Hyponatremia due to pulmonary tuberculosis: review of 200 cases

Pulmonary Tuberculosis (PTB) is one of the common diseases with high prevalence of mortality and morbidity in developing countries. Various complications have been reported along with PTB. The subclinical electrolyte imbalances are customary in cases with PTB.

The aim of this study was the evaluation of patients with PTB and hyponatremia.

We evaluated patients with diagnosis of secondary PTB who have been admitted to Baqiyatallah hospital, Tehran, Iran from 2005 till 2010. The diagnosis of PTB was based on the appearance of acid fast bacilli in sputum smears or sputum cultures, without any evidence of miliary TB. Demographic and laboratory characteristics relative to electrolytes were recorded according inclusion and exclusion criteria.

The mean age was 59.22 ± 20.57 years and 91 (45.5%) patients were male. The mean serum sodium concentration was 134.54 ± 4.95 mmol/L and more than half of subjects (51%) have shown hyponatremia. The mean age difference between hyponatremic and eunatremic groups was statistically significant (61.95 versus 56.02 years) (P = 0.047). No significant relationship was found between hyponatremia and gender, anti-TB medications and co-morbidity conditions.

In this study, an older age was suggested as an important predisposing factor for hyponatremia in patients with PTB which had been observed as less of a determinant. We recommend further evaluations for hyponatremia in patients presenting with PTB, particularly for those who are older.