Recent Poisonings from Edible Mushrooms!

A report on a few new kinds of mushroom poisoning
gleaned from Hanna Tschekunow’s NYMS talk on mushroom poisoning (3/13/05) at the Museum of Natural History
by Gary Lincoff 2005

Hanna gave a presentation on mushroom poisoning at our annual Winter Lecture Series at the American Museum of Natural History on Sunday, March 13, 2005. She covered the basics, of course, and went into some detail about newly reported cases of mushroom poisoning caused by previously edible kinds. She reviewed the data that have been compiled about mushrooms such as Tricholoma flavovirens (Man on Horseback), Pleurocybella porrigens (Angel Wings) and the disjunct pair Clitocybe amoenolens (the Perfume Clitocybe of Morocco & southern Europe) and Clitocybe acromelalga (of Japan).

TRICHOLOMA FLAVOVIRENS [Man on Horseback]

Tricholoma equestre, as it is known in Europe, has caused poisonings in southwestern France where it is found in sandy soil under pine trees. The kind of poisoning it causes is called rhabdomyolysis (where the iron containing red pigment myoglobin leaks out of muscle cells and into the blood. As myoglobin degrades it produces kidney toxins that, untreated, can lead to kidney failure.) Symptoms in one case in which the mushrooms were eaten at several consecutive meals caused fatigue, muscle weakness (muscles stiffened), myalgia, loss of appetite, mild nausea, and profuse sweating. In most cases there is also a red-brown coloration of the urine.

There are several questions involved in this kind of poisoning. The first is whether the mushroom causing the poisoning in southwestern France, called Tricholoma equestre, is the same as the mushroom we collect and eat in this country, also growing in sandy soils and under pine, and which we call Tricholoma flavovirens. Some DNA studies have suggested that they are not the same. In any case, there have been no mushroom poisonings from this mushroom reported in the U.S. Another question has to do with repeated meals. Every case reported involves eating the mushroom over several meals, again and again. If this is an essential component of the poisoning, a single meal might be delicious and harmless, and enough.

PLEUROCYBELLA PORRIGENS [Angel’s Wings]

Angel’s Wings, Pleurocybella porrigens, is another well-known and well-liked edible mushroom. One recent article about poisoning caused by eating this mushroom said, in part: “In September and October, 2004, an outbreak of encephalopathy of unknown etiology ocurred in certain areas of Japan…These patients had a history of chronic renal failure, most of them had undergone hemodialysis, and also had a history of eating Sugihiratake (Pleurocybella porrigens), an autumn without known toxicity. Each patient had a history of eating the mushroom within 2-3 weeks of the onset of neurological symptoms…The onset was subacute; the initial symptoms were tremor…weakness of the extremities, consciousness disturbance and intractable seizures…Three to eight days after onset, however, conspicuous lesions appeared in (the cerebral cortex area of the brain)…Of ten cases studied, three patients died at 13, 14 and 29 days after onset.” The other 7 recovered, but only 3 recovered completely, the others showing different symptoms lingering for different periods of time.

In Japan, in 2004, it was hotter than usual, it rained a lot in August, the Pleurocybella porrigens came up in early September, earlier than usual, and were both very abundant and twice their usual size. Individual caps had become the size of an adult human palm. The mushrooms grow in stumps in pine and cedar trees. By early November, scattered over 8 prefectures in Japan, there were 46 cases of brain illnesses from these mushrooms, and 14 deaths.

No poisonings from this mushroom have been reported in the U.S. or anywhere else, to date. A pre-existing kidney condition appears to be required. Brain lesions appear to be the proximate cause of death.

CLITOCYBE AMOENOLENS & CLITOCYBE ACROMELALGA

Another hitherto unknown poisonous mushroom has been reported from Europe. The mushroom is known as Clitocybe amoenolens. It looks like Clitocybe inversa, and it is also said to resemble Hygrophoropsis aurantiaca. The poisoning appears to be the same as that caused by Clitocybe acromelalga in Japan. The article, available on the web, as are many articles on mushroom poisoning, said, in part: “Seven cases (of Clitocybe amoenolens poisoning) observed and followed over 4 years are reported. All ill patients had eaten the same mushroom species, gathered in the same French alpine valley. Clinical features of erythromelalgia were observed. This syndrome was first described in Japan after Clitocybe acromelalga ingestion. It had never been observed in Europe before.” Erythromelalgia is a maldistribution of blood flow with some areas not getting enough blood and calling for more. Extra blood gets through other open vessels…This continues until the appearance of the skin shows too much blood flow…The skin, especially of the hands and feet, appears and remains bright red and feels warm to hot to the touch, and these symptoms are painful. Patients avoid warm weather, some need to have their legs elevated for extended periods of time, and some are confined to bed. Symptoms can last for months. All digits can be affected. Even the tip of the nose can be affected. No specific treatment is known to be effective. Pain relievers, such as aspirin, or aspirin-free analgesics, are taken as needed.

This mushroom is not known to exist in the U.S., but it and closely related species that can cause this kind of poisoning might very well occur here as well. For our area, besides looking like the false chanterelle, Hygrophoropsis aurantiaca, it also looks somewhat like Clitocybe gibba, except that Clitocybe amoenolens is much more colorful (with orange or rusty pigments) and distinctly fragrant (perfume like).

 
Conclusion: This is not an article to tell you not to eat edible mushrooms. Rather, you should be aware of a couple of things you may have ignored in the past. First, if you find a large quantity of a mushroom and you eat multiple meals with that mushroom, you may be taking a risk you would not be taking with a single meal. Second, if you have a pre-existing kidney condition, or possibly involving some other organ in the body, you may want to know more about what you are eating before you join in with everyone else and collect something for the table. Third, if you have learned to recognize all the really important poisonous mushrooms and you have concluded that everything else is, well, if not edible, not dangerous, shelve that idea. There are innocuous-looking mushrooms out there that can cause long lasting pain. In sum, if you have any existing medical condition, be aware that you have to be more careful than others, and everyone has to know the mushroom he is eating, and everyone should eat mushrooms in moderation.
 
One last scary story to keep you up at night. A man with AIDs cooked some edible Coprinus cinereus to eat. A spore from that mushroom got into his mouth and germinated in an open wound. He had become a substrate. The mushroom mycelium grew through him, and he died. An epidemiologist I spoke with about this case assured me that this will only happen to AIDs patients in a very late stage of the disease. Medicines being taken now to treat HIV/AIDs can prevent this from happening at earlier stages. I guess that's comfort of a sort. But to die from cooking an edible mushroom! Mushrooms are more complex and more opportunistic than many of us ever give them credit for being. Caveat emptor et collector!