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Geoffrey M Trim, Heino Lepp, Matthew J Hall, Robin V McKeown, Geoffrey
W McCaughan,
Geoffrey G Duggin and David G Le Couteur
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Introduction -
Clinical records -
Discussion -
Acknowledgements -
References -
Authors' details
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Introduction |
The "deathcap" mushroom, Amanita phalloides, accounts for
most deaths after mushroom ingestion.1,2 There are four clinical
phases of poisoning: an initial asymptomatic latent phase, a
gastrointestinal phase characterised by watery diarrhoea, a
honeymoon period when symptoms temporarily resolve, and a final
hepatic phase characterised by hepatic and renal failure. In an
adult, death may ensue within 7-10 days of ingestion of a single
cap.1,2 We report seven cases of
poisoning by A. phalloides mushrooms that occurred in the
Australian Capital Territory (ACT) between 1988 and 1998. The only
other Australian reports have been from Victoria,3,4 and there is
now concern that the mushroom may be becoming more widespread in
Australia.
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Clinical records |
The seven cases are summarised in the Box. Patients comprised six
adults aged 20-46 years and a seven-year-old child. All patients had
eaten cooked mushrooms that they had picked in gardens or streets of
Canberra, except the child, who had eaten part of a raw mushroom she had
picked in her schoolyard. Three Laotians were poisoned at the
same time when they mistook A. phalloides for the
superficially similar-appearing paddy straw mushroom
(Volvariella volvacea), common in South-East Asia.
The dose ranged from a quarter to eight mushrooms. All patients
presented after one to two days with diarrhoea and, in most cases,
vomiting, except the child, who vomited within two hours and was
brought for medical attention immediately. The diagnosis was made on
initial presentation in only this child and the other 1998 patient
(Patient 2).
Three patients developed significant hepatic dysfunction, and two
were transferred to a liver transplant unit, one of whom died. Details
of the two who were transferred follow.
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Patient 1 |
In 1995, a 46-year-old man ate eight mushrooms which he had picked in a
north Canberra suburb. He presented with vomiting and diarrhoea the
next day, but, as he was confident that the mushrooms were not A.
phalloides, he was discharged home after receiving intravenous
rehydration. He presented again two days later with hepatic and renal
failure.
Initial investigations revealed the following serum levels:
alanine aminotransferase (ALT) > 10 000 U/L (reference range
[RR], 5-55 U/L); bilirubin, 114 µmol/L (RR, 3-20
µmol/L); creatinine, 535 µmol/L (RR, 40-90
µmol/L); and prothrombin time - international normalised
ratio (PT-INR) > 10. A mycologist identified A.
phalloides growing in the street where the patient had picked the
mushrooms and also identified the mushroom stalks that he had
discarded in a rubbish bin.
The patient was transferred to a liver transplant unit but died from
hepatic failure six days after mushroom ingestion. Postmortem
examination of his liver revealed complete necrosis of parenchyma,
with one residual island of intensely vacuolated hepatocytes with
severe intracanalicular biliary stasis. No viable hepatocytes were
seen.
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Patient 2 |
In 1998, a 39-year-old man ate three mushrooms picked from his back
garden in an inner Canberra suburb. The mushrooms were cooked
as a pasta sauce. He had been previously well but had been taking
griseofulvin for six months to treat a fungal toenail infection.
Eighteen hours after ingestion, he developed watery diarrhoea. He
presented to hospital with dehydration and epigastric discomfort 36
hours after ingestion.
Initial investigations revealed the following serum levels: ALT,
914 U/L; bilirubin, 24 µmol/L; and creatinine, 102
µmol/L. He had evidence of metabolic acidosis, with pH of 7.30
(RR, 7.34-7.44) and bicarbonate level of 18.6 mmol/L (RR, 22-26
mmol/L). The mushrooms were identified as A. phalloides by a
mycologist.
The patient was transferred to a liver transplant unit and treated
with intravenous fluids, high dose penicillin and
N-acetylcysteine. Three days after mushroom ingestion, his
serum ALT level peaked at 8199 U/L, and PT-INR at 4.7, but he did
not develop encephalopathy. He subsequently made an uneventful
recovery.
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Discussion |
Our seven patients poisoned by A. phalloides mushrooms in the
ACT is the only series reported in Australia. In five of our seven
patients, the diagnosis was not made on initial presentation, and in
one it was not suspected at all, despite a history of mushroom
ingestion and characteristic clinical picture. Three patients
developed significant hepatic dysfunction, two were transferred to
a liver transplant unit and one died. There have been only two other
reports of poisoning by A. phalloides mushrooms in
Australia,3,4 both in Victoria. Neither
case was diagnosed on initial presentation, and one was
fatal.3
A. phalloides is a mycorrhizal fungus (ie, it grows in a
symbiotic association with the roots of trees, primarily oak trees).
It produces a range of toxins (amatoxins). The major toxin, a cyclic
peptide, amanitin, inhibits RNA polymerase II and is not inactivated
by cooking, freezing or drying. The lethal dose is about 0.1 mg/kg,
which may be contained in as little as one mushroom.5 Amanitin is
usually cleared rapidly, mainly by renal excretion.6
Recommended treatment of A. phalloides poisoning includes
vigorous gastrointestinal decontamination.7 Early and
aggressive decontamination may have prevented toxicity in the
seven-year-old child. Supportive care, including intravenous
rehydration, is thought responsible for most of the improvement in
mortality, from well over 50% early this century to 20%-30% in recent
decades.1 Many specific antidotes
have been used, although no prospective-trial evidence is
available. Retrospective clinical studies and animal studies
support the use of high dose penicillin (0.5-1 million units/kg per
day) and parenteral silibinin, an extract of milk thistle available
only in Europe. Both are thought to act by inhibiting amatoxin
uptake into hepatocytes and by interfering with its
enterohepatic circulation.1,7 Cimetidine, a hepatic
enzyme inhibitor, may be harmful.8 We speculate that, in
Patient 1, long-term use of griseofulvin (a hepatic enzyme inducer)
before poisoning may have increased the rate of detoxification of
amatoxin and thereby contributed to survival. Liver
transplantation may be used in cases that fail to respond to more
conservative measures. It has been performed successfully for this
indication in the United States since 1985,9 but has not been attempted
for this indication in Australia.
A. phalloides mushrooms have been described in many regions
of south-eastern Australia. Collections have been made in several
Melbourne suburbs,4,10,11 and the Victorian
country centres of Riddells Creek, Morwell and Walhalla.11 The National
Herbarium of Victoria and the State Herbarium in Adelaide hold
collections of A. phalloides or very similar species from New
South Wales, Tasmania and Victoria. A. phalloides mushrooms
were first reported in Canberra in 19614 and are now widespread in the
ACT.
Although A. phalloides is found primarily in association
with oak trees, there is concern among mycologists and toxicologists
that it may develop the ability to grow in association with other
trees, particularly Australian natives, and thereby spread
dramatically. Associations between Eucalyptus spp. and
Amanita spp. other than A. phalloides have been
reported in other countries,12 and between
Eucalyptus spp. and A. phalloides itself in
Africa.13,14 There is anecdotal
evidence of A. phalloides forming mycorrhizae with
Eucalyptus spp. in Canberra (Richard Windsor, consultant
botanist, Canberra, ACT, personal communication).
A. phalloides is not the only mushroom to contain amatoxins.
In the northern hemisphere, these toxins are found in other
Amanita species and in species within the genera
Conocybe, Galerina and Lepiota,1 which also occur
in Australia. Four cases of Lepiota helviola poisoning have
been reported from Adelaide. In each, hepatotoxicity occurred and
amatoxins were identified.4,15
A. phalloides is now widely distributed in south-eastern
Australia, and may become more widespread if it develops the ability
to grow in association with eucalyptus trees. Increased community
and clinician awareness is needed to reduce the incidence of
poisoning and to improve outcomes. Wild mushrooms should not be eaten
unless definitely identified as non-poisonous. Clinicians should
consider A. phalloides poisoning in patients with vomiting,
diarrhoea or abnormal liver function.
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Acknowledgements | |
We thank Graham Bell (State Herbarium, Adelaide) and Tom May
(National Herbarium of Victoria) for information about Amanita
phalloides collections in their herbaria, and Richard Windsor
(Canberra, ACT) for his comments about A. phalloides and
Eucalyptus spp. in Canberra.
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References |
- Benjamin DR. Amatoxin syndrome. Mushrooms: poisons and panaceas
-- a handbook for naturalists, mycologists and physicians. New York:
W H Freeman and Company, 1995: 198-241.
-
Pond SM, Olson KR, Woo OF, et al. Amatoxin poisoning in northern
California, 1982-1983. West J Med 1986; 145: 204-209.
-
Nicholson FB, Korman MG. Death from Amanita poisoning. Aust N Z J
Med 1997; 27: 448-449.
-
Southcott RV. Notes on some poisonings and other clinical effects
following ingestion of Australian fungi. S Aust Clin 1974; 6:
442-478.
-
Weiland T. Poisonous principles of mushrooms of the genus
Amanita. Science 1968; 159: 946-952.
-
Jaeger A, Jehl F, Flesch F, et al. Kinetics of amatoxins in human
poisoning: therapeutic implications. J Toxicol Clin
Toxicol 1993; 31: 63-80.
-
Floersheim GL. Treatment of human amatoxin mushroom poisoning:
myths and advances in therapy. Med Toxicol 1987; 2: 1-9.
-
Schneider SM, Vanscoy G, Michelson EA. Failure of cimetidine to
affect phalloidin toxicity. Vet Hum Toxicol 1991; 33: 17-18.
-
Klein AS, Hart J, Brems JJ, et al. Amanita poisoning:
treatment and the role of liver transplantation. Am J Med
1989; 86: 187-193.
-
Reid DA. A monograph of the Australian species of Amanita
Pers. ex Hook (Fungi). Aust J Bot Supplementary Series No.
8, 1980: 48.
-
Cole FM. Amanita phalloides in Victoria. Med J
Aust 1993; 158: 849-850.
-
May TW, Wood AE. Extra-Australian species associated with
Eucalyptus. Fungi of Australia. Volume 2A. Canberra: Australian
Biological Resources Study and CSIRO, CSIRO, 1997: 239-240.
-
Malencon G, Bertault R. Flore des champignons supérieurs du
Maroc. Tome I. Rabat, Morocco: Faculté des Sciences, 1970: 75.
-
Pegler DN. Amanitaceae. A preliminary agaric
flora of East Africa. London: HMSO, 1977: 296-297.
-
Lloyd C, White J, Downes S, et al. Amatoxin poisoning following
ingestion of Lepiota helviola. Report of two cases with
hepatotoxicity. Abstracts of the 10th World Congress on Animal,
Plant and Microbial Toxins. Singapore; 1991 3-8 Nov. 1991: 345.
(Received 11 Feb, accepted 24 Jun, 1999)
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| | Authors' details |
Canberra Hospital, Canberra, ACT.
Geoffrey M Trim, MB BS, Clinical Pharmacology Registrar;
Robin V McKeown, PhC, Poisons Information Service;
David
G Le Couteur, FRACP, PhD, Associate Professor, The Canberra
Clinical School of the University of Sydney.
Australian National Herbarium, Centre for Plant Biodiversity
Research, Canberra, ACT.
Heino Lepp, BSc(Hons), Scientific Associate.
Royal Prince Alfred Hospital, Sydney, NSW.
Matthew J Hall, MB BS, Gastroenterology Registrar;
Geoffrey W McCaughan, FRACP, PhD, Physician-in-Charge,
Australian National Liver Transplant Unit;
Geoffrey G Duggin,
FRACP, Head, Toxicology Unit.
Reprints will not be available from the authors.
Correspondence:
Associate Professor D G Le Couteur, Department of Clinical
Pharmacology, The Canberra Hospital, Yamba Drive, Garran, ACT
2605.
Email: david_lecouteurATdpa.act.gov.au
©MJA 1999
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|  | Amanita phalloides mushrooms at different stages of the lifecycle. A mature "deathcap" typically has a greenish-brown to white cap, white gills on the underside of the cap, a white frill-like ring on a white to pale yellow-green stem, and a white underground cup.
The deathcap may be mistaken by those unfamiliar with fungi for mushrooms of the genus Agaricus, the type most commonly grown for consumption. The deathcap also superficially resembles the edible paddy straw mushroom (Volvariella volvacea).
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