In a new case study, doctors in Brazil report that they found particles of the novel coronavirus in the cardiac tissue of an 11-year-old child who died from heart failure caused by an inflammatory syndrome related to Covid-19—and they say their findings mark some notable firsts in coronavirus research.

A 'healthy' 11-year-old dies from heart failure—and researchers detect the coronavirus

The case study, which was published Thursday in The Lancet Child & Adolescent Health, documents the case of a "previously healthy" 11-year-old girl of African descent in Brazil. The child began experiencing a abdominal pain, muscle aches and pain, and pain while swallowing, and she had a fever that lasted for seven days. The child also had cracked lips and non-exudative conjunctivitis, which often are present in patients with Kawasaki disease—a rare condition that causes inflammation throughout the body.

The child presented at the hospital with signs of congestive heart failure, hypoxia, and respiratory distress, according to the case study. She was admitted to a pediatric ICU, but she developed cardiac failure and died one day after admission, the case study notes.

Researchers theorized that the patient may not have had Kawasaki disease, but that she instead had developed an inflammatory syndrome known as Pediatric Multi-System Inflammatory Syndrome Potentially Associated with Covid-19, or MIS-C. MIS-C patients experience many of the same symptoms caused by Kawasaki disease, but MIS-C is linked with an infection from the novel coronavirus.

According to a recent CDC report, MIS-C is a rare but severe condition that has been reported in both young children and adolescent patients who've been infected with the novel coronavirus, including some who didn't know they had been infected and did not experience symptoms of Covid-19, the disease caused by the coronavirus. In children who are infected with the virus and develop MIS-C, the condition typically manifests around two to four weeks after infection, CDC said.

The new case study notes that, in the 11-year-old girl's case, researchers confirmed that she had been infected with the novel coronavirus via a diagnostic test using a nasopharyngeal swab after the patient had died. A histopathological exam also revealed that the patient had heart inflammation, including myocarditis, pericarditis, and endocarditis—and, after further tests and examinations, researchers ultimately found particles of the novel coronavirus in the patient's cardiac and pulmonary tissues.

What's notable about the findings?

While there have been previous reports of doctors finding particles of the novel coronavirus around the heart muscles in adult Covid-19 patients, the researchers wrote that their case study "is the first to [their] knowledge to document the presence of viral particles in the cardiac tissue of a child affected by MIS-C." Further, the researchers noted that they detected "viral particles … in different cell lineages of the heart, including cardiomyocytes, endothelial cells, mesenchymal cells, and inflammatory cells," which differs from previous research that did not detect viral particles in those types of cells.

Marisa Dolhnikoff, an author of the case study and a physician with the University of Sao Paulo's Department of Pathology, said, "The presence of the virus in various cell types of cardiac tissue" in the young patient "shows that myocarditis in this case is likely a direct inflammatory response to the virus infection in the heart."

The case study also might help to confirm that MIS-C is one possible symptom of Covid-19, "and that the heart may be the target organ," Dolhnikoff said. 

C. Michael Gibson, CEO of the Baim Institute for Clinical Research, called the report "concerning," saying the case "shows for the first time that the virus can actually invade the heart muscle cells themselves."

Still, Scott Aydin, medical director for pediatric cardiac intensive care at Mount Sinai Kravis Children's Hospital, said the case "unfortunately [is] not all that surprising," as providers and researchers have long suspected that MIS-C could result in injury to the myocardium. "This important work is just the next step in further understanding the mechanisms of how Covid-19 creates havoc in the human body and the choices of possible therapies we have to treat children with Covid-19 and MIS-C," Aydin said.

Separately, Anish Koka, a cardiologist in Philadelphia, noted that finding "widespread organ dissemination" due to a virus is not "unusual." But Koka also explained that finding viral particles in an organ doesn't always mean the virus is responsible for any injury detected in the organ.

For instance, Koka noted that, in the case of the 11-year-old girl, researchers detected low loads of the coronavirus in her heart and lungs. That could mean the virus was "a potential trigger of a widespread inflammatory response that result[ed] in organ damage, rather than the virus itself infecting and destroying organs," Koka said (Brooks, Medscape, 8/24; Phend, MedPageToday, 8/24).