The Latent Phase of Amanita phalloides Poisoning
A 45-year-old man presents 36 hours after eating a meal of wild mushrooms he foraged; a mycologist reviewing his photographs identifies Amanita phalloides. He had 12 hours of profuse vomiting and diarrhea that stopped 12 hours ago, and he now feels nearly well. Examination shows mildly dry mucous membranes and right upper quadrant tenderness. AST 1,850 U/L, ALT 2,100 U/L, total bilirubin 3.2 mg/dL, INR 1.8, creatinine 1.4 mg/dL, platelets 120,000/µL, glucose 78 mg/dL. He is admitted to a hospital with no transplant center and no silibinin on formulary. His wife and 10-year-old son shared the meal and are currently asymptomatic.
1. Explain what is happening over this timeline, why the current improvement is dangerous, and what the laboratory values predict.
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Amanita phalloides amatoxins inhibit RNA polymerase II, so cells that transcribe heavily - hepatocytes and proximal tubular cells - die over hours to days rather than immediately. That produces a characteristic sequence:
- Latency (6–24 hours): minimal symptoms while toxin is absorbed and taken up by hepatocytes via OATP transporters.
- Gastrointestinal phase (6–24 hours): violent vomiting, diarrhea, and abdominal pain, often mistaken for gastroenteritis; this is when fluid losses occur.
- Apparent recovery (24–72 hours): symptoms settle as the gut empties, but hepatic injury is progressing. Clinicians and patients are most likely to disengage here.
- Hepatic phase (48–96 hours): rising transaminases, coagulopathy, jaundice, encephalopathy, renal failure, and in severe cases fulminant hepatic failure.
The current values already show established injury: transaminases in the thousands, a bilirubin that is beginning to rise, and an INR of 1.8 indicating synthetic dysfunction. The near-normal examination is not reassurance; it is the eye of the storm. A falling transaminase with a rising INR and bilirubin would be a far worse sign than a high transaminase, because it means hepatocytes are being lost rather than leaking. Renal impairment suggests amatoxin uptake in tubular cells and volume depletion. This patient needs to be at a transplant center.
2. Design treatment with the resources available, including the evidence for each intervention and the role of decontamination at this stage.
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Silibinin is the best-studied antidote (it blocks OATP-mediated hepatic uptake) and is most effective within 24–48 hours, but it is not stocked here. Pursue it anyway: it can be obtained from Europe or through an emergency investigational new drug request to the regulator, and a transplant center is more likely to have access. Start it if it arrives.
N-acetylcysteine is reasonable off-label therapy: use the standard intravenous regimen (150 mg/kg over 1 hour, 50 mg/kg over 4 hours, 100 mg/kg over 16 hours). Evidence in amatoxin poisoning is observational, but the risk is low and the potential benefit in a patient with evolving hepatic failure is real.
High-dose penicillin G (roughly 300,000–1,000,000 units/kg/day, up to about 40 million units/day) is the classic alternative, also acting on OATP uptake. Watch for sodium load, seizures, and hypersensitivity.
Decontamination: activated charcoal within 1–4 hours of ingestion is standard; at 36 hours with resolved vomiting there is little yield, though some clinicians give repeated doses for enterohepatic recirculation. Do not force it in a patient who is vomiting.
Supportive care: aggressive fluid and electrolyte replacement, correct hypoglycemia, avoid nephrotoxins and hepatotoxins, treat coagulopathy only for bleeding or procedures, and involve nephrology for continuous renal replacement if renal failure develops. Transfer to a transplant center now - before encephalopathy makes transport hazardous.
3. When do you refer for transplant, what criteria would you use, and how do you manage the two asymptomatic family members?
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Refer immediately, not when criteria are met. Amatoxin poisoning can progress over 24 hours from an INR of 1.8 to fulminant failure, and transfer becomes far riskier once encephalopathy, cerebral edema, or shock develops. Contact the transplant center now and describe the ingestion, the timeline, and the trend.
Criteria: King's College criteria for non-paracetamol fulminant hepatic failure are the conventional framework - an INR above 6.5 alone, or any three of: age under 10 or over 40 years, an aetiology of non-A non-B hepatitis or drug reaction, a jaundice-to-encephalopathy interval over 7 days, an INR above 3.5, or bilirubin above 300 µmol/L. Recognize their limits: they were derived for a mixed population, and a young patient with amatoxin poisoning can deteriorate before they are satisfied. Prognostic markers such as factor V, lactate, and the clinical trajectory inform the discussion. The threshold for listing should be low in a previously healthy 45-year-old with a known amatoxin ingestion.
Family members: shared ingestion means shared risk, and asymptomatic is not safe at 36 hours. Obtain AST, ALT, bilirubin, INR, and creatinine on both the wife and the son now and again at 48–72 hours. If the child has eaten any portion, discuss prophylactic silibinin or N-acetylcysteine with a poison center, and involve pediatrics. Admit for observation rather than reassuring them by telephone. Give the family the honest prognosis while the patient can still participate in decisions.