On postoperative day 3 following an open reduction and internal fixation of a right tibial… — USMLE Step 2 CK

On postoperative day 3 following an open reduction and internal fixation of a right tibial fracture, a 51-year-old male is evaluated by the on-call physician for acute, severe agitation and confusion. The fracture was sustained during a motor vehicle collision. The patient lives alone and a comprehensive medical history is unavailable. Current temperature is 38.7°C (101.7°F), pulse is 126/min, blood pressure is 168/102 mm Hg, and respirations are 22/min. On examination, the patient is profoundly diaphoretic and continuously attempts to pull out his intravenous catheter. When approached, he points frantically toward the ceiling and claims that swarms of insects are dropping onto his bed. Neurological examination reveals a coarse, bilateral resting tremor of the upper extremities. The surgical incision is clean, intact, and without erythema. Cardiopulmonary auscultation is unremarkable. Which of the following is the most appropriate next step in management?

Intravenous administration of diazepamAnswer
B
Blood cultures and empiric piperacillin-tazobactam
C
Intramuscular administration of haloperidol
D
Psychiatric consultation for schizophreniform disorder
E
Computed tomography angiography of the chest

Answer

The most appropriate next step is the intravenous administration of a long-acting benzodiazepine, such as diazepam.

The patient's presentation of fever, marked autonomic hyperactivity (tachycardia, hypertension, diaphoresis), coarse resting tremor, and visual hallucinations occurring roughly 72 hours (postoperative day 3) after an unplanned hospital admission is the classic presentation of delirium tremens. Delirium tremens is a severe, life-threatening manifestation of alcohol withdrawal. Because patients often live alone and do not disclose their alcohol use history upon admission for trauma, the withdrawal syndrome unmasks itself a few days into their stay. The gold standard for treating severe alcohol withdrawal is the administration of benzodiazepines (e.g., diazepam, lorazepam, or chlordiazepoxide). These drugs enhance the inhibitory effect of GABA, counteracting the glutamate-driven excitatory state of withdrawal, thereby reducing agitation, stabilizing vital signs, and preventing withdrawal seizures.

Step-by-Step Solution

Analyze the patient's timeline and physical exam findings.

The patient developed fever, severe autonomic hyperactivity (tachycardia, hypertension, diaphoresis), coarse tremor, and visual hallucinations ('insects') on postoperative day 3.

Recognizing the '48 to 96 hour' window after hospital admission is critical for identifying alcohol withdrawal in patients who have abruptly ceased covert drinking.

Establish the most likely diagnosis.

The clinical picture is pathognomonic for delirium tremens (severe alcohol withdrawal).

Alcohol acts as a CNS depressant by enhancing GABA and inhibiting glutamate. Abrupt cessation leads to a hyper-excitable state, manifesting as the symptoms seen in this patient.

Determine the optimal acute pharmacological management.

Select a medication that safely replaces the inhibitory effect of alcohol, which is a benzodiazepine.

Benzodiazepines stimulate GABA receptors, mitigating the severe withdrawal symptoms, correcting autonomic instability, and preventing fatal complications such as seizures.

Key Concept

Patients with undisclosed alcohol use disorder often present with delirium tremens (hallucinations, tremor, autonomic instability) 48 to 96 hours after hospital admission; first-line treatment is a benzodiazepine.

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