Mesenteric Vasculitis and Urinary System Involvement Presenting As the Initial Manifestations of Systemic Lupus Erythematosus Treated Successfully With Glucocorticoids and Rituximab: A Case Report.

We describe a case of systemic lupus erythematosus (SLE) presenting initially with mesenteric vasculitis and urinary system involvement without any other SLE clinical features and a weakly positive antinuclear antibody on initial testing. She is a 15-year-old healthy female who presented with severe abdominal pain, diarrhea, vomiting, and weight loss for more than one month. She later developed cystitis and bilateral hydronephrosis. Her repeated autoantibody panel and computed tomography of the abdomen were diagnostic for mesenteric vasculitis related to SLE, and a colonic biopsy showed occlusive thromboangiopathy related to associated antiphospholipid antibody syndrome. She responded well to intravenous methylprednisolone, rituximab, and anticoagulation. Mycophenolate mofetil and hydroxychloroquine were used later for maintenance treatment. Lupus mesenteric vasculitis (LMV) is rare but a serious, potentially life-threatening, gastrointestinal complication associated with SLE. Clinical features are not very specific, making them challenging to diagnose. Thus, early diagnosis requires a high index of suspension especially in cases presenting with gastrointestinal symptoms without a previously established diagnosis of SLE. LMV occurs as an initial presentation of SLE in children more than adults. So, it is wise to investigate children presenting with gastrointestinal manifestations and involvement of other organs especially the urinary system thoroughly with autoantibodies and abdominal imaging to rule out or confirm the diagnosis of LMV and to start treatment early and aggressively.