Frequency of latent and smear positive tuberculosis in chronic psychotic disorders

Screening is one of the ways to combat Tuberculosis (TB) and should be mostly concentrated on groups showing some symptoms of the disease. Tuberculosis can be transferred from person to person in laboratories, prisons and psychiatry hospitals. The purpose of this study was to survey pulmonary TB in patients with schizophrenia in Rasht.

In this descriptive-cross sectional, Two hundred fifty seven consecutive patients with chronic psychotic disorder hospitalized in psychotic hospitals underwent purified protein derivative (PPD) test. PPD test was done with the unit 5T which was injected subcutaneously on anterior surface and at the top of left forearm. The results of the test were interpreted by the pen technique method and based on transverse diameter of induration of about 48-72 hrs. Induration size due to hypersensitivity to PPD more than 10mm was considered positive. Patients with positive PPD test underwent complementary sputum smear. Data were analyzed using chi- square and T test.

The mean age of patients was 45±10 years; 75.5% were male, 74.7% were single, 10.5% married, 7.8% divorced, and 68.1% were smokers. These patients suffered from chronic psychotic disorder at the mean time of 15±7.9 years. In 74 patients (28%) positive PPD test were recorded, but active pulmonary TB was not found in complementary experiments of PPD sample. Based on data analysis, only age and gender showed a significant relationship with the results of the PPD test (P < 0.05).

This study showed that patients with positive PPD test are much more than the normal population, but active pulmonary TB was not observed in our samples. Since these patients are in clinical and closed places, more programs for screening are required.