Amanita phalloides in Victoria

Mushroom Poisoning by Macrolepiota neomastoidea

There are currently over 5,000-known species of mushrooms worldwide. Only 20-25% of mushrooms have been named, and 3% of these are poisonous. More than 95% of mushroom poisoning cases occur due to difficulties associated with the identification of mushroom species. Most of the fatal mushroom poisoning cases recorded to date have been related to the Amanita species. Until now, a case of fatal poisoning caused by Macrolepiota neomastoidea (M. neomastoidea) has not been reported in Asia. A 57-year-old male patient was admitted to the emergency room with nausea, vomiting, diarrhea, and abdominal pain. He reported ingesting wild mushrooms with his mother and sister about 2 days ago. His mother and sister were treated with only supportive care, but he was admitted to the intensive care unit and underwent liver transplantation due to acute liver failure. We are reporting a case of fatal M. neomastoidea intoxication from wild mushrooms, a rare case of mushroom poisoning.

A retrospective study of mushroom poisoning in Iran

The objective of this study was to describe the pattern of mushroom poisoning in adults admitted to the Loghman Hakim Hospital Poison Center from 1992 to 2002. All patients ≥ 12 years of age were included in the study. The frequency of mushroom poisoning with respect to age, sex, season, reason, place of residence, latent phase, clinical and laboratory findings, treatment, and outcome of patients was investigated. Of the 72 421 poisoning cases admitted to Loghman-Hakim Hospital Poison Center from 1992 to 2002, only 37 were poisoned by consumption of toxic mushrooms. As some of the patients' files were incomplete, only 25 files were included in the study. Of this number, 68% were male. The patients' age ranged between 12 and 65 years, with a mean of 31 years of age. All cases were accidental and mostly from Tehran (36%) and the northern provinces (rainy woodlands) of Iran (32%). Autumn was the most common season for poisoning with a frequency of 80%. The latent phase of poisonings was between 0.5 and 12 hours. The most frequently reported symptoms were vomiting (84%), nausea (60%), abdominal pain (60%) and diarrhea (40%). Jaundice was observed in 44% of cases, with a 50% rate of hepatic encephalopathy. A total of 66% of patients were discharged and the duration range of hospitalization was 1-12 days.

In conclusion, people should be more informed of the dangers posed by wild mushrooms. Training of physicians and nurses in the accurate diagnosis and management of patients poisoned with poisonous mushrooms would improve the rate of survival.

The safety of edible fungi purchased at Melbourne markets

OBJECTIVE

To determine if toxic mushroom species are sold at Melbourne fruit and vegetable markets.

METHODS

We purchased a specimen of every mushroom on sale at six large Melbourne markets on four separate days evenly spread during the period April to June, 2005. These specimens were identified by a specialist mycologist at the Royal Botanic Gardens Melbourne.

RESULTS

Ten edible mushroom species, but no toxic species, were identified.

CONCLUSIONS

Mushrooms purchased from Melbourne markets appear to be safe.

IMPLICATIONS

While this study provides no evidence that public health is at risk from mushrooms sold at Melbourne markets, it has important limitations. Ongoing periodic surveillance is warranted.

Mycotoxins revisited: Part I

Mushrooms are ubiquitous in nature. They are an important source of nutrition; however, certain varieties contain chemicals that can be highly toxic to humans. Industrially cultivated mushrooms are historically very safe, but foraging for mushrooms or accidental ingestion of mushrooms in the environment can result in serious illness and death. The emergency department is the most common site of presentation for patients suffering from acute mushroom poisoning. Although recognition can be facilitated by identification of a characteristic toxidrome, the presenting manifestations can be variable and have considerable overlap with more common and generally benign clinical syndromes. The goal of this two-part article is to review the knowledge base on this subject and provide information that will assist the clinician in the early consideration, diagnosis and treatment of mushroom poisoning. Part I, presented in this issue of the Journal, reviews the epidemiology and demographics of mushroom poisoning, the physical characteristics of the most toxic varieties, the classification of the toxic species, and an overview of the cyclopeptide-containing mushroom class. Part II, to be published in the next issue of the Journal, will be focused on the presentation of the other classes of toxic mushrooms along with an up-to-date review of the most recently identified poisonous varieties.

Treatment of amatoxin poisoning: 20-year retrospective analysis

BACKGROUND

Amatoxin poisoning is a medical emergency characterized by a long incubation time lag, gastrointestinal and hepatotoxic phases, coma, and death. This mushroom intoxication is ascribed to 35 amatoxin-containing species belonging to three genera: Amanita, Galerina, and Lepiota. The major amatoxins, the alpha-, beta-, and gamma-amanitins, are bicyclic octapeptide derivatives that damage the liver and kidney via irreversible binding to RNA polymerase II.

METHODS

The mycology and clinical syndrome of amatoxin poisoning are reviewed. Clinical data from 2108 hospitalized amatoxin poisoning exposures as reported in the medical literature from North America and Europe over the last 20 years were compiled. Preliminary medical care, supportive measures, specific treatments used singly or in combination, and liver transplantation were characterized. Specific treatments consisted of detoxication procedures (e.g., toxin removal from bile and urine, and extracorporeal purification) and administration of drugs. Chemotherapy included benzylpenicillin or other beta-lactam antibiotics, silymarin complex, thioctic acid, antioxidant drugs, hormones and steroids administered singly, or more usually, in combination. Supportive measures alone and 10 specific treatment regimens were analyzed relative to mortality.

RESULTS

Benzylpenicillin (Penicillin G) alone and in association was the mostfrequently utilized chemotherapy but showed little efficacy. No benefit was found for the use of thioctic acid or steroids. Chi-square statistical comparison of survivors and dead vs. treated individuals supported silybin, administered either as mono-chemotherapy or in drug combination and N-acetylcysteine as mono-chemotherapy as the most effective therapeutic modes. Future clinical research should focus on confirming the efficacy of silybin, N-acetylcysteine, and detoxication procedures.

Poisoning by Amanita phalloides ("deathcap") mushrooms in the Australian Capital Territory

Amanita phalloides ("deathcap") mushrooms are widespread in south-eastern Australia. Seven patients presented to hospital in the Australian Capital Territory with poisoning by this mushroom between 1988 and 1998. Three developed hepatoxicity and one died. Because A. phalloides is becoming more widespread, increased community and medical awareness is needed to reduce the frequency and morbidity of poisoning.

Toxins of Amanita phalloides

The most poisonous mushroom toxins are produced by Amanita phalloides (death cap). The occurrence and chemistry of three groups of toxins (amatoxins, phallotoxins and virotoxins) are summarized. The concentration and distribution of toxins in certain species are variable, with the young fruit body containing lower, and the well-developed fungus higher concentrations, but there is a high variability among specimens collected in the same region. Regarding phallotoxins, the volva (the ring) is the most poisonous. The most important biochemical effect of amatoxins is the inhibition of RNA polymerases (especially polymerase II). This interaction leads to a tight complex and the inhibition is of a non-competitive type. Non-mammalian polymerases show little sensitivity to amanitins. The amatoxins cause necrosis of the liver, also partly in the kidney, with the cellular changes causing the fragmentation and segregation of all nuclear components. Various groups of somatic cells of emanation resistance have been isolated, including from a mutant of Drosophila melanogaster. The phallotoxins stimulate the polymerization of G-actin and stabilize the F-actin filaments. The interaction of phallotoxins occurs via the small, 15-membered ring, on the left side of the spatial formula. The symptoms of human poisoning and the changes in toxin concentrations in different organs are summarized. Conventional therapy includes: (1) stabilization of patient's condition with the correction of hypoglycaemia and electrolytes; (2) decontamination; and (3) chemotherapy with different compounds. Finally, certain antagonists and protective compounds are reviewed, bearing in mind that today these have more of a theoretical than a practical role.