Abstract
The major causes of central diabetes insipidus (CDI) are neoplastic or infiltrative lesions of the hypothalamus or pituitary gland, severe head injuries, or pituitary or hypothalamic surgery. Lymphocytic infundibuloneurophysitis (LINH) is associated with autoimmune inflammatory disease of the pituitary gland, but the exact etiology is unknown. CDI caused by viral infections has been rarely reported. Here, we describe the case of a 22-year-old man who was in good health until 2 months prior to admission, presented with acute development of polyuria and polydipsia, and showed increased urinary volume up to 9000 mL/day. The patient showed elevated serum osmolality and low urine osmolality, with a low level of antidiuretic hormone. Endocrinological findings revealed CDI, but his arterial pituitary function appeared normal. Magnetic resonance imaging revealed significant enlargement of the pituitary stalk. We suspected CDI due to LINH based on non-transsphenoidal biopsy findings. He was diagnosed as type A influenza,and given oral therapeutic agents. However, acute onset of polyuria and polydipsia occurred 10 days after the influenza diagnosis. The available epidemiological information regarding the outbreak of influenza around that time strongly suggested that the patient was infected with the A/H1N1 influenza virus, although this virus had not been detected on polymerase chain reaction testing. In the present case, the autoimmune mechanism of LINH may have been associated with novel influenza A/H1N1 virus infection.
