Syndrome of inappropriate antidiuretic hormone (SIADH) in measles and malaria infections.

Sodium concentrations and osmolalities of simultaneously obtained venous blood and urine have been determined in a total of 61 children consisting of 18 children with malaria infection, 18 children with measles infection and 25 age- and sex-matched controls. The mean plasma osmolalities in the malaria and measles groups were significantly lower than in the control group (p less than 0.01). There was no difference between the measles and malaria groups either in their plasma osmolality (p greater than 0.20) or urine osmolality (p greater than 0.10). The u/p ratios for both osmolality and sodium concentrations where significantly higher for both the measles and malaria groups than for the matched controls. There was no difference in the u/p values between the malaria and measles groups (0.02 greater than p greater than 0.10). We conclude from these results that measles and malaria infected children demonstrate inappropriate secretion of ADH. Every child with these conditions should be carefully evaluated for the detection of evidence of SIADH. This is more important for children with measles who are frequently anorexic and may need intravenous infusion for maintenance of hydration.