Foraging for edible wild mushrooms is becoming increasingly popular say the authors of a
case study of a woman who had to have a liver transplant after ingesting mushrooms she thought were
safe to eat.
The authors warn that poisonous and edible mushrooms can be very
similar in appearance.
Dr. Adina Weinerman of Sunnybrook Health Sciences Centre in Toronto, Canada, and colleagues
explain how eating the wrong mushrooms can result in liver failure and even death.
Even fungus experts can find it hard to distinguish mushrooms that are safe to eat from harmful
ones, they note in a paper published in the Canadian Medical Association Journal.
There is no antidote for mushroom poisoning. The authors recommend doctors caring for patients
with the condition should treat it aggressively, monitor the liver closely, and ask a poison control
center about additional treatments. They should also investigate liver donation in case of liver
failure.
If administered promptly, charcoal can absorb mushroom toxin. But unfortunately, because
symptoms take time to appear, patients present themselves at emergency departments too late for this
to be effective.
The true incidence of mushroom poisoning is hard to quantify because of the likely high number
of unreported cases. The authors say in the US around 6,000 cases are reported annually, most of
which are associated with mild symptoms.
Mushroom poisoning is more common in Western Europe, where around 50-100 deaths are reported
every year.
Mushroom poisoning proceeds through three phases
In their paper, the authors describe the case of a 52-year-old immigrant Asian woman living in
Canada who had been picking wild mushrooms in a local park with her husband, who used to forage for
wild mushrooms in his native country.
The woman – who had been healthy before experiencing sudden abdominal pain, nausea, vomiting and
watery diarrhea – eventually required a liver transplant.
She had eaten the mushrooms 12 hours before attending the emergency department. She
brought some of the mushrooms with her to the hospital: they were Amanita bisporigera, a
highly toxic species.
There are over 600 types of Amanita fungi, and they cause the most deaths from mushroom
poisoning.
Mushroom poisoning proceeds through three phases. The first phase occurs 6-24 hours after
ingestion and produces stomach and gut pain, nausea, vomiting and diarrhea.
The second phase is a “false recovery” phase where the symptoms seem to go away and the patient
feels better. The authors warn this can lead to premature discharge from the emergency department or
hospital.
In the third and final phase of mushroom poisoning, which usually occurs around 48 hours after
ingestion, liver failure sets in, followed by multi-organ failure and even death.
‘Poisonous and edible mushrooms can be very similar in appearance’
In 2013, experts from Rutgers New Jersey Medical School warned that the growing popularity of wild mushroom foraging in the US may lead to
increased hospitalizations and serious illness. The majority of reported cases of mushroom poisonings, they said, were of immigrants who were
used to foraging in their native lands.
The Canadian authors of this latest paper make the same observation and conclude:
“Patients should be counseled that poisonous and edible mushrooms can be very
similar in appearance and that wild mushrooms of uncertain identity should not be eaten. This
information is especially important for immigrants who might mistake local poisonous mushrooms for
familiar edible species from their native land.”
They urge people to report cases of mushroom poisoning to the appropriate authorities so the
toxic fungi can be located and further cases prevented.
The North American Mycological Association have an online form where you can report
cases of mushroom poisoning.
Tips for mushroom foragers
In their guide to mushrooming, the Missouri Department of Conservation recommend you do
all of the following if you forage for edible wild mushrooms:
- Join a mushroom club and go on forays and workshops
- Learn about mushrooms and how to identify them
- Use several field guides – one picture is not enough – and read the details carefully
- Show your finds to experts
- Don’t let your nose guide you – poisonous mushrooms can smell and taste good too
- Collect and identify what you think is the same species again and again
- Learn how mushrooms from the same species can look very different as they mature and in
different seasons
- And learn how mushrooms from different species can look very similar – a common cause of
mushroom poisoning is green-spored Lepiota (Chlorophyllum molybdites), young specimens of
which look just like the common white button mushrooms you can buy
And most importantly – if in doubt – throw it out! Be 100% sure it is edible before you put it in
your mouth.
Written by Catharine Paddock PhD
Copyright: Medical News Today