Toxic Fungi of Western North America

by Thomas J. Duffy, MD

Fatality rates from selected studies published since 1970

Dr. George Floersheim and his associates at Basel, Switzerland in 1982 studied 205 European patients poisoned by Amanita phalloides (68) using the statistical method of multiple regression. In this mathematical model, a selected individual treatment and its patient outcome is compared to the average outcome for all the other treatments given. His group also made adjustments for age and for severity (the latter as judged by delay of symptom onset). The death rate was 16.5% for adults and 51.3% for children. Other than charcoal, standard ER and intensive care unit (ICU) management, the only treatment that reduced mortality was massive doses of penicillin, although silibinin compounds and hyperbaric oxygen showed borderline effectiveness. (68) Floersheim tried Penicillin-G, because it reduced the entry of amanitins into the cells of experimental animals. The study protocol used Penicillin-G sodium rather than the potassium salt, to avoid kidney toxicity. No subsequent human study has had the numbers of subjects needed to confirm or refute the findings.

Barrter et al. reported on severe US poisoning cases from 1974-1978. Sixty seven of the seventy five patients were thought to be amatoxin cases. All had good criteria for amanitin poisoning, but not all specimens were available or identified by mycologists. The mortality rate was 10.4%. (48d) With education and migrant assimilation, the north American rate should approximate the 5.5-9% mortality found in the developed nations of Europe.

The current mortality rate in California appears to be about 8%, an estimate based on the reported rates over the past 25 years and the gradual improvement in these rates. Reports from the San Francisco and Los Angeles Poison Control Centers, San Francisco General Hospital, Los Angeles County Hospital, UCSF Pharmacology Department and consultations with local mycological societies provide the core of this estimate. (47),(60,61) Some of the California amanitin poisonings were not reported to the North America Mycological Association, although they were reported to the appropriate Poison Control Centers.

There are inadequate data on children under the age of 10. Their death rates are probably between 15 and 22% extrapolating from Floersheim's European study. (68)

Fatality rates from Mexico show that untreated poisonings have roughly 50% mortality rates. Those patients that are treated in hospital have a prognosis close to that in the United States.