Emergency Medicine · Toxicology
The facts most likely to be tested
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Benzodiazepines are first-line, dosed by the CIWA-Ar scale; long-acting diazepam or chlordiazepoxide are preferred unless liver disease.
Always give IV thiamine BEFORE glucose to prevent precipitating Wernicke encephalopathy.
The highly testable timeline: minor withdrawal at 6-36 h, withdrawal seizures at 12-48 h, and delirium tremens at 48-96 h.
Alcoholic hallucinosis features hallucinations with an intact sensorium, whereas delirium tremens has a fluctuating altered sensorium and severe autonomic instability.
In advanced liver disease or the elderly, use the LOT drugs (lorazepam, oxazepam, temazepam) that skip phase I hepatic metabolism.
Labs supporting chronic use include macrocytosis (MCV >100), AST:ALT >2:1, and elevated GGT.
Avoid antipsychotics (haloperidol) for hallucinations unless refractory, as they lower the seizure threshold; kindling progressively lowers thresholds with repeated episodes.
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A 52-year-old man with a long history of heavy daily alcohol use is admitted after a fall. Seventy-two hours after his last drink, he becomes acutely confused, agitated, and disoriented, reporting that bugs are crawling on his skin. Temperature is 38.6 C, blood pressure is 178/102 mm Hg, and pulse is 128/min. He is tremulous and diaphoretic with a fluctuating sensorium.
Which of the following is the most appropriate first-line treatment?
Benzodiazepines (e.g., diazepam or lorazepam), dosed by the CIWA-Ar scale.
Fluctuating altered sensorium, severe autonomic instability, and formication 72 hours after the last drink are diagnostic of delirium tremens. Benzodiazepines restore GABAergic tone and are the first-line therapy; IV thiamine should also be given before any glucose to prevent Wernicke encephalopathy.
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Etiology / Epidemiology
Triggered by abrupt cessation or significant reduction of heavy, prolonged alcohol use, often precipitated by unexpected hospital admission for trauma or severe illness.
Clinical Manifestations
Progresses predictably from early tremors and diaphoresis, to alcoholic hallucinosis, withdrawal seizures, and finally the life-threatening delirium tremens.
Diagnosis
A clinical diagnosis where severity and treatment dosing are strictly guided by the CIWA-Ar scale.
Treatment
Benzodiazepines are the first-line treatment, and IV thiamine must be given before glucose to prevent Wernicke encephalopathy.
Prognosis
Progression to delirium tremens carries a high mortality risk if untreated due to cardiovascular collapse or fatal arrhythmias.
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Epidemiology & Etiology
Occurs in patients with chronic alcohol use disorder following abrupt cessation or significant dose reduction. It is frequently precipitated by an intercurrent illness (e.g., pneumonia, pancreatitis, or trauma) that forces unexpected hospital admission. The timeline of symptoms is highly predictable, making the exact time since the last drink a critical historical detail. The most severe manifestation, delirium tremens, occurs in roughly 5% of patients hospitalized for alcohol withdrawal.
Pertinent Anatomy
The pathology primarily involves the central nervous system, specifically disrupting the balance between inhibitory and excitatory synapses in the cortex and limbic system. Autonomic ganglia are also profoundly overstimulated, leading to the dangerous sympathetic surge seen in severe withdrawal. The reticular activating system is hyperactive, causing the severe insomnia and agitation characteristic of the condition.
Pathophysiology
Chronic alcohol consumption acts as a CNS depressant by enhancing the inhibitory neurotransmitter GABA and suppressing the excitatory neurotransmitter glutamate at NMDA receptors. To compensate, the brain downregulates GABA receptors and upregulates NMDA receptors. Abrupt cessation removes the alcohol-induced depression, leaving unmasked NMDA receptor overactivity and GABA deficiency. This results in profound, unchecked CNS and autonomic hyperactivity, a process exacerbated by kindling, where repeated withdrawal episodes lead to progressively lower seizure thresholds.
Clinical Manifestations
The timeline of symptoms is classic and highly testable. At 6-36 hours, minor withdrawal presents with tremor, anxiety, diaphoresis, and alcoholic hallucinosis (visual, tactile, or auditory hallucinations with an intact sensorium). At 12-48 hours, patients are at risk for generalized tonic-clonic seizures. Finally, at 48-96 hours, delirium tremens emerges, characterized by a fluctuating altered sensorium, severe autonomic instability (tachycardia, hypertension, fever), and severe hallucinations, classically described as formication (the sensation of bugs crawling on the skin).
Diagnosis
Diagnosis is strictly clinical based on a history of cessation and typical sympathomimetic symptoms. The Clinical Institute Withdrawal Assessment for Alcohol (CIWA-Ar) is the gold-standard tool used to quantify symptom severity and dictate symptom-triggered medication dosing. Laboratory workup is supportive and often reveals macrocytosis (MCV > 100), an elevated AST:ALT ratio > 2:1, and an isolated elevated GGT indicating chronic heavy alcohol use.
Treatment
Benzodiazepines are the first-line therapy, administered via symptom-triggered dosing using the CIWA-Ar scale. Long-acting agents like diazepam or chlordiazepoxide are generally preferred for their self-tapering active metabolites. However, the "LOT" drugs (lorazepam, oxazepam, temazepam) skip phase I hepatic metabolism and must be used in patients with advanced liver disease or the elderly. Crucially, administer IV thiamine before any glucose-containing fluids to prevent the precipitation of Wernicke encephalopathy. Avoid antipsychotics (e.g., haloperidol) for hallucinations unless the patient is refractory, as they lower the seizure threshold.
Prognosis
Minor withdrawal typically resolves within 2 to 7 days with appropriate supportive care. However, untreated delirium tremens has a historical mortality rate of up to 15%. Death most commonly results from arrhythmias, respiratory failure, or concurrent infections like aspiration pneumonia. Patients requiring high-dose benzodiazepines require close hemodynamic monitoring, often in an ICU setting, to prevent iatrogenic respiratory depression.
Differential Diagnosis
1. Thyrotoxicosis: Presents with tachycardia, tremor, and diaphoresis but features a suppressed TSH and lacks a history of abrupt alcohol cessation.
2. Benzodiazepine/Barbiturate withdrawal: Clinically identical to alcohol withdrawal (GABA-mediated) but distinguished by a positive urine drug screen or specific prescription medication history.
3. Sympathomimetic toxicity (Cocaine/Amphetamines): Presents with profound autonomic hyperactivity and psychosis but classically features mydriasis and a positive toxicology screen.
4. Wernicke Encephalopathy: Features the classic triad of encephalopathy, oculomotor dysfunction, and gait ataxia, but lacks the prominent autonomic hyperactivity and tremors seen in withdrawal.