Researchers document the adverse consequences of myocarditis in preschool students, caused by a regional outbreak of parvovirus B19 in northern Greece.
Myocarditis is a rare but serious disease known for inflammation of the heart muscle, also known as the myocardium. In severe cases of myocarditis, the heart muscle becomes extremely weak and fails to pump blood effectively. This, in turn, can lead to heart failure and death. Thorough and timely intervention is important to ensure effective treatment of myocarditis.
Parvovirus B19, a single-stranded DNA virus spread by respiratory droplets, is known to infect infants. It is associated with mild flu-like symptoms, including fever, joint pain, and a red rash on the cheek, called a “slapped cheek” rash or erythema infectiosum. Recent reports have linked parvovirus B19 to cases of myocarditis in children. However, due to their mild nature, parvovirus B19 symptoms are often ignored. Nevertheless, the symptoms of myocarditis require appropriate diagnosis and treatment, making it essential to study cases of parvovirus B19-associated myocarditis and understand its impact on infected children.
To this end, a group of researchers, led by Dr. Filippos-Paschalis Rorris of the Onassis Cardiac Surgery Center, Athens, Greece, decided to report some cases of myocarditis caused by a regional outbreak of parvovirus B19 in children of preschool age. “While the majority of viruses that cause myocarditis affect heart muscle cells, parvovirus B19 works differently. Endothelial cells, forming the inner lining of the coronary arteries, are targeted by this virus. This causes a decrease in cardiac blood flow and leads to myocardial dysfunction, it is crucial to investigate cases of myocarditis caused by the virus,” Dr. Rorris explained. The research letter was published in Pediatric investigation on January 3, 2025 and is based on five reports of parvovirus B19 myocarditis in preschool children from the Thessaloniki region of northern Greece.
Researchers used polymerase chain reaction (PCR) to confirm the presence of parvovirus B19 in children, while echocardiography, followed by cardiac magnetic resonance (CMR) imaging, confirmed myocarditis in them. All reported left ventricular failure, which restricted blood flow in the lower left chamber of the heart, and were therefore admitted to the pediatric intensive care unit.
-Among the children admitted, one suffered a cardiac arrest and did not survive. This patient’s ejection fraction was extremely low, indicating that the heart was failing to pump enough blood with each beat. Laboratory values and diagnostic details of the remaining four patients were collected over the next few days. Patients also received inotropic support, known to change the force of contraction of the heart, as well as heart failure medications whenever necessary and immunoglobulin therapy.
All four surviving patients reported abnormal levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP), troponin I (TnI), and left ventricular ejection fraction (LVEF). High levels of NT-proBNP indicate that the heart is working harder to pump blood. Elevated TnI levels are caused by infections, injuries, and conditions affecting the heart. LVEF is used to measure how well the heart pumps oxygen-rich blood to the body. Of the four surviving patients, one patient with an LVEF of 15% showed no signs of improvement and was referred for heart transplantation.
These findings may improve the future management of parvovirus B19 myocarditis in children and infants. As Dr. Rorris mentions, “The cardiac biopsy, where a small amount of heart muscle is removed, is considered the gold standard for diagnosis. However, it can become invasive for children. This is why we wanted our diagnostic confirmation to be based on CMR, a non-invasive method. procedure, and a PCR test was performed to confirm the presence of parvovirus in the blood. Adding further, Dr. Maria Kontou, another researcher associated with the study, says: “We were also intrigued by the sudden escalation of illness caused by the virus in a particular area. This may be due to a higher level of parvovirus virulence. »
Because parvovirus B19 myocarditis in children is associated with mortality and morbidity, prompt diagnosis and treatment by specialists is necessary. Further research based on virus-specific therapies as well as myocarditis-specific treatment may reduce the risk in children in the future.
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