leads to hepatic outflow obstruction, centrilobular congestion, and eventually fibrosis. Patients present with painful hepatomegaly, ascites (often refractory), and rapid progression to liver failure. It is a crucial differential in a young patient with acute-onset ascites and hepatomegaly ^[2].
  • Congestive Hepatopathy (Cardiac Cirrhosis): Chronic right-sided heart failure (e.g., severe tricuspid regurgitation, constrictive pericarditis) causes sustained high pressure in the hepatic veins. This results in chronic passive congestion, centrilobular hepatocyte atrophy, and fibrosis, eventually leading to a "nutmeg liver" and cirrhosis. The liver is often firm, smooth, and pulsatile. Key clues are elevated jugular venous pressure (JVP) and other signs of heart failure ^[2].

These conditions cause hepatomegaly, abnormal LFTs, and systemic symptoms but may not have yet progressed to the architectural distortion of cirrhosis.

• Chronic Viral Hepatitis (B, C, D): Active inflammation can cause hepatomegaly, fatigue, and jaundice. The liver may be tender. The absence of stigmata of chronic liver disease and portal hypertension suggests the disease is still in the hepatitis stage rather than cirrhotic. This is a pre-cirrhotic stage of the same disease ^[2].
• Autoimmune Hepatitis (AIH): An immune-mediated attack on hepatocytes, typically in young to middle-aged women. Can present with acute hepatitis or insidious onset of fatigue and jaundice. May progress to cirrhosis if untreated. Diagnosed by high serum IgG, positive autoantibodies (ANA, ASMA, anti-LKM1), and characteristic histology (interface hepatitis, plasma cell infiltrate) ^[2].
• Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): This encompasses simple steatosis and its inflammatory form, MASH. Patients are often asymptomatic but may have mild hepatomegaly and elevated ALT/AST. Severe hepatomegaly with a soft, smooth edge can be a clue, especially in obese or diabetic patients. Progression to cirrhosis is possible but takes years ^[2].
• Infiltrative Disorders:
  • Amyloidosis: Protein deposits in the liver sinusoids cause massive, rock-hard hepatomegaly. LFTs are often surprisingly normal until late stages. Look for other systemic signs (macroglossia, periorbital purpura, renal disease).
  • Granulomatous Hepatitis: Sarcoidosis, TB, fungal infections. Causes persistent hepatomegaly and mild LFT derangement. Diagnosis often requires liver biopsy showing non-caseating (sarcoid) or caseating (TB) granulomas.

These can cause hepatomegaly, RUQ pain, and constitutional symptoms, potentially mimicking decompensated cirrhosis or HCC.

• Hepatocellular Carcinoma (HCC): This is both a complication of cirrhosis and a differential for new liver masses. It is the commonest primary liver cancer (80%) and frequently associated with cirrhosis (80% in Hong Kong) ^[3]. A new-onset hepatic bruit, rapid clinical deterioration, or a disproportionate rise in AFP in a cirrhotic patient should raise suspicion. HCC can also arise in non-cirrhotic livers, particularly with HBV ^[2].
• Cholangiocarcinoma: Adenocarcinoma of the bile ducts. Perihilar tumors (Klatskin tumors) present with obstructive jaundice early. Intrahepatic tumors can present as a liver mass without jaundice, mimicking HCC. Risk factors include PSC, RPC, and liver flukes (Clonorchis sinensis in HK) ^[4]. It is not typically associated with high AFP.
• Liver Metastases: Metastatic disease is far more common than primary liver cancer. Carcinomas from the colon, stomach, pancreas, breast, and lung are common culprits. The liver may be enlarged, nodular, and hard. Imaging typically shows multiple, hypovascular lesions, in contrast to the hypervascular profile of HCC ^[1][2].
• Benign Liver Tumours:
  • Hemangioma: The most common benign liver tumor ^[2]. Usually asymptomatic and found incidentally. Giant hemangiomas can cause abdominal discomfort. It is hyperechoic on USG and shows characteristic peripheral nodular enhancement on CT with slow fill-in.
  • Focal Nodular Hyperplasia (FNH): A benign hyperplastic response to a congenital vascular malformation. Common in young women. It is a usually solitary lesion with a central stellate scar on imaging. It has no malignant potential and does not rupture ^[2].
  • Hepatic Adenoma: A benign neoplasm strongly associated with oral contraceptive use. Presents as a usually solitary RUQ mass. The major risk is spontaneous rupture and hemorrhage, and it carries a small risk of malignant transformation to HCC ^[2].

These cause pruritus, jaundice, and hepatomegaly, but the primary pathology is in the bile ducts.

• Primary Biliary Cholangitis (PBC): An autoimmune disorder destroying small intrahepatic bile ducts. Presents with pruritus and fatigue, often in middle-aged women. Key diagnosis: elevated ALP + positive Anti-Mitochondrial Antibodies (AMA). Can progress to biliary cirrhosis ^[5].
• Primary Sclerosing Cholangitis (PSC): Inflammation and fibrosis of intra- and extra-hepatic bile ducts, leading to a "beaded" appearance on cholangiography. Strongly associated with Inflammatory Bowel Disease (especially Ulcerative Colitis). Presents with pruritus, jaundice, and recurrent cholangitis. A major risk factor for cholangiocarcinoma ^[6].

• Causes of Ascites:
  • Heart Failure: Causes transudative ascites via increased hepatic sinusoidal pressure (congestive hepatopathy) and systemic venous pressure. Differentiated by elevated JVP, cardiomegaly, and peripheral edema.
  • Nephrotic Syndrome: Severe hypoalbuminemia leads to reduced oncotic pressure and generalized edema, including ascites. Urinalysis shows massive proteinuria.
  • Peritoneal Carcinomatosis: Metastatic seeding of the peritoneum (e.g., from ovarian, gastric, colon cancer) causes exudative, often bloody ascites. Fluid cytology is diagnostic.
  • Tuberculous Peritonitis: Causes exudative ascites with high lymphocyte count. Patients often have fever, night sweats, and may have evidence of TB elsewhere.
• Causes of Upper GI Bleeding (mimicking variceal hemorrhage): Peptic ulcer disease, gastritis, Mallory-Weiss tear, and gastric cancer can all present with hematemesis. In a patient without known liver disease, these are more common than varices ^[7].

These are specific etiologies of cirrhosis that must be identified due to targeted treatments.

• Hemochromatosis: Iron overload leads to progressive fibrosis. Look for triad: cirrhosis, diabetes mellitus ("bronze diabetes"), and skin pigmentation. Diagnosed with high transferrin saturation and ferritin, confirmed by genetic testing (HFE gene) or liver biopsy with iron quantification ^[2].
• Wilson's Disease: Copper accumulation. Can present as acute hepatitis, chronic liver disease, or neurological symptoms (parkinsonism, psychiatric). Keys: Kayser-Fleischer rings (on slit-lamp exam), low serum ceruloplasmin, high urinary copper ^[2].
• Alpha-1 Antitrypsin Deficiency: Mutant protein (PiZZ) polymerizes in hepatocytes. Can present with neonatal cholestasis, childhood cirrhosis, or emphysema in adults. Diagnosed by low serum A1AT level and phenotype/genotype confirmation ^[2].

The following Mermaid diagram summarizes the clinical approach to differentiating the causes of a patient presenting with signs of chronic liver disease and portal hypertension.

There is no single "diagnostic criteria" checklist for cirrhosis itself. Instead, diagnosis is based on a combination of findings. For compensated cirrhosis (often asymptomatic), the diagnosis may be subtle and rely more on imaging or biopsy. For decompensated cirrhosis, the presence of clear complications (ascites, variceal hemorrhage, hepatic encephalopathy) in the right clinical context is often sufficient.

However, for specific diseases causing cirrhosis, there are established criteria:

• Primary Biliary Cholangitis (PBC): Diagnosis requires at least 2 of the following: 1) ALP ≥ 1.5x ULN, 2) Positive AMA at titer ≥1:40, and 3) Histologic evidence of non-suppurative destructive cholangitis ^[1][10].
• Hepatocellular Carcinoma (HCC): In a cirrhotic liver, a liver lesion >1 cm with the typical vascular pattern on dynamic imaging (arterial hyperenhancement and venous/delayed phase washout) is diagnostic without the need for biopsy ^[8][11].

The functional severity of cirrhosis is formally classified using the Child-Pugh Score (which grades from A to C) and quantified by the Model for End-Stage Liver Disease (MELD) score, critical for transplant prioritization.

When cirrhosis is suspected, follow a logical, tiered investigation strategy. The following algorithm outlines the pathway from initial suspicion to confirmation and etiological diagnosis.

This is the most critical step, as it can halt progression and even lead to regression of fibrosis in some cases.

• Chronic Hepatitis B (HBV):

  • Goal: Suppress viral replication to undetectable levels (HBV DNA).
  • First-line Agents: Entecavir or Tenofovir (TAF/TDF). These are potent nucleos(t)ide analogs with high barriers to resistance. They are indicated in all cirrhotic patients with detectable HBV DNA, regardless of ALT level ^[1][9].
  • Mechanism: They inhibit the HBV reverse transcriptase, stopping viral DNA synthesis.
  • Monitoring: HBV DNA, LFTs, renal function (for Tenofovir).

• Chronic Hepatitis C (HCV):

  • Goal: Achieve sustained virologic response (SVR), which is a "cure."
  • Agents: Direct-acting antivirals (DAAs) – e.g., Sofosbuvir/Velpatasvir, Glecaprevir/Pibrentasvir. These are oral, well-tolerated, and have >95% cure rates in 8-12 weeks.
  • Mechanism: They target specific non-structural proteins of HCV (NS3/4A protease, NS5A, NS5B polymerase) crucial for viral replication.

• Alcohol-Related Liver Disease (ALD):

  • Cornerstone: Complete, lifelong abstinence. This is non-negotiable and can dramatically improve prognosis.
  • Support: Referral to addiction services, counseling, and potentially medications like acamprosate or naltrexone (if liver function allows).
  • Nutrition: Correct malnutrition and specific vitamin deficiencies (especially B vitamins).

• Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD/MASH):

  • Goal: Weight loss and control of metabolic drivers.
  • Lifestyle: Weight loss of 7-10% is the most effective therapy. Achieved through calorie restriction and exercise (150+ min/week).
  • Pharmacotherapy: For patients with MASH and significant fibrosis, consider GLP-1 agonists (e.g., semaglutide) or other metabolic agents. Vitamin E may be considered in non-diabetic patients.

• Autoimmune Hepatitis (AIH):

  • Goal: Induce and maintain remission to prevent progression.
  • First-line: Prednisolone (induction) followed by Azathioprine (maintenance). Budesonide (a topical steroid with high first-pass metabolism) may be used in non-cirrhotic patients.
  • Mechanism: Suppress the immune-mediated attack on hepatocytes.

• Primary Biliary Cholangitis (PBC):

  • First-line: Ursodeoxycholic acid (UDCA) at 13-15 mg/kg/day. It improves liver biochemistry, delays histological progression, and improves transplant-free survival ^[10][11].
  • Mechanism: Thought to replace toxic endogenous bile acids, stimulate bile flow, and have anti-apoptotic effects on cholangiocytes.
  • Second-line: Obeticholic acid (a FXR agonist) for patients with an inadequate biochemical response to UDCA.

• Genetic/Metabolic Disorders:

  • Hemochromatosis: Weekly therapeutic phlebotomy to deplete iron stores. Target ferritin < 100 ng/mL.
  • Wilson's Disease: Copper chelation with D-penicillamine or Trientine. Zinc acetate (induces metallothionein, blocking copper absorption) for maintenance.
  • Alpha-1 Antitrypsin Deficiency: Supportive. No specific therapy for the liver disease other than avoiding alcohol/smoking. Augmentation therapy is for lung disease.

The choice of therapy depends on tumor stage, liver function (Child-Pugh), and patient performance status. The Hong Kong Liver Cancer (HKLC) Staging System is commonly used locally ^[7][8], but the overview below is grouped by treatment category rather than reproducing the full HKLC stage map.

A. Curative Therapies (for Early-Stage HCC):

• Hepatic Resection:
  • Ideal Candidate: Single tumor, Child-Pugh Class A cirrhosis, no clinically significant portal hypertension, and adequate future liver remnant (FLR >40%). Portal hypertension is assessed by the presence of varices, splenomegaly with thrombocytopenia, or HVPG ≥10 mmHg ^[8][12].
  • Advantage: Potential cure with preservation of native liver.
  • Disadvantage: High recurrence rate (~70% at 5 years) due to "field change" in the cirrhotic liver.
• Liver Transplantation:
  • Ideal Candidate: Meets Milan Criteria (single ≤5cm, or ≤3 nodules each ≤3cm, no vascular invasion/extrahepatic spread) and has decompensated cirrhosis (Child-Pugh B/C).
  • Advantage: Cures both the cancer and the underlying liver disease.
  • Contraindications: Macroscopic vascular invasion, extrahepatic metastasis, active infection, active substance abuse.
  • Bridging Therapy: While on the waitlist, treatments like TACE or RFA are used to prevent tumor progression.
• Local Ablation (e.g., Radiofrequency Ablation - RFA):
  • Ideal Candidate: Small tumors (< 3 cm), ≤3 nodules, not suitable for resection/transplant. Often used for lesions deep in the liver parenchyma.
  • Mechanism: Image-guided insertion of a needle electrode that generates heat, destroying the tumor.

B. Palliative/Locoregional Therapies (for Intermediate-Stage HCC):

• Transarterial Chemoembolization (TACE):
  • Ideal Candidate: Large or multifocal HCC, Child-Pugh A/B, no main portal vein thrombosis, no extrahepatic spread.
  • Mechanism: Catheter is advanced into the hepatic artery branches feeding the tumor. A mixture of chemotherapeutic drug (e.g., doxorubicin) and an embolic agent (e.g., lipiodol/gelfoam) is injected. This achieves high local drug concentration and cuts off the tumor's blood supply (HCC is hypervascular and fed predominantly by the hepatic artery).
  • Contraindications: Decompensated cirrhosis (Child-Pugh C), main portal vein thrombosis (risk of liver infarction), extensive tumor burden (>50% liver involvement), poor performance status ^[7][13].
• Transarterial Radioembolization (TARE / SIRT): Uses radioactive microspheres (Yttrium-90). Particularly useful for tumors with portal vein thrombosis.

C. Systemic Therapy (for Advanced-Stage HCC):

• First-line: Atezolizumab (anti-PD-L1) + Bevacizumab (anti-VEGF). Immunotherapy + anti-angiogenic combination.
• Other options: Lenvatinib (multi-kinase inhibitor), Sorafenib (the original standard, now often second-line).

This is the definitive treatment for eligible patients with decompensated cirrhosis or early HCC within criteria.

• Indications: End-stage liver disease (Child-Pugh C, MELD score ≥15), HCC within Milan/UCSF criteria, acute liver failure, certain metabolic diseases.
• Contraindications (Absolute): Active/uncontrolled infection/sepsis outside biliary tree, extrahepatic malignancy, advanced cardiopulmonary disease, active substance abuse, inability to comply with lifelong immunosuppression.
• Prioritization: In HK, the MELD score is used. For HCC patients meeting Milan criteria, they receive a standard "exception score" to reflect their mortality risk from cancer while waiting.
• Post-Transplant Management: Lifelong immunosuppression (e.g., tacrolimus, mycophenolate) to prevent rejection, with monitoring for side effects (renal impairment, diabetes, hypertension, infection, malignancy).

The most common complication of cirrhosis and the most frequent first decompensating event. ^[1]

• Pathophysiology: This isn't just about low albumin. It's a hemodynamic cascade:
  1. Portal Hypertension (HVPG ≥10 mmHg) ^[2] → Splanchnic arterial vasodilation (from excess nitric oxide).
  2. This leads to effective arterial hypovolemia (the arteries are too dilated, so the body senses low blood volume).
  3. This triggers the activation of the Renin-Angiotensin-Aldosterone System (RAAS) and the sympathetic nervous system.
  4. Result: Sodium and water retention by the kidneys.
  5. The retained fluid, driven by the high portal pressure and hypoalbuminemia (which reduces plasma oncotic pressure), leaks into the peritoneal cavity as ascites and into the interstitial spaces as peripheral edema.
• Clinical Features: Abdominal distension, increased waist size, flank dullness, shifting dullness, fluid thrill. Lower limb pitting edema is often concomitant.
• Key Point: Diagnostic paracentesis is the FIRST step in the evaluation of new-onset ascites to rule out infection (SBP) and confirm the cause ^[1].

A life-threatening infection of ascitic fluid without a surgically treatable source. It's a classic example of how cirrhosis disrupts host defense.

• Pathophysiology:
  • Bacterial Translocation: Gut bacteria migrate across the edematous, congested intestinal wall into the mesenteric lymph nodes.
  • Impaired Clearance: Portosystemic shunting bypasses the liver's Kupffer cells (the body's filter), allowing bacteria to reach the systemic circulation.
  • Vulnerable Fluid: Ascitic fluid has low opsonic activity (low complement and immunoglobulin levels), making it a poor culture medium for killing bacteria ^[3].
• Diagnosis: Ascitic fluid neutrophil count > 250 cells/mm³. Culture may be negative (Culture-Negative Neutrocytic Ascites), but treatment is still required.
• Clinical Features: May be subtle – fever, mild abdominal pain, worsening encephalopathy, or renal function. Can also present with no symptoms.

The most dramatic and immediately life-threatening complication. Mortality from the first bleed is 20-30%.

• Pathophysiology: Portal hypertension (HVPG ≥12 mmHg) ^[2] forces blood through collateral vessels. The esophageal and gastric varices are thin-walled and prone to rupture. Rupture risk is driven by the tension on the variceal wall (Laplace's law: tension ∝ pressure x radius / wall thickness).
• Clinical Features: Sudden, painless, large-volume hematemesis (vomiting bright red blood) and/or melena. May present with hypovolemic shock.
• Why it's deadly: The combination of hypovolemia, impaired synthetic function (coagulopathy), and the stress of bleeding can precipitate hepatic encephalopathy, hepatorenal syndrome, and infection.

A spectrum of neuropsychiatric disturbances caused by the liver's failure to detoxify gut-derived substances.

• Pathophysiology: The central theory involves hyperammonemia. The failing liver cannot convert ammonia (NH₃) to urea. Portosystemic shunting also allows ammonia to bypass the liver. Ammonia crosses the blood-brain barrier, causing astrocyte swelling and cerebral edema, disrupting neurotransmission.
• Clinical Spectrum: Ranges from minimal HE (poor concentration, psychometric defects) to overt HE (confusion, personality change, asterixis - "liver flap", drowsiness, coma).
• Precipitants: Always search for a trigger: Infection (SBP!), GI bleed, constipation, dehydration, electrolyte imbalance, sedatives, or high protein intake ^[4].

A functional, potentially reversible renal failure in advanced cirrhosis. It is a diagnosis of exclusion.

• Pathophysiology: A severe progression of the same hemodynamic derangement causing ascites.
  1. Profound splanchnic vasodilation leads to severe effective hypovolemia.
  2. This causes intense renal vasoconstriction (via RAAS and SNS) to maintain systemic blood pressure.
  3. The result is drastically reduced renal perfusion and glomerular filtration rate (GFR), but the renal tubules themselves are intact (hence "functional").
• Types:
  • Type 1 HRS: Rapid, progressive renal failure (doubling of creatinine to >2.5 mg/dL in < 2 weeks). Often triggered by SBP or GI bleed. Dismal prognosis.
  • Type 2 HRS: Steady, moderate renal impairment (creatinine 1.5-2.5 mg/dL). Usually associated with refractory ascites.
• Diagnostic Clues: Oliguria, rising creatinine, very low urine sodium (< 10 mmol/L), and bland urine sediment (no cells/casts).

The most common primary liver cancer and a major cause of death in cirrhotic patients. Cirrhosis is the single greatest risk factor.

• Epidemiology in HK: 80% of HCC in Hong Kong occurs in HBsAg-positive individuals ^[5]. HCC complicates HCV almost exclusively on a background of cirrhosis (100%), while it can occur in non-cirrhotic livers in HBV (20%) due to HBV's direct oncogenic effect ^[6].
• Pathogenesis: Chronic inflammation, hepatocyte regeneration, and genetic mutations (e.g., p53 from aflatoxin) lead to dysplastic nodules and eventually HCC. The whole cirrhotic liver is at risk ("field cancerization").
• Why Prognosis is Often Poor: Patients are often asymptomatic until the tumor is large (>8 cm) ^[7]. The underlying cirrhosis limits treatment options (resection, transplant) and predisposes to liver failure post-treatment. HCC also has a high propensity for vascular invasion (portal vein thrombosis) and intrahepatic metastasis ^[5].
• Screening: All cirrhotic patients should have 6-monthly ultrasound and AFP surveillance.

• Hepatic Hydrothorax: Pleural effusion (usually right-sided) due to passage of ascitic fluid through diaphragmatic defects. Managed like ascites.
• Hepatopulmonary Syndrome (HPS): Triad of cirrhosis, hypoxemia, and intrapulmonary vascular dilatations. Patients develop platypnea (shortness of breath when upright) and orthodeoxia (worsening hypoxia when upright). Clubbing is common.
• Portopulmonary Hypertension (POPH): Pulmonary arterial hypertension (mean PA pressure >25 mmHg) in the setting of portal hypertension. Presents with dyspnea, fatigue, and can lead to right heart failure.
• Cirrhotic Cardiomyopathy: Impaired cardiac contractility and response to stress in the setting of cirrhosis, despite a normal or high resting cardiac output. Can unmask during procedures like TIPS or transplant.

• Pruritus: Debilitating itching due to retained bile acids and other pruritogens. Worse at night.
• Steatorrhea & Fat-Soluble Vitamin (A, D, E, K) Deficiency: Due to reduced bile acid secretion, impairing fat digestion and absorption. Can lead to night blindness (Vit A), osteomalacia/osteoporosis (Vit D), neuropathy (Vit E), and coagulopathy (Vit K).
• Hepatic Osteodystrophy: Metabolic bone disease (osteoporosis/osteopenia) from vitamin D deficiency, chronic inflammation, and direct inhibitory effects of cholestasis on osteoblasts.
• Hyperlipidemia: Particularly in PBC, with a characteristic elevation of lipoprotein-X. Notably, this does not seem to increase atherosclerotic risk.
• Cholangiocarcinoma: A major life-threatening complication of Primary Sclerosing Cholangitis (PSC). The risk is lifelong, and screening with MRI/MRCP and CA19-9 is recommended.