Tricyclic Antidepressant Overdose

Abstract

Audience: Emergency medicine residents and medical students on emergency medicine rotations.Introduction: Though the incidence of tricyclic antidepressant (TCA) overdoses has decreased due to increasing prescriptions of selective-serotonin reuptake inhibitors (SSRI's), tricyclic antidepressants remain in the top 25 causes of poisoning deaths. 1 Patients who attempt suicide with a TCA have a fatality rate of 70% if they do not reach a healthcare facility; however, that rate is lowered to 3% if the patient reaches a facility for treatment. 2 Women are at higher risk of toxicity than men, particularly in the age range of 20-29. 2 Emergency medicine physicians should be skilled in the electrocardiogram (ECG) interpretation of acute TCA overdose, and need to be comfortable in the emergent management of patients who are unable, or unwilling, to verbalize the medication they ingested. This oral boards case tests the learners' approach to a patient with undifferentiated altered mental status, while attempting to focus the learner on intentional overdose as the likely diagnosis. Upon completing this oral board case, learners should be able to recognize the classic pattern of a widened QRS complex, rightaxis deviation, and large terminal R-wave (>3mm) in TCA overdose, and treat accordingly with high doses of sodium bicarbonate until the ECG improves. Though a toxicologist's support is an important adjunct, emergency physicians should be confident in managing this case from presentation to appropriate intensive care unit admission.Objectives: At the end of this oral boards session, learners will be able to: 1) discuss the appropriate laboratory testing and workup for a patient with undifferentiated altered mental status, 2) discuss the importance of obtaining an ECG in a timely manner in order to investigate the broad differential of altered mental status, 3) identify the classic ECG findings of a patient with TCA overdose, 4) review the treatment of TCA overdose, 5) discuss the appropriate disposition of a patient with TCA overdose. Method: Oral boards case.