Severe alcohol withdrawal — assessment, pharmacotherapy and the thiamine-first rule

Assessment (5 marks). This is severe alcohol withdrawal, evolving toward delirium tremens, in a hypoglycaemic patient at risk of a withdrawal seizure. I run an ABCDE in parallel with the focused assessment. Airway — he is agitated but protecting his airway; I nurse him in the lateral position with suction available. Breathing — high-flow oxygen, saturations, capnography. Circulation — two large-bore cannulae, full monitoring (HR, BP, oxygen saturation, temperature). Disability — the bedside glucose of 2.6 mmol/L must be treated (see below). I confirm the tremor, the diaphoresis, the agitation, the tactile hallucinations, and the autonomic hyperactivity, and I score the CIWA-Ar (10-item scale) — he is clearly in the severe range, well above 15 to 20, predicting delirium tremens. The focused history (from the notes, the paramedics and the family) establishes the quantity and duration of intake, the timing of the last drink, any prior withdrawal or seizure, and the drug history including anticoagulants. I examine for signs of chronic liver disease, the source of sepsis (chest, abdomen, cellulitis), the gait and eye movements of Wernicke, and any sign of head injury from the fall. The investigations in parallel: electrolytes including sodium and magnesium, LFTs and coagulation, renal function, amylase, CK, lactate, VBG, ethanol level, paracetamol and salicylate, ECG (QT), CXR, urinalysis, and a CT head because he has fallen and is now confused — I will not attribute this to withdrawal alone. Crucially, agitation in the alcoholic is a diagnosis of informed exclusion: I actively exclude sepsis, hyponatraemia, hypoglycaemia, hepatic encephalopathy, Wernicke and an intracranial bleed.^[1][3]

Pharmacological management (7 marks). This is severe withdrawal with autonomic instability and hallucinations: I admit him to a high-dependency or intensive care bed and treat with an intravenous benzodiazepine. Intravenous diazepam, repeated guided by the CIWA-Ar until he is calm but rousable; diazepam loading exploits a prolonged elimination half-life for sustained benefit over days. If he had chronic liver disease I would use intravenous lorazepam instead. Benzodiazepines are first-line because abrupt cessation leaves an unopposed excitatory state, and the Mayo-Smith meta-analysis and the Cochrane review confirm they reduce seizures and delirium tremens; symptom-triggered (CIWA-driven) regimens outperform fixed-schedule on cumulative dose and duration. I give thiamine 100 mg intravenously as routine prophylaxis (escalating to 500 mg IV three times daily for three to five days if Wernicke is suspected), folate 1 mg, and magnesium sulphate 1 to 2 g intravenously to correct hypomagnesaemia and lower the seizure threshold. Balanced crystalloid for dehydration; treat any identified sepsis within the first hour. I re-score the CIWA-Ar every 1 to 2 hours and titrate. If the withdrawal is benzodiazepine-refractory I add phenobarbital 130 to 260 mg IV with respiratory monitoring. An antipsychotic is NOT first-line — it lowers the seizure threshold and prolongs the QT — and is reserved for psychosis persisting after adequate benzodiazepine loading.^[2][3]

The thiamine-before-glucose order, with rationale (3 marks). I give thiamine 100 mg intravenously FIRST, then 50 mL of 50 per cent dextrose intravenously to correct the 2.6 mmol/L glucose, in that order. The rationale is that glucose metabolism consumes thiamine pyrophosphate; giving intravenous dextrose to a thiamine-depleted alcoholic acutely exhausts the remaining thiamine and can precipitate Wernicke encephalopathy (confusion, ataxia, ophthalmoplegia), which progresses to the irreversible Korsakoff amnestic syndrome if missed. The 2025 national VA cross-sectional study by Jasti (120 dextrose-before-thiamine encounters in 114 veterans, no Wernicke cases on ICD or chart review) found acute dextrose unlikely to precipitate Wernicke — treat the hypoglycaemia without delay, with thiamine alongside. In practice I give thiamine empirically to every heavy drinker on arrival, before any glucose-containing fluid; the order is thiamine then dextrose, never the reverse, and I continue thiamine orally after discharge.^[4]