Acute Late-Stage Myocarditis in the Crab-Eating Macaque Model of Hemorrhagic Smallpox

The knowns and unknowns of cardiac autoimmunity in viral myocarditis

Myocarditis can result from various infectious and non-infectious causes that can lead to dilated cardiomyopathy (DCM) and heart failure. Among the infectious causes, viruses are commonly suspected. But the challenge is our inability to demonstrate infectious viral particles during clinical presentations, partly because by that point, the viruses would have damaged the tissues and be cleared by the immune system. Therefore, viral signatures such as viral nucleic acids and virus-reactive antibodies may be the only readouts pointing to viruses as potential primary triggers of DCM. Thus, it becomes hard to explain persistent inflammatory infiltrates that might occur in individuals affected with chronic myocarditis/DCM manifesting myocardial dysfunctions. In these circumstances, autoimmunity is suspected, and antibodies to various autoantigens have been demonstrated, suggesting that immune therapies to suppress the autoimmune responses may be necessary. From this perspective, we endeavoured to determine whether or not the known viral causes are associated with development of autoimmune responses to cardiac antigens that include both cardiotropic and non-cardiotropic viruses. If so, what their nature and significance are in developing chronic myocarditis resulting from viruses as primary triggers.

Cardiac Involvement in Monkeypox Outbreak

Unusual presentations and uncommon clinical manifestations of Monkeypox (Mpox) in the current outbreak highlight the need to focus on cardiac symptoms of the virus. Owing to limited discussion regarding cardiac involvement in recent cases of Mpox, we conducted a scoping review to determine the range of existing research and provide a descriptive overview of the current literature on these manifestations. This review was conducted using a previously developed six-stage methodological approach and keeping in view the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping Reviews (PRISMA-ScR). Records retrieved from PubMed, ScienceDirect and Google Scholar, using a two-step search strategy, were subjected to title and abstract screening, followed by full text screening of remaining articles against specified eligibility criteria. Relevant information was extracted and summarized. Our search yielded 707 records. Following title and abstract screening, 23 articles were retrieved for full text screening. Finally, a total of nine articles were included in this review (three case series and six case reports discussing a total of 13 patients). Myocarditis was identified as the most frequently reported cardiac manifestation of Mpox. Novel clinical presentations included pharyngitis, sore throat, proctalgia, and perianal irritation. Most patients reported chest pain as the primary symptom of cardiac system involvement. Elevated troponin was the most commonly reported investigation finding followed by an elevated C- Reactive Protein. There exists a lack of high-quality studies investigating cardiac system involvement in the current outbreak of Mpox. More information is needed regarding risk factors for cardiac complications, disease progression, and cardio tropism and immunological response to improve preventive/therapeutic strategies. We highlight the paucity of relevant data and call for further discussion to improve the understanding of cardiac manifestations of Mpox. This scoping review sheds light on the underexplored cardiac manifestations of Mpox and highlights the need for heightened awareness of cardiac symptoms in the current outbreak.

Myocarditis Attributable to Monkeypox Virus Infection in 2 Patients, United States, 2022

We report 2 immunocompetent and otherwise healthy adults in the United States who had monkeypox and required hospitalization for viral myocarditis. Both patients were unvaccinated against orthopoxviruses. They had shortness of breath or chest pain and elevated cardiac biomarkers. No immediate complications were observed. They were discharged home after symptoms resolved.