Toxic Fungi of Western North America

by Thomas J. Duffy, MD

Treatment of gyromitrin toxicity

The initial treatment is charcoal (50-100 grams or 1 mg/kg of body weight), antiemetics, fluid and electrolyte replacement. Sorbitol may be used to provoke diarrhea, but this treatment is hazardous unless central venous pressure or right atrial pressure is measured. The one-time dose of sorbitol is 1-2g/kg of body weight for adults and 1-1.5 g/kg for children under 12 (roughly 150 grams for adults and 50 grams for children as the total amount). If methemoglobinemia is high (over 20-30% or with the patient showing signs or symptoms), the use of 1% methylene blue (0.1-0.2 ml/Kg body weight of 1% solution) intravenously is indicated. This dose may be repeated every four hours if methemoglobinemia is refractory.

Seizure precautions should be in effect. If convulsions do occur, they may be controlled by the standard anticonvulsants given intravenously. If an IV line has not been established and a sedative medication is desired, a minor tranquilizer with fairly rapid onset of action such as oxazepam is best. If convulsions occur in a child, the pediatric dose of diazepam is 0.1 mg per kilogram of body weight. Newer anticonvulsants are likely to replace diazepam and neurological consultation should be obtained if time and circumstances allow. Moderately large doses of pyridoxine such as 1 mg per kg IV will combat to some degree CNS toxicity due to vitamin B6 inhibition by the toxin. High doses of B6 (such as the 25 mg/Kg once advised) should be avoided, since vitamin B6 in large dosage may cause neuritis.

In additional to routine chemistry tests and complete blood cell count, the blood should be monitored for free hemoglobin, methemoglobin and haptoglobin.

Severe hemolysis may require infusion of packed red cells or exchange transfusions. Kidney and liver failure are treated as usual. Some of these drugs may be unsafe in pregnancy as little data is available. However, the hydralazines of MMH poisoning are probably much more toxic to a fetus.