妊娠中の全身性エリテマトーデスと急性炎症性脱髄性多発神経炎：まれな多系統性症例

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease associated with significant maternal and fetal risks during pregnancy. Lupus nephritis further increases morbidity, while neurological complications are less common. Acute inflammatory demyelinating polyneuropathy (AIDP), a variant of Guillain-Barré syndrome, is exceptionally rare in pregnancy. We describe a 24-year-old primigravida at 14 weeks of gestation who presented with progressive lower limb weakness, numbness, and diplopia. Laboratory tests demonstrated proteinuria and hypoalbuminemia, which were initially attributed to pregnancy. Forty-eight hours later, she re-presented with worsening weakness and inability to walk. Neurological assessment, cerebrospinal fluid analysis, nerve conduction studies, and strongly positive pan-neurofascin antibodies confirmed AIDP. Further evaluation revealed nephrotic syndrome secondary to class III lupus nephritis. During immunosuppressive therapy, including tacrolimus, she developed lupus-related myocarditis with reduced ejection fraction. The pregnancy was further complicated by intrauterine growth restriction, oligohydramnios, and preeclampsia, necessitating emergency cesarean section at 27 + 1 weeks. Both mother and infant survived with ongoing multidisciplinary follow-up. This case highlights an exceptionally rare multisystem presentation of SLE in pregnancy, involving lupus nephritis, AIDP, and myocarditis. Early recognition and coordinated multidisciplinary management are essential to optimize maternal and fetal outcomes in such complex cases.