Juvenile idiopathic inflammatory myopathies after COVID-19 infection

Juvenile idiopathic inflammatory myopathies (JIIM) are more often diagnosed in pediatric patients following COVID-19 infection if they are racial minorities, older, and present with non-classic cutaneous manifestations, according to a recent study.

Viral infections have been associated with JIIM, including juvenile dermatomyositis, juvenile polymyositis, and overlap myositis. Researchers believe that COVID-19 can cause genetically susceptible individuals to experience autoimmune diseases, including idiopathic inflammatory myopathies.

An association has been observed between COVID-19 infection and anti-melanoma differentiation-associated gene 5 antibody-related dermatomyositis, leading investigators to believe there is a connection between underlying autoimmune and inflammatory mechanisms.

As few studies analyzed JIIM following COVID-19 infection, investigators conducted a study analyzing JIIM cases including clinical characteristics in patients before and after the emergence of COVID-19. Patients were recruited for the study from The Children’s Hospital at Montefiore and were included if they had been diagnosed with JIIM before age 19 at the hospital.

Data was collected on exposure to COVID-19, along with demographic, clinical, and laboratory information. Participants were divided into pre-COVID and post-COVID groups, with the pre-COVID group containing individuals diagnosed with JIIM prior to January 1, 2020.

Of the 44 patients included in the study, 34 had been diagnosed pre-COVID and 10 post-COVID. Known exposure or infection of COVID-19 was seen in 5 of the 10 post-COVID patients. These patients more often were non-Hispanic Black or Asian, experienced disease onset at a higher age, and were observed with non-classic cutaneous manifestations.

Patients diagnosed post-COVID often had muscle weakness of greater severity than those pre-COVID, but rate of muscle weakness was similar between the 2 groups. The time from symptom onset to diagnosis also did not differ pre- and post-COVID.

Based on these results, investigators urged clinicians to consider JIIM even in cases without classic cutaneous manifestations. They also encouraged further investigation on how COVID-19 impacts JIIM compared to other viruses.

Reference

Perfetto J, Yoo D, Tamashiro C, Perron M, Vasquez Canizares N, Wahezi D. Impact of SARS-CoV-2 on the Clinical Presentation of Juvenile Idiopathic Inflammatory Myopathies [abstract]. Presented at: ACR Convergence 2022, Philadelphia, Pennsylvania. November 11 to November 14, 2022.