A Case of Accidental Isoniazid Overdose Presenting With Nonspecific Symptoms

Abstract

A 68-year-old male with a history of end-stage renal disease and latent tuberculosis on isoniazid (INH), and no psychiatric history presented with a five-day history of anorexia, fatigue, and nausea. Physical exam in the emergency department was notable for somnolence, right upper extremity tremor, and diffuse abdominal pain. Initial workup revealed an anion gap metabolic acidosis with elevated lactate, prompting admission to the general ward for empiric IV antibiotics for suspected bacteremia from his permacath. Within a few hours of admission, he became increasingly encephalopathic and had two episodes of copious hematemesis. Repeat studies revealed a cholestatic pattern of liver injury and new-onset coagulopathy. With an overall clinical picture consistent with fulminant hepatic failure, our pharmacy team initiated a comprehensive pill count of all his medications, which established that he had been inadvertently taking up to six times the recommended dose of INH. With INH discontinuation and supportive therapy, he improved and was discharged on hospital day eight. Our experience provides lessons in the timely recognition and management of this rarely reported toxidrome in the United States.

Acute Izoniazid Poisoning With Presentation of a Clinical Case

“…Depletion of GABA stores is the most likely cause of epileptic seizures in isoniazid poisoning. [1,2,9,17,18] There are also individual features of isonicotinic acid poisoning, and in some people, its metabolism is significantly slower. [6,9,19,20] Clinical manifestation of acute poisoning.…”

“…These symptoms may occur 30 minutes after taking the drug. [1,17,19,21] The paraclinic is characterized by severe metabolic acidosis. Early toxic effects include: vomiting, slurred speech, dizziness and tachycardia, but acute overdose may lead to the development of epileptic seizure without any previous symptoms.…”

“…Early toxic effects include: vomiting, slurred speech, dizziness and tachycardia, but acute overdose may lead to the development of epileptic seizure without any previous symptoms. [2, 9,17] In severe poisoning, a coma develops rapidly and lasts 24-36 hours, persisting after cessation of seizures and correction of acidosis. [2, 9,17] Acute toxic effects of isoniazid also include hypotension, hyperthermia, acute renal failure, toxic hepatitis, hyperglycemia, glycosuria and ketonuria.…”

“…[2, 9,17] In severe poisoning, a coma develops rapidly and lasts 24-36 hours, persisting after cessation of seizures and correction of acidosis. [2, 9,17] Acute toxic effects of isoniazid also include hypotension, hyperthermia, acute renal failure, toxic hepatitis, hyperglycemia, glycosuria and ketonuria. [1,6,19,22] Diagnosis.…”