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Survival Following Investigational Treatment of Amanita Mushroom Poisoning: Thistle or Shamrock? Gores KM et al. Chest 2014 Oct 1 [Epub ahead of print]
Amatoxins are potent RNA inhibitors, shutting down protein synthesis and producing hepatonecrosis and, occasionally, renal injury.
There is not generally accepted treatment for amatoxin-induced hepatotoxicity aside from supportive care, early multi dose activated charcoal, and liver transplant if indicated. There are, however, a number of unproven therapies that have been used and advocated in the past.
This case report, from the University of Iowa College of Medicine, describes a 71-year-old man who presented with vomiting, diarrhea and weakness 3 days after ingesting mushrooms foraged in northwestern Iowa. Laboratory examination revealed elevated AST (2313 IU/L) and ALT (2730 IU/L), but only slightly elevated total bilirubin and an INR of 1.3 (normal up to 1.2). There was evidence of renal insufficiency with a creatinine of 2.7 mg/dL (normal, 0.51 – 1.2 mg/dL). Treatment was started with IV N-acetylcysteine and penicillin. The next day he became encephalopathic and was started on the experimental drug silibinin.
Silibinin is derived from the milk thistle plant (Silybum marianum). It is has not been FDA approved, but was available as part of a phase 2/3 Open Multicenter Clinical Trial. The drug apparently inhibits entry of amatoxin into hepatocytes. It is generally believed that, if it is to be effective at all, it must be given early. In this patient, who had already developed hepatic encephalopathy, it is unlikely it provided any benefit.
In any case, the encephalopathy and kidney injury resolved on hospital day 3 and was discharged two days later. Even the authors admit that it is not clear whether this seemingly miraculous recovery could be attributed to the thistle (silibinin) or the shamrock (luck).
This paper has many defects. The exact mushroom consumed was never identified. The complete treatment regimen is never identified. And although the authors make a big thing about the importance of shared decision-making when administering experimental drugs, they never disclose exactly how that worked in this case.
For an interesting article on Amanita phalloides in Slate, click here.
[Photograph of Amanita phalloides from wikipedia.org]
Treating Amanita phalloides poisoning: is silibinin superior to chicken dung?
Silibinin or Silly Putty for Mushroom Poisoning?