893. Myocarditis and Pericarditis as a Complication of Mpox: An International Case Series and Literature Review
Authors: Halani Sheliza , Cai Sean , Monge Juan Carlos , Brouillard Philippe , Tremblay Cécile , Blanco Jose Luis , Pinho Ana Isabel , Rodriguez-Nava Guillermo , Narasimhan Supriya , Cooper Joseph , Kadlecik Peter , Tan Darrell H S 
Published: November 2023

Abstract

Background
Mpox virus was declared a public health emergency of international concern by the World Health Organization in July 2022. The full range of clinical manifestations of this emerging infectious disease continues to be elucidated.

Methods
We present a case series and literature review of patients with mpox myocarditis and pericarditis, including demographics, clinical symptoms, diagnostic and management strategies, and outcomes.

Results
We identified 13 patients aged 21-51 (median 32) years with polymerase chain reaction-confirmed mpox and myopericarditis (n=3), pericarditis (n=1), or myocarditis (n=9), from 6 countries on 3 continents. All but one were men. One was HIV-positive (viral load undetectable) and 4 were on HIV pre-exposure prophylaxis. None had prior cardiac disease and 3 used tobacco. Most acquired mpox via sexual contact; one heterosexual patient reported non-sexual close contact. Cutaneous/mucosal lesions occurred in 11/13 patients, and fever in 11/13. Where reported, cardiac symptom onset was 2-8 (median 5.5) days after mpox illness onset. C-reactive protein ranged from 9.3-154.5 (median 52.6) mg/L. Diagnosis of myocarditis/myopericarditis was based on symptoms (chest discomfort 11/12, dyspnea 3/4), elevated troponin (range 165-21200 ng/L, peaking 1-2 days after cardiac symptom onset), supportive electrocardiogram (ECG) findings (diffuse or territorial ST elevation, T-wave inversions, and/or non-specific ECG changes 9/12), and/or cardiac imaging findings (pericardial effusion 1/12, left ventricle [LV] abnormalities on echocardiogram 4/12, abnormal cardiac MRI in 7/7 done acutely). In the pericarditis case, ECG showed widespread ST elevation and echocardiogram showed hyperdynamic LV. Treatments included ASA or non-steroidal anti-inflammatory drugs (n=7), tecovirimat (n=5), colchicine (n=4), ACE-inhibitors (n=3) and bisoprolol (n=3). All were hospitalized, with lengths of stay of 4-10 days, and at least 3 patients required intensive care. Cardiac symptom recovery occurred within 1-3 days of admission; in at least 1 patient symptoms continued beyond 1 month.

Conclusion
Mpox is rarely associated with myocarditis and/or pericarditis, with cardiac symptoms beginning on day 2-8 after illness onset. Long-term outcomes require further study.

Disclosures
Cécile Tremblay, MD, Association canadienne de protection médicale: Expert Testimony|Astra-Zeneca: Advisor/Consultant|Astra-Zeneca: Honoraria|Canadian Institutes of Health Research: Grant/Research Support|Gilead: Advisor/Consultant|Gilead: Grant/Research Support|Gilead: Honoraria|GlaxoSmithKline: Advisor/Consultant|GlaxoSmithKline: Honoraria|Medicago: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Merck: Honoraria|National Institute of Health: Grant/Research Support|Sanofi: Advisor/Consultant Darrell H. S. Tan, MD PhD, Abbvie: Grant/Research Support|Gilead: Grant/Research Support|Glaxo Smith Kline: Grant/Research Support