A Rare Case of Lupus Nephritis with Hemophagocytic Lymphohistiocytosis

Introduction: In this case, we present a 19 yo female with SLE and lupus nephritis complicated by HLH. The following describes her initial presentation and diagnosis, followed by the treatment of this uncommon complication of SLE. Case Description: A 19 yo female with a family history of autoimmune disease reported fatigue, joint pain, and a rash on her feet 6 months prior to admission. 3 days prior to admission, she experienced nausea, vomiting, and abdominal distension. On admission, the patient was found to have pancytopenia, severe AKI with proteinuria, and imaging suggestive of cirrhosis with ascites and splenomegaly. Her ANA and anti-DS DNA were positive. Subsequent workup, including a kidney biopsy and bone marrow biopsy, led to a diagnosis of SLE complicated by LN class IV and HLH/MAS. The patient was treated with dexamethasone per the HLH-94 protocol, in addition to HCQ and MMF for SLE and LN. Her inflammatory markers normalized, and AKI resolved. At 6-month follow-up, she had tapered off steroids and continued on HCQ and MMF. Discussion: Hepatic involvement is rare in SLE and suggests a secondary complication such as aPL-related TMA, autoimmune hepatitis, secondary Still disease, or, as in this patient, HLH. sHLH is a rare disorder that is life-threatening if not promptly treated. It is a diagnostic challenge for clinicians given the overlap in presentation between autoimmune disease and infection. sHLH is an uncommon but severe complication of SLE, where it is called macrophage activation syndrome. It is described in ~8% of new SLE cases, mostly in children. Differentiating features for MAS are high fever, elevated AST, LDH, ferritin, TG, and neutropenia. SLE patients presenting with MAS are more likely to have renal disease. Treatment options for sHLH include disease-specific therapy or chemotherapy. In this patient, disease remission was achieved by combining SLE induction treatment with a higher-than-typical steroid regimen guided by HLH treatment protocols.