Poisoning with Amanita pantherina and Amanita muscaria: Two different syndromes?

Amanita pantherina and Amanita muscaria contain ibotenic acid and muscimol. Ibotenic acid is known to act on glutamic acid receptors in the central nervous system and has excitatory action. On the other hand, muscimol acts on GABA receptors and has depressant action. After ingestion ibotenic acid is metabolized to muscimol. Amanita pantherina contains less ibotenic acid and more muscimol compared to Amanita muscaria. The aim of our study was to compare the clinical picture in Amanita pantherina and Amanita muscaria poisoning. In a retrospective study we evaluated the clinical picture of patients poisoned with Amanita pantherina and Amanita muscaria who were hospitalized in our Poison Control Center (PCC) during the last 20 years. Amanita muscaria and Amanita pantherina ingestions were confirmed by a mycologist. Fisher exact test was used for categorical variables. A p value of less than 0.05 was considered as significant. 13 patients poisoned with Amanita muscaria and 7 patients poisoned with Amanita pantherina were hospitalized in our PCC. 9 patients poisoned with Amanita muscaria picked up and ate a mushroom supposed to be Amanita caesarea and all 7 patients poisoned with Amanita pantherina picked up a mushroom supposed to be Amanita rubescens. Patients poisoned with Amanita muscaria were more often confused, agitated and had hallucinations and convulsions compared to the patients poisoned with Amanita pantherina, but these differences were not significant (p>0.05). On the other hand, patients poisoned with Amanita pantherina were significantly more commonly comatose (p0.05). Anticholinergic signs were not observed in our patients. Agitated patients were successfully treated with benzodiazapine. Loss of conciousness was significantly more common in Amanita pantherina than Amanita muscaria poisoning. This could be due to the smaller amount of excitatory ibotenic acid in Amanita pantherina compared to Amanita muscaria. Accordingly, so-called ibotenic syndrome after Amanita muscaria and Amanita pantherina poisoning could be divided into two subtypes, but the clinical importance of differentiation should be further evaluated.