Case Report: Rare Case of Systemic Lupus Erythematosus (SLE) Presenting as CIDP in Male

Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) is a rare but recognized neurological manifestation of systemic autoimmune disorders, including Systemic Lupus Erythematosus (SLE). However, SLE presenting primarily as CIDP, especially in a young male, is extremely uncommon. We report a 32-year-old male with a previous diagnosis of CIDP who presented with progressive blackish discoloration of fingers and toes, sensory-motor neuropathy, alopecia, and acute dyspnea. Examination showed digital gangrene, mild muscle wasting, neuropathic deficits, and heart failure with reduced ejection fraction (LVEF 25%). Autoimmune evaluation revealed high-titer ANA (1:3200, speckled), strongly positive U1-RNP/Sm, positive anti-Sm, positive nucleosome and histone antibodies, low complements (C3/C4), and low-positive antiphospholipid antibodies. Nerve conduction studies showed sensory-motor polyradiculoneuropathy. Echocardiography revealed global LV hypokinesia and pericardial effusion. The patient improved with high-dose steroids, anticoagulation, and standard heart failure therapy; EF improved to 49% on repeat echocardiogram. This case highlights the need to suspect SLE in males presenting with CIDP-like neuropathy, especially when systemic features evolve. Digital gangrene, myocarditis, and immune- mediated polyradiculoneuropathy may coexist as initial manifestations of lupus.