Mushroom Poisoning

Abstract

Mushroom poisoning is a form of not so uncommon poisoning resulting from the ingestion of mushrooms containing toxic substances. The most common reason of mushroom poisoning is misidentification of a toxic mushroom as an edible species. Mushroom poisonings occur every year between June and December which is the best growing season for mushroom. Its symptoms can vary from slight gastrointestinal discomfort to death in about ten days.¹ To prevent mushroom poisoning, mushroom gatherers familiarize themselves with the mushrooms they intend to collect, as well as with any similar-looking toxic species.

Introduction

Mushrooms can be found extensively in a variety of natural environments and visual identification of mushroom species is well established. Some mushrooms are well known because of their nutritional and therapeutical properties. But some species are also known because of their toxicity causing fatal accidents every year mainly due to misidentification. Mushrooms are identified traditionally by their appearance, taste, colour, odour, presence of scales etc.

Table 1: Differences between Poisonous and edible mushrooms ²

Deadly fungus species commonly found in South East Asia

The following table is a list of deadly mushroom commonly found in South East Asia with their active toxic agent and toxic effect in body.

Table 2: List of deadly fungus species commonly found in South East Asia ³

Pathophysiology

Each poisonous mushroom species contains one or more toxins, which may be classified on the basis of the mushroom’s physiologic and clinical effects in humans. The clinical spectrum and toxicity vary with the following factors. ^4,5

1. Species consumed
2. Amount consumed
3. Season
4. Geographic location where the mushroom was grown
5. Preparation method
6. Individual response to the toxins

Signs and symptoms

Poisonous mushrooms contain a variety of different toxins that can differ markedly in toxicity. Therefore, symptoms of mushroom poisoning may vary from gastric upset to organ failure resulting in death. Serious symptoms do not always occur immediately after eating, often not until the toxin attacks the kidney or liver, sometimes days or weeks later. The most common consequence of mushroom poisoning is simply gastrointestinal upset. Most “poisonous” mushrooms contain gastrointestinal irritants that cause vomiting and diarrhea (sometimes requiring hospitalization), but usually no long-term damage. However, there are a number of recognized mushroom toxins with specific, and sometimes deadly, effects. Amatoxins, gyromitrins, and orellanine are the toxins most commonly implicated in fatal mushroom poisonings worldwide.⁴

Mushroom poisoning can be classified into the following 3 major categories on the basis of the time from ingestion to the development of symptoms.⁵

• Early symptom category – Symptoms generally appear within the first 6 hours of mushroom ingestion and include gastrointestinal (GI), allergic, and neurologic syndromes
• Late symptom category – Signs and symptoms begin to appear between 6 and 24 hours after ingestion and may include hepatotoxic, nephrotoxic, and erythromelalgic syndromes
• Delayed symptom category – Symptoms appear more than 24 hours after ingestion and include mostly nephrotoxic syndromes.

Management of mushroom poisoning

KEY TESTING⁶

• Mushroom identification if possible
• For dehydrated patients: serum electrolytes, BUN, creatinine, urinalysis
• For patients with weakness or myalgias: CK
• For suspected cyclopeptide exposure: transaminases, INR

General management⁷

• Supportive care is the mainstay of management for any toxic mushroom ingestion.
• Most patients will need no treatment other than intravenous (IV) fluids if dehydrated and antiemetics.
• Activated charcoal should be considered for patients presenting within 1 to 2 hours of ingestion.
• There is no clear antidote for amatoxin-containing mushrooms though many therapies are empirically used.

Mushrooming Poisoning syndrome with treatment ⁸

Prevention

Prevention is best achieved by eating only commercially cultivated mushrooms, and identification of mushrooms is best left to experts. Mushrooms should be regularly removed from sites where children are routinely present. Education regarding the poisonous nature of wild mushrooms may act as a deterrent to careless mushroom foraging and ingestion.

References

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3. Ward J, Kapadia K, Brush E, et al. Amatoxin poisoning: Case reports and review of current therapies. J Emerg Med. 2013;44(1):116–121.
4. Benjamin DR. “Amatoxin syndrome”: 198–214. in: Mushrooms: poisons and panaceas – a handbook for naturalists, mycologists and physicians. New York: WH Freeman and Company. 1995.
5. Saller R, Brignoli R, Melzer J, Meier R (February 2008). “An updated systematic review with meta-analysis for the clinical evidence of silymarin” (PDF). ForschKomplementärmed. 15 (1): 9–20. doi:10.1159/000113648. PMID 18334810. S2CID 23468345
6. Diaz JH. Evolving global epidemiology, syndromic classification, general management, and prevention of unknown mushroom poisonings. Crit Care Med. 2005 Feb. 33(2):419-26. [Medline].
7. Diaz JH. Syndromic diagnosis and management of confirmed mushroom poisonings. Crit Care Med. 2005 Feb. 33(2):427-36. [Medline].
8. Mushroom Poisoning ©2011 UpToDate

Author Information

Aye-Mya-Theingi-Win¹, Nyunt-Thein²

1. Consultant Physician, Tropical and Infectious Diseases Department, Yangon General Hospital
2. Senior Consultant Physician, Former Head of Department of Medicine, Emeritus Professor of Medicine, University of Medicine (1), Yangon