Case Presentation: Systemic Lupus Erythematous (SLE) is an autoimmune condition with a broad variety of clinical presentations. Ascites is a rare feature of SLE, only present in approximately 10% of patients1. Possible causes include serositis, pancreatitis, nephritis, and nephrotic syndrome, constrictive pericarditis and peritoneal inflammation secondary to vasculitis. Though there are documented cases of ascites due to lupus peritonitis2,3, peritoneal involvement is uncommon in patients with SLE. We present the case of a 40-year-old man with past medical history of coronary artery disease and end stage renal disease secondary to IgG4 related disease who initially presented with lethargy and melena which resolved without treatment. Subsequent imaging showed large volume intra-abdominal ascites which was determined to be exudative in nature based on the peritoneal fluid analysis. Peritoneal fluid leukocyte cell count was 100, LDH 117 U/L, and albumin was 3.1 g/dl. Serum LDH was 357 U/L, and serum albumin was 3.1 g/dL. The calculated SAAG < 1.1 g/dl suggested ascites from non-portal hypertensive causes. Infectious and malignancy related studies, including cytology, were negative. Other pertinent labs included ESR 107 mm/hr, CRP 31 mg/dl, low C3 78 mg/dl and dsDNA antibodies elevated to 11 IU/ml. At a prior admission several months before this hospitalization, rheumatology consultation considered SLE to be probable based on renal, hematologic, glandular and potential cardiac manifestations with positive dsDNA, RNP, anti-Smith and low C3. Diagnosis was not definitive at that time. In the absence of infection and malignancy related etiology and in consultation with the rheumatology service, the ascites at this presentation was determined to be likely due to lupus peritonitis. The patient improved clinically and was discharged on a prednisone taper with outpatient follow-up.
Discussion: This case demonstrates the difficulty of SLE recognition in a patient with an uncommon presentation, such as ascites. This is particularly true in patients with coexisting autoimmune conditions, which can cloud the clinical picture. Lupus peritonitis may mimic other infectious or malignant etiologies, delaying diagnosis.
Conclusions: This case report highlights the complexity of diagnosis in a patient with multiple autoimmune conditions, as well as the variability with which SLE can present. It is important for physicians consider the myriad of ways in which SLE can present for accurate identification, diagnosis and treatment.