Successful diagnosis of hyperpyrexia induced by isoniazid in a child with suspected extra-pulmonary tuberculosis.

A 9-year-old boy received a rifampicin-isoniazid-ethambutol regimen for suspected extra-pulmonary tuberculosis, and glucurolactone and vitamin B6 to provide liver protection and decrease neurotoxicity associated with isoniazid. Baseline serum aminotransferase and total bilirubin levels were within normal limits before anti-tubercular treatment. After 4 days of treatment, the patient's body temperature increased (from 38.0°C to 40.1°C) and on the 11th day of treatment, serum chemistry results showed 400 U/L aspartate transaminase, 535 U/L alanine aminotransferase and 76.8 μmol/L total bile acid, which likely indicated drug-induced hepatic injury. After discontinuing isoniazid or administering anti-tubercular therapy without isoniazid, hyperpyrexia gradually resolved; hyperpyrexia reappeared following rechallenge with isoniazid. The patient's liver function returned to normal after symptomatic treatment. Thus, hyperpyrexia that accompanied hepatic injury was considered to be related to isoniazid. This case indicated that hyperpyrexia could also appear during anti-tubercular treatment owing to its hepatotoxicity.