Ibotenic Acid Mushroom Toxicity Clinical Presentation

Ask the patient about how many mushrooms were consumed, how they were prepared, and when the mushrooms were eaten. The concentration of active substances is low in any one mushroom, but generally about 1 mushroom in young children and 3 or more in adolescents and adults produce toxic symptoms.^[10] The effects of mushrooms vary greatly, and cooking may not alter toxicity. An amount as small as a mouthful can cause symptoms.^[9]

Obtain a history of the exposure that includes the following:

• Quantity of mushrooms ingested
• Preparation of the mushroom (eg, raw, cooked)
• Source of the mushroom (eg, outdoors, the Internet)
• Time of the ingestion
• Symptoms and time of onset after ingestion
• Prehospital treatment including home remedies
• Medications regularly taken and any coingestants

The timing of symptom onset is a crucial element of the history in differentiating life-threatening or severe mushroom poisonings from those that are less serious and typically have an onset of symptoms well within 5 hours of ingestion such as the mushrooms of the ibotenic acid group.^{[4, 5, 1, 2, 3]}

Mushrooms from the cyclopeptide (Amanita phalloides) or orellanine (Cortinarius mushrooms) groups that can produce hepatic or renal failure, respectively, typically produce symptoms 6-24 h after ingestion.

Amanita smithiana (allenic norleucine group) found in the Northwestern states can also be nephrotoxic, but it has an onset of gastrointestinal distress within 1-12 hours.^[15] These mushrooms are often confused with edible pine mushrooms.

For mushroom ingestions in the Pacific Northwest region of the United States, patients who have early-onset symptoms (< 3 h after ingestion) and remain symptomatic should be fully evaluated in a hospital until the mushroom identity is confirmed to be nontoxic or the patient’s condition improves.^[3]

Identification of the actual mushroom consumed is important but is typically impossible because the mushroom in question has already been digested.

A muscaria has a scarlet cap, is 5-30 cm in diameter and contains white warts. The stalk is white, is frequently hollow, and is often as long as 15-20 cm. A prominent cup (volva) is found at the bottom of the stalk, with numerous rings superiorly. The gills of A muscaria are free and white. The spores are also white. Its appearance can vary depending on the geographic location. The scarlet cap is predominantly found in western North America. Caps that are orange to yellow-orange caps are most frequent in eastern North America.

A muscaria can occur alone or in groups on the ground of forests, in grassy areas and lawns, and especially under trees.

Different types of mushrooms can be found in the same location, and a single sample can lead to false identification of the mushroom that was ingested. Consider all possible mushrooms in the immediate vicinity of where the ingestion occurred.

When no specimen is brought in by a patient with a suspected mushroom ingestion, sending an experienced forager to the site to collect any mushrooms growing in the area might be helpful.

When mushrooms are obtained for identification, the entire mushroom should be dug up to preserve the architecture of the bulb, stem, and cap. Place individual mushrooms in a dry paper bag, not a plastic or cloth bag. Transporting the mushrooms in a careful, dry manner minimizes destruction of the natural architecture of the mushrooms, discoloration of the cap or gills, and premature release of the spores. Do not refrigerate or crush the mushrooms.

Collecting the patient's gastric contents by means of gastric lavage or after emesis might yield identifiable spores.

Remote viewing of the mushroom by digital photography and Internet transmission may aid the identification of unknown mushrooms by mycologists.^[16]

Once ingested, A muscaria produces symptoms within 30-90 minutes. Peak effects occur at 2-3 hours. The initial symptom is drowsiness, followed by confusion, ataxia, dizziness, euphoria, and intoxication. These symptoms can proceed to hyperkinesis, muscle jerks, spasms, and delirium. Deep sleep or coma can occur and generally lasts 4-8 hours.

• If symptoms such as vomiting, diarrhea, and abdominal pain begin 5 hours or more after ingestion, poisoning with the potentially life-threatening or severe mushrooms such as the cyclopeptide (Amanita phalloides) or orellanine (Cortinarius mushrooms) groups, which can produce hepatic or renal failure, respectively, should be considered.^{[4, 5, 1, 2, 3]}Amanita smithiana (allenic norleucine group) found in the Northwestern United States can also be nephrotoxic, but it has an onset of gastrointestinal distress within 1-12 hours after ingestion.^[15] For mushroom ingestions in the Pacific Northwest region of the United States, patients who have early-onset symptoms (< 3 h after ingestion) and remain symptomatic should be fully evaluated in a hospital until the mushroom identity is confirmed or the patient's condition improves.^[3]
• Vital signs: Pulse and blood pressure are usually unchanged.
• Respiration: Breathing is slow and regular, similar to that in deep sleep.
• GI: GI upset and vomiting occur but are not common. When vomiting or diarrhea does occur, fluid and electrolyte changes are uncommon.
• Integumentary: Skin may be reddened and warm to the touch.
• Musculoskeletal: Muscle spasms may occur.
• Neurologic: Agitation and CNS depression may occur. Especially in children, tonic-clonic seizures, fasciculations, and myoclonic jerking lasting 6-9 hours have been reported.^[9] Seizures in adults are uncommon. Initial excitation leads to stupor, then coma; severe lethargy alternating with agitation is common, and a deep sleep may occur. Agitation, babbling, confusion, screaming, irritability, hallucinations, dizziness, ataxia, euphoria progressing to muscle jerks, spasms, delirium, racing thoughts, and giddiness may be seen. Headache may last several days. Illusions of sight and sound are produced by misinterpretation of sensory input.

• Incorrect mushroom identification by a naive forager such as an immigrant who mistakes one of the local poisonous varieties for an edible mushroom native to his or her homeland or a novice mushroom harvester
• Intentional ingestion by a suicidal person
• Unintentional ingestion by a child who found mushrooms growing in yards or outdoor play areas
• Foul play in which an individual is poisoned by someone else
• Inadvertent poisoning from dried mushrooms purchased on the Internet or from other sources where the composition of the mushroom is unreliable or where the mushroom might contaminated with unknown toxic compounds