JOURNAL OF THE LOUISIANA STATE MEDICAL SOCIETY
mushroom poisoning literature, Graeme made the following observations. 13 (1) There are about 100,000 known species of fungi with about 800 new species of fungi includingmushrooms being named each year. (2) There are about 100 known species of mushrooms that are poisonous to human with new species constantly being identified and edible species being reclassified as poisonous. (3) The incidences of toxic mushroom ingestions and consequential fatalities are increasing with most fatalities due to amatoxin-containing mushrooms, especially Amanita phalloides. 13 In conclusion, retrospective longitudinal studies and meta- analyses have confirmed that toxic mushroom exposures are increasing in the US and worldwide today; several new mushroom syndromes have been described in the US and elsewhere; most exposures were unintentional with good outcomes; children younger than six years were at greatest risk of mushroom poisoning; and deaths, although rare, occurred most commonly in adult amateur mushroom hunters who consumed hepatotoxic or nephrotoxic mushrooms.
Amanita mushroom poisoning in Ukrainian immigrants in the Boston area in which the authors attributed their successful supportive management to the early identification of the ingested mushrooms as amatoxin-containing on an initial photograph transmitted to a consulting Poison Control Center mycologist. 16 Clinical Case Reports and Case Series of Nephrotoxic Mushroom Poisonings The nephrotoxicity of Cortinarius species mushrooms was initially described in Poland in 1957 by Stanislaw Grzymala who reported a series of 102 cases of acute renal failure with 11 fatalities in patients who had consumed cooked Cortinarius orellanus mushrooms. 17 By 1962, Grzymala had isolated a crude extract from C. orellanus which he named orellanine and which caused renal toxicity when administered to experimental animals. 18 In 1990, Bouget and coinvestigators in France reported a case series of 26 healthy young men who developed acute renal failure after ingesting mushroom soup made with Cortinarius orellanus . 19 All patients were hospitalized within two weeks with 12 patients presenting with acute tubulointerstitial nephritis on renal biopsies. 19 Of these 12 patients, eight required hemodialysis and recovered rapidly; and the remaining four developed chronic renal failure lasting for months. 19 Of the remaining 14 of the 26 initially poisoned patients, 12 developed leukocyturia, and all 12 had normal renal function at one-year follow-up. 19 Duvic and coinvestigators later followed 12 of the 26 men who had developed renal failure in the Bouget et al case series for a period of 13 years after ingesting the C. orellanus mushroom soup. 20 Of these 12 patients, seven recovered normal renal function, four had kidney transplants, and one patient on hemodialysis died in a car accident. 20 Duvic et al. estimated the incidence of acute renal failure following Cortinarius orellanus ingestions to range from 30-46% with renal failure regressing over several months in 60% of cases. 20 Although most Cortinarius poisonings have been reported from Poland and France, Cortinarius species mushrooms are widely distributed in the coniferous forests of the Scandinavian countries, Britain, North America, Canada, and Australia. 21 In 1995, Holmdahl and Blohme reported a case series of 22 patients who were poisoned after consuming cooked Cortinarius speciosissimus (synonym C. rubellus ) mushrooms in Sweden during the period, 1979-1993 (Figure 1). 22 Nine patients developed chronic renal failure, and five patients required kidney transplants. 22 Three of these patients were transplanted after up to six months of hemodialysis. 22 Two patients who did regain some renal function had to be restarted on hemodialysis 24 and 30 months later and also received kidney transplants. 22 The authors concluded that delayed renal failure could follow partial renal recovery by years and that renal transplantation could guarantee successful outcomes even years after mushroom poisonings. 22 Their case series was the first to utilize kidney transplantation in the management of end-stage renal disease
The Nephrotoxic Mushroom Species
Table 1 compares the distinguishing morphological features of the nephrotoxic mushroom species and identifies the edible mushrooms that nephrotoxic mushrooms are most commonly mistaken for by amateur mushroom foragers worldwide. All four genera and most species of these mushrooms may be found in Louisiana with the exception of Russula subnigricans, an Asian species found primarily in China, Taiwan, Korea, and Japan. 14
Identifying Nephrotoxins in Mushrooms and Poisoned Patients
Today, heat-stable nephrotoxins such as orellanine (a tetrahydroxylated-N-oxide bipyridine) in Cortinarius species mushrooms and allenic norleucine (2-amino-4,5-hexadienoic acid) in Amanita smithiana can be most accurately measured directly in the serum and urine of poisoned patients using immunological and chromatographic techniques, such as enzyme-linked immunosorbent assay (ELISA), radioimmunoassay, thin-layer chromatography, high- performance liquid chromatography, and gas chromatography- mass spectrometry. These analytical procedures are, however, time-consuming, require trained laboratory technicians, and are often not immediately or uniformly available. Visual and microscopic identification of poisonous mushrooms and their spores by experts may offer a more rapid means of identifying mushrooms as potentially nephrotoxic. 15 In addition to immunological and chromatographic analyses, mushrooms can now be tentatively identified as potentially nephrotoxic in the field using digital telephone images transmitted directly to expert mycologists. 15,16 If the mushrooms can be presumed to be poisonous, then valuable on-scene observations can be utilized to justify immediate hospital admission for aggressive, supportive therapy before renal failure ensues. 15,16 In 2012, Ward et al. reported two cases of hepatotoxic
164 J La State Med Soc VOL 169 NOVEMBER/DECEMBER 2017
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