Publication:

Acute isoniazid toxicity presenting with refractory seizures, severe metabolic acidosis, and rhabdomyolysis: a case report

Isoniazid remains widely used in India due to the high burden of tuberculosis and HIV, with toxicity being an important clinical concern. While peripheral neuropathy and hepatotoxicity are common, acute overdose presenting with seizures and rhabdomyolysis is uncommon and potentially fatal. A 21-year-old male presented following intentional ingestion of approximately 9 g of isoniazid, with two episodes of generalized tonic–clonic seizures. On admission, he was drowsy but arousable (GCS 12/15). Initial management included gastric lavage and activated charcoal. Laboratory findings showed elevated creatine phosphokinase (2556 U/l) and mild metabolic acidosis. Liver enzymes rose from day 2, peaked by day 5, and normalized by day 12. CPK levels peaked on days 5–6 and declined thereafter, correlating with generalized myalgia. The patient was treated with intravenous fluids, 5 g pyridoxine, and alkaline diuresis, with gradual clinical and biochemical recovery. He was discharged on day 14 after psychiatric evaluation. This case emphasizes the need to recognize isoniazid toxicity, classically characterized by seizures, metabolic acidosis, and altered sensorium. Early administration of pyridoxine and supportive care are essential for a favorable outcome.