Slowly developing isoniazid poisoning

A 9-year-old girl suffering from nephrotic syndrome and pulmonary tuberculosis was given a dose of 700 mg of isoniazid three times daily for six days by her mother, with the intention to compensate for having terminated therapy without medical advice. She developed the general pattern of reactions characteristic of acute isoniazid overdose i.e. nausea and vomiting followed by stupor, hypereflexia and a bilateral Babinski's sign. A transient hepatic injury, illustrated by increased values of liver enzymes, was also present. The clinical picture, the course of the illness, the treatment and outcome are described