Lupus Enteritis as the Early Manifestation of Systemic Lupus Erythematosus Successfully Managed With Belimumab: A Case Report.

Lupus enteritis (LE) is an uncommon cause of abdominal pain in individuals with systemic lupus erythematosus (SLE). This condition is explained by the inflammation of the intestinal wall caused by the accumulation of immune complexes and activation of the complement system. A 19-year-old previously healthy Kuwaiti woman arrived at the emergency department (ED) complaining of diffuse abdominal pain, non-bloody diarrhea, and nausea. The symptoms started two days before presentation. The patient described the abdominal pain as sudden, sharp, and stabbing in nature, with a severity of 10 out of 10, and mainly located in the suprapubic area. On examination, the patient's vital signs were normal. She had no skin rash, oral ulcers, arthritis, or palpable lymphadenopathy. Her abdomen was soft on palpation, with diffuse tenderness. Her initial laboratory investigations showed a normal hemoglobin level and WBC count but lymphopenia (0.6 x 109/L; normal, 1-3 x 109/L). A computed tomography (CT) scan of the abdomen showed small bowel loops with diffuse edematous wall thickening with target signs. The descending and sigmoid colon, and the rectum walls were also thickened and edematous. Significant pericolonic fat stranding and free fluid with preserved enhancement suggested an active systemic inflammatory process. Anti-nuclear antibody and anti-double stranded DNA antibody test results were positive. Acute abdominal pain was managed with IV corticosteroids, and 10 mg/kg IV belimumab was initiated. The patient was followed up in OPD after one, three, and six months, where she did not mention any relapse of LE nor any side effects from belimumab. The diagnosis of LE in this case was challenging because of the absence of a prior diagnosis of SLE. Clinical manifestations of this condition, which include abdominal discomfort, vomiting, and diarrhea, are non-specific and can be mistaken for several chronic gastrointestinal disorders, posing a diagnostic problem. Although belimumab is not commonly used to treat LE, we were able to successfully manage the patient using it, making it a promising new method for treating LE.