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Mushrooms and Toadstools
920
Mushrooms and Toadstools " BOLETUS mittere difficile est," wrote MARTIAL, implying that he would sooner be parted from his money than his mushrooms. His enthusiasm is shared by one of our national advisers on gastronomy,l and in parts of Europe the popularity of edible mushrooms has led to their near-extinction around the main towns.2 This widespread use of fungi for food has led to a formidable mortality: EURIPIDES mourned a whole family who succumbed to accidental poisoning, and the death-roll in Europe since then contains such illustrious names as the Emperors CLAUDIUS and JoviAN, Pope CLEMENT VII, and the Austrian Emperor CHARLES VI. Deaths were reported from France by the hundred at the beginning of this century,3 and as late as 1948 the toll in Germany In this country was about two hundred a year .4 been common to have mushroom-poisoning appears until the 17th century,5 but it has since declined pari passu with the harvesting of wild mushrooms and no longer rates a separate entry in the Registrar 6General’s report; nonetheless, cases are still reported. In the United States it is also a declining disease which causes an estimated fifty deaths a year.7 In France unsuccessful attempts to prevent poisoning " were once made by the appointment of mushroom inspectors" at markets, and in the U.S.S.R. batches of mushrooms are still inspected for poisonous contaminants.8 But the identification of picked mushrooms is particularly difficult. Virtually the only mushrooms on sale in this country are the cultivated variety, Agaricus bisporus 9; and, since the culture-media usually employed do not support the growth of the most poisonous varieties, the possibility of accidental contamination is now very remote. The identification of mushrooms after ingestion calls for more mycological skill than is possessed by most doctors who report cases of poisoning. Some species are poisonous only when eaten uncooked or over-mature, in large quantities, or at certain seasons. Estimates of the number of poisonous species therefore vary widely. In a review of mushroompoisoning in the eastern United States, BUCK 10 mentions fifty-three species which are thought to be poisonous, and most of these are also found in Great Britain. But RAMSBOTTOM5 regards only about twenty British fungi-some 1-2% of all species of higher fungi found here-as definitely dangerous. The risk of mushroom-poisoning is due not so much to the high prevalence of poisonous varieties as to their close resemblance to some of the edible mushrooms and to the inadequate criteria of identification often applied. Some of the mystique and folklore that surrounded fungi in the Middle Ages has persisted into the 20th century, and unreliable tests, such as the blackening of silver .
1. 2. 3.
4. 5. 6. 7.
Carrier, R. Sunday Times, June 3, 1962. Kleijn, H. Mushrooms and Other Fungi. London, 1962. Ford, W. W. in Legal Medicine and Toxicology (edited by F. Peterson, W. S. Haines, and R. W. Webster); vol. 2; p. 817. Philadelphia, 1923. Lewes, D. Brit. med. J. 1948, ii, 383. Ramsbottom, J. Mushrooms and Toadstools; p. 38. London, 1959. Curry, A. S. Brit. med. J. 1962, i, 687. Block, S. S., Stephens, R. L., Barretto, A., Murrill, W. A. Science,
1955, 121, 505. Beloruchev, E. A. Hyg. & Sanit., Moscow, 1959, 24, 52. Elliott, W., Hall, M., Kerr, D. N. S., Rolland, C. F., Smart, G. A., Swinney, J. Lancet, 1961, ii, 630. 10. Buck, R. W. New Engl. J. Med. 1961, 265, 681. 8. 9.
spoons, may still be used instead of accurate botanical indentification. African natives are said to acquire great skill in selecting mushrooms," but the number " sent down " in the school of experience may be considerable.12 Certainly, in other hands, practice without careful botanical study has proved disastrously inadequate and several recent outbreaks of poisoning have involved life-long mushroom collectors.9 13—15 Thus, even the experienced, before eating an unfamiliar fungus, would be well advised to have it identified by an expert
mycologist.16 The commonest cause of fatal poisoning is the consumption of one of the bulb Agarics (usually Amanita phalloides in Europe, A. capensis in South Africa,17 and sometimes A. verna or A. virosa in the United States 10) in mistake for the common mushroom. These poisonous species contain five potent toxins-cyclical polypeptides, which have been isolated and studied by the WEILANDS in Germany.18 The offending mushrooms are not unpleasant to eat, and no symptoms develop for six to twenty-four hours after their ingestion : diarrhoea and vomiting with fluid depletion, hypoglycæmia, and convulsions ensue in the next few days; acute hepatic failure, haemorrhagic complications,19 and acute renal failure develop in the following week; tremor, mental changes, and coma are often preterminal events.20 The toxins, which are highly resistant to enzymatic breakdown, are presumably eliminated by excretion in the urine. If anuria supervenes, hasmodialysis may provide an alternative excretory pathway, but the dialysance of amanita toxins has not yet been studied. A wide variety of remedies has been prescribed to counteract the toxins, and polypharmacy is still advocated.21 The value of none of these measures has been established by adequate clinical trial, and the only treatment that can be recommended is supportive-evacuation of the stomach and bowel, fluid and electrolyte replacement, glucose administration, and the usual steps against hepatic and renal failure-including hsemodialysis where indicated.9 Fortunately the lesions produced are not permanent, and recovery of full cerebral, renal, and hepatic function is the rule if the patient survives the acute illness. A. phalloides usually grows near trees, is larger than the common mushroom, and has a greenish cap and white gills; but its only constant distinguishing feature is the presence both of a volva (membrane) around the bulb and of a ring around the stem. This combination is found in all the genus Amanita, but can be recognised with certainty only in mature complete specimens. Two poisonous amanitas which are more easily distinguished from common mushrooms-A. pantherina and A. muscaria-are sometimes eaten in mistake for the edible A. rubescens, and children may be attracted by their bright 11. Charters, A. D. Cent. Afr. J. Med. 1960, 6, 213. 12. McCarter, G. R. B. ibid. 1959, 5, 412. 13. Casanova, P. Marseille méd. 1959, 96, 535. 14. Cann, H. M., Verhulst, H. L. Amer. J. Dis. Child. 1960, 101, 134. 15. Flogstad, D. L. Wis. med. J. 1961, 60, 333. 16. Lloyd, O. C. Lancet, 1961, ii, 723. 17. Sapeika, N., Uys, C. J., McKenzie, D. S. Afr. J. Lab. din. Med. 1960, 6, 12. 18. Weiland, T., Weiland, O. Pharmacol. Rev. 1959, 11, 87. 19. Lamarche, M., Feve, J. M. C.R. Soc. Biol. 1960, 154, 1279, 20. Neuhann, W. Samml. Vergiftungsf. 1933, 12, 59. 21. Michon, P., Larcon, M., Lemarche, M., Grignon, G., Huriet, C., Vicari, F. Pr. méd. 1961, 69, 1327.
921
colours. Both contain muscarine, a substance resembling atropine (probably I-hyoscyamine), and possibly a third pilztoxin, in varying proportions .1022 A. pantherina has a high alkaloid content and its ingestion may prove fatal; but A. muscaria, a bright red-and-white toadstool, seldom causes death and has been eaten to produce pleasurable intoxication by vikings and eskimos and Americans of the prohibition era. It was once employed as a fly-killer. Inocybe patoullardii, another dangerous British fungus with a superficial resemblance to the common mushroom, also contains muscarine in very high concentration. After the ingestion of any of these three mushrooms, and of several other species, symptoms appear early; they may be predominantly those of atropine poisoning (mental irritation, dilated pupils, hot red skin, dry mouth) or those of muscarine poisoning (vomiting, muscle cramps, diarrhoea, bradycardia, hypotension, sweating, pinpoint pupils, and salivation). Atropine is a pharmacological antagonist of muscarine, blocking the latter’s stimulatory effect on parasympathetic nerve-endings, and is itself sometimes recommended as treatment for predominant muscarine poisoning. The most dangerous manifestations of poisoning with either atropine or muscarine are cerebral irritation and convulsions, and these are probably best treated by sedation with barbiturates or phenothiazines.23 The other measures required are symptomatic-gastric lavage, fluid replacement, and, sometimes, hypertensive
’I
I
drugs. (fungi with crenated spore-bearing tissue in a of place cap) and truffles (subterranean fungi without cap or stem) are now seldom eaten in Britain, but at one time they were so prized by epicures that dogs, goats, and even pigs were trained to hunt them. They are still popular on the Continent, and a related species, Gyromitra esculenta, is eaten in Poland-where it occasionally causes poisoning.24 This fungus contains a hxmolysin, helvellic acid, which is destroyed by adequate cooking, drying, or salting; other toxins are probably responsible for the hepatic and cerebral damage that are prominent features of the poisoning. Other poisonous mushrooms found in this country are of interest rather than importance. They include Panaeolus campanulatus, a delicate reddish-brown mushroom which commonly grows on dung and rich soil and which is also found in central America; it was regarded as sacred by the Aztecs and called teonanacatyl - food of the gods. It is still eaten there by the natives to produce pleasurable hallucinations and has acquired some popularity at American undergraduate parties. Several other Mexican fungi with hallucinogenic effects are being studied by neurologists in the United States 25 26; and at least one pure toxin, psilocybin, has been isolated. Delusions are vivid and bizarre : one Morels
;
i ’
:
’
;
patient averred that she
inside a stomach tube Accidental poisoning with of similar properties, is fairly was
instead of vice versa."
stropharia,
a
fungus
22. Lewis, B. S. Afr. med. J. 1955, 29, 262. 23. Roch, M., Mach, J. Praxis, 1960, 9, 225. 24. Raszeja, S. Pat. pol. 1959, 10, 35. 25. Stein, S. I. Mycopathologia, 1958, 9, 263. 26. Stein, S. I. ibid. 1959, 11, 205.
in East Africa. Several of the clitocybes (mushrooms with funnel-shaped caps, which might be confused with the edible chanterelle) cause gastrointestinal upsets which are unpleasant rather than serious. The common ink-cap has an effect similar to that of disulfiram (’Antabuse’). A newly recognised form ofmushroom-poisoning has been reported from Poland 27: the fungus—Cortinarius orellanus-which is common in European forests, causes renal-tubular after a latent period of up to two weeks. It is still generally regarded as edible, since, in the past, the length of the latent period has obscured diagnosis; but it may now turn out to be a not uncommon cause of poisoning in Europe. common
damage
Annotations EXPLORATION MEDICINE
IN
increasingly competitive world, the value of training rigorously for all athletic performances has become clear. Even in the absence of competitors, proper training brightens the prospects and diminishes the hazards of expeditions which demand (as most do) a high degree of physical fitness. There is more to training than the mere improvement of muscular and cardiovascular performance. At a symposium on exploration medicine held in London on Oct. 25 and 26 by the Royal Geographical Society, the Medical Research Council, and the medical services of the Navy, Army, and Air Force, Sir John Hunt observed that the ability to endure hardship is enhanced by previous experience. His view is undoubtedly correct; but it should not be regarded as a carte blanche for training programmes to include severe hardships or privations. Privations, particularly of food or water, are borne by the body as well as by the mind, and from the physiological viewpoint it is sometimes difficult to see what good they can accomplish. This slightly different approach by trainers and doctors to the common problem of human performance and requirements was frequently apparent throughout the symposium, which considered successively the medical aspects of heat, cold, and high altitude, and the problems an
of survival in these environments. On this as on other occasions, the difference was illustrated by comparison of recommendations based on the observed needs of groups of men in carefully recorded circumstances with the feats of one individual or another in apparently comparable but less clearly defined conditions. The first example came early in the symposium, when Sir Vivian Fuchs and Mr. Wilfred Thesiger challenged a recommendation by Dr. C. S. Leithead to the effect that the minimum fluid allowance in expeditions across hot deserts should be 8 pints per head per day, to be taken in small amounts at regular intervals as required by thirst. During travels in Kenya, Sir Vivian had judged it advantageous to limit his fluid intake while on the move; while Mr. Thesiger reported that he had gone for 15 days in the Rub Al. Khali in southern Arabia on a pint of brackish water daily. Later, Wing-Commander P. D. G. V. Whittingham counselled strongly against the drinking of sea-water by those cast adrift on rafts or dinghies; and the question was then raised of how Dr. Alain Bombard 28 did so and survived. 27. Raszeja, S. Pat. pol. 1960, 28. See Lancet, 1953, ii, 998.
11,
113.
Mushrooms and Toadstools " BOLETUS mittere difficile est," wrote MARTIAL, implying that he would sooner be parted from his money than his mushrooms. His enthusiasm is shared by one of our national advisers on gastronomy,l and in parts of Europe the popularity of edible mushrooms has led to their near-extinction around the main towns.2 This widespread use of fungi for food has led to a formidable mortality: EURIPIDES mourned a whole family who succumbed to accidental poisoning, and the death-roll in Europe since then contains such illustrious names as the Emperors CLAUDIUS and JoviAN, Pope CLEMENT VII, and the Austrian Emperor CHARLES VI. Deaths were reported from France by the hundred at the beginning of this century,3 and as late as 1948 the toll in Germany In this country was about two hundred a year .4 been common to have mushroom-poisoning appears until the 17th century,5 but it has since declined pari passu with the harvesting of wild mushrooms and no longer rates a separate entry in the Registrar 6General’s report; nonetheless, cases are still reported. In the United States it is also a declining disease which causes an estimated fifty deaths a year.7 In France unsuccessful attempts to prevent poisoning " were once made by the appointment of mushroom inspectors" at markets, and in the U.S.S.R. batches of mushrooms are still inspected for poisonous contaminants.8 But the identification of picked mushrooms is particularly difficult. Virtually the only mushrooms on sale in this country are the cultivated variety, Agaricus bisporus 9; and, since the culture-media usually employed do not support the growth of the most poisonous varieties, the possibility of accidental contamination is now very remote. The identification of mushrooms after ingestion calls for more mycological skill than is possessed by most doctors who report cases of poisoning. Some species are poisonous only when eaten uncooked or over-mature, in large quantities, or at certain seasons. Estimates of the number of poisonous species therefore vary widely. In a review of mushroompoisoning in the eastern United States, BUCK 10 mentions fifty-three species which are thought to be poisonous, and most of these are also found in Great Britain. But RAMSBOTTOM5 regards only about twenty British fungi-some 1-2% of all species of higher fungi found here-as definitely dangerous. The risk of mushroom-poisoning is due not so much to the high prevalence of poisonous varieties as to their close resemblance to some of the edible mushrooms and to the inadequate criteria of identification often applied. Some of the mystique and folklore that surrounded fungi in the Middle Ages has persisted into the 20th century, and unreliable tests, such as the blackening of silver .
1. 2. 3.
4. 5. 6. 7.
Carrier, R. Sunday Times, June 3, 1962. Kleijn, H. Mushrooms and Other Fungi. London, 1962. Ford, W. W. in Legal Medicine and Toxicology (edited by F. Peterson, W. S. Haines, and R. W. Webster); vol. 2; p. 817. Philadelphia, 1923. Lewes, D. Brit. med. J. 1948, ii, 383. Ramsbottom, J. Mushrooms and Toadstools; p. 38. London, 1959. Curry, A. S. Brit. med. J. 1962, i, 687. Block, S. S., Stephens, R. L., Barretto, A., Murrill, W. A. Science,
1955, 121, 505. Beloruchev, E. A. Hyg. & Sanit., Moscow, 1959, 24, 52. Elliott, W., Hall, M., Kerr, D. N. S., Rolland, C. F., Smart, G. A., Swinney, J. Lancet, 1961, ii, 630. 10. Buck, R. W. New Engl. J. Med. 1961, 265, 681. 8. 9.
spoons, may still be used instead of accurate botanical indentification. African natives are said to acquire great skill in selecting mushrooms," but the number " sent down " in the school of experience may be considerable.12 Certainly, in other hands, practice without careful botanical study has proved disastrously inadequate and several recent outbreaks of poisoning have involved life-long mushroom collectors.9 13—15 Thus, even the experienced, before eating an unfamiliar fungus, would be well advised to have it identified by an expert
mycologist.16 The commonest cause of fatal poisoning is the consumption of one of the bulb Agarics (usually Amanita phalloides in Europe, A. capensis in South Africa,17 and sometimes A. verna or A. virosa in the United States 10) in mistake for the common mushroom. These poisonous species contain five potent toxins-cyclical polypeptides, which have been isolated and studied by the WEILANDS in Germany.18 The offending mushrooms are not unpleasant to eat, and no symptoms develop for six to twenty-four hours after their ingestion : diarrhoea and vomiting with fluid depletion, hypoglycæmia, and convulsions ensue in the next few days; acute hepatic failure, haemorrhagic complications,19 and acute renal failure develop in the following week; tremor, mental changes, and coma are often preterminal events.20 The toxins, which are highly resistant to enzymatic breakdown, are presumably eliminated by excretion in the urine. If anuria supervenes, hasmodialysis may provide an alternative excretory pathway, but the dialysance of amanita toxins has not yet been studied. A wide variety of remedies has been prescribed to counteract the toxins, and polypharmacy is still advocated.21 The value of none of these measures has been established by adequate clinical trial, and the only treatment that can be recommended is supportive-evacuation of the stomach and bowel, fluid and electrolyte replacement, glucose administration, and the usual steps against hepatic and renal failure-including hsemodialysis where indicated.9 Fortunately the lesions produced are not permanent, and recovery of full cerebral, renal, and hepatic function is the rule if the patient survives the acute illness. A. phalloides usually grows near trees, is larger than the common mushroom, and has a greenish cap and white gills; but its only constant distinguishing feature is the presence both of a volva (membrane) around the bulb and of a ring around the stem. This combination is found in all the genus Amanita, but can be recognised with certainty only in mature complete specimens. Two poisonous amanitas which are more easily distinguished from common mushrooms-A. pantherina and A. muscaria-are sometimes eaten in mistake for the edible A. rubescens, and children may be attracted by their bright 11. Charters, A. D. Cent. Afr. J. Med. 1960, 6, 213. 12. McCarter, G. R. B. ibid. 1959, 5, 412. 13. Casanova, P. Marseille méd. 1959, 96, 535. 14. Cann, H. M., Verhulst, H. L. Amer. J. Dis. Child. 1960, 101, 134. 15. Flogstad, D. L. Wis. med. J. 1961, 60, 333. 16. Lloyd, O. C. Lancet, 1961, ii, 723. 17. Sapeika, N., Uys, C. J., McKenzie, D. S. Afr. J. Lab. din. Med. 1960, 6, 12. 18. Weiland, T., Weiland, O. Pharmacol. Rev. 1959, 11, 87. 19. Lamarche, M., Feve, J. M. C.R. Soc. Biol. 1960, 154, 1279, 20. Neuhann, W. Samml. Vergiftungsf. 1933, 12, 59. 21. Michon, P., Larcon, M., Lemarche, M., Grignon, G., Huriet, C., Vicari, F. Pr. méd. 1961, 69, 1327.
921
colours. Both contain muscarine, a substance resembling atropine (probably I-hyoscyamine), and possibly a third pilztoxin, in varying proportions .1022 A. pantherina has a high alkaloid content and its ingestion may prove fatal; but A. muscaria, a bright red-and-white toadstool, seldom causes death and has been eaten to produce pleasurable intoxication by vikings and eskimos and Americans of the prohibition era. It was once employed as a fly-killer. Inocybe patoullardii, another dangerous British fungus with a superficial resemblance to the common mushroom, also contains muscarine in very high concentration. After the ingestion of any of these three mushrooms, and of several other species, symptoms appear early; they may be predominantly those of atropine poisoning (mental irritation, dilated pupils, hot red skin, dry mouth) or those of muscarine poisoning (vomiting, muscle cramps, diarrhoea, bradycardia, hypotension, sweating, pinpoint pupils, and salivation). Atropine is a pharmacological antagonist of muscarine, blocking the latter’s stimulatory effect on parasympathetic nerve-endings, and is itself sometimes recommended as treatment for predominant muscarine poisoning. The most dangerous manifestations of poisoning with either atropine or muscarine are cerebral irritation and convulsions, and these are probably best treated by sedation with barbiturates or phenothiazines.23 The other measures required are symptomatic-gastric lavage, fluid replacement, and, sometimes, hypertensive
’I
I
drugs. (fungi with crenated spore-bearing tissue in a of place cap) and truffles (subterranean fungi without cap or stem) are now seldom eaten in Britain, but at one time they were so prized by epicures that dogs, goats, and even pigs were trained to hunt them. They are still popular on the Continent, and a related species, Gyromitra esculenta, is eaten in Poland-where it occasionally causes poisoning.24 This fungus contains a hxmolysin, helvellic acid, which is destroyed by adequate cooking, drying, or salting; other toxins are probably responsible for the hepatic and cerebral damage that are prominent features of the poisoning. Other poisonous mushrooms found in this country are of interest rather than importance. They include Panaeolus campanulatus, a delicate reddish-brown mushroom which commonly grows on dung and rich soil and which is also found in central America; it was regarded as sacred by the Aztecs and called teonanacatyl - food of the gods. It is still eaten there by the natives to produce pleasurable hallucinations and has acquired some popularity at American undergraduate parties. Several other Mexican fungi with hallucinogenic effects are being studied by neurologists in the United States 25 26; and at least one pure toxin, psilocybin, has been isolated. Delusions are vivid and bizarre : one Morels
;
i ’
:
’
;
patient averred that she
inside a stomach tube Accidental poisoning with of similar properties, is fairly was
instead of vice versa."
stropharia,
a
fungus
22. Lewis, B. S. Afr. med. J. 1955, 29, 262. 23. Roch, M., Mach, J. Praxis, 1960, 9, 225. 24. Raszeja, S. Pat. pol. 1959, 10, 35. 25. Stein, S. I. Mycopathologia, 1958, 9, 263. 26. Stein, S. I. ibid. 1959, 11, 205.
in East Africa. Several of the clitocybes (mushrooms with funnel-shaped caps, which might be confused with the edible chanterelle) cause gastrointestinal upsets which are unpleasant rather than serious. The common ink-cap has an effect similar to that of disulfiram (’Antabuse’). A newly recognised form ofmushroom-poisoning has been reported from Poland 27: the fungus—Cortinarius orellanus-which is common in European forests, causes renal-tubular after a latent period of up to two weeks. It is still generally regarded as edible, since, in the past, the length of the latent period has obscured diagnosis; but it may now turn out to be a not uncommon cause of poisoning in Europe. common
damage
Annotations EXPLORATION MEDICINE
IN
increasingly competitive world, the value of training rigorously for all athletic performances has become clear. Even in the absence of competitors, proper training brightens the prospects and diminishes the hazards of expeditions which demand (as most do) a high degree of physical fitness. There is more to training than the mere improvement of muscular and cardiovascular performance. At a symposium on exploration medicine held in London on Oct. 25 and 26 by the Royal Geographical Society, the Medical Research Council, and the medical services of the Navy, Army, and Air Force, Sir John Hunt observed that the ability to endure hardship is enhanced by previous experience. His view is undoubtedly correct; but it should not be regarded as a carte blanche for training programmes to include severe hardships or privations. Privations, particularly of food or water, are borne by the body as well as by the mind, and from the physiological viewpoint it is sometimes difficult to see what good they can accomplish. This slightly different approach by trainers and doctors to the common problem of human performance and requirements was frequently apparent throughout the symposium, which considered successively the medical aspects of heat, cold, and high altitude, and the problems an
of survival in these environments. On this as on other occasions, the difference was illustrated by comparison of recommendations based on the observed needs of groups of men in carefully recorded circumstances with the feats of one individual or another in apparently comparable but less clearly defined conditions. The first example came early in the symposium, when Sir Vivian Fuchs and Mr. Wilfred Thesiger challenged a recommendation by Dr. C. S. Leithead to the effect that the minimum fluid allowance in expeditions across hot deserts should be 8 pints per head per day, to be taken in small amounts at regular intervals as required by thirst. During travels in Kenya, Sir Vivian had judged it advantageous to limit his fluid intake while on the move; while Mr. Thesiger reported that he had gone for 15 days in the Rub Al. Khali in southern Arabia on a pint of brackish water daily. Later, Wing-Commander P. D. G. V. Whittingham counselled strongly against the drinking of sea-water by those cast adrift on rafts or dinghies; and the question was then raised of how Dr. Alain Bombard 28 did so and survived. 27. Raszeja, S. Pat. pol. 1960, 28. See Lancet, 1953, ii, 998.
11,
113.