Atypical Onset of Systemic Lupus Erythematosus with Acute Pancreatitis and Class II Lupus Nephritis: A Rare Case Report

Abstract

Systemic Lupus Erythematosus (SLE) is a multisystem autoimmune disease with diverse clinical manifestations; gastrointestinal involvement is uncommon, and acute pancreatitis as the initial presentation of SLE is exceedingly rare, with its coexistence alongside lupus nephritis at disease onset posing a diagnostic challenge that may delay appropriate treatment. We report a 37-year-old female who presented with a two-week history of progressively worsening right upper quadrant abdominal pain, vomiting, low-grade fever, generalized edema, and abdominal distension. Laboratory investigations revealed leukopenia, anemia, elevated serum amylase and lipase levels, severe hypoalbuminemia, nephrotic-range proteinuria, and hypocomplementemia. Magnetic resonance cholangiopancreatography demonstrated edematous pancreatitis with a peripancreatic fluid collection, gross ascites, and bilateral pleural effusion. Common etiologies of acute pancreatitis, including gallstones, alcohol use, hypertriglyceridemia, viral hepatitis, and drug-induced causes, were excluded. Further autoimmune evaluation showed strongly positive antinuclear antibodies with markedly reduced complement levels, and renal biopsy confirmed class II lupus nephritis. Based on the clinical, serological, and histopathological findings, a diagnosis of SLE presenting as acute pancreatitis with concurrent lupus nephritis was established. The patient responded favorably to intravenous methylprednisolone, followed by oral corticosteroids, mycophenolate mofetil, and an angiotensin receptor blocker. This case underscores that acute pancreatitis may rarely represent the first manifestation of SLE and should be considered in patients with unexplained pancreatitis accompanied by multisystem features such as cytopenias, serositis, hypocomplementemia, or significant proteinuria, and highlights the value of early autoimmune evaluation and prompt immunosuppressive therapy in preventing disease progression and improving clinical outcomes