Long QT syndrome caused by adrenal insufficiency secondary to IgG4-related hypophysitis: a case report and review of the literature

Abstract

A 55-year-old-man presented with low-grade fever, general fatigue, appetite loss and body weight loss. An electrocardiogram (ECG) showed the presence of long QT syndrome (LQTS), and laboratory tests revealed elevated serum immunoglobulin G4 (IgG4) concentration and adrenal insufficiency. Imaging studies revealed lymphadenopathy, salivary and lacrimal gland enlargement, interstitial pneumonia, multiple bilateral kidney nodules, periaortitis, and enlargement of the pituitary gland and stalk. Histological examination of the lip and salivary gland showed infiltration with IgG4-positive plasma cells. We diagnosed the patient with IgG4-related disease and adrenal insufficiency-induced LQTS secondary to IgG4-related hypophysitis. The patient was treated with prednisolone, which normalized the QT interval, resolved the extrapituitary organ lesions, and shrank the pituitary and stalk. Although LQTS has been reported in patients with adrenal insufficiency, to our knowledge, this is the first case of LQTS with adrenal insufficiency caused by IgG4-related hypophysitis. Since LQTS can be life-threatening, our finding suggests that patients with IgG4-related hypophysitis should be examined for ECG abnormalities.