A Case of Myocarditis Observed in a Patient With Monkeypox Infection

Monkeypox virus particles, illustration. Monkeypox is a zoonotic virus from the Poxviridae family that causes monkeypox, a pox-like disease. At the centre of the monkeypox virus is a core nucleoprotein that contains the DNA (deoxyribonucleic acid) genome. This is surrounded by an outer envelope. This virus, which is found near rainforests in Central and West Africa causes disease in humans and monkeys, although its natural hosts are rodents. It is capable of human to human transmission. In humans it causes fever, swollen glands and a rash of fluid-filled blisters. It is fatal in 10 per cent of cases.
It has been found that the monkeypox infection may cause heart problems, including acute myocarditis.

Infection with the monkeypox virus may be associated with cardiac injury, according to a case study published in JACC: Case Reports.

Monkeypox disease is caused by a viral infection from the same family as smallpox. Patients with monkeypox present with a pimple or blister-like rash on the hands, face, feet, or genitals, among other symptoms. Although endemic to parts of Africa, the first monkeypox infection was reported in the European Union in May of 2022. Since that time, infections have been increasing in nonendemic countries including the United States.

Myocarditis is typically observed among patients with viral infections and has previously been associated with smallpox. As monkeypox and smallpox are related, there is the potential for a similar association to occur with monkeypox.

In this case report, a 31-year-old man with confirmed monkeypox presented with malaise, myalgia, and fever with skin lesions on the face, hands, and genitalia. The patient returned to the emergency department at São João University Hospital Centre in Portugal 3 days after initial presentation with chest tightness radiating through the patient’s left arm.

Initial electrocardiography indicated sinus rhythm with nonspecific ventricular repolarization abnormalities. The patient was found to have elevated C-reactive protein, creatine phosphokinase, high-sensitivity troponin I, and brain natriuretic peptide, indicative of cardiac injury.

Cardiac magnetic resonance mapping indicated the patient had myocardial inflammation and was diagnosed with acute myocarditis 1 week after the onset of monkeypox symptoms.

The patient recovered fully and was discharged from the hospital after 1 week.

This case study is limited by its scope. Additional study is needed to evaluate the relationship between monkeypox and the potential for acute myocarditis or other cardiovascular injury.

There may be a possible causal relationship between the monkeypox virus and myocarditis. Increased awareness of this association is needed such that patients with monkeypox-associated myocarditis receive adequate treatment.


Monkeypox Has Potential to Cause Heart Problems [press release]. Washington: the American College of Cardiology (ACC). Published September 2, 2022. https://www.acc.org/About-ACC/Press-Releases/2022/09/01/15/31/Monkeypox-Has-Potential-to-Cause-Heart-Problems. Accessed September 2, 2022.