Review Question - QID 105625

This patient's presentation is consistent with a TCA overdose given his altered mental status, dilated pupils, and wide QRS complex on ECG. TCA overdose is best treated with sodium bicarbonate.

TCA overdose can be fatal due to rapid gastrointestinal absorption of the drug and its associated neurologic and cardiovascular toxicities. TCAs have anticholinergic properties and can cause dry/flushed skin, decreased bowel sounds, constipation, hyperreflexia, and dilated pupils. The hallmark of a TCA overdose is a widerned QRS interval (not the serum TCA level which is less accurate when determining toxicity). The best initial step in management for a suspected TCA overdose is sodium bicarbonate administration.

Figure/Illustration A shows an ECG (bottom) with a wide QRS complex which is classic for a TCA overdose. Note the prolonged QRS interval when compared to a normal sinus rhythm ECG (top).

Incorrect Answers:
Answer 1: Aspirin is the best initial treatment for any patient presenting with acute coronary syndrome including a STEMI which presents with chest pain, dyspnea, and ST elevation on ECG.

Answer 2: Calcium gluconate is the best initial step in management in hyperkalemia with ECG changes. Though severe hyperkalemia can present with QRS prolongation, it does not explain the other anticholinergic symptoms this patient is experiencing.

Answer 3: Physostigmine is a treatment for an anticholinergic toxidrome which presents with dry/flushed skin, confusion, constipation, and urinary retention. Though TCAs do have anticholinergic properties, it is more dire to first give sodium bicarbonate to treat any possible fatal arrythmias.

Answer 4: Serum and urine toxicology would not change management in this patient as a low or high serum TCA level would still warrant sodium bicarbonate administration given this patient's prolonged QRS interval.

Bullet Summary:
The best initial step in management in TCA overdose is administration of sodium bicarbonate.