Urea/Creatinine Ratio’s Correlation with Creatine Kinase Normalization in Pediatric COVID-19 Patients with Myositis: Evaluating Prognostic and Predictive Value

Coronavirus disease 2019 (COVID-19) has been chiefly linked with substantial respiratory complications. However, emerging studies have brought attention to the occurrence of severe muscle inflammation (myositis) related to COVID-19, potentially leading to multi-organ failure and increased mortality. Myositis is generally characterized by heightened serum creatine kinase (CK) levels. Acute myositis is characterized by an infiltration of viruses into calf muscle fibers, which may cause a subsequent inflammatory response leading to calf muscle pain. Symptomatic and supportive management, along with explanation and reassurance, is all that is required in managing this condition. While the association between myositis and severe outcomes has been recognized in adults, it remains less understood in the pediatric population. The current retrospective study, conducted at Policlinico San Marco University Hospital in Catania, aimed to analyze clinical and laboratory factors associated with myositis in pediatric patients with SARS-CoV-2 infection. Between January 2022 and January 2023, ten pediatric patients diagnosed with myositis and SARS-CoV-2 infection were evaluated. The study highlighted clinical manifestations such as fever, calf muscle pain, and abnormal gait. Lab results showed elevated CK levels among other findings. All patients underwent treatment, with the majority recovering without complications. A notable correlation was observed between CK levels, blood urea nitrogen (BUN), and the urea/creatinine ratio (UCR). The study also discusses potential pathophysiological mechanisms behind SARS-CoV-2's impact on skeletal muscles, emphasizing an indirect inflammatory response. Our findings underscore that while myositis in children with SARS-CoV-2 infection appears to follow a benign and self-limiting trajectory, it is crucial to monitor specific markers for early intervention and management. Further research is warranted to elucidate the underlying mechanisms and improve clinical outcomes.