Fatal Immunohaemolysis after the Consumption of the Poison Pax Mushroom: A Focus on the Diagnosis of the Paxillus Syndrome with the Aid of Two Case Reports

This retrospective report focuses on the diagnosis of the Paxillus syndrome, based on two fatal cases of haemolysis following the consumption of Paxillus involutus. These mushrooms are still consumed regularly, despite earlier reports of life-threatening autoimmune haemolytic anaemia. Such cases are nevertheless rare, and thus far no toxin could be identified that causes this unusual form of mushroom poisoning. All these factors contribute to the difficulty in diagnosing the Paxillus syndrome. The following aspects support the diagnosis in the two cases presented here: Both patients consumed the mushroom oftentimes before, yet allegedly without ill effects. Symptoms occurred 2–3 h after the last consumption, exacerbating into circulatory collapse, multiorgan failure, and death. Disseminated intravascular coagulation was identified as cause of death by autopsy of patient 1. Patient 2 died of multiorgan failure, mainly hepatic. Our mycological analyses could identify the consumed mushroom in both cases as Paxillus involutus. Furthermore, we could exclude anticoagulants and several other drugs as trigger for the haemolysis by post-mortem toxicological analysis. However, findings in each of the two cases may have led to the haemolysis, independent of the consumption of Paxillus involutus. Patient 1 carried the anti-erythrocytic antibody, auto-anti-e. Patient 2 contracted chronic hepatitis C years prior to the current incident. Considering the rarity of the Paxillus syndrome, our findings suggest that these patients were particularly susceptible for haemolysis after consuming this mushroom over a prolonged period. Occurrence of the Paxillus syndrome may thus be restricted to regular consumers of Paxillus involutus mushrooms with an existing predisposition for haemolysis.