Clinical presentation

The clinical course of Amanita phalloides poisoning is shown in Clinical course of Amanita phalloides poisoning.

The clinical effects of Amanita phalloides poisoning are often delayed for several hours after ingestion. Patients are usually asymptomatic for at least 6 hours and this time frame aids the diagnosis. Earlier onset of gastrointestinal symptoms suggests exposure to less dangerous mushroom species that cause gastrointestinal irritation; however, this does not exclude Amanita phalloides exposure because the patient may have ingested a mixture of mushroom species.

The duration of the asymptomatic period after ingestion of Amanita phalloides has been inversely linked to the severity of liver toxicity—ie the shorter the time to onset of symptoms, the worse the prognosis.

Other signs that suggest a poor prognosis are:

  • acute kidney injury associated with development of acute liver injury
  • progressive rise in blood lactate concentration, or blood lactate concentration more than 5 mmol/L in the presence of acute liver injury
  • rising serum alanine aminotransferase (ALT) concentration—may take up to 24 hours after ingestion to rise, even in fatal poisoning
  • rising international normalised ratio (INR) 3 days after ingestion or INR of more than 6.0 at day 4 after ingestion.
Table 1. Clinical course of Amanita phalloides poisoning

Time after ingestion of Amanita phalloides

Clinical effects

up to 18 hours

may be asymptomatic

6 to 24 hours

gastroenteritis (abdominal pain, nausea, vomiting, profuse watery diarrhoea)

dehydration with or without hypotension

metabolic acidosis, electrolyte disturbances, acute kidney injury

normal or mildly abnormal liver aminotransferase enzymes

1 to 7 days

resolving gastroenteritis

progressive liver injury leading to liver failure, coagulopathy, acute kidney injury (including hepatorenal syndrome)

multiorgan failure (mortality 10 to 30%)

for prognostic markers, see Key investigations and Treatment for liver failure

more than 7 days

complete resolution in most survivors over weeks or months

chronic hepatitis in some survivors

Note: Adapted with permission of John Wiley & Sons, Inc from: Roberts DM, Hall MJ, Falkland MM, Strasser SI, Buckley NA. Amanita phalloides poisoning and treatment with silibinin in the Australian Capital Territory and New South Wales. Med J Aust 2013;198(1):43-7. [URL]. © 2013 AMPCo Pty Ltd. All rights reserved.