Vasopressin cell antibodies and central diabetes insipidus in a patient with systemic lupus erythematosus and dermatomyositis.

We describe a 39-year-old woman who presented central diabetes insipidus (CDI), during active systemic lupus erythematosus (SLE) concomitant with dermatomyositis. CDI is rarely reported in association with SLE and has never been reported with dermatomyositis. After treatment with intravenous cyclophosphamide (IV CYC) with concurrent oral prednisolone, CDI improved and vasopressin replacement therapy was completely withdrawn. Serum autoantibodies to vasopressin cell (AVPcAb), detected at diagnosis before immunosuppressive treatment, disappeared in 2 months. To our knowledge, this is the first case of CDI in SLE overlapping with dermatomyositis. Interestingly, it was characterized by the presence of AVPcAb before the treatment and by their disappearance after IV CYC and steroid therapy with restoration of normal postpituitary function.