Author: Dr. Gitanjali Devi
Mushrooms are the fleshy, spore-bearing fruiting bodies of higher (macro) fungi, typically produced above ground on soil or on their food source. There are about 1,40,000 species of fungi in the world, out of which mushroom having 15,000 to 14,000 species and about 2000 are edible (Graeme, 2014). Two families and 2 taxa belonged to class- Ascomycetes viz., Family- Helvellaceae and Morchellaceae and nine families and 38 taxa to class-Basidiomycetes viz., Family-Agaricaceae, Amanitaceae, Boletaceae, Cantharellaceae, Coprinaceae, Ganodermataceae, Hydnagiaceae, Lycoperdaceae and Russulaceae are found in India. Ethnic Indian tribes are known to consume nearly 283 species of wild mushrooms out of 2000 species and around 100 species of mushrooms in India are known to be poisonous to humans (Diaz, 2005).
Mushrooms have been collected for eating throughout the world for thousands of years and during that time many people become ill or died when they inadvertently consumed poisonous mushrooms. Mushroom poisoning or mycetism refers to harmful effects from ingestion of toxic substances present in a mushroom. The most common reason for the occurrence of mushroom poisoning is collecting and eating a species of mushroom that closely resembles (in terms of colour and general morphology) one that is poisonous. The toxins present are secondary metabolites produced by the fungus that can differ markedly in toxicity and may be divided into classes according to their chemical structures (Deshmukh et. al., 2006). The severity of mushroom poisoning may vary depending on the geographic location where the mushroom is grown, growth condition, the amount of mushroom consumed, and genetic characteristics of the mushroom. Boiling, cooking, freezing or processing may not alter the toxicity of mushroom. Mortality rate depends on the patient's age and general health.
Poisonous mushrooms are classified by the physiologic and clinical effects of their poisons:
1. Amanitoxins and Phallotoxins: The toxins involved are complex polypeptides (Cyclopeptides). Cyclopeptides include amatoxins , phallotoxins and virotoxins. This group of toxins is responsible for most fatalities in mushroom poisoning. e.g. Amanita phalloides,A. verna, A. virosa, A.bisporigera,A. ocreata, A.suballiacea, Galerina autumnalis,G. marginata , G. sulcipes, Lepiota helveola ,L. chlorophyllum , L. josserandi , L. fulvella ,L.subincarnata , L.brunneoincarnata and L.brunneolilacea .This species forms mycorrhizae and is associated with trees belonging to the genus Casuarina (Iron Wood), Eucalyptus and Melaleuca (Paper Bark). The mushrooms are usually associated with the root tips of the trees. Thus, they may be some distance away from the tree. However, it is estimated that over 90% of mushroom fatalities is due to consumption of only one species,Amanita phalloides. The victims described the taste of A. phalloides as mild to quite good, so large amounts of it are normally consumed. The alpha-amanitin rapidly attacks the intestine, liver and kidney. However, any discomfort from this toxin is not immediate. It may be as long as 24 hours before any symptoms occur. The victim will experience diarrhea, profuse vomiting and abdominal pains, which usually last from four to six days. The amatoxins will have caused collapse of kidney and liver function. The victim will then eventually go into a coma and death usually follows.
2. Norleucine: Amanita smithiana and Amanita proxima, have also been associated with an acute oliguric renal failure. These mushrooms cause vomiting and diarrhea 1-12 hours after ingestion, followed by renal failure in 3-6 days. Exposure to norleucine-containing mushrooms may require temporary hemodialysis.
3. Gyromitrin is a volatile hydrazine derivative synthesized by 'false morels' - Gyromitra esculenta, G. infula. In the stomach, gyromitrin is rapidly hydrolyzed into Monomethylhydrazine (MMH). Symptoms of this toxin usually appear approximately 2-12 hours after consumption. MMH causes initial bloated feelings, followed by nausea, and the usual vomiting, diarrhea and abdominal cramps and destruction of blood cells. Severe headaches and pain may also occur and linger for some time. If more severe poisoning has occurred, i.e., individuals who have eaten large amounts of mushrooms containing Gyromitrin, symptoms of liver toxicity will occur after between 36-48 hours. Jaundice and convulsion may occur, followed by coma and eventually death after 2-7 days. In addition, it is hemolytic, and toxic to the central nervous system and irritates the gastrointestinal tract. Pyridoxine hydrochloride should be administered.
4. Orellanine: Cortinarius orellanus,C.rubellus, C.orellanus, C. speciosissimus, C. splendens, C. gentilis and C.rainierensis, belongs to the subgenus Dermocybe, contain this toxin. This toxin causes no symptoms for 3-20 days after ingestion. The mushrooms often contain other toxins in addition to orellanine; therefore people having eaten mushrooms containing orellanine may experience early symptoms as well. In mild poisoning cases, symptoms sometimes did not appear until 10-17 days after eating the mushroom. Typically around day 11, the process of kidney failure begins, and is usually symptomatic by day 20. These symptoms can include pain in the area of the kidneys, thirst, vomiting, headache and fatigue .There is a great deal of variation with respect to the recovery of the poisoned victim. In cases where renal damage has occurred, there may be a period of mild renal failure followed by complete recovery. However, in some cases, renal failure may occur and the victim will require lifelong hemodialysis or a kidney transplant, or in some instances coma, followed by death, will occur.
5. Muscarine: Mushrooms containing this toxin are very nondescript and are often referred to as little white or brown mushrooms, Clitocybe dealbata, Inocybe, Omphalotus species and some red-pored Boletes. The toxin stimulates the exocrine glands where sweat, saliva and tears are produced within 15 to 30 minutes of consumption. Other symptoms include nausea, vomiting and diarrhea, urge to urinate, constriction of pupils, blurred vision, muscle spasms, slow heart-beat and a drop in blood pressure. Although rare, death has been known to occur. However, when this has occurred, the victim usually has had a history of cardiovascular disease. The accepted treatment is intravenous injection of atropine.
6. Ibotenic acid and muscimol: The most well known species of mushroom, having toxins in this group is Amanita muscaria, Amanitacokeri, A. gemmata, A. pantherina and Panaeolus campanulatus. Amanita muscaria having its scarlet pileus that is covered with yellowish-white spots. This species forms mycorrhizae with pine trees and is common in temperate areas of the world. Onset of symptoms in this group may occur 30-120 minutes after consumptions. The toxins act on the central nervous system causing the victims to suffer from symptoms similar to alcohol intoxication. i.e., unable to walk or walk with drunken gait, confusion between 30 and 120 minutes of consumption. Alternation between lethargy and hyperactivity. Nausea and vomiting may also occur if large amounts of mushrooms have been consumed. This is followed by a deep sleep with dreams, lasting about two hours. The victim usually recovers.
7. Coprine: Coprinus atramentarius is the most common species known to contain this toxin. Also known from C. insignis, C. quadrifidus and C. variegatus. Although unpleasant, consumption of mushroom is not fatal. A rather unique toxin in that symptoms occur only if mushroom is consumed with a drink containing alcohol. Symptoms begin approximately 30-60 minutes after consumption and will continue as long as there is alcohol in the system. Symptoms include hot flushes of the face and neck, a metallic taste in the mouth, tingling sensations in the limbs, numbness in the hands, palpitations, a throbbing headache, nausea and vomiting. Recovery is normally spontaneous once the body is rid of the alcohol.
8. Psilocybin and Psilocin: Hallucinogenic compounds are found in four agaric genera, Psilocybe, Panaeolus, Conocybe and Gymnopilus. Symptoms begin approximately 10-30 minutes after consumption. The toxins in this group have a strong effect on the central nervous system. Some of the common symptoms include uncontrollable laughter, hallucinations, optical distortions, euphoria and disembodied experience. The effects are normally about 4-5 hours, followed by sleep. It is observed that the ingestion of large quantities of some mushrooms in this group can be fatal or cause severe toxic effects. Hallucinations may be suppressed by chlorpromazine and convulsions by diazepam.
9. Gastrointestinal irritant: This is a group of unrelated toxins. However, they all cause similar symptoms when consumed Agaricus, Amanita, Boletus, Chlorophyllum, Entoloma, Hebeloma, Lactarius, Marasmius, Naematoloma, Russula, Scleroderma, Tricholoma . Symptoms from the mushroom begin 30-90 minutes following consumption. All cause varying degrees of digestive upset. Commonest symptoms are diarrhea, vomiting and abdominal cramps. Normally, symptoms clear up in 3-4 hours and complete recovery several days later. Some cases of fatality have been recorded, but these are usually cases in which large quantities of mushrooms have been consumed or if the victims were young children.
10. Involutin: Ingestion of Paxillus involutus may result in the acute onset of abdominal pain, nausea, vomiting, and diarrhea within 30 minutes to 3 hours of ingestion, followed by an immune complex-mediated hemolytic anemia with hemoglobinuria, oliguria, anuria, and acute renal failure.
Precautions for mushroom poisoning:
- Awareness camp
- Educating people about scientific aspects of mushroom poisoning as well as health hygiene.
- Medical awareness
Graeme, K. A. (2014). Mycetism: A review of the recent literature. J Med Toxicol 2: 1-17.
Diaz, J.H. (2005). Syndromic diagnosis and management of confirmed mushroom poisonings. Crit Care Med 33:427-436
Deshmukh, S.K., Natarajan, K. and Verekar S.A. (2006) Poisonous and hallucinogenic mushrooms of India. Int J Med Mushr 8:251-262.
About Author / Additional Info:
Junior Scientist, Department of Nematology, Assam Agricultural University