Posted: March 18th, 2022

Toxic Mushroom Ingestion: Understanding Amanita phalloides and Its Life-Threatening Effects

Amanita phalloides Poisoning: Clinical Phases, Management Strategies, and Outcomes”

Toxic Mushroom Ingestion: Understanding Amanita phalloides and Its Life-Threatening Effects

PHARMACOLOGY/TOXICOLOGY CASE STUDY

History:
A 17-year-old male presents to the emergency department after accepting a dare from his friends to eat ten mushrooms picked in the Pacific Northwest. The patient admits to eating only one mushroom and was asymptomatic until approximately seven hours after ingestion. He now reports severe vomiting and diarrhea. The patient brought one of the mushrooms with him, which was identified as Amanita phalloides.

PMH: None.

Physical Examination:

• T: 99.4°F
• HR: 120 bpm
• RR: 17 breaths per minute
• BP: 100/60 mm Hg
• General: Pale, lethargic appearance.
• HEENT: Normal examination. Mucous membranes are dry.
• Pulmonary: Clear to auscultation.
• CV: Tachycardic, no murmurs.
• Abdomen: Soft, non-tender.
• Neurologic: GCS = 15, cranial nerves II-XII intact.
• Skin: Pale with a 5-second capillary refill.

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QUESTIONS CASE STUDY

1. What are the phases of Amanita phalloides poisoning, and what are the major toxicities associated with each phase?
2. What type of mushroom is responsible for the majority of mushroom-related fatalities in North America?
3. What management strategies should be employed for this patient?

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CASE STUDY #13: AMANITA PHALLOIDES POISONING

1. Phases of Amanita phalloides Poisoning and Associated Toxicities:
   Amanita phalloides poisoning typically progresses through three distinct phases:
   • Phase I (6–24 hours post-ingestion): This phase is characterized by gastrointestinal symptoms, including nausea, vomiting, severe abdominal cramps, and watery diarrhea, which may become bloody. These symptoms can lead to significant dehydration, metabolic acidosis, electrolyte imbalances, hypoglycemia, and shock.
   • Phase II (18–36 hours post-ingestion): This phase is often misleading, as patients may appear to improve clinically. However, liver enzymes (e.g., ALT, AST) begin to rise, indicating ongoing liver damage. Clinicians must be cautious not to mistake this phase for recovery, as it can lead to underestimation of the severity of the poisoning.
   • Phase III (2–4 days post-ingestion): This phase is marked by hepatic failure, often progressing to multi-organ failure. Death typically occurs 6–16 days after ingestion if untreated.
2. Mushroom Responsible for Most Fatalities in North America:
   Cyclopeptide-containing mushrooms, particularly those in the Amanita genus (e.g., Amanita phalloides), account for approximately 90% of mushroom-related fatalities in North America. These mushrooms contain amatoxins, which are highly toxic cyclopeptides that inhibit RNA polymerase II, leading to cell death, particularly in the liver and kidneys.
3. Management Strategies for Amanita phalloides Poisoning:
   • Initial Stabilization: Focus on aggressive fluid and electrolyte replacement to address dehydration and metabolic acidosis.
   • Supportive Care: Monitor liver function tests, coagulation profiles, and blood glucose levels closely. Hypoglycemia should be treated promptly with intravenous dextrose.
   • Specific Therapies: Although no definitive antidote exists, several treatments have been used with varying success:
     • High-dose penicillin G: May inhibit the uptake of amatoxins by hepatocytes.
     • Silymarin (milk thistle extract): Acts as an antioxidant and may protect liver cells from damage.
     • N-acetylcysteine (NAC): May help mitigate liver injury by replenishing glutathione stores.
     • Liver Transplantation: Considered in cases of severe liver failure unresponsive to medical management.
   • Consultation: Early consultation with a medical toxicologist and a liver transplant center is critical.
   Additional Considerations:
   • Notify the patient’s friends and ensure their health and safety, as they may have also ingested the mushrooms.
   • Public health authorities should be informed if there is a risk of further exposures in the community.

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Revised Questions and Answers

1. What are the phases of Amanita phalloides poisoning, and what are the major toxicities associated with each phase?
   Amanita phalloides poisoning progresses through three phases:
   • Phase I (6–24 hours): Gastrointestinal symptoms (nausea, vomiting, diarrhea) leading to dehydration, metabolic acidosis, and shock.
   • Phase II (18–36 hours): Apparent clinical improvement, but rising liver enzymes indicate ongoing liver damage.
   • Phase III (2–4 days): Hepatic and multi-organ failure, often resulting in death if untreated.
2. What type of mushroom is responsible for the majority of mushroom-related fatalities in North America?
   Cyclopeptide-containing mushrooms, particularly Amanita phalloides, are responsible for approximately 90% of mushroom-related fatalities in North America due to their amatoxin content.
3. What management strategies should be employed for this patient?
   • Initial Stabilization: Aggressive fluid and electrolyte replacement.
   • Supportive Care: Monitor liver function, coagulation, and blood glucose.
   • Specific Therapies: High-dose penicillin G, silymarin, N-acetylcysteine, and consideration of liver transplantation in severe cases.
   • Consultation: Early involvement of a medical toxicologist and liver transplant center.

References:

1. Garcia, J., Costa, V. M., Carvalho, A., Baptista, P., de Pinho, P. G., & Carvalho, F. (2015). Amanita phalloides poisoning: Mechanisms of toxicity and treatment. Food and Chemical Toxicology, 86, 41-55. https://doi.org/10.1016/j.fct.2015.09.008
2. Enjalbert, F., Rapior, S., Nouguier-Soulé, J., Guillon, S., Amouroux, N., & Cabot, C. (2002). Treatment of amatoxin poisoning: 20-year retrospective analysis. Journal of Toxicology: Clinical Toxicology, 40(6), 715-757. https://doi.org/10.1081/CLT-120015836
3. Ward, J., Kapadia, K., Brush, E., & Salhanick, S. D. (2013). Amatoxin poisoning: Case reports and review of current therapies. Journal of Emergency Medicine, 44(1), 116-121. https://doi.org/10.1016/j.jemermed.2012.02.020

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