Microscopics diagnostic difficulties and the role of amanitin determination in poisoning caused by Amanita phalloides

Abstract Introduction: The consumption of mushrooms (Basidiomycota) in Poland is one of the highest in Europe. It is particularly high in the 3rd quarter of each year, which is accompanied by an increase in the number of mushroom poisonings. This study aims to present difficulties with microscopic identification, the most popular method for diagnosing mushroom poisoning in hospital settings, when it comes to detecting Amanita phalloides spores in biological material. Materials and methods: Spore analysis was carried out using aqueous solutions containing reference spores of different mushrooms: death cap (Amanita phalloides), parasol mushroom (Macrolepiota procera), field mushroom (Agaricus campestris), yellow knight mushroom (Tricholoma equestre), and green cracking russula (Russula virescens). The spore analysis was also carried out for a meal (soup) containing selected spores. Spores were identified using a light microscope and staining with Sudan III and Meltzer’s reagent. A statistical analysis of mushroom poisoning cases was also performed at the Department of Clinical and Forensic Toxicology, Pomeranian Medical University in Szczecin using records for 2015–2019. Conlusions: Analysis of data from 2015–2019 from the Department of Clinical and Forensic Toxicology at the Pomeranian Medical University in Szczecin showed a marked increase in mushroom poisoning cases in the 3rd quarter of each year. Analysis of materials containing Amanita phalloides spores revealed their high similarity to oil drops and other cell structures present in biological material, resulting in the low reliability of microscopic identification. Therefore, as the absence of Amanita phalloides spores in the tested biological material does not rule out poisoning with this mushroom, a more advanced instrumental analysis (ELISA, LC/MS) is recommended.