Alkohol
Published on September 7, 2026
Risk Factors
Alcohol Intoxication
Binge drinking, adolescents, college-age adults, chronic alcohol use disorder, concurrent sedative use
Alcohol Withdrawal
Chronic heavy drinker who abruptly stops or significantly reduces intake; history of prior withdrawal seizures; concurrent illness forcing cessation (hospitalization, trauma)
Etiology
Alcohol Intoxication
Direct CNS depression by ethanol via GABA-A receptor potentiation and NMDA receptor inhibition
Alcohol Withdrawal
Loss of chronic ethanol-mediated GABA-A stimulation and unopposed NMDA/glutamate excitatory rebound
Presentation
Alcohol Intoxication
Slurred speech, ataxia, disinhibition, somnolence, stupor, or coma depending on severity
Alcohol Withdrawal
Tremulousness, agitation, anxiety, insomnia, nausea/vomiting, seizures, or florid delirium tremens
Classic Exam
Alcohol Intoxication
Nystagmus, conjunctival injection, smell of alcohol, depressed reflexes, hypothermia in severe cases
Alcohol Withdrawal
Tremor (especially hands), diaphoresis, tachycardia, hypertension, hyperthermia, agitation, visual/tactile hallucinations
Diagnostics
Alcohol Intoxication
Elevated serum ethanol level, elevated osmolal gap, possible hypoglycemia, possible metabolic acidosis if co-ingestion
Alcohol Withdrawal
Clinical diagnosis using CIWA-Ar score; labs show hypomagnesemia, hypokalemia, elevated GGT, elevated MCV, possible thrombocytopenia
Management
Alcohol Intoxication
Supportive care, airway protection, IV fluids, thiamine before glucose, monitor for aspiration and respiratory depression
Alcohol Withdrawal
Benzodiazepines (symptom-triggered using CIWA-Ar), thiamine, folate, electrolyte repletion, ICU for delirium tremens
Keywords
Alcohol Intoxication
"Found down," "smells of alcohol," "unresponsive with depressed respirations," "elevated osmolal gap"
Alcohol Withdrawal
"Stopped drinking 2 days ago," "tremulous," "sees bugs on the wall," "seizure 48 hours after last drink," "diaphoretic and tachycardic"
01Pathophysiology
Alcohol Intoxication
Ethanol is a small, water-soluble molecule that freely crosses the blood-brain barrier. Its primary mechanism of CNS depression involves two simultaneous actions: potentiation of GABA-A receptor activity (the brain's primary inhibitory system) and inhibition of NMDA glutamate receptors (the brain's primary excitatory system). The net result is global CNS depression that scales with blood alcohol concentration.
At low concentrations, ethanol preferentially suppresses cortical inhibitory circuits, which paradoxically produces disinhibition and euphoria. This is why mildly intoxicated patients appear talkative and impulsive rather than sedated. As levels rise, deeper brain structures are affected: the cerebellum (causing ataxia and dysarthria), the reticular activating system (causing stupor and coma), and ultimately the medullary respiratory centers (causing respiratory depression and death).
A critical biochemical consequence is that ethanol metabolism by alcohol dehydrogenase generates excess NADH, shifting the NAD+/NADH ratio. This drives several testable metabolic derangements: hypoglycemia (impaired gluconeogenesis), lactic acidosis (pyruvate shunted toward lactate), and hypertriglyceridemia. The excess NADH also explains why the osmolal gap is elevated: ethanol is an osmotically active substance that is measured by the osmometer but not accounted for in the calculated osmolality formula.
Alcohol Withdrawal
In the chronic drinker, the brain has adapted to the constant presence of ethanol. To maintain homeostasis against persistent GABA enhancement and NMDA suppression, the CNS downregulates GABA-A receptors and upregulates NMDA receptors and voltage-gated calcium channels. When ethanol is suddenly removed, this compensatory state is unmasked: the patient now has reduced inhibitory tone and dramatically increased excitatory tone. This produces a state of CNS hyperexcitability that manifests as tremor, autonomic hyperactivity, seizures, and potentially fatal delirium tremens.
The reason withdrawal can kill is straightforward: unopposed sympathetic and excitatory activity leads to hyperthermia, cardiovascular collapse, and refractory seizures. Delirium tremens carries a mortality rate of up to 37% if untreated, though with modern ICU care this drops to approximately 1 to 5%.
Kindling is a tested concept: each successive episode of withdrawal sensitizes the brain, making future withdrawal episodes progressively more severe. A patient with a history of prior withdrawal seizures is at significantly higher risk for severe withdrawal.
02Classification and Clinical Manifestation
Severity by Blood Alcohol Concentration
20 to 50
Clinical Stage
Mild euphoria
Key Features
Relaxation, mild impairment of judgment, slight decrease in fine motor coordination
50 to 100
Clinical Stage
Impaired judgment
Key Features
Emotional lability, impaired reaction time, legally impaired in most jurisdictions
100 to 200
Clinical Stage
Obvious intoxication
Key Features
Ataxia, slurred speech, nystagmus, significant cognitive impairment
200 to 300
Clinical Stage
Severe intoxication
Key Features
Marked ataxia, vomiting (aspiration risk), stupor, hypothermia
300 to 400
Clinical Stage
Stupor/Coma
Key Features
Respiratory depression, loss of protective reflexes, risk of aspiration pneumonia
>400
Clinical Stage
Potentially lethal
Key Features
Respiratory arrest, cardiovascular collapse, death (though chronic drinkers may tolerate much higher levels)
BAC (mg/dL) | Clinical Stage | Key Features |
|---|---|---|
20 to 50 | Mild euphoria | Relaxation, mild impairment of judgment, slight decrease in fine motor coordination |
50 to 100 | Impaired judgment | Emotional lability, impaired reaction time, legally impaired in most jurisdictions |
100 to 200 | Obvious intoxication | Ataxia, slurred speech, nystagmus, significant cognitive impairment |
200 to 300 | Severe intoxication | Marked ataxia, vomiting (aspiration risk), stupor, hypothermia |
300 to 400 | Stupor/Coma | Respiratory depression, loss of protective reflexes, risk of aspiration pneumonia |
>400 | Potentially lethal | Respiratory arrest, cardiovascular collapse, death (though chronic drinkers may tolerate much higher levels) |
A chronic heavy drinker may be ambulatory and conversational at a BAC that would render a naive drinker comatose. The vignette will often specify "chronic alcohol use" to explain a seemingly paradoxical presentation.
Alcohol Withdrawal
Minor withdrawal (tremulousness)
Time After Last Drink
6 to 12 hours
Clinical Features
Anxiety, insomnia, tremor, mild tachycardia, mild hypertension, GI upset, intact sensorium
Severity
Mild
Alcoholic hallucinosis
Time After Last Drink
12 to 24 hours
Clinical Features
Visual, auditory, or tactile hallucinations with intact orientation and clear sensorium (patient knows the hallucinations are not real)
Severity
Moderate
Withdrawal seizures
Time After Last Drink
12 to 48 hours
Clinical Features
Generalized tonic-clonic seizures, typically brief and self-limited; may occur in clusters; no postictal focal deficits
Severity
Moderate to Severe
Delirium tremens (DT)
Time After Last Drink
48 to 96 hours (peak at 72 hours)
Clinical Features
Global confusion, profound autonomic instability (fever, tachycardia, hypertension, diaphoresis), agitation, hallucinations with loss of orientation, tremor
Severity
Life-threatening
Syndrome | Time After Last Drink | Clinical Features | Severity |
|---|---|---|---|
Minor withdrawal (tremulousness) | 6 to 12 hours | Anxiety, insomnia, tremor, mild tachycardia, mild hypertension, GI upset, intact sensorium | Mild |
Alcoholic hallucinosis | 12 to 24 hours | Visual, auditory, or tactile hallucinations with intact orientation and clear sensorium (patient knows the hallucinations are not real) | Moderate |
Withdrawal seizures | 12 to 48 hours | Generalized tonic-clonic seizures, typically brief and self-limited; may occur in clusters; no postictal focal deficits | Moderate to Severe |
Delirium tremens (DT) | 48 to 96 hours (peak at 72 hours) | Global confusion, profound autonomic instability (fever, tachycardia, hypertension, diaphoresis), agitation, hallucinations with loss of orientation, tremor | Life-threatening |
The timeline is the single most important discriminator on the exam. When the vignette says "48 hours after admission for pneumonia, the patient becomes confused, diaphoretic, and tremulous," the answer is delirium tremens until proven otherwise.
03Diagnostic Workup
Best Initial Test
Intoxication
Serum ethanol level
Withdrawal
Clinical diagnosis using CIWA-Ar (Clinical Institute Withdrawal Assessment for Alcohol, revised)
Gold Standard
Intoxication
Serum ethanol level (also the best initial test)
Withdrawal
Clinical assessment and CIWA-Ar scoring (no confirmatory lab test exists)
Key Labs
Intoxication
Serum ethanol, serum osmolality + calculated osmolal gap, blood glucose, BMP, ABG/VBG, serum ketones if acidotic
Withdrawal
BMP (hypokalemia, hypomagnesemia, hypophosphatemia), CBC (macrocytosis, thrombocytopenia), hepatic panel (elevated AST > ALT, typically 2:1 ratio), GGT, lipase
Imaging
Intoxication
CT head if altered mental status to rule out subdural hematoma or other traumatic pathology
Withdrawal
CT head if first seizure, focal neurological deficits, or persistent altered mental status to exclude structural pathology
Special Considerations
Intoxication
Always check serum osmolal gap; if anion gap metabolic acidosis is present, consider methanol or ethylene glycol co-ingestion
Withdrawal
Always check magnesium (seizure threshold lowering); blood smear may show target cells or macrocytosis
Test | Intoxication | Withdrawal |
|---|---|---|
Best Initial Test | Serum ethanol level | Clinical diagnosis using CIWA-Ar (Clinical Institute Withdrawal Assessment for Alcohol, revised) |
Gold Standard | Serum ethanol level (also the best initial test) | Clinical assessment and CIWA-Ar scoring (no confirmatory lab test exists) |
Key Labs | Serum ethanol, serum osmolality + calculated osmolal gap, blood glucose, BMP, ABG/VBG, serum ketones if acidotic | BMP (hypokalemia, hypomagnesemia, hypophosphatemia), CBC (macrocytosis, thrombocytopenia), hepatic panel (elevated AST > ALT, typically 2:1 ratio), GGT, lipase |
Imaging | CT head if altered mental status to rule out subdural hematoma or other traumatic pathology | CT head if first seizure, focal neurological deficits, or persistent altered mental status to exclude structural pathology |
Special Considerations | Always check serum osmolal gap; if anion gap metabolic acidosis is present, consider methanol or ethylene glycol co-ingestion | Always check magnesium (seizure threshold lowering); blood smear may show target cells or macrocytosis |
For intoxication, the approach is predominantly supportive and the diagnostic goal is to rule out dangerous co-ingestants and traumatic injuries. The serum ethanol level confirms the diagnosis, but the osmolal gap is the more nuanced test point. Ethanol elevates the osmolal gap because it raises measured osmolality without affecting calculated osmolality. The formula for the osmolal gap is:
A normal osmolal gap is less than 10 mOsm/kg. In ethanol intoxication, the gap is elevated but the anion gap is typically normal. If you see an elevated osmolal gap with an elevated anion gap metabolic acidosis, think toxic alcohol ingestion (methanol or ethylene glycol), not simple ethanol intoxication. This is a classic exam pivot.
Always obtain a blood glucose in any intoxicated patient. Ethanol impairs hepatic gluconeogenesis, and hypoglycemia can mimic or compound the CNS depression of intoxication. CT head is indicated whenever the altered mental status is disproportionate to the measured ethanol level, or when there is any sign of head trauma, since chronic alcohol users are at high risk for subdural hematoma.
For withdrawal, there is no single confirmatory laboratory test. The diagnosis is clinical and graded by the CIWA-Ar scale, which scores ten domains: nausea/vomiting, tremor, paroxysmal sweats, anxiety, agitation, tactile disturbances, auditory disturbances, visual disturbances, headache, and orientation/clouding of sensorium. Scores range from 0 to 67:
< 10
Severity
Mild
Action
Observation, no pharmacotherapy typically required
10 to 18
Severity
Moderate
Action
Consider benzodiazepine administration
> 20
Severity
Severe
Action
Aggressive benzodiazepine dosing, consider ICU admission
CIWA-Ar Score | Severity | Action |
|---|---|---|
< 10 | Mild | Observation, no pharmacotherapy typically required |
10 to 18 | Moderate | Consider benzodiazepine administration |
> 20 | Severe | Aggressive benzodiazepine dosing, consider ICU admission |
The CIWA-Ar protocol is the backbone of symptom-triggered therapy, which is the preferred approach over fixed-dose scheduling because it results in lower total benzodiazepine doses and shorter treatment duration.
Laboratory studies in withdrawal serve to identify complications and comorbidities: hypomagnesemia (lowers seizure threshold and must be corrected), hypokalemia (often refractory until magnesium is repleted), thrombocytopenia (direct marrow toxicity of ethanol), and the classic AST:ALT ratio greater than 2:1 that suggests alcoholic liver disease.
04Management and Treatment
Acute Stabilization
Intoxication
ABCs, airway protection, lateral decubitus position to prevent aspiration, IV access
Withdrawal
Benzodiazepines guided by CIWA-Ar, IV fluids, continuous monitoring
First-Line Pharmacotherapy
Intoxication
Thiamine 100 mg IV before any glucose administration, then D50W if hypoglycemic
Withdrawal
Chlordiazepoxide (mild/moderate, oral) or Diazepam/Lorazepam (severe, IV)
Adjunctive Therapy
Intoxication
IV normal saline, electrolyte repletion, antiemetics
Withdrawal
Thiamine 500 mg IV x 3 days (if Wernicke suspected), folate 1 mg daily, magnesium 2 g IV, potassium repletion
Refractory Cases
Intoxication
Intubation and mechanical ventilation for respiratory failure; hemodialysis only in rare severe toxicity
Withdrawal
Phenobarbital or propofol infusion in ICU for benzodiazepine-resistant DT
Long-Term
Intoxication
Brief intervention, motivational interviewing, referral to addiction medicine
Withdrawal
Naltrexone 50 mg daily (or 380 mg IM monthly) or Acamprosate 666 mg TID for relapse prevention; Disulfiram 250 mg daily as aversion therapy
Setting | Intoxication | Withdrawal |
|---|---|---|
Acute Stabilization | ABCs, airway protection, lateral decubitus position to prevent aspiration, IV access | Benzodiazepines guided by CIWA-Ar, IV fluids, continuous monitoring |
First-Line Pharmacotherapy | Thiamine 100 mg IV before any glucose administration, then D50W if hypoglycemic | Chlordiazepoxide (mild/moderate, oral) or Diazepam/Lorazepam (severe, IV) |
Adjunctive Therapy | IV normal saline, electrolyte repletion, antiemetics | Thiamine 500 mg IV x 3 days (if Wernicke suspected), folate 1 mg daily, magnesium 2 g IV, potassium repletion |
Refractory Cases | Intubation and mechanical ventilation for respiratory failure; hemodialysis only in rare severe toxicity | Phenobarbital or propofol infusion in ICU for benzodiazepine-resistant DT |
Long-Term | Brief intervention, motivational interviewing, referral to addiction medicine | Naltrexone 50 mg daily (or 380 mg IM monthly) or Acamprosate 666 mg TID for relapse prevention; Disulfiram 250 mg daily as aversion therapy |
Alcohol Intoxication
The cornerstone is supportive care. Most intoxicated patients recover with time as the liver metabolizes ethanol at a roughly fixed rate of 15 to 20 mg/dL per hour. The critical steps are:
Airway protection is the priority. Position the patient in the lateral decubitus (recovery) position to reduce aspiration risk. Intubate if the gag reflex is absent or respiratory depression is present.
Thiamine 100 mg IV must be given before any glucose-containing fluids. This is one of the most tested management pearls in all of emergency medicine. Glucose administration in a thiamine-depleted patient can precipitate or worsen Wernicke encephalopathy by exhausting the remaining thiamine stores (thiamine is a cofactor for pyruvate dehydrogenase and other enzymes in glucose metabolism). The classic teaching: "banana bag" = thiamine first, then glucose.
Correct hypoglycemia with D50W (50 mL of 50% dextrose IV) after thiamine.
IV normal saline for volume repletion and to support renal clearance.
Check for co-ingestants and trauma. An intoxicated patient with a GCS that does not improve as the BAC falls needs CT imaging to exclude intracranial pathology.
There is no role for activated charcoal in alcohol intoxication (ethanol is absorbed too rapidly). There is no role for routine gastric lavage. Hemodialysis is technically effective at clearing ethanol but is reserved for extreme cases (BAC > 500 mg/dL with hemodynamic instability), which are rarely tested.
Alcohol Withdrawal
The management follows a graded, symptom-triggered protocol:
Benzodiazepines are first-line therapy. They work by directly substituting for ethanol's effect at the GABA-A receptor, counteracting the hyperexcitable state.
Chlordiazepoxide
Route
Oral
Typical Dosing
25 to 100 mg every 6 hours, tapered over 3 to 5 days
Notes
Preferred for mild to moderate withdrawal; long half-life provides smooth taper; avoid in liver failure
Diazepam
Route
IV/Oral
Typical Dosing
5 to 20 mg IV every 5 to 15 minutes until CIWA < 10
Notes
Long-acting; active metabolites; preferred for rapid loading in severe withdrawal; avoid in liver failure
Lorazepam
Route
IV/IM/Oral
Typical Dosing
2 to 4 mg IV every 15 to 20 minutes until CIWA < 10
Notes
Preferred in hepatic impairment (no active metabolites, glucuronidation only); preferred in elderly
Drug | Route | Typical Dosing | Notes |
|---|---|---|---|
Chlordiazepoxide | Oral | 25 to 100 mg every 6 hours, tapered over 3 to 5 days | Preferred for mild to moderate withdrawal; long half-life provides smooth taper; avoid in liver failure |
Diazepam | IV/Oral | 5 to 20 mg IV every 5 to 15 minutes until CIWA < 10 | Long-acting; active metabolites; preferred for rapid loading in severe withdrawal; avoid in liver failure |
Lorazepam | IV/IM/Oral | 2 to 4 mg IV every 15 to 20 minutes until CIWA < 10 | Preferred in hepatic impairment (no active metabolites, glucuronidation only); preferred in elderly |
The exam loves to test the choice between these: Lorazepam is the answer when the patient has liver disease, because chlordiazepoxide and diazepam undergo hepatic oxidation and produce active metabolites that can accumulate dangerously.
Thiamine repletion: 100 mg IV daily for prophylaxis. If Wernicke encephalopathy is suspected (confusion, ophthalmoplegia, ataxia), the dose is high-dose IV thiamine: 500 mg IV three times daily for 2 to 3 days, then 250 mg daily for 3 to 5 days.
Folate 1 mg daily for macrocytic anemia due to folate deficiency.
Magnesium sulfate 2 g IV: Critical because hypomagnesemia lowers the seizure threshold and makes hypokalemia refractory to potassium replacement.
For withdrawal seizures: Benzodiazepines are first-line. Phenytoin is not effective for alcohol withdrawal seizures and should not be used. This is a frequently tested point. The seizures are not due to an epileptic focus; they are due to global excitatory rebound, and GABA-ergic agents are the correct treatment.
Benzodiazepine-resistant delirium tremens: Defined as persistent symptoms despite adequate benzodiazepine dosing (some patients require hundreds of milligrams of diazepam equivalents). The next step is phenobarbital (a barbiturate that acts at a different site on the GABA-A receptor) or propofol infusion in the ICU setting with mechanical ventilation. Dexmedetomidine (an alpha-2 agonist) is an adjunct for controlling sympathetic hyperactivity but does not treat seizures.
Long-term relapse prevention (tested in outpatient management questions):
Naltrexone (50 mg PO daily or 380 mg IM monthly): Opioid receptor antagonist that reduces the rewarding effects of alcohol. Contraindicated in patients on opioids or with acute hepatitis/liver failure.
Acamprosate (666 mg PO three times daily): Modulates glutamate/NMDA activity to reduce cravings. Safe in liver disease but contraindicated in severe renal impairment (CrCl < 30 mL/min). The exam tests this contrast directly: liver disease = use acamprosate; kidney disease = use naltrexone.
Disulfiram (250 mg PO daily): Inhibits aldehyde dehydrogenase, causing accumulation of acetaldehyde if alcohol is consumed (flushing, nausea, vomiting, hypotension). Requires informed, motivated, supervised patients. Not first-line.
05Differential Diagnosis and Distractors
Wernicke encephalopathy
Why It Is Similar
Also presents in alcoholic patients with confusion and ataxia
Key Discriminator
Classic triad: ophthalmoplegia (lateral rectus palsy/nystagmus) + confusion + ataxia. The ataxia here is cerebellar gait ataxia, not simple intoxication stumbling. Responds to thiamine, not time.
Hepatic encephalopathy
Why It Is Similar
Confusion and asterixis in an alcoholic patient
Key Discriminator
Look for stigmata of chronic liver disease (jaundice, ascites, spider angiomata), elevated ammonia, fetor hepaticus. Asterixis (flapping tremor) is the signature finding, not the fine tremor of withdrawal.
Hypoglycemia
Why It Is Similar
Altered mental status, diaphoresis, confusion, and tachycardia overlap with both intoxication and withdrawal
Key Discriminator
Fingerstick glucose is low (< 70 mg/dL). Resolves immediately with glucose administration. Always check glucose in any altered patient.
Subdural hematoma
Why It Is Similar
Alcoholic patients fall frequently; altered mental status may be attributed to intoxication
Key Discriminator
Mental status does not improve as BAC falls, or worsens. Focal neurological deficits, unilateral pupil dilation. CT shows crescent-shaped hyperdensity (acute) or hypodensity (chronic).
Meningitis/Encephalitis
Why It Is Similar
Fever, altered mental status, possible seizures overlap with DT
Key Discriminator
Nuchal rigidity, positive Kernig/Brudzinski signs, CSF pleocytosis. DT patients are febrile from autonomic instability, not infection, but you cannot distinguish clinically without LP if in doubt.
Benzodiazepine or opioid intoxication
Why It Is Similar
CNS depression, altered mental status, respiratory depression
Key Discriminator
Opioids: miotic (pinpoint) pupils, responds to naloxone. Benzodiazepines: responds to flumazenil (though flumazenil is rarely used due to seizure risk). Ethanol: no specific antidote, elevated osmolal gap.
Toxic alcohol ingestion (methanol, ethylene glycol)
Why It Is Similar
Elevated osmolal gap, altered mental status in a "drunk-appearing" patient
Key Discriminator
Anion gap metabolic acidosis distinguishes toxic alcohols from ethanol. Methanol: visual complaints ("snowstorm vision"), retinal edema. Ethylene glycol: calcium oxalate crystals in urine, renal failure.
Thyroid storm
Why It Is Similar
Tachycardia, fever, agitation, tremor, and diaphoresis overlap with DT
Key Discriminator
Look for goiter, exophthalmos, lid lag. TSH is suppressed with elevated free T4/T3. No history of alcohol cessation.
Neuroleptic malignant syndrome (NMS)
Why It Is Similar
Fever, altered mental status, autonomic instability
Key Discriminator
"Lead-pipe" rigidity is the hallmark. History of recent antipsychotic use or dose change. Markedly elevated CK.
Serotonin syndrome
Why It Is Similar
Fever, agitation, autonomic instability, tremor
Key Discriminator
Clonus (especially lower extremity), hyperreflexia, diarrhea. History of serotonergic medication use. Onset is rapid (within hours of medication change).
Differential | Why It Is Similar | Key Discriminator |
|---|---|---|
Wernicke encephalopathy | Also presents in alcoholic patients with confusion and ataxia | Classic triad: ophthalmoplegia (lateral rectus palsy/nystagmus) + confusion + ataxia. The ataxia here is cerebellar gait ataxia, not simple intoxication stumbling. Responds to thiamine, not time. |
Hepatic encephalopathy | Confusion and asterixis in an alcoholic patient | Look for stigmata of chronic liver disease (jaundice, ascites, spider angiomata), elevated ammonia, fetor hepaticus. Asterixis (flapping tremor) is the signature finding, not the fine tremor of withdrawal. |
Hypoglycemia | Altered mental status, diaphoresis, confusion, and tachycardia overlap with both intoxication and withdrawal | Fingerstick glucose is low (< 70 mg/dL). Resolves immediately with glucose administration. Always check glucose in any altered patient. |
Subdural hematoma | Alcoholic patients fall frequently; altered mental status may be attributed to intoxication | Mental status does not improve as BAC falls, or worsens. Focal neurological deficits, unilateral pupil dilation. CT shows crescent-shaped hyperdensity (acute) or hypodensity (chronic). |
Meningitis/Encephalitis | Fever, altered mental status, possible seizures overlap with DT | Nuchal rigidity, positive Kernig/Brudzinski signs, CSF pleocytosis. DT patients are febrile from autonomic instability, not infection, but you cannot distinguish clinically without LP if in doubt. |
Benzodiazepine or opioid intoxication | CNS depression, altered mental status, respiratory depression | Opioids: miotic (pinpoint) pupils, responds to naloxone. Benzodiazepines: responds to flumazenil (though flumazenil is rarely used due to seizure risk). Ethanol: no specific antidote, elevated osmolal gap. |
Toxic alcohol ingestion (methanol, ethylene glycol) | Elevated osmolal gap, altered mental status in a "drunk-appearing" patient | Anion gap metabolic acidosis distinguishes toxic alcohols from ethanol. Methanol: visual complaints ("snowstorm vision"), retinal edema. Ethylene glycol: calcium oxalate crystals in urine, renal failure. |
Thyroid storm | Tachycardia, fever, agitation, tremor, and diaphoresis overlap with DT | Look for goiter, exophthalmos, lid lag. TSH is suppressed with elevated free T4/T3. No history of alcohol cessation. |
Neuroleptic malignant syndrome (NMS) | Fever, altered mental status, autonomic instability | "Lead-pipe" rigidity is the hallmark. History of recent antipsychotic use or dose change. Markedly elevated CK. |
Serotonin syndrome | Fever, agitation, autonomic instability, tremor | Clonus (especially lower extremity), hyperreflexia, diarrhea. History of serotonergic medication use. Onset is rapid (within hours of medication change). |
06Traps and High-Yield Pearls
The most common way students lose points on alcohol questions is by failing to respect the timeline of withdrawal. A vignette describing a hospitalized patient who becomes agitated and confused on hospital day 3 is not describing "ICU delirium" or "sundowning" if the patient has a known history of heavy drinking. The answer is delirium tremens. Exam writers deliberately embed the alcohol history earlier in the vignette (sometimes in the social history section that students skim past) and present the withdrawal complication as if it were a new problem.
The second classic trap is phenytoin for alcohol withdrawal seizures. Phenytoin works by stabilizing sodium channels and is effective for structural epilepsy, but alcohol withdrawal seizures arise from GABA/glutamate imbalance, not a focal seizure disorder. Phenytoin does not prevent or treat these seizures. The correct answer is always benzodiazepines. If the student sees "seizure" and reflexively picks phenytoin, they have fallen for the distractor.
The third recurring trap involves Wernicke encephalopathy. The vignette will describe a malnourished alcoholic patient who is brought in with confusion and is given IV dextrose. The patient then deteriorates. The question asks what should have been done differently. The answer: thiamine must be administered before glucose. This is non-negotiable and tested repeatedly.
The fourth trap is the choice of benzodiazepine in liver disease. A patient with known cirrhosis or significantly impaired hepatic function who is in withdrawal must receive lorazepam (or oxazepam), not diazepam or chlordiazepoxide. The active metabolites of the longer-acting agents accumulate and cause prolonged, dangerous sedation.
Finally, for long-term pharmacotherapy, the exam tests whether you can match the drug to the patient's comorbidities: naltrexone for the patient with intact liver but kidney issues; acamprosate for the patient with liver disease but intact kidneys. If you see "elevated LFTs" or "cirrhosis" in the stem, the relapse prevention drug is acamprosate. If you see "CKD" or "creatinine 3.5," the answer is naltrexone.
The core competency being tested across all alcohol questions is pattern recognition under time pressure: identifying the correct syndrome on the intoxication-withdrawal spectrum, applying the right timeline, choosing the right agent for the right patient, and never forgetting to give thiamine first.