GC161 Alcohol And The Brain From Psychiatric To Neuropsychiatric Perspectives
An integrated clinical framework examining alcohol's effects on the brain across both psychiatric manifestations (such as mood disorders, psychosis, and dependence) and neuropsychiatric consequences (including cognitive impairment, Wernicke-Korsakoff syndrome, and alcohol-related brain damage).
This lecture by Dr Heid Lo (HKU Psychiatry) is a bridge lecture connecting psychiatry, neurology, and medicine through the single lens of alcohol. It spans from the addictive/psychiatric dimension (how alcohol hijacks neurotransmission, DSM-5 criteria, withdrawal) through the neuropsychiatric dimension (Wernicke-Korsakoff, cerebellar degeneration, Marchiafava-Bignami, central pontine myelinolysis) to the systemic (hepatic encephalopathy, fetal alcohol syndrome, stroke risk, suicide). The lecture culminates in a must-know clinical pearl: the 6 causes of confusion in alcoholism — a systematic framework for the confused alcoholic patient that examiners love to test.
Why this matters for exams: Alcohol questions appear across psychiatry, neurology, medicine (hepatology), and public health papers. This lecture is the go-to source for psychiatry-neurology crossover material. Past papers repeatedly test definitions of moderate drinking, standard drinks, alcohol and stroke/cardioprotection controversies, and delirium tremens vs alcoholic hallucinosis.
Learning Objectives (from slide 2) [1]
- Understand alcohol-related addictive problems (AUD, intoxication, withdrawal)
- Know alcohol-related medical conditions and brain changes
- Distinguish alcohol-induced psychiatric disorders from comorbid psychiatric conditions
- Understand the bidirectional relationship between alcohol and psychiatric disorders
- List the 6 causes of confusion in alcoholism
1. Alcohol-Related Addictive Problems
Alcohol exerts its CNS effects through two primary mechanisms: [1]
- Increases sensitivity of GABA receptors → enhances inhibitory GABAergic neurotransmission (downregulated in the chronic state)
- Inhibition of NMDA receptors → reduces excitatory glutamatergic neurotransmission (upregulated in the chronic state)
- Indirectly alters release of serotonin, dopamine, norepinephrine, aspartate
Why this matters from first principles:
- Acutely, alcohol is a CNS depressant: it boosts inhibition (GABA) and blocks excitation (glutamate). This explains sedation, impaired coordination, and anxiolysis.
- Chronically, the brain compensates: GABA receptors downregulate (fewer receptors, less responsive), and NMDA receptors upregulate (more receptors, primed for excitation). The brain is now in a "hyper-excitable" state that is masked by ongoing alcohol intake.
- When alcohol is suddenly removed, the mask comes off → withdrawal features are essentially unopposed glutamate excitation + insufficient GABA inhibition → autonomic hyperactivity, seizures, delirium tremens.
- The dopamine alteration explains the rewarding/reinforcing properties that drive addiction.
A problematic pattern of alcohol use leading to clinically significant impairment or distress, manifested by at least 2 of the following within a 12-month period: [1]
| # | Criterion | Conceptual Domain |
|---|---|---|
| 1 | Taken in larger amounts or longer than intended | Loss of control |
| 2 | Persistent desire or unsuccessful efforts to cut down | Loss of control |
| 3 | Great deal of time spent obtaining, using, or recovering | Loss of control |
| 4 | Craving | Compulsive drive |
| 5 | Failure to fulfill major role obligations | Social impairment |
| 6 | Continued use despite interpersonal problems | Social impairment |
| 7 | Important activities given up or reduced | Social impairment |
| 8 | Recurrent use in physically hazardous situations | Risky use |
| 9 | Continued use despite knowledge of physical/psychological harm | Risky use |
| 10 | Tolerance (need more for same effect, or diminished effect at same dose) | Pharmacological |
| 11 | Withdrawal (characteristic syndrome, or substance taken to relieve/avoid withdrawal; benzodiazepine can substitute) | Pharmacological |
Severity grading: 2-3 criteria = Mild; 4-5 = Moderate; ≥6 = Severe
DSM-5 vs ICD-10 Exam Trap
Diagnostic criteria: [1]
- A. Recent ingestion of alcohol
- B. Clinically significant problematic behavioral/psychological changes (inappropriate sexual/aggressive behavior, mood lability, impaired judgment)
- C. One or more: slurred speech, incoordination, unsteady gait, nystagmus, impairment in attention or memory, stupor or coma
- D. Not attributable to another medical condition or substance
Impairment at Different Blood Alcohol Concentrations:
| Blood Alcohol (mg/dL) | Clinical Features |
|---|---|
| 20-30 | Slowed motor performance, decreased thinking ability |
| 30-80 | Increases in motor and cognitive problems |
| 80-200 | Incoordination, judgment errors, mood lability, deterioration in cognition |
| 200-300 | Nystagmus, marked slurring of speech, alcoholic blackouts |
| > 300 | Impaired vital signs and possible death |
Breathalyzer conversion: 0.1 mg/L = blood level 21 mg/dL (×2100) [1]
Why the thresholds matter: 80 mg/dL is the typical legal driving limit in many jurisdictions. Above 200 mg/dL, blackouts become likely. Above 300 mg/dL, respiratory depression and death become real risks.
Key features: [1]
- Transient amnesia lasting hours
- Memory impairment (anterograde) — cannot form new memories of events during the blackout
- No impairment of conscious level — the person appears awake and functioning
- Mechanism: Inhibition of NMDA receptors in hippocampus → failure of long-term potentiation (LTP)
Why this is important: Blackouts are NOT loss of consciousness. The patient is awake, talking, acting — but the hippocampal memory-encoding machinery is offline because NMDA receptors (critical for LTP, the molecular basis of memory consolidation) are blocked by alcohol. This is why people can "do things" during a blackout they have zero recall of the next day. It is a common exam discriminator: blackout ≠ unconsciousness.
Occurs 6-24 hours after last drink [1]
- Autonomic hyperactivity: tremulousness, sweating, nausea, vomiting, anxiety, agitation, tachycardia
- Hypertension, hyperreflexia, insomnia, nightmares, sweating, hyperthermia
- Pathophysiology: Downregulation of GABA receptors + reversal of NMDA inhibition → glutamate overactivity
- Disappears in 2-7 days
Clinical timeline of alcohol withdrawal:
| Time After Last Drink | Feature |
|---|---|
| 6-12 hours | Tremor, anxiety, nausea, sweating, tachycardia |
| 12-24 hours | Alcoholic hallucinosis (auditory, in clear consciousness) |
| 12-48 hours | Withdrawal seizures (generalized tonic-clonic) |
| 24-96 hours | Delirium tremens (peak 48-72h) |
2. Alcohol-Related Medical Conditions and Brain Changes
Severe form of alcohol withdrawal [1]
- Occurs 24-96 hours after abstention
- Confusion, hallucination (typically visual), severe agitation, seizure
- Mortality 5%
- Medical emergency requiring hospitalisation
Management of DT: [1]
- Benzodiazepine in decreasing dosage (lorazepam/diazepam/others) — first-line
- Anticonvulsants (carbamazepine) — for seizure prophylaxis
- Proactive use of parenteral vitamins (thiamine) — ALWAYS give before glucose (see below)
- Neuroleptics for control of agitation — use cautiously (lower seizure threshold)
- Fluid & electrolyte balance
Thiamine BEFORE Glucose — Classic Exam Rule
In any confused alcoholic patient, always give IV thiamine BEFORE IV glucose. Glucose loading in a thiamine-depleted patient will consume the remaining thiamine stores (thiamine is a cofactor for pyruvate dehydrogenase in glucose metabolism), precipitating or worsening Wernicke encephalopathy. This is one of the most tested points in clinical medicine [1][3].
| Feature | Delirium Tremens | Alcoholic Hallucinosis |
|---|---|---|
| Consciousness | Clouded sensorium | Clear consciousness |
| Hallucinations | Typically visual | Typically auditory |
| Onset | 24-96h after cessation | During heavy drinking or shortly after |
| Trigger | Reduction/cessation of alcohol | Chronic heavy drinking |
| Other features | Confusion, agitation, seizures, autonomic instability | Distressing auditory content, may develop into schizophrenia-like picture |
| Treatment | Benzodiazepines | Antipsychotics + abstinence |
"Differentiate from delirium tremens — reduction in alcohol intake, clouded sensorium, visual hallucination" — this is a direct slide note from the lecture and is frequently tested [1].
Clinical features: [1]
- Confusion
- Memory impairment / Attention problems / Hallucination
- Ophthalmoplegia / Nystagmus
- Ataxia (truncal)
- Peripheral neuropathy (50%)
- Hypothermia
- Apathy
- Coma (rare)
Key facts: [1]
- Mostly alcoholic, some non-alcoholic
- Caused by thiamine deficiency
- Only 20% detected in life (Harper 1983) — massively underdiagnosed
- Medical emergency
- 20% mortality
- Treatment: IM/IV Thiamine
- Progression to Korsakoff's Psychosis in 84% (Victor 1989)
The classic triad is Confusion + Ophthalmoplegia + Ataxia, but the full triad is present in only ~10-16% of cases. Any one feature in a malnourished or alcoholic patient should trigger empirical thiamine replacement.
Why thiamine deficiency causes Wernicke: Thiamine (vitamin B1) is a cofactor for pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, and transketolase. These enzymes are critical for cellular energy metabolism. Brain regions with high metabolic demands (periventricular grey matter, mammillary bodies, medial thalamus, periaqueductal grey) are preferentially vulnerable [1][3].
Key features: [1]
- Severe irreversible loss of short-term memory
- Inability to learn and later recall new information
- Confabulation ± (patient fills memory gaps with fabricated stories, not deliberately lying)
- No clouding of consciousness
- No general impairment of other cognitive functions
Why it is irreversible: Korsakoff syndrome represents structural neuronal loss (especially in mammillary bodies and medial thalamus), unlike Wernicke which is primarily a metabolic/functional crisis that can be reversed with thiamine if caught early. The 84% progression rate from Wernicke → Korsakoff underscores why Wernicke is a medical emergency [1].
Pathological findings: [1]
- Petechial haemorrhages, neuronal loss, gliosis, brown discolouration
- Locations: periventricular grey matter, 3rd ventricle, Sylvian aqueduct, 4th ventricle, diencephalon, midbrain, pons, medulla
Non-alcoholic causes of WKS: [1]
| Cause | Mechanism of Thiamine Deficiency |
|---|---|
| Hyperemesis of pregnancy | Prolonged vomiting → ↓intake |
| Systemic malignancy | Catabolic state → ↑demand, ↓intake |
| GI surgery | Malabsorption |
| Haemodialysis / peritoneal dialysis | Thiamine loss |
| Prolonged intravenous feeding | Glucose load without thiamine |
| Refeeding after prolonged fasting/starvation | Glucose load depletes remaining thiamine |
| Anorexia nervosa | ↓intake |
| Dieting/starvation | ↓intake |
| Gastric plication | Malabsorption |
| AIDS | Multiple factors |
Common defect: Thiamine deficiency [1]
Thiamine-deficiency amnesic syndromes → affect diencephalon and brainstem [1] Non-thiamine-deficiency amnesic syndromes → affect medial temporal lobe [1]
Other causes of medial temporal lobe amnesic syndrome: [1]
- Closed head trauma, penetrating wounds, focal tumour, encephalitis (especially HSV), hypoxia (CO poisoning), infarction (posterior cerebral artery territory), neurosurgery
This distinction matters because the clinical flavour differs: diencephalic lesions produce more confabulation and disorientation, while temporal lobe lesions produce more "pure" amnesia [3].
West Haven Criteria — 4 stages of severity: [1]
| Stage | Features |
|---|---|
| Stage 1 | Trivial lack of awareness, shortened attention span, impaired addition/subtraction, hypersomnia/insomnia/sleep inversion, euphoria or depression. Asterixis can be detected |
| Stage 2 | Lethargy or apathy, mild disorientation, inappropriate behavior, slurred speech, obvious asterixis |
| Stage 3 | Gross disorientation, bizarre behavior, semi-stupor to stupor, asterixis generally absent |
| Stage 4 | Coma |
Glasgow Coma Scale may also be used [1]
Pathophysiology (from supporting sources): Ammonia (NH3) accumulates due to impaired hepatic detoxification and portosystemic shunting → crosses BBB → metabolised to glutamine in astrocytes → ↑intracellular osmolarity → astrocyte swelling → cerebral edema and neuroinflammation [4][5].
Key facts: [1]
- Heavy drinking → 30% chance
- 1-4 per 1000 live births (US)
- Brain findings: Microcephaly, agenesis of corpus callosum, cerebellar hypoplasia
- Most common cause of preventable mental retardation
- Low birth weight
- Facial dysmorphology (smooth philtrum, thin vermillion border, short palpebral fissures)
- Growth retardation
Why "most common cause of preventable mental retardation": Unlike genetic causes of intellectual disability (e.g., Down syndrome), FAS is entirely preventable through maternal abstinence from alcohol during pregnancy.
Key features: [1]
- Thiamine deficiency
- Atrophy of cerebellum (vermis)
- Unsteady gait, truncal instability, lower limb ataxia
- Postural hand tremor, dysarthria, nystagmus
- Degeneration of Purkinje cells
Why the vermis? The cerebellar vermis controls truncal coordination and gait. The Purkinje cells are particularly metabolically active and vulnerable to thiamine deficiency and direct alcohol toxicity. This is why alcoholic cerebellar degeneration predominantly affects gait and truncal stability rather than fine limb coordination.
Key features: [1]
- Severe chronic drinkers — originally described in Italian drinkers of crude red wine
- Subacute demyelination disease
- Fits, spasticity, rigidity, paralysis
- Coma, death
- Affects mid corpus callosum (vacuolation and degeneration)
- 40-60 years old
- Frontal lobe syndrome, dementia, personality change
Why the corpus callosum? The exact mechanism is unclear but thought to involve direct toxic effects of alcohol metabolites and nutritional deficiency targeting the myelin of the largest white matter tract. The corpus callosum connects the two hemispheres, so demyelination here produces disconnection syndromes and frontal lobe dysfunction.
Key features: [1]
- Demyelination of pons
- Dysarthria / dysphagia
- Spastic paralysis of all 4 limbs (quadriparesis)
- Caused by infusion of hypertonic saline for treatment of hyponatraemia (too-rapid correction)
- Personality change, inappropriate affect, delusion
- Other causes: cirrhosis, liver transplant, uraemia, haemodialysis, prolonged vomiting, diuretics
Central Pontine Myelinolysis — The Rate of Sodium Correction
The critical teaching point is that CPM/ODS occurs when hyponatraemia is corrected too rapidly ( > 10-12 mEq/L per 24 hours). Alcoholic patients are at particularly high risk because they often present with chronic hyponatraemia (from beer potomania, poor nutrition, or SIADH). The safe rate of correction is ≤8-10 mEq/L per 24 hours. Examiners test this concept across medicine and neurology papers [1][6].
Summary from lecture: [1]
| Stroke Type | % of Strokes | Light/Moderate Drinking | Heavy Drinking |
|---|---|---|---|
| Haemorrhagic | 15% | — | ↑Risk |
| Ischaemic | 85% | ↓Risk | ? |
Wine specifically: Copenhagen City Heart Study showed wine intake ↓ risk of stroke (after adjusting for confounders), while beer/spirits showed no relation [1] Both findings are marked as CONTROVERSIAL on the slides [1]
From the lecture: [1]
- Impairment in visuospatial processing
- Memory impairment
- EEG abnormalities
- Reduction in cerebral blood flow
- Reduction in cerebral glucose metabolism
Key statistics: [1]
- 7% of alcohol abusers die of suicide
- Alcoholism is a factor in 30% of all completed suicides
- 50% of suicide attempts have consumed alcohol at the time of the attempt
- 96% of alcoholics who die by suicide continue alcohol use up to the end of their lives
3. Alcohol-Related Psychiatric Disorders
The lecture makes a critical distinction between alcohol-induced psychiatric disorders (caused by alcohol, resolve with abstinence) and alcohol-comorbid psychiatric disorders (independent psychiatric illness co-existing with alcoholism).
3.1 Alcohol-Induced Psychiatric Disorders
Key features: [1]
- Chronic heavy drinkers
- Auditory hallucination in clear consciousness
- Distressing in content
- Some develop schizophrenia, some remit after stopping alcohol
- Treatment: antipsychotics + advice to abstain from alcohol
Key features: [1]
- Chronic heavy drinking
- Clear sensorium
- Schizophrenia-like syndrome
- Remission on stopping alcohol
- Recurrence with relapse of alcoholism
Key features: [1]
- Moderate or heavy alcohol use
- Major depression or mania
- Persists for up to 4 weeks after abstinence
- Clears up on stopping alcohol
Key features: [1]
- Symptoms occur while patient on heavy alcohol consumption
- Symptoms subside gradually on abstinence, but may persist up to 6 months
- Can manifest as: GAD, panic disorder, phobic anxiety disorders, social phobia, OCD, PTSD
- Must be distinguished from alcohol withdrawal syndrome
Alcohol-Induced vs Withdrawal Anxiety
This is an exam trap. Alcohol withdrawal anxiety presents 6-24 hours after last drink with autonomic features and resolves in 2-7 days. Alcohol-induced anxiety disorder occurs during ongoing heavy use and can persist up to 6 months after stopping. The presence of autonomic hyperactivity, tremor, and acute onset points to withdrawal; gradual onset during use points to induced disorder [1].
How to identify comorbid (independent) psychiatric disorders: [1]
- Evidence of psychiatric disorders before onset of alcohol abuse/dependence
- Evidence of persistent psychiatric symptoms during extended alcohol-free periods ( > 4 weeks)
- First-degree biological relative with documented psychiatric disorder
Prevalence of alcoholism in various psychiatric conditions: [1]
| Psychiatric Condition | % with Comorbid Alcoholism |
|---|---|
| Antisocial personality disorder | 80% |
| Bipolar I disorder | 60% |
| Schizophrenia | 30% |
| Drug addiction | 20% |
| Anxiety disorders (social phobia, panic disorder) | Common |
Why schizophrenia patients drink (from the lecture): [1]
- Alcohol decreases feeling of isolation
- Temporarily reduces symptoms of anxiety/depression/insomnia
- But INCREASES psychotic symptoms & mood swings
- Leads to disruptive behaviour, suicide, treatment non-compliance, drug abuse, poor clinical outcome
- Drug accumulation due to hepatic damage (impaired metabolism of antipsychotics)
Cross-addiction: [1]
- 20% of drug abusers are alcoholic
- Alcoholics are 6 times more prone to become drug abusers
The lecture emphasizes a bidirectional, confounded relationship: [1] Alcoholism ↔ Psychiatric symptoms, with confounding factors complicating causal inference
This means: alcohol can cause psychiatric symptoms, psychiatric symptoms can drive alcohol use, and both may share common risk factors (genetic vulnerability, social adversity, etc.).
MUST KNOW — 6 Causes of Confusion in Alcoholism
This is the single most exam-relevant list from this lecture. When faced with a confused alcoholic patient, systematically consider all six: [1]
- Intoxication — recent heavy drinking, ↑BAC, resolves with time
- Delirium Tremens — 24-96h after cessation, clouded consciousness, visual hallucinations, autonomic storm, seizures
- Head Injury — alcoholics are prone to falls and assaults; always consider subdural haematoma (especially chronic SDH in elderly alcoholics)
- Metabolic Disturbances — hypoglycaemia (alcohol inhibits gluconeogenesis via NAD+ consumption by alcohol dehydrogenase), hyponatraemia, hypomagnesaemia, hypokalaemia, hypophosphataemia
- Hepatic Encephalopathy — asterixis, raised ammonia, precipitants include GI bleed, infection, constipation, sedatives
- Wernicke Encephalopathy — thiamine deficiency, ophthalmoplegia, ataxia, confusion; medical emergency
Why this list matters clinically: An alcoholic patient presenting with confusion could have ANY combination of these. They are not mutually exclusive. A patient could simultaneously have DT + hypoglycaemia + an undiagnosed subdural haematoma. The clinical approach must systematically exclude each one.
5. Integration with Other GC Material
Alcohol causes multiorgan involvement with multiple simultaneous presentations: psychiatric/CNS/seizures/cardiomyopathy/AF/gout/acute and chronic pancreatitis [7] Concomitant presentations in alcoholic liver disease include: withdrawal (D2+ onward), delirium tremens, infections, cirrhotic complications (variceal bleeding, ascites, SBP, HE) [7]
- Standard drink = 14 grams of pure alcohol (this is tested almost every year — see past papers) [9]
- Moderate consumption (AHA definition): up to 1 drink/day for women, up to 2 drinks/day for men [9]
- Equivalents: 1 standard drink ≈ 12 oz (355 mL) beer (5%), 5 oz (148 mL) wine (12%), 1.5 oz (44 mL) spirits (40%)
The 2025 MCQ asks about current HK tax duty on wine — the answer is 0% (Hong Kong abolished wine duty in 2008 for wine/alcohol ≤30% ABV) [10].
6. Exam Intelligence
| Trap | Correct Understanding |
|---|---|
| Alcoholic blackout = loss of consciousness | No. Blackout = transient amnesia in clear consciousness; NMDA inhibition in hippocampus blocks LTP |
| DT = any alcohol withdrawal | No. DT is the severe form (24-96h), with confusion, visual hallucinations, seizures, 5% mortality |
| Alcoholic hallucinosis = DT | No. Hallucinosis = auditory hallucinations in clear consciousness during/after heavy drinking. DT = visual hallucinations in clouded consciousness during withdrawal |
| Korsakoff = general dementia | No. Korsakoff = selective severe anterograde amnesia with confabulation, clear consciousness, other cognitive functions relatively preserved |
| Wernicke always presents with classic triad | No. Classic triad present in only ~10-16%; any one feature + alcoholism/malnutrition = give thiamine |
| CPM caused by hyponatraemia | No. CPM caused by too-rapid correction of hyponatraemia |
| Alcohol-induced mood disorder lasts forever | No. Persists up to 4 weeks after abstinence then resolves; if > 4 weeks, think comorbid independent disorder |
| Moderate alcohol is cardioprotective | Controversial. Higher quality studies show no benefit; the apparent benefit may be due to former-drinker bias in controls |
- Define a standard drink and moderate consumption (appears in 2017, 2020, 2021, 2022 papers)
- 6 causes of confusion in alcoholism
- DT vs alcoholic hallucinosis
- Wernicke-Korsakoff pathology and treatment
- Alcohol-induced vs comorbid psychiatric disorders — distinguishing features
- DSM-5 criteria for AUD
- Mechanism of alcohol (GABA/NMDA) and how this explains withdrawal
- Fetal alcohol syndrome features
7. Past Paper Questions
Stem: "It has been advocated by some people that moderate consumption of alcoholic beverages can help to reduce risk of coronary heart disease. (a) What is the meaning of moderate alcohol consumption? (2 marks) (b) How much pure alcohol does a standard drink contain? (1 mark) (c) What amount liquor, wine, and beer is a standard drink? (3 marks) (d) What is the recommendation by the American Heart Association regarding alcohol use for cardioprotection for non-drinker and established moderate drinkers? (4 marks)"
Markscheme:
- (a) Up to 1 drink/day for women, up to 2 drinks/day for men (AHA definition)
- (b) 14 grams of pure alcohol
- (c) Beer: 12 oz (355 mL), Wine: 5 oz (148 mL), Spirits/Liquor: 1.5 oz (44 mL)
- (d) AHA does NOT recommend non-drinkers start drinking for cardioprotection. For established moderate drinkers, they may continue but should not increase intake. The evidence for cardioprotection is confounded by former-drinker bias.
Stem: Meta-analysis figure showing pooled RR of mortality for moderate drinkers vs non-drinkers by study quality. "(a) Compare and interpret the result of pooled relative risks from studies with higher quality/no bias and those with bias. (3 marks) (b) Name one possible reason behind the former drinker bias in some studies. (2 marks) (c) According to the American Heart Association, what is the meaning of moderate alcohol consumption, respectively for men and women? (2 marks)"
Markscheme:
- (a) Higher quality / no abstainer bias studies show RR ~1.04 (no significant benefit); studies with bias show RR ~0.86 (apparent benefit). The apparent cardioprotective effect disappears when methodological biases are controlled for.
- (b) Former drinkers who quit due to ill health are included in the "non-drinker" control group, making non-drinkers appear less healthy and moderate drinkers appear relatively healthier.
- (c) Up to 1 drink/day for women, up to 2 drinks/day for men.
Stem: "The finding of an association between moderate consumption of alcohol and a cardioprotective effect in some epidemiological studies was considered to be due to a potential bias related to the selection of control group. What kind of persons being included in the control group were responsible for the said bias?"
- A. Former drinkers who quit drinking because of health reason ✅
- B. Former social drinkers who no longer need to be involved in socialising events routinely serving alcohol
- C. People who didn't drink due to their concerns about potential health impact of alcohol
- D. People who didn't like to drink
Answer: A. The "former drinker bias" occurs because people who stopped drinking due to health problems (cardiovascular disease, liver disease, etc.) are misclassified as "non-drinkers," making the non-drinking group appear sicker and inflating the apparent benefit of moderate drinking.
Stem: "According to the American Heart Association, moderate alcohol consumption refers to having up to 1 standard drink per day for women and up to 2 standard drinks per day for men. What is the amount of pure alcohol contained in 1 standard drink?"
- A. 4 grams
- B. 14 grams ✅
- C. 24 grams
- D. 34 grams
Answer: B (14 grams). This is tested nearly every year.
Stem: "You are performing a general examination on a 45-year-old male patient who presents with a history of alcohol abuse... Which of the following is NOT considered a stigmata of chronic liver disease?"
- A. Jaundice
- B. Livedoid reticularis ✅
- C. Palmar erythema
- D. Spider angioma
Answer: B. Livedoid reticularis (livedo reticularis) is associated with vasculitis, antiphospholipid syndrome, and cholesterol embolism — NOT chronic liver disease. Stigmata of CLD include spider angiomata, palmar erythema, jaundice, gynaecomastia, Dupuytren contracture, clubbing, leukonychia, parotid enlargement, caput medusae.
Stem: "With the current alcohol taxation in Hong Kong, people have a tendency to continue consuming alcohol. To prevent public health risks, you decided to write an editorial letter to advocate for an increase in alcohol taxation. What is the current Hong Kong tax duty on wine?"
- A. 0% ✅
- B. 5%
- C. 10%
- D. 15%
Answer: A (0%). Hong Kong abolished wine duty in 2008 for wines/alcohol ≤30% ABV. This was a public health question testing awareness of alcohol policy.
Stem: "A 60-year-old man with known alcoholic liver cirrhosis was admitted for increased confusion. Arterial serum ammonia was noted at 115 umol/L (normal: 6-47 umol/L). Which of the following is MOST LIKELY to precipitate the patient's confusion?"
- A. Alcohol withdrawal
- B. Bleeding gastric ulcer ✅
- C. Diagnostic paracentesis
- D. Recent diagnosis of hepatocellular carcinoma
Answer: B. GI bleeding is one of the most common precipitants of hepatic encephalopathy because blood protein in the GI tract is broken down by bacteria into ammonia, which then cannot be cleared by the failing liver. While alcohol withdrawal could also cause confusion, the question specifically points to elevated ammonia (115 umol/L), making HE the primary diagnosis, and a bleeding gastric ulcer is the most likely precipitant among the options.
Stem: "A 55-year-old male patient with a history of alcoholic cirrhosis presented with massive haematemesis... (a) Name two differential diagnoses for the patient's hypotension and oliguria... (b) Name one aim for blood transfusion... (c) What are the three risks of blood transfusion? (d) What are the three potential complications from massive transfusion?"
Brief markscheme: DDx for hypotension/oliguria: hypovolaemic shock from GI bleeding, hepatorenal syndrome, septic shock (SBP). Aim: restore circulating volume, maintain tissue oxygenation, correct anaemia. Risks: transfusion reactions (allergic, febrile, haemolytic), infection, TRALI. Massive transfusion complications: hypothermia, hypocalcaemia (citrate toxicity), hyperkalaemia, coagulopathy (dilutional), metabolic alkalosis.
| Domain | Approach in Alcoholic Patient |
|---|---|
| History | CAGE/AUDIT screening; quantity/frequency/duration; last drink timing; previous withdrawal/seizures/DT; psychiatric history; social/occupational impact; drug co-use; family history |
| Examination | Stigmata of CLD; nutritional status; neurological exam (cerebellar signs, nystagmus, ophthalmoplegia, peripheral neuropathy); mental state exam; tremor; GCS |
| Investigations | FBC (macrocytosis without anaemia), LFT (↑GGT is the most sensitive marker of alcohol use), RFT, electrolytes (Na, K, Mg, PO4), glucose, ammonia, coagulation, thiamine/B12/folate, blood alcohol level, urine toxicology screen, CT brain (if head injury suspected), MRI (Wernicke: periventricular/mammillary body lesions; CPM: pontine T2 hyperintensity) |
| Acute Management | Thiamine IV/IM BEFORE glucose; BDZ for withdrawal (CIWA-guided); correct electrolytes; treat precipitants of HE; CT brain for head injury; monitor on CIWA protocol |
| Long-term Management | Motivational interviewing; relapse prevention (naltrexone, acamprosate, disulfiram); treat comorbid psychiatric disorders; AA/support groups; nutritional rehabilitation; hepatology follow-up; social worker involvement |
| Prevention | Public health alcohol policy (taxation, advertising regulation); screening in primary care (AUDIT); brief interventions; patient education; abstinence in pregnancy (prevent FAS) |
High Yield Summary
Must-Know Points for Exam:
- Mechanism: Alcohol enhances GABA (↓ chronic) and inhibits NMDA (↑ chronic); withdrawal = unopposed glutamate excitation
- AUD (DSM-5): ≥2 of 11 criteria in 12 months; severity by count
- Blackout: Amnesia in CLEAR consciousness; NMDA blockade in hippocampus → failed LTP
- Withdrawal: 6-24h; tremor, autonomic hyperactivity; resolves 2-7 days
- DT: 24-96h; confusion, VISUAL hallucinations, clouded sensorium, seizures, 5% mortality; Rx = BDZ + thiamine + supportive
- Wernicke: Confusion + ophthalmoplegia + ataxia; thiamine deficiency; 20% mortality; 84% → Korsakoff; GIVE THIAMINE BEFORE GLUCOSE
- Korsakoff: Irreversible anterograde amnesia, confabulation, clear consciousness; NO cure
- Non-alcoholic WKS causes: Hyperemesis, GI surgery, TPN, anorexia nervosa, refeeding
- 6 causes of confusion in alcoholism: Intoxication, DT, head injury, metabolic (hypoglycaemia), hepatic encephalopathy, Wernicke encephalopathy
- Alcohol-induced vs comorbid: Induced resolves with abstinence (mood ≤4 weeks, anxiety ≤6 months); comorbid persists > 4 weeks alcohol-free
- Comorbidities: ASPD 80%, Bipolar I 60%, Schizophrenia 30%, Drug addiction 20%
- Standard drink = 14g pure alcohol; moderate = ≤1/day women, ≤2/day men (AHA)
- Former-drinker bias explains apparent cardioprotective effect of moderate drinking
- HK wine tax = 0%
- FAS = most common cause of preventable mental retardation
Active Recall - Lecture Notes
[1] Lecture slides: GC 161. Alcohol and the Brain From Psychiatric to Neuropsychiatric Perspectives.pdf (all slides p1-50) [2] Lecture slides: CFB (PSY02) Classification and Diagnosis of Psychiatric Illness.pdf [3] Senior notes: Ryan Ho Psychiatry.pdf (Section 5.1.2 Alcohol-related Disorders, p97-107) [4] Senior notes: MBBS Final MB (Medicine) (Felix PY Lai).pdf (Hepatic Encephalopathy, p807) [5] Senior notes: MBBS Final MB (Surgery) (Felix PY Lai).pdf (Hepatic Encephalopathy, p463) [6] Senior notes: Ryan Ho Neurology.pdf (Coma, p92) [7] Lecture slides: GC 240. MASLD and Alcoholic Liver Disease.pdf (p14-15) [8] Lecture slides: GC 037. Common neurological problems in older people.pdf (p23) [9] Past papers: 2017 Fourth Summative SAQ.pdf (Q11, p5) [10] Past papers: 2025 Fourth Summative MCQ.pdf (Q26, p11) [11] Past papers: 2020 Fourth Summative SAQ.pdf (Q11, p12) [12] Past papers: 2021 Fourth Summative Assessment MCQ.pdf (Q98, p36) [13] Past papers: 2022 Fourth Summative MCQ.pdf (Q91, p34) [14] Past papers: 2024 Fourth Summative MCQ.pdf (Q11, p5) [15] Past papers: 2025 Fourth Summative MCQ.pdf (Q34, p14) [16] Past papers: 2025 Fourth Summative SAQ.pdf (Q2, p4)
GC160 The Woman Needs That Drug Oral Contraceptives Drugs Affecting Uterine Motility
Oral contraceptives are estrogen-progestin or progestin-only formulations that prevent ovulation, alter the endometrium, and thicken cervical mucus, while uterine motility drugs such as oxytocin, ergot alkaloids, prostaglandins, and tocolytics either stimulate or inhibit uterine contractions to manage labor, postpartum hemorrhage, or preterm labor.
GC163 I Am A Superman Bipolar Disorder
Bipolar disorder is a chronic mood disorder characterized by episodic fluctuations between mania (or hypomania)—during which grandiose delusions such as believing oneself to be a superhero may occur—and depression, with intervening periods of euthymia.