Serial T1-weighted magnetic resonance imaging changes in a patient with central diabetes insipidus, possibly due to lymphocytic infundibuloneurohypophysitis

Abstract

Central diabetes insipidus (CDI), characterized by polydipsia and polyuria due to vasopressin deficiency, is familial, idiopathic or secondary. Idiopathic CDI, which accounts for 10% to 30% of cases of CDI (1), is characterized by selective hypofunction of the hypothalamic‐neurohypophysial system. Idiopathic CDI could be an autoimmune disorder (2). Imura et al. (3) studied the processes of idiopathic CDI by magnetic resonance imaging (MRI), found abnormalities in the pituitary stalk and neurohypophysis, and performed biopsies that demonstrated lymphocytic inflammation. Their cases were diagnosed with CDI due to lymphocytic infundibuloneurohypophysitis. Their study provided new insight into the pathogenesis of CDI. However, they did not demonstrate the serial changes by MRI. We demonstrate the serial T1-weighted MRI changes in a 52-year-old woman with CDI possibly due to lymphocytic infundibuloneurohypophysitis. The initial MRI findings on admission were prominent pituitary-stalk thickening and neurohypophysial enlargement. These findings suggested that the patient had lymphocytic infundibuloneurohypophysitis (3‐5). The serial T1weighted MRI changes which occurred over the years were (i) prominent pituitary-stalk thickening and neurohypophysial enlargement, (ii) their improvement, and finally (iii) empty sella. The MRI changes are associated with the clinical course of the disease. Steroids were not administered to the patient; she recovered from CDI spontaneously. This is the first report to demonstrate the natural course of serial MRI changes in a patient with CDI possibly due to lymphocytic infundibuloneurohypophysitis. A 52-year-old woman had been well until 27 October 2002, when she began to have extreme thirst and excessive urine output. She visited us on 2 December 2002. She had extreme thirst and had started to drink more than 2literswater aday.Shehad decreased anti-diuretic hormone (ADH) levels (0.3ng/l, reference range 0.3‐ 3.5ng/l) with a low urine osmolality of 100mOsm/kg, high plasma osmolality of 310mOsm/kg (reference range 278‐305mOsm/kg), and a high serum