Object : Clinical toxicity with the treatment of tricylclic antidepressants (TCAs), including imipramine, is anticholinergic effects and central nervous system toxicity. Of these, the most life-threatening toxicity remains the development of cardiac dysrhythmias. Conduction delays such as QRS and corrected QT prolongation, wide QRS complex tachycardia, and the Brugada electrocardiographic pattern (BEP) have been reported. Sodium bicarbonate decreases QRS widening and suppresses dysrhythmias by providing excess sodium to reverse the TCA-induced sodium-channel blockade and possibly by binding directly to the myocardium.
Result : A 3-year-old boy presented to the emergency department with generalized tonic-clonic movements, fever and vomiting. The history was significant for the ingestion of four imipramine tablets (one tablet contains 25 mg, 7.69 mg/kg) obtained from a kindergarten friend, 15 hours previously. The patient was successfully treated with intravenous diazepam, one dose, for the generalized seizures. An electrocardiogram displayed a wide QRS complex tachycardia, with a down slopping ST segment elevation and a prominent J wave in lead V2, characteristic of the BEP found in the Brugada syndrome (Fig. 1). The patient was treated with a sodium bicarbonate infusion. However, the BEP persisted (Fig. 2). Three days after admission the BEP resolved (Fig. 3). The patient had a complete clinical recovery, and was discharged to home on the seventh hospital day.
Conclusion : We describe a patient that presented with convulsions, tachycardia with a wide QRS complex, a BEP, and anuresis associated with an accidental over dose ingestion of imipramine, and the outcome of treatment with sodium bicarbonate.