Acute exogenous poisoning with mushrooms
Apparently this is quite an important topic! There's a bunch of pages in the textbook and two lectures on the topic, I didn’t realise so many people got poisoned from mushrooms! There are around 100 toxic species and can be potentially fatal.
GI features commonly occur in fungi poisoning, and in some species that go on to cause more severe organ damage, the GI symptoms are the first indicator, so it is important to monitor such patients. Species include Agaricus spp, Chlorophyllum spp, Coprinus spp and Entoloma sspp. GI symptoms usually present within 3 hours, with nausea, vomiting, diarrhoea and abdominal pain, if they are not systemically dangerous then symptoms should resolve within 24 hours. Management in such cases is supportive and symptomatic, with management of fluid balance, but no antidotes are required.
Certain fungi containing cyclopeptides (e.g. amatoxins, phallotoxins and virotoxins) are potent hepato-toxins, causing fatty degeneration and centrilobular necrosis of the liver. These fungi have a 5-24 hour latent period followed by GI toxicity (nausea, vomiting, cramping abdominal pain, watery diarrhoea hypotension, tachycardia, lactic acidosis, electrolyte abnormalities), followed by a period of apparent recovery (2-6 days) followed by signs of liver damage with jaundice, liver and kidney failure and even death. Such patients should be carefully monitored and treated with all relevant supportive management, along with penicillin (which reduces uptake of amatoxins).
Image: “Amanita phalloides 2011 G1” by George Chernilevsky, Public domain, via Wikimedia Commons.
Fungi producing nephrotoxic features are those from the Cortinarius family (deadly webcap and fools webcap). These have a latent period of at least 36 hours, but rarely up to 17 days, prior to a prerenal phase of symptoms, with GI toxicity, followed by a renal phase, where acute renal damage will occur, with 10% going on to get chronic kidney failure. Management is supportive and symptomatic, dialysis may be required in some cases.
Fungi producing haematologic features (mainly the Brown Roll-rim) fungi, can cause haemolytic anaemia by an IgG mediated autoimmune reaction, presenting often as AKI in affected individuals, management is with plasma exchange to remove immune complexes.
Many fungi produce neuropsychiatric features (Jewelled Deathcap, Fly Agaric, Panther cap). They contain ibotenic acid that acts as a glutamate receptor agonist. And muscimol, a GABA-A receptor agonist. These lead to GI symptoms along with visual and/or auditory hallucinations. Bradycardia and pyrexia have also been reported.