|
Cher Collègue,
Les intoxications au Japon commencent à déclencher des déclarations irrationnelles en France par déformation de l’information. Il serait préférable de parler d’encéphalopathies des dialysées à la suite de la consommation de champignons comestibles pour les gens en bonne santé. La théorie des « mutants » est folklorique (comment les champignons peuvent-ils muter en même temps dans toute une zone ?)
Alors voyons les choses rationnellement : [Cher Alain, rationnel ne veut pas dire irascible...à chacun son métier ! Les journalistes ont la lourde charge de recueillir l'info et de prévenir le public, leurs hypothèses sont ce qu'elles sont, 13 décès c'est peut-être "classique" pour un croque-mort, mais le public a le doit d'être ému ! ]
Les personnes atteintes et décédées étaient des personnes atteintes d’insuffisance rénale et ont fait une encéphalopathie des dialysées qui est une complication tout à fait classique ! C’est une complication qui est en fait une encéphalopathie métabolique à la suite de l’accumulation de substances habituellement non toxiques, mais qui le deviennent car non éliminées par le rein et c’est comme cela que les insuffisants rénaux meurent (par l’urée le plus souvent). Le traitement par la dialyse ne permet pas d’éliminer toutes les substances (ou mal) et c’est pour cela que les dialysés doivent respecter un régime alimentaire assez contraignant. Dans le champignon il y a probablement une substance mal éliminée et qui en s’accumulant devient toxique (de manger de la soupe à l’oseille tous les jours risque de donner le même résultat et personne n’irait prétendre que seule l’oseille mutante est toxique…). La cause principale à l’heure actuelle de cette encéphalopathie des dialysés est l’aluminium et les appareils de dialyse ne doivent pas en contenir de même que l’eau utilisée, bien entendu tous les aliments qui en contiennent en quantité importante sont à bannir. Pour ce champignon tout concorde pour dire qu’il contient une substance à seuil de ce type et que les personnes atteintes en ont trop mangé (comme pour le bidaou) et les récoltes abondantes attestent ceci. (en plus elles ont peut-être fait cuire leurs champignons dans des récipients en aluminium malgré les recommandations des médecins japonais qui sont au courant).
Donc, de grâce, ne nous affolons pas avec une nouvelle espèce de champignon toxique ! Contentons nous de l’ajouter à la longue liste des aliments interdits aux insuffisants rénaux surtout s’ils sont dialysés.
Le Japan Poison Information Center a publié une synthèse des intoxications par le sugi-hira-také que nous versons au dossier, suivi de quelques articles complémentaires. Bonne lecture.
Nous remercions le Dr. Ph. Saviuc (Toxicovigilance, CHU Grenoble) qui vient de les répercuter sur Medline.
Acute encephalopathy outbreak in the northwest part of Japan: Present situation
-----------------------------------------------------------------------------------------------------
The Japanese Ministry of Health, Labor, and Welfare(“MHLF”) was reported by Niigata Prefecture on October 14, 2004 of an outbreak of acute encephalopathy of unknown etiology from which elder persons suffered especially with chronic
renal dysfunction and hemodialysis, residing in Murakami City area (2002 population: 81 861) of the said prefecture. In addition, the following cases have subsequently been reported from the Koide HC district of the prefecture.
Including the latter cases, Niigata prefecture briefed in their first report on 11 cases (Murakami district-9, Koide district-2) developed illness in between September 27 and October 12, 2004. The average age of these cases was 71 years (range: 53 to 89 years). Seven of the patients were female, and nine of
them had certain degrees of renal dysfunction, of whom, more than a half had experienced on dialysis treatment prior to illness onset.
Reflecting the said report by Niigata, MHLF immediately requested the Japan Poison Information Center (“JPIC”) to fully cooperate with MHLF and Niigata Prefecture in studying the cause of the said outbreak. Accordingly, JPIC sent Dr. Ohashi and Dr. Murata to Niigata and they attended the urgently organized meeting there on October 16. On October 21, Dr. Murata again participated in the second Niigata meeting together with Dr. Okumura from JPIC.
Clinical Features
Patients initially presented with mild prodromes such as light headedness, general malaise, and difficulty ambulating. But no GI symptoms such as vomiting or diarrhea was observed. Several days later, tremor-like involuntary movements or
myoclonus developed and within 24 hours intractable status epilepticus was appeared. Any infectious symptoms such as fever, headache, or stiff neck was absent in most cases, showing that the chief symptom was only seizure with mild
deterioration of consciousness. More than half of the patients required endotracheal intubation and mechanical ventilation because of the strong sedation and muscle relaxant for seizure control. One patient was placed on dialysis after admission. Four of them died of organ failure within a week , one has been discharged, and 6 remaining are still hospitalized so far.
Cerebrospinal fluid (CSF) examinations have revealed elevated protein levels without the increased cell counts; bacterial and viral cultures have been negative to date. CSF specimens have also tested negative for Japanese encephalitis virus, West Nile virus, dengue virus, cytomegalovirus, varicella-zoster virus, and herpes simplex virus by polymerase chain reaction (PCR). Results of serological tests of both CSF and sera are pending.
Brain CT scanning and MRI studies have not yielded any common findings to show any clues for encephalitis nor encephalopathy.
Clue
Recent attention has been paid to a species of mushroom, _Pleurocybella porrigens_, as a possible causative agent. This mushroom, primarily grown in the wild, has been a favorite dietary item in these areas in Japan for many years and
is prepared in various ways. No known toxin, or cases of acute poisoning due to ingestion, have been previously associated with this species. Although all of the cases consumed _P. porrigens_ in varying quantities and frequencies prior to
onset of illness, there is no conclusive epidemiological evidence linking this food item with disease occurrence at the present time.
Spread
This outbreak has been spread thorough the neighboring areas, such as Akita, Yamagata, Fukushima prefectures between September and October. We identified now the first case of this outbreak to be a patient in Akita Prefecture. The first patient was hospitalized on the mid September and he already died of this disorder. He had pre-existing renal dysfunction with the hemodialysis regularly, and he took mushrooms before the onset of seizure and deterioration of
consciousness.
The possibility of toxins from mushrooms
As for acute poisoning of mushrooms, it is thought that any kinds of mushrooms may contain somewhat toxic substances. But Pleurocybella porrigens is one of the most popular mushrooms for food in Japan, and there has not been reported any poisoning caused from this mushroom so far now.
It is thought that kinds of lectins, glycoproteins which is included a lot in Pleurocybella porrigens, might cause blood coagulation, but any European and American study reports as a deadly intoxication material in these kinds of lectins are not found.
Because it is often found that a virus becomes causal agent as for the encephalopathy, a setting of this case may be complicated more. Even if there are many dialyzed patients with chronic renal disease, there may be some substances which may be excreted into urine other than known toxic substances included in mushrooms.
The possible cause for the pathogenesis of this encephalopathy could be speculated as follows; psilocybin, ibotenic acid, orellanine, and Gyromitrin. As for the tastiness of mushrooms, ibotenic acid and this derivative, tricholomic acid, may be considered to be the chief ingredient in some mushrooms. If so, Pleurocybella porrigens might be changed the character in nature, showing toxic ibotenic acid and this derivative. When ibotenic acid are taken a lot, ibotenic acid may be decarbonated into muscimol, inducing neurotoxic effect. Orellanine may cause nephrotoxicity, but it is known to be contained only in 3 Cortinarius pseudosalor. Gyromitirin containing in Gyromitra escuenta is water-soluble toxin, but this kind of mushroom could not be found in those affected areas so far now.
Neurotoxicity, Seizure
Gyromitrin rapidly decomposes in the stomach to form acetaldehyde and N-methyl-N-formylhydrazine, which is converted to monomethylhydrazine (MMH) by slow hydrolysis. MMH exposure is similar to that of isoniazid in that it generates functional pyridoxine deficiency by inhibition of pyridoxine kinase. Pyridoxine kinase inhibition interferes with production of pyridoxal phosphate, an essential cofactor for a number of enzymatic steps, including glutamic acid decarboxylase (GAD).
Gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter of the brain, is produced from glutamate (an excitatory neurotransmitter) by the enzyme GAD. MMH also may inhibit GAD directly. The resultant GABA deficiency, with loss of inhibitory neurotransmission, may lead to seizures. Thus there is still the possibility of the relation of some substances affecting GABA metabolism to induce seizure and encephalopathy.
The present status of this unknown etiology encephalopathy in Japan (dated on November 8, 2004)
Prefecture numbers/pre-existing renal dysfunction / mushroom / death
Niigata 15/10/15/5
Yamagata 7/5/4/3
Akita 23/20/21/6
Fukushima 2/2/2/0
Ishikawa 1/1/1/0
Miyagi 1/1/1/0
Gifu 1/0/1/0
Fukui 1/1/1/1
Total 51/40/46/15
Conclusion
We could not speculate so far that any kinds of toxins in mushrooms taken in Japan may cause the present illness showing severe acute encephalopathy.
And also we cannot exclude the possibility of any mutant species of mushrooms totally. Now we have collected Pleurocybella porrigens all over the northern parts of Japan, including Niigata Prefecture and Akita Prefecture, and started to analyze their contents to be related with the pathogenesis of encephalopathy.
Edited by Atsuo MURATA, M.D., Ph.D., Leading Member of the Expert MDs, Japan Poison Information Center, and Associate Professor, Dept. of Trauma & Critical Care Medicine, Kyorin University School of Medicine Japan Poison Information Center
Yoshitaka NAKADA, M.D., Ph.D., Chairman Toshiharu YOSHIOKA, M.D., Ph.D., Executive Director Noriyoshi OHASHI, M.D., Executive Director Tetsu OKUMURA, M.D., Ph.D., Leading Member of the Expert MDs, JPIC, and Assistant Professor, Laboratory of Emergency Medicine & Disaster Medicine, Juntendo University Yumiko KUROKI, Ph.D., Director, Tsukuba Office Yoko ENDO, Director, Osaka Office National Institute of Infectious Diseases Nobuhiko OKABE, M.D., Ph.D., Director, Infectious Disease Surveillance Center
Contact Address
Attn: Yumiko KUROKI, Ph.D., Director, Tsukuba Office
Address: Japan Poison Information Center Amakubo 1-2, Tsukuba, Ibaraki, 305-0005 Japan
E-mail: head-jpic@j-poison-ic.or.jp
_____________________________
No To Shinkei. 2004 Dec;56(12):999-1007
[An outbreak of encephalopathy after eating autumn mushroom (Sugihiratake; Pleurocybella porrigens) in patients with renal failure: a clinical analysis of ten cases in Yamagata, Japan][b]
[Article in Japanese]
Kato T, Kawanami T, Shimizu H, Kurokawa K, Sato H, Nakajima K, Nomoto T, Seta T, Kamei T, Yoshino H, Sasagawa I, Ito M, Karasawa S, Kimura H, Suzuki Y, Degawa N, Tagawa A, Ataka K, Ando S, Omae T, Shikama Y.
Department of Neurology, Hematology, Metabolism, Endocrinology and Diabetes (DNHMED), Yamagata University School of Medicine, Yamagata 990-9585, Japan.
In September and October, 2004, an outbreak of encephalopathy of unknown etiology occurred in certain areas of Japan including Yamagata, Akita, and Niigata prefectures. These patients had a history of chronic renal failure, most of them had undergone hemodialysis, and also had a history of eating Sugihiratake (Pleurocybella porrigens), an autumn mushroom without known toxicity. Since clinical details of this type of encephalopathy remain unknown, we analyzed the clinical, radiological and electroencephalographic (EEG) features of ten cases of this encephalopathy in Yamagata prefecture. The summary of the present study is as follows: 1. Ten patients had chronic renal failure, and seven underwent hemodialysis. 2. Each patient had a history of eating Sugihiratake within 2-3 weeks of the onset of neurological symptoms. 3. The onset was subacute; the initial symptoms were tremor, dysarthria, and/or weakness of the extremities, which lasted an average of 4.5 days (ranging from 2 to 11 days), followed by severe consciousness disturbance and intractable seizures, resulting in status epilepticus in 5 patients. Myoclonus was also seen in 4 patients and Babinski reflex in 3. 4. Brain CT and MRI examinations were unremarkable in the early stages of the disease. Three to eight days after onset, however, conspicuous lesions appeared in the areas of the insula and basal ganglia in 6 patients. On MRI, these brain lesions were hyperintense on T2-weighted and FLAIR images, and hypointense on T1-weighted images. 5. EEG examination was performed in 6 patients, all of whom showed abnormal EEG findings. Periodic synchronous discharge (PSD) was seen in 2 patients, spike and wave complex in one patient, and non-specific slow waves in 3. 6. Prognosis was different from case to case. Three patients died at 13, 14, and 29 days after onset. Two patients still showed persistent disturbance of consciousness one month after onset. One patient showed parkinsonism after recovering from consciousness disturbance. Four patients recovered nearly completely around one month after onset In 3 of the 4 recovered patients, renal failure was not severe and they did not need to undergo hemodialysis. This suggests that the degree of renal failure is a key for the prognosis of this type of encephalopathy. The present study suggests that this endemic disease is a newly recognized clinical entity of encephalopathy.
______________________________
Japan: Acute neurological disorders in Niigata
On 14 Oct 2004, the Ministry of Health, Labor, and Welfare, Tokyo, Japan, was notified of an outbreak of acute encephalopathy of unknown etiology among adults residing in the Murakami Health Center (HC) district, Niigata Prefecture. Additional cases have subsequently been reported from the Koide HC district. A total of 11 cases (Murakami-nine, Koide-two) developed illness 27 Sep-12 Oct 2004. The median age of the cases was 71 years (range: 53 to 89 years); seven were female. Nine cases had varying degrees of renal dysfunction, of which, over half were on dialysis treatment prior to illness onset. Patients initially presented with symptoms such as lightheadedness, general malaise, and difficulty ambulating. Vomiting or diarrhea was not observed. Several days later, tremor-like involuntary movements or myoclonus developed, followed by intractable status epilepticus. Fever, headache, or stiff neck was absent in most cases. Cerebrospinal fluid (CSF) examinations have revealed elevated protein levels without pleocyosis; bacterial and viral cultures have been negative to date. CSF specimens have also tested negative for Japanese encephalitis virus, West Nile virus, dengue virus, cytomegalovirus, varicella-zoster virus, and herpes simplex virus by PCR. Results of serological tests of both CSF and sera are pending. Brain CT and MRI studies have not yielded common findings. Four cases have died, one has been discharged, and six remain hospitalized.
On 16 Oct 2004, a team from the National Institute of Infectious Diseases' (NIID) Field Epidemiology Training Program (FETP) arrived in Murakami City to assist in the investigation of the outbreak. Investigations are ongoing to describe the clinical and epidemiological characteristics of cases, to determine the extent of the outbreak, to identify potential etiologic agents and risk factors associated with illness, and to develop appropriate control and prevention measures. Recent attention has been paid to the mushroom Pleurocybella porrigens as a possible causative agent. This mushroom, primarily grown in the wild, has been a favorite dietary item in these areas. No known toxin, or cases of acute poisoning due to ingestion, has been previously associated with this species. Although all of the cases consumed P. porrigens, there is no conclusive epidemiological evidence linking it with disease occurrence at the present time. However, to better determine the potential toxicity of this mushroom, samples from the outbreak-affected areas will be sent to the National Institute of Health Sciences for chemical analysis. In the interim, NIID will continue to collaborate with clinical experts and public health officials toward identifying and/or ruling out any potential infectious or non-infectious etiologies. (Promed 11/5/04)
________________________
Oyster mushroom deaths in Japan
#3270805 - 10/24/04 07:36 AM
"2 more brain fever deaths in Akita; Mushroom link eyed
Yomiuri Shimbun
Two more people were confirmed to have died and two more have been hospitalized in Akita Prefecture due to a mysterious brain fever that has claimed the lives of five men and women in Niigata and Yamagata prefectures since September.
A man in his 60s and a woman in her 40s were both diagnosed with, and later died of, the acute brain fever sometime between last month and the beginning of this month, according to the prefecture's Health Policy Division.
They both received treatment, such as dialysis for renal failure, as did the victims in Niigata and Yamagata prefectures. The man reportedly had eaten a type of edible oyster mushroom, as had one of the two individuals currently in hospital for the same illness, both of whom are experiencing renal problems.
The division received the information regarding all four people Friday night from medical institutions in the prefecture.
Officials are rushing to identify the cause of the illness and are looking into whether there are other such cases within the prefecture.
Meanwhile, Yamagata Prefecture officials confirmed Friday that a man in his 70s who was confirmed to have died from the brain fever had in fact eaten the same type of mushrooms.
Also, in Niigata Prefecture, where three residents were confirmed to have succumbed to the fever, three more people are suspected of having contracted the acute fever. The three are said to be struggling to remain conscious as a result of the disease.
All three are on dialysis, and at least one had reportedly eaten the same variety of oyster mushroom.
The Health, Labor and Welfare Ministry on Friday informed prefectural and city governments nationwide to tell people with reduced renal capacity to refrain from eating the fungi.
The ministry also said it planned to dispatch specialists from the National Institute of Infectious Diseases to Niigata, Yamagata or Akita prefectures if they so requested.
While the acute brain fever is still considered mysterious, the fact that patients diagnosed with the illness in the prefectures reportedly ate the oyster mushrooms reinforces the idea the fungi may be playing some role in the disease.
The oyster mushrooms--called sugihiratake in Japanese--have long been used in food, and have never been reported to be harmful.
But, according to Toshimitsu Fukiharu, a senior researcher at the Natural History Museum and Institute, Chiba, "The makeup of mushrooms can easily change depending on habitat and strain."
With this summer's heat, and the depletion of the natural environment due to heavy rains brought on by several typhoons, a change in the mushrooms may have occurred, creating an excessive amount of a poison whose trace amounts had previously gone unnoticed."
Mysterious mushrooms suspected in deaths of 5 kidney patients
Five people died and eight suffered symptoms of an acute brain condition after they ate a type of mushroom in Niigata and Yamagata prefectures, it has been learned.
All of the victims had kidney disorders, and those affected had eaten the same type of mushroom, Pleurocybella porrigens, commonly known as "angel's wings," officials from the Ministry of Health, Labor and Welfare said.
The ministry has sent experts to examine an area of Niigata Prefecture where some of the mushrooms were collected, but the exact cause of the deaths remains unclear. Ministry officials are warning people with kidney disorders not to eat Pleurocybella porrigens.
After receiving a report on the apparent poisoning from Niigata prefectural authorities, the ministry sent workers from the National Institute of Infectious Diseases and the Japan Poison Information Center to examine the area.
The Japanese Society for Dialysis Therapy also plans to conduct an investigation of similar cases because many patients with serious kidney disorders receive dialysis treatment.
Acute encephalopathy, the condition that the five people died of, occurs when a person is infected with a virus or bacteria, and a toxic substance enters the body.
Ministry officials said it was hard to imagine that the mushrooms were the cause of the deaths because those who ate them did not show any signs of food poisoning such as vomiting. They added that there was probably a low possibility that their symptoms were caused by infections as their families and those around them had not shown any similar symptoms.
Officials said it was possible that a toxic mold on the mushrooms or chemical spray was responsible, but no such substance has been found.
Environmental Science Research Niigata plans to conduct animal and other tests in the future to determine whether angel wings can be toxic.
Noriyoshi Ohashi, managing director of the Japan Poison Information Center and deputy director of the Tsukuba Medical Center Hospital, said he would expect more patients if it was a case of food poisoning. "It's a type of mushroom that's eaten widely locally, and if this was poisoning, one would expect there to be more patients. We can't say anything more until we carry out further investigations."
Ichiei Narita, an assistant professor at Niigata University, said in some cases those with kidney disorders were unable to expel toxic substances from their bodies, but he added that he had not heard of any increase in cases in which patients receiving dialysis treatment developed acute encephalopathy.
Akira Hishida, a professor at Hamamatsu University School of Medicine, said that it was still possible elements of the mushrooms had entered the bodies of the victims and seeped into their bloodstream without being expelled, thereby damaging brain cells. (Mainichi and wire reports, Japan, Oct. 22, 2004)
|
/http%3A%2F%2Fstorage.canalblog.com%2F15%2F47%2F1309869%2F104420640_o.jpg)
/http%3A%2F%2Fstorage.canalblog.com%2F16%2F79%2F1309869%2F125607190_o.png)
/http%3A%2F%2Fstorage.canalblog.com%2F90%2F48%2F1309869%2F113945017_o.jpg)