Doctors at Georgetown University Hospital don’t see many victims of mushroom poisoning. This September, however, when 4 new cases cropped up in 2 weeks, they had an opportunity to try an investigational drug on these patients – a drug that led all patients to a full recovery.
The substance is called silibinin, and is derived from the milk thistle plant. It works by preventing the mushroom’s poisonous amatoxins from reaching and damaging liver cells.
Amatoxins are released by the Amanita mushroom, a poisonous genus that accounts for 95 percent of human illnesses from mushrooms in the U.S..
The treatment of mushroom poisoning has historically been an imperfect science. Given the rarity of these illnesses in the United States, doctors do not have many opportunities to figure out what works best for these patients.
A little over 1,300 illnesses were linked to mushroom poisoning in 2010, according to the American Association of Poison Control Centers. Of these cases, 41 were considered severe, and 3 deaths occurred.
Indeed, the occurrence of 4 cases in the D.C. metro area in a span of 2 weeks is “extremely rare,” says Dr. Jaqueline Laurin, a liver specialist at Georgetown Hospital and the doctor who prescribed silibinin to the patients there, who before last month had not yet treated a case of Amanita poisoning in her 17-year career.
While silibinin has been approved for use in Europe, and has proven effective there, in the U.S. it is only approved for conditional use. Doctors must submit an application to the National Institutes of Health to gain access to it for a patient.
Dr. Laurin had read about silibinin’s success in Europe and in studies in the United States. So when 4 patients from the D.C. metro area presented with high liver toxicity after ingesting amanita mushrooms, she decided the drug was worth a shot.
And though 3 out of the 4 patients arrived outside of the 24 hr window – the time after ingestion in which treatment is most successful – all 4 achieved full recoveries and have now been discharged from the hospital.
Laurin says silibinin likely led to a better outcome for the patients than the standard forms of treatment for mushroom poisoning.
Penicillin G is one of the drugs most commonly given to patients who have eaten poisonous fungi. However, while the drug “has a similar effect, it doesn’t appear to have as strong an effect as silibinin,” she says.
But, Laurin explains, in order for silibinin to be more widely accepted as a treatment for Amanita mushrooms, its effects must be more widely studied.
“The problem with the silibinin is there aren’t any large controlled trials, especially against placebos, for ethical reasons,” she says.
And while rains continue to fall in the northeast, Laurin warns residents there – and anyone picking wild mushrooms – to be sure they know what they’re putting on the table.
“People are out there with their field guides picking mushrooms, but field guides may not have enough detail to be able to help people tell the difference between the edible varieties and the poisonous varieties,” she says.
Symptoms of amanita poisoning usually appear 6 to 12 hours after ingestion. Patients experience severe, watery diarrhea, nausea and vomiting. After 1-2 days, symptoms disappear for a period of time, but amatoxins continue to attack the liver, and can remain in the body anywhere from 5 to 7 days.