Serum and urine sodium levels in dengue patients

We evaluated serum and urine sodium levels in children with dengue infections. Children with acute febrile illness admitted to Bhumibol Adulyadej Hospital in Bangkok from January 1999 to January 2000 were enrolled. Serum and urine sodium levels were measured before initiating intravenous fluid therapy. Two milliliters of blood were obtained on admission and before discharge to test for anti-dengue virus antibody using the enzyme-linked immunosorbent assay technique. Hyponatremia was defined as a serum sodium level <130 mEq/l and depletion of circulatory volume was defined as a urine sodium level < 20 mEq/l. Out of 93 enrolled patients, 49 were categorized as dengue patients and 44 were as non-dengue patients. Six dengue patients developed shock whereas 43 patients did not. The mean serum sodium level was significantly lower in dengue patients compared to non-dengue patients (p-value < 0.0001). Hyponatremia was 9.7 times more common in dengue patients. Among dengue patients, the mean serum sodium level was significantly lower in shock patients compared to non-shock patients (p-value = 0.003). However, the prevalence of hyponatremia was not different between the two groups. The mean urine sodium level was significantly lower in dengue patients compared to non-dengue patients (p-value < 0.0001). A urine sodium level < or = 20 mEq/l was 8.1 times more common in dengue patients. Among dengue patients, the mean urine sodium level was not significantly different between shock and non-shock patients. In shock patients, a urine sodium level < or = 20 mEq/l was 7.6 times more common.