Hyponatraemia due to the syndrome of inappropriate antidiuretic hormone secretion in adults with respiratory syncytial virus infection.

We present a case of severe hyponatraemia due to syndrome of inappropriate antidiuretic hormone (SIADH) in a patient with respiratory syncytial virus (RSV) infection. A retrospective analysis of all patients admitted to our hospital with RSV in the preceding 3-year period revealed hyponatraemia in 41 (28%) cases, of which 13 (8.9%) were moderate or severe. SIADH was explored and confirmed in five (3.4%) patients, raising this as an important, previously unrecognised, complication of RSV infection in adults. Physician awareness of SIADH as a potential complication of RSV will facilitate early diagnosis and treatment of this potentially fatal disorder.