Twenty children from 2 months to 7 years (mean age 2.74 years +/- 1.62) diagnosed to have
tuberculous meningitis (TBM) were evaluated for serial serum
sodium levels and osmolality of cerebrospinal fluid (CSF), serum and urine on admission and the results compared with 20 age and nutritionally matched controls, and these investigations repeated on day 3 and day 10. Mean serum
sodium levels (130.7 +/- 6.26 mEq/L), and osmolality of CSF (272.0 +/- 7.0 mOsm/kg) and serum (275.5 +/- 6.09 mOsm/kg) were significantly lower (p < 0.001) than in controls.
Hyponatremia was detected in 65% of cases on admission, 47% on day 3 and in 30.8% on day 10. All the patients with
hyponatremia had biochemical evidence of syndrome of inappropriate secretion of
antidiuretic hormone (
SIADH) on admission. Incidence of
SIADH gradually decreased to 41.2% on day 3 and 15.4% on day 10. In some of the cases serum
sodium levels and osmolality of serum and CSF took about 3 weeks to return to normal. CSF osmolality was lower than concomitant serum osmolality in patients as well as in controls. In patients with
SIADH, CSF osmolality followed the same trend as serum values and returned to normal in 2-3 weeks. Overall mortality was 25%. Two out of 3 patients who expired during first 3 days had
SIADH but in those cases who survived there was no correlation with degree of meningeal inflammatory changes or ultimate outcome.
SIADH is commonly associated with TBM and should be diagnosed early in order to modify the
fluid therapy in these cases.(ABSTRACT TRUNCATED AT 250 WORDS)