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Toxicity, Mushroom - Amatoxin
Updated: Jul 19, 2007
Introduction
Background
Of more than 5000 species of mushrooms in the United States, approximately 100 are poisonous, and less than a dozen are deadly.
Most fatalities resulting from mushroom ingestion are associated with amatoxins within the mushrooms. Amatoxins (cyclic octapeptides) represent 1 of 3 groups of cyclopeptides and are heat-stable, insoluble in water, and not destroyed by drying. At least 5 subtypes of amatoxins exist; alpha and beta amatoxins are the most significant subtypes.
Alpha amatoxin inhibits RNA polymerase II, which ultimately leads to cell death. Amanita toxins are found in several Amanita species and some members of the genera Galerina and Lepiota. Even experienced mushroom pickers may mistake death cap (Amanita phalloides) for one of its benign cousins.
Pathophysiology
Amatoxin poisoning can be divided into 3 stages.
- Amatoxin poisoning has a characteristic latent period of 6-12 hours postingestion before onset of clinical symptoms. After this asymptomatic period, abdominal cramping, vomiting, and profuse watery diarrhea (rice water, choleralike) occur. Fluid losses may be severe enough to cause profound dehydration and even circulatory collapse.
- Once this acute gastrointestinal phase is over (usually after 24 h), the second stage begins. Although the patient appears to have improved clinically, ongoing liver damage is occurring as indicated by laboratory abnormalities (elevation of serum aminotransferase levels, prothrombin time). This stage may last as long as 2-3 days.
- Hepatic and renal injury become clinically apparent and may progress to fulminant hepatic failure in the third phase. Death may occur in 3-7 days.
Frequency
United States
In 1996, 10,584 mushroom exposures were reported to the American Association of Poison Control Centers.1
- Eighty-eight percent of reported mushroom exposures were unidentified.
- Only 54 were identified as amatoxin exposures; however, this number is undoubtedly an underestimation given the number of unknown mushroom exposures.
- One author estimates incidence of mushroom exposures at 5 exposures per 100,000 population per year.
International
No adequate database exists to estimate worldwide exposures.
- Mushroom foraging is more common in parts of Europe and Russia than in other parts of the world.
- From mid-July to September of 1998, 9 people died and 180 were poisoned from mushrooms in Russia.
- In July and August of 1997, 34 people died of mushroom poisoning across Russia.
Mortality/Morbidity
Ninety-five percent of all mushroom fatalities in North America are associated with cyclopeptide-containing species (amatoxins). Worldwide, most mushroom fatalities are ascribed to amatoxins. Amatoxins are associated with mortality rates ranging from 10-60%.
Ingestion of a single Amanita phalloides mushroom can be lethal.
Age
- Most accidental mushroom exposures occur in children younger than 6 years.
- Mortality is higher in children because they absorb a larger dose of toxins per body weight.
Clinical
History
With amatoxin ingestion, onset of GI symptoms typically is delayed 6-12 hours or more. An earlier onset of symptoms suggests that another mushroom is responsible for symptomatology. However, if the patient's meal included several different mushrooms, an earlier onset of symptomatology does not rule out concomitant amatoxin ingestion.
- Presenting complaints include severe abdominal pain, cramping, nausea and vomiting, profuse diarrhea, and weakness.
- With delayed presentation, complaints may include symptoms attributable to hepatic dysfunction, such as jaundice, lethargy, or bruising.
- If a mushroom sample is available, place it in a dry paper bag (do not moisten or refrigerate).
Physical
Assessing the patient's volume status is an important component of the initial evaluation. With delayed presentations, look for signs of hepatic or CNS dysfunction.
- Vital signs
- Tachycardia
- Hypotension
- Skin
- Poor turgor
- Jaundice, bruising (with hepatic failure)
- Abdomen
- Mild tenderness
- Diarrhea, may have a positive result on a Hemoccult test (guaiac positive)
- Neurologic (if hepatic failure or hypoglycemia)
- Confusion
- Lethargy
- Coma
Causes
- Accidental childhood ingestions
- Misidentification of mushroom by forager
- Deliberate seeking of psychotropic mushrooms
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References
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Ganzert M, Felgenhauer N, Zilker T. Indication of liver transplantation following amatoxin intoxication. J Hepatol. Feb 2005;42(2):202-9. [Medline].
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Goldfrank LR. Mushrooms: toxic and hallucinogenic. In: Goldfrank's Toxicologic Emergencies. 5th ed. Appleton & Lange; 1994:951-961.
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Paydas S, Kocak R, Erturk F, Erken E, Zaksu HS, Gurcay A. Poisoning due to amatoxin-containing Lepiota species. Br J Clin Pract. Nov 1990;44(11):450-3. [Medline].
Pond SM, Olson KR, Woo OF, et al. Amatoxin poisoning in northern California, 1982-1983. West J Med. Aug 1986;145(2):204-9. [Medline].
Warden CR, Benjamin DR. Acute renal failure associated with suspected Amanita smithiana mushroom ingestions: a case series. Acad Emerg Med. Aug 1998;5(8):808-12. [Medline].
Yamada EG, Mohle-Boetani J, Olson KR, Werner SB. Mushroom poisoning due to amatoxin. Northern California, Winter 1996-1997. West J Med. Dec 1998;169(6):380-4. [Medline].
Further Reading
Keywords
amatoxin toxicity, mushroom ingestion, poisonous mushroom, mushroom toxicity, mushroom poisoning, amatoxin, Amanita toxin, Amanita, Galerina, Lepiota, cyclopeptide-containing species, amatoxin poisoning, mushroom exposure, Amanita phalloides, A phalloides
