New Onset Systemic Lupus Erythematosus Mimicking COVID-19-Associated Multisystem Inflammatory Syndrome

Introduction: The COVID-19 pandemic has caused catastrophic disease worldwide, affecting mostly adults and elderly patients, while children are usually less severely affected. Nevertheless, over the past months there has been accumulating data regarding a novel clinical constellation termed COVID-19-associated multisystem inflammatory syndrome in children (MIS-C). We describe an unusual case of COVID-19 infection in an adolescent female, associated with diagnostic criteria of both MIS-C and systemic lupus erythematosus (SLE).

Case report: A 16-year-old girl was admitted with fever, weakness, vomiting, diarrhea and joint pain of recent onset. 17 days earlier she suffered from mild respiratory symptoms, and tested positive for COVID-19. On admission she was pale, tachypneic and hypertensive. Urinalysis showed proteinuria, microhematuria, glucosuria and sterile pyuria. Blood tests revealed pancytopenia, elevated serum creatinine of 1.31mg/dl, albumin-3g/dl, LDH-346u/l (reference range (RR): 125-220), INR-1.46, D-dimers- 3616ng/mL (RR: 0-500), CRP-13mg/dl (RR: 0-0.5), BNP-888pg/ml (RR: 5-363), C3-42mg/dl (RR: 72-156), C4-6mg/dl (RR 13-37), ANA-1U (Borderline 1.0-1.2), Anti-dsDNA>200IU/ml (RR<20), lupus anticoagulant-positive. Echocardiography showed mild pericardial effusion. She responded favorably to intravenous methylprednisolone, combined with oral anti-hypertensives and subcutaneous low-molecular-weight heparin. Kidney biopsy findings were compatible with lupus nephritis class IV.

Discussion: The observed overlap between the clinical and laboratory manifestations of MIS-C and systemic lupus erythematosus (SLE) renders accurate diagnosis rather challenging, especially during the COVID-19 pandemic, and may profoundly impair clinical decision making and appropriate management. It remains to be seen whether COVID-19 infection may serve as a trigger for SLE initiation.