Toxic Fungi of Western North America
The clinical picture of gyromitrin poisoning
Since MMH is unstable with heating: boiling, drying and canning usually remove all or most of this toxin. The cooking fumes have caused dizziness, nausea and malaise.
Recovery from gyromitrin poisoning ensues in one to three days, unless severe methemoglobinemia, hemolysis, central nervous system symptoms, liver or kidney failure supervene. Liver failure occurs more often than renal failure. The fatality rate in the 1960's was as high as 2-4% in the Mid-West, but deaths are rare now. No deaths have occurred in the Western states. Other than lightheadedness from inhaling cooking fumes and GI symptoms from eating them, gyromitras are singularly symptom-free in the West. Five poisoning cases presenting themselves to Idaho hospitals survived. (91) Wells and Kempton reported a case of Gyromitra infula poisoning in Alaska with symptoms compatible with MMH toxicity. However, the species was later determined to be Gyromitra ambigua, a species in which the presence of gyromitrin had not previously been documented. (125),(139)
The usual presence of headache, often fever and some of the CNS symptoms (vertigo, loss of coordination, seizures) and particularly a history of false morel ingestion distinguish this syndrome from amatoxin poisoning. Without a history of Gyromitra ingestion, the clinical picture is to some extent a peculiar combination of the symptoms found in amanitin and ibotenic acid poisonings.
However, there also may be hemolysis (destruction of circulating red blood cells) with free hemoglobin in the urine. Methemoglobinemia may also occur in which the hemoglobin (a ferrous heme) is oxidized to methemoglobin (a ferric heme). The ferric iron form picks up oxygen very poorly and cyanosis occurs along with shortness of breath. An initially rapid pulse due to dehydration and stress may give way to a slow one and more serious cardiac arrhymias may occur. Neither hemolysis nor methemoglobinemia occur in amanita poisoning.