NREMT Emergency Medical Technician (EMT) Cognitive ExamMedical EmergenciesHard
A 30-year-old female is found unresponsive at home. Her husband reports she has a history of depression and may have taken an overdose of her medication. On assessment, she has dilated pupils, dry skin, a heart rate of 130 bpm, and a blood pressure of 90/60 mmHg. Her ECG shows a wide QRS complex. What class of medication overdose is most likely?
- ASelective Serotonin Reuptake Inhibitors (SSRIs)
- BBenzodiazepines
- CTricyclic Antidepressants (TCAs)
- DOpioids
Show answer & explanationAnswer & explanation
Correct answer: C. Tricyclic Antidepressants (TCAs)
The combination of symptoms—unresponsiveness, dilated pupils, dry skin, tachycardia, hypotension, and especially the wide QRS complex on ECG—is highly characteristic of a tricyclic antidepressant (TCA) overdose. TCAs cause anticholinergic effects (dry skin, dilated pupils, tachycardia) and significant cardiotoxicity, manifesting as widened QRS and dysrhythmias.
Why the other options are wrong
- A. SSRIs can cause serotonin syndrome but typically do not cause wide QRS complexes or pronounced anticholinergic effects like dry skin and dilated pupils to this degree.
- B. Benzodiazepine overdose typically causes central nervous system depression (unresponsiveness, respiratory depression) but does not cause dilated pupils, dry skin, or wide QRS complexes.
- D. Opioid overdose typically causes pinpoint pupils, respiratory depression, and CNS depression, and does not cause a wide QRS complex or dilated pupils.
Tricyclic Antidepressant (TCA) Overdose
A life-threatening overdose characterized by a classic anticholinergic toxidrome (dry skin, dilated pupils, tachycardia) and significant cardiotoxicity, including wide QRS complex and dysrhythmias.
- Anticholinergic effects (hot, dry, blind, mad, red).
- Cardiotoxicity: wide QRS, dysrhythmias, hypotension.
- CNS depression, seizures.
- Requires aggressive supportive care and often sodium bicarbonate.
Memory trick: TCA: Tachy, Cardiac, Anticholinergic