Excessive secretion of antidiuretic hormone in infections with respiratory syncytial virus.

The association between infections with respiratory syncytial virus and plasma concentrations of antidiuretic hormone was assessed in 48 patients who had been admitted to hospital. The mean (SEM) concentration of antidiuretic hormone was significantly raised in patients with bronchiolitis (9.3 (1.4) ng/l) compared with non-pulmonary respiratory syncytial virus infections that cause apnoea or upper respiratory tract symptoms (6.1 (1.7) ng/l). The highest concentrations of antidiuretic hormone were seen in patients receiving mechanical ventilation (18.0 (6.7) ng/l). There were no differences in mean serum sodium concentrations among the subgroups. Hypertranslucency on chest radiograph or an arterial carbon dioxide tension above 6.67 kPa were associated with a significantly higher concentration of antidiuretic hormone. Increased or normal maintenance fluid intake in children with pulmonary respiratory syncytial virus infections may cause the same symptoms of fluid overload as the syndrome of inappropriate secretion of antidiuretic hormone. Patients with pulmonary respiratory syncytial virus infection, hypertranslucency in chest radiograph, hypercapnia, or mechanical ventilation are at risk for raised concentrations of antidiuretic hormone. Restricted fluid intake and careful monitoring of fluid balance and plasma electrolyte concentrations are therefore necessary in these patients.