If you’ve been fortunate to live in the parts of the US that were soggier than usually as of late – or unfortunate enough to have had flooding from hurricanes and tropical storms – then you’ve be noticing a tremendous burst of mushrooms.
For mycologists – mushroom enthusiasts – there are two classic chestnuts: “There are old mushroom collectors and bold mushrooms collectors, but there are no old, bold mushroom collectors.”
Or, in a more concise Croatian proverb, “All mushrooms are edible, but some only once.”
As such, this is the time of year that emergency rooms and regional poison centers begin to see a burst in poisonings from mushroom ingestion, due primarily to amateur misidentification of the fruiting bodies.
Just this past week, Jason McClure at Medscape Oncology News (free reg req’d) wrote about the unusual bloom of mushrooms in the northeastern US and the concomitant bloom of mushroom poisonings this fall.
But “mushroom poisoning” is an imprecise diagnosis for the ER physician. The constellation of symptoms caused by toxic mushrooms is as diverse as the colors and shapes of these wonders of nature. From another Medscape article on emergency management of mushroom poisoning by Dr. Rania Habal from the Emergency Medicine department of NYU:
Mushrooms are best classified by the physiologic and clinical effects of their poisons. The traditional time-based classification of mushrooms into an early/low toxicity group and a delayed/high toxicity group may be inadequate. Additionally, many mushroom syndromes develop soon after ingestion. For example, most of the neurotoxic syndromes, the Coprinus syndrome (ie, concomitant ingestion of alcohol and coprine), the immunoallergic and immunohemolytic syndromes, and most of the GI intoxications occur within the first 6 hours after ingestion.
Ingestions most likely to require intensive medical care involve mushrooms that contain cytotoxic substances such as amatoxin, gyromitrin, and orellanine. Mushrooms that contain involutin may cause a life-threatening immune-mediated hemolysis with hemoglobinuria and renal failure. Inhalation of spores of Lycoperdon species may result in bronchoalveolitis and respiratory failure that requires mechanical ventilation.
Mushrooms that contain the GI irritants psilocybin, ibotenic acid, muscimol, and muscarine may cause critical illness in specific groups of people (eg, young persons, elderly persons). Hallucinogenic mushrooms may also result in major trauma and require care in an intensive care setting. Lastly, coprine-containing mushrooms cause severe illness only when combined with alcohol (ie, Coprinus syndrome).
Among the poisonous mushrooms, Amanita phalloides is perhaps the most deadly. If you’ve spent any time in a biochemical laboratory you will have learned of the primary toxin of the mushroom, α-amanitin. This potency of this toxin comes from its remarkably high affinity for RNA polymerase II, the primary RNA polymerase for making messages that are converted into proteins.