Differential Diagnosis for 40-year-old Male Presenting with Unconsciousness Following Generalized Tonic-Clonic Seizure

• Single Most Likely Diagnosis
  • Tricyclic Antidepressant (TCA) Toxicity: Given the patient's history of depression and the use of amitriptyline, a TCA, the presentation of generalized tonic-clonic seizure, wide complex tachycardia concerning for ventricular tachycardia, and metabolic acidosis are consistent with TCA toxicity. TCA overdose can lead to cardiac arrhythmias, seizures, and altered mental status, making it a highly plausible diagnosis.
• Other Likely Diagnoses
  • Hypertensive Emergency: Although the patient has a history of hypertension, the acute presentation of seizure and cardiac arrhythmia could suggest a hypertensive emergency, especially if the blood pressure is significantly elevated. However, the absence of explicit blood pressure values in the scenario makes this less clear.
  • Migraine-related Complications: Given the patient's history of migraines, it's possible that the seizure could be related to a migraine complication, such as a migrainous infarction or status migrainosus, though these would less likely explain the wide complex tachycardia.
• Do Not Miss Diagnoses
  • Cardiac Ischemia/Myocardial Infarction: Although the patient has no known history of cardiac problems and a recent normal ECG, cardiac ischemia or myocardial infarction can present atypically, especially in younger individuals, and can cause arrhythmias and seizures. Missing this diagnosis could be fatal.
  • Intracranial Hemorrhage: The history of hypertension and the presentation with a seizure raise the possibility of an intracranial hemorrhage, which is a medical emergency requiring immediate intervention.
  • Infection (e.g., Meningitis, Encephalitis): Infections of the central nervous system can present with seizures and altered mental status. Although the CBC was normal, this does not rule out all infections, and missing such a diagnosis could be deadly.
• Rare Diagnoses
  • Mitochondrial Myopathies: Conditions like MELAS syndrome (Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes) could present with seizures, metabolic acidosis, and cardiac arrhythmias, though they are rare and would typically have other distinguishing features.
  • Pheochromocytoma: A rare tumor of the adrenal gland that can cause episodic hypertension, arrhythmias, and potentially seizures due to catecholamine surges. However, this would be an uncommon cause of the patient's presentation.