Fatal case of community-acquired pneumonia coinfected with monkeypox virus: clinical and autopsy findings.

Background: Monkeypox (Mpox) has been declared an international public health emergency. The Mpox infection is commonly auto-limited. However, complications, such as secondary bacterial infection, including pneumonitis and encephalitis, have been described, which can lead to death. We report the clinical evolution and autopsy findings of a patient with an atypical presentation and clinical course. Case Summary: The patient had no significant past medical history and was diagnosed with community-acquired pneumonia and monkeypox virus co-infection. The studied subject developed cardiorespiratory arrest with asystole and hypoxic encephalopathy, leading to death around 72 h after hospitalization. The main macroscopic findings in the lungs were condensation associated with bronchopneumonia in the lower regions of both lungs and not thrombi in the pulmonary artery. In the heart, no myocardial abnormalities and no evidence of valvular or vascular abnormalities were observed. Congestion was found in the kidneys and liver. Moderate to severe edema along with congestion of the leptomeninges was found in the brain. The main histopathological findings were lung tissue with diffuse lympho-histiocytic infiltrate, hemorrhagic necrosis of alveolar septa, vascular congestion, and intra-alveolar edema. The perivascular lymphocytic infiltrate in Virchow-Robin spaces was suggestive of encephalic abnormalities. Differentiation between complications due to Mpox and complications associated with Mpox was a limitation due to the lack of immunohistochemical and molecular studies in tissues. Conclusion: This case illustrates the severe Mpox disease that can be developed in immunocompetent, non-HIV individuals and the possible association of Mpox with other infectious diseases acquired in the community.