An unusual presentation of Juvenile-onset systemic lupus erythematosus: Budd–Chiari syndrome with secondary antiphospholipid syndrome and lupus nephritis: a case report

Abstract Background Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease affecting young women. Budd–Chiari syndrome (BCS), caused by hepatic venous outflow obstruction, is a rare manifestation often associated with secondary antiphospholipid syndrome (APS). Case summary A 17-year-old girl presented with progressive abdominal distension, pedal edema, fever, weight loss, arthralgia, oral ulcers, alopecia, and amenorrhea. Initially managed as chronic liver disease after recurrent presumed spontaneous bacterial peritonitis, imaging revealed chronic BCS. Further evaluation demonstrated positive antinuclear and anti-double-stranded DNA antibodies, hypocomplementemia, proteinuria, and Class IV lupus nephritis. Persistent antiphospholipid antibody positivity confirmed secondary APS. Treatment with corticosteroids, mycophenolate mofetil, hydroxychloroquine, and planned indefinite anticoagulation resulted in marked clinical improvement. Conclusion SLE with secondary APS should be considered in young women presenting with unexplained BCS to enable early diagnosis, prompt immunosuppressive therapy, and prevention of irreversible organ damage.