Hallucinogenic Mushroom Toxicity Clinical Presentation

Updated: Jan 23, 2021
  • Author: Louis Rolston-Cregler, MD; Chief Editor: Sage W Wiener, MD  more...
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Obtain a history of the exposure that includes the following:

  • Quantity of mushrooms ingested – The concentration of active substances is low in any individual mushroom, but as a general rule, toxic symptoms result from the consumption of about 1 mushroom by young children and 3 or more by adolescents and adults [14] ; an amount as small as a mouthful can cause symptoms [13]

  • Preparation of the mushroom (eg, raw or cooked) – The effects of mushrooms vary greatly, and cooking may not alter toxicity

  • Source of the mushroom (eg, outdoors or the Internet)

  • Time of ingestion

  • Symptoms seen after ingestion and time between ingestion and onset – Symptoms tend to appear more quickly after ingestion of hallucinogenic mushrooms than after ingestion of more lethal mushrooms

  • Prehospital treatment, including home remedies

  • Medications regularly taken and any co-ingestants

The timing of symptom onset is important for distinguishing life-threatening or severe mushroom poisonings from less serious ones, which typically have an onset of symptoms well within 5 hours of ingestion (as is the case for poisonings involving hallucinogenic mushrooms). If symptoms such as vomiting, diarrhea, and abdominal pain begin 5 hours or more after ingestion, mushrooms that can cause potentially life-threatening or severe toxicity (eg, A phalloides or Cortinarius spp) should be considered. [23, 24, 25, 26, 27]

Note, however, that Amanita smithiana, a mushroom found in the northwestern United States, is characterized by the onset of GI distress within 1-12 hours after ingestion. [28] For mushroom ingestions in the Pacific Northwest, patients who have early-onset symptoms (< 3 hours after ingestion) and remain symptomatic should be fully evaluated in a hospital until the mushroom identity is confirmed or the patient’s condition improves. [27]

Identification of the actual mushroom consumed is important but is typically impossible because the mushroom in question has already been digested. (See Identification of Mushroom Specimens.) Collecting the patient’s gastric contents by means of gastric lavage or after emesis might yield identifiable spores. Remote viewing of digital images of an unknown mushroom may facilitate its identification by a mycologist. [29]

For more information on differentiating among various mushroom poisonings, see Mushroom Toxicity.

Mushrooms containing ibotenic acid and muscimol

Symptoms of poisoning with ibotenic acid or muscimol typically begin 30 minutes to 1 hour after ingestion; in rare cases, however, symptom onset may be delayed as long as 3 hours.

Hallucinations may be accompanied by dysarthria, ataxia, and muscle cramps and may persist for as long as 8 hours. However, a case report described an otherwise healthy 48-year-old man who accidentally ingested A muscaria mushrooms and experienced a 5-day paranoid psychosis accompanied by visual and auditory hallucinations. [18] By day 6, his condition had returned to baseline, with no long-term adverse effects reported.

Central nervous system (CNS) effects range from agitation to coma. Heavy intoxication may cause vomiting, diarrhea, and seizures.

Fatal A pantherina poisonings have been reported in the Pacific Northwest region of the United States. [4, 20, 30]

Mushrooms containing psilocybin

Alterations in perception begin within 30 minutes of ingestion of psilocybin-containing mushrooms and generally subside after 6 hours.

Widely varying CNS manifestations (eg, euphoria, visual and religious hallucinations, and feeling closer to nature) have been reported. Visual hallucinations may include perceived motion of stationary objects or surfaces. [31] Patients presenting in the emergency department (ED) may describe more unpleasant effects, such as fear, agitation, confusion, delirium, psychosis, and schizophrenia-like syndromes.

Symptoms may include nausea and sympathomimetic activity such as mydriasis and tachycardia. Symptoms in children include hyperpyrexia and seizures.


Physical Examination

Physical examination typically yields the following findings:

  • Vital signs – Pulse and blood pressure are usually unchanged.

  • Respiration – Breathing is slow and regular, similar to that in deep sleep

  • Gastrointestinal (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 (eg, ataxia, incoordination, confusion, delirium, and psychosis) – Agitation and CNS depression may occur; especially in children, tonic-clonic seizures, fasciculations, and myoclonic jerking lasting 6-9 hours have been reported [13] ; seizures in adults are uncommon

In these intoxications, neurologic findings predominate. 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. Fever, tachycardia, and hypotension may occur because of agitation.