Malicious Mushrooms
I absolutely adore mushrooms! They look so cute and they are also quite delicious. Of course, that doesn't mean I go out and search for them in the wild... As you will soon see!
Early Symptom Onset
The toxic effects of the first group of mushrooms set in within minutes, but usually do not last more than a few hours.
First up is the typical round brown-capped mushroom, Coprinus atramentarius. What makes this group of mushrooms unique are the gills on the inside of its cap. They eventually turn black and liquify, resembling ink. For this reason, these mushrooms are commonly known as inky caps. They are found growing in clusters around tree stumps. The toxin in inky caps is coprine. It usually is not an issue unless the mushroom is eaten within a few hours of drinking alcohol. Inky caps are actually edible mushrooms. The metabolite of coprine blocks aldehyde dehydrogenase, leading to the accumulation of aldehyde in the body. This is an incredibly uncomfortable sensation, often described as the worst hangover. Some symptoms include redness in the face, nausea, vomiting, and general discomfort. Death is rare, so treatment is generally supportive. Antidotes for alcohol overdose, like fomepizole, might be useful.
Late Symptom Onset
In contrast to the mushrooms described above, the effects of the poisons in the following mushrooms may not appear for hours to days after the mushroom is ingested.
With the brilliant red cap, members of the Amanita species are some of the most familiar mushrooms. It is the mushroom seen illustrated in children's books and even in video games. Which mushroom gives Mario more health? These mushrooms live in woody areas and may have a tan cap instead of red. There are multiple toxins in the Amanita mushrooms. Ibotenic acid is similar to the neurotransmitter glutamic acid. Its effects are seen more in children, such as involuntary muscle movements and seizures. Muscimol resembles GABA. The manifestations of GABA are commonly seen in adults, including hallucinations, dizziness, delirium, and somnolence. Treatment for both ibotenic acid and muscimol is supportive care. Amanita muscaria and Amanita pantherina also contain muscarine. They are just two of many mushrooms that have muscarine. The ivory funnel (Clitocybe dealbata) and the jack-o'-lantern mushroom (Omphalotus olearius), both named for their color and appearance, can also lead to muscarine toxicity. The symptoms associated with muscarine toxicity are generally mild. They include decreased heart rate, pupil constriction, and increased body fluids. These fluids include saliva, tears, and urine. You might have noticed that this is the complete opposite of the anticholinergic toxidrome from last lesson. In fact, the treatment for muscarine toxicity is atropine.Let's throw some magic into the mix! Magic mushrooms (Psilocybe cyanescens, Psilocybe caerulipes, Gynopilus spectabilius) contain psilocybin. In the body, psilocybin is converted to psilocin, which is similar to serotonin and LSD. Effects start within 30 to 60 minutes and resolve after 6 to 12 hours. Common symptoms include uncoordinated movement, hallucinations, and overactive restlessness. In rare cases, psilocybin ingestion can lead to kidney failure, seizures, or heart attacks.
Mushrooms that contain cyclopeptides are most toxic to the liver. The symptoms set in after 5 to 24 hours. Death is possible after 2 to 6 days. Due to my attempt to shorten this lesson, I will only be focusing on one mushroom in this group - the death cap (Amanita phalloides). This mushroom has a greenish cap. Death cap has multiple toxins, including phallotixin, virotoxin, and amanitin. A lethal dose of amanitin is 0.1 mg/kg. One gram of dried death cap mushroom contains 1.5 to 2.5 mg of amanitin. The toxin interferes with RNA polymerase II. It affects areas of high cell turnover, including the lining of the gastrointestinal tract, liver, and kidney. Amanitin is poorly but rapidly absorbed in the gut. However, amanitin is reabsorbed in the body circulating from the bile to the blood. In the treatment of amanitin toxicity, activated charcoal effectively absorbs amanitin. Penicillin G and milk thistle may block some of the effects of amanitin.
Members of the Gyromitra species have a brain-like appearance. If eaten raw, these mushrooms can be very poisonous. Ironically, the toxin mainly affects the brain. They contain gyromitrin, which is metabolized to hydrazine. Hydrazine reacts with pyridoxine, better known as vitamin B6. This disrupts the neurotransmitter GABA, causing seizures. Treatment for gyromitrin toxicity include activated charcoal, pyridoxine, and benzodiazepines for the seizures.
Finally, the lethal webcaps (Cortinarius species)! They are rusty brown to orange in color. The toxin in lethal webcaps is orellanine. It is similar in structure to paraquat and diquat, types of pesticides. Orellanine is easily detectable because it is fluorescent. The effects of orellanine may not appear until 2 to 3 days after ingestion, sometimes not even for weeks. Orellanine is extremely toxic to the kidney, leading to renal failure.
