A 14-year-old girl diagnosed with systemic lupus erythematosus following the onset of peritonitis

Abstract

Lupus peritonitis, a condition that can develop during the active phase of systemic lupus erythematosus (SLE), is characterized by abdominal pain, vomiting, diarrhea, and ascites effusion. Reports of pediatric cases are few. Blood tests in a 14-year-old girl with no history of cutaneous rashes who presented with abdominal distention, pedal edema, and abdominal pain revealed hypoalbuminemia, hyponatremia, and thrombocytopenia. After hospital admission for further evaluation and treatment, hypocomplementemia was detected; however, the ds-DNA antibody and urinary protein test results were negative. Imaging revealed severe ascites. Steroid administration alleviated the ascites over time, and the patient’s laboratory values improved. A subsequent renal biopsy revealed lupus nephritis International Society of Nephrology/Renal Pathology Society class III(A), and SLE was diagnosed. The patient then received steroid pulse therapy, hydroxychloroquine, and mycophenolate mofetil, achieving remission. This case was challenging to diagnose because some SLE diagnostic criteria were not met. Understanding lupus peritonitis and performing a renal biopsy are crucial for early diagnosis.