[Acute quinine poisoning treated with high dose of diazepam]

High concentrations of quinine, the drug of choice for severe malaria, are toxic to the cardiovascular system, producing hypotension and abnormal myocardial conduction.

An 8 year-old girl was admitted for fever, headache and arthralgias. Examination of a thick film of blood showed Plasmodium falciparum (parasitemia: 2%). She was given quinine intravenously. Ventricular tachycardia (150/min) and status epilepticus were seen 48 hours later, necessitating ventilatory support, plasma volume expander and IV sodium thiopental. On admission to an intensive care unit, the patient had hypothermia, was comatose (stage IV) with a reactive mydriasis and bradycardia (30/min). ECG confirmed bradycardia and showed a widened QRS complex. There was also a bilateral retinal edema. The blood level of quinine was 61 mumol/liter (therapeutic levels: 6-15). Retrospective inquiry revealed that the quinine initially administered had been incorrectly diluted. The child was treated with furosemide and adrenaline, followed by dobutamine and albumin infusion. She was then given diazepam (initial dose: 2 mg/kg then 6 mg/kg/day divided into 4 doses) intravenously, plus lidocaine, methylprednisolone and glycerol. The sinusal rhythm became normal 1 hour after the first bolus of diazepam. Consciousness gradually improved over the 10 days after admission while treatment was progressively discontinued. There were no sequelae, except for a transitory bilateral blindness.

The cardiovascular side-effects of quinine poisoning can be reversed with diazepam, as has previously been reported in cases of chloroquine poisoning.