A monkeypox patient went to the emergency room after waking up in the middle of the night with chest tightness that spread to his upper left arm.

Researchers say monkeypox could cause additional complications, including heart issues, according to a new study.

The research, published in JACC: Case Reports, focused on a case of monkeypox possibly being linked to acute myocarditis, which occurs when the myocardium — the heart muscle — becomes inflamed.

After feeling ill for 5 days, the patient sought medical attention. He complained of “malaise, myalgias, and fever, followed by the eruption of multiple swollen and umbilicated cutaneous lesions on his face, hands, and genitalia,” according to the authors.

The 31-year-old patient underwent a PCR test to confirm the monkeypox diagnosis before returning home. Three days later, the patient went to the emergency room after waking up in the middle of the night with chest tightness that spread to his upper left arm.

According to the authors, the patient still had visible monkeypox blisters at the time, and doctors performed a battery of tests to rule out any heart problems.

Following an abnormal ECG, the providers ran blood tests and discovered that the patient had elevated levels of C-reactive protein, creatine phosphokinase, high-sensitivity troponin I, and brain natriuretic peptide.

These specific blood tests revealed that there was a cardiovascular problem.

The doctors performed a cardiac magnetic resonance study and diagnosed the patient with acute myocarditis based on the abnormalities on the ECG and the irregular blood work.

While this can be a life-threatening condition in more severe cases, the patient in this particular case recovered fully. 

Monkeypox is a zoonotic virus, which means it can spread between animals and humans. It is related to the variola virus, which causes smallpox, according to the Centers for Disease Control and PreventionTrusted Source (CDC).

While monkeypox has been around for decades, cases were mostly limited to regions in Africa. However, monkeypox has recently made headlines due to an outbreak of the virus that quickly spread outside of the continent.

Since then, monkeypox cases have steadily increased, with the CDC reporting approximately 52,000 cases. The virus has been linked to 15 deaths around the world.