nzaznin zeinali nezhad - 21DOCS Test Area

IntroductionTuberculosis (TB), which is caused by bacteria of the Mycobacterium tuberculosis complex, is one of the oldest diseases known to affect humans and a leading cause of death worldwide (1).Approximately one-third of the global population is infected with a lifetime risk of 10% for developing tuberculosis (TB) disease. In 2017, there were 10.4 million reported cases of TB worldwide, corresponding to an incidence rate of 133 cases per 100,000 individuals. Among these cases, 90% were adults over the age of 15, and 64% were male. (2).Iran is considered a high-burden country for tuberculosis, with a notable incidence rate. The endemicity of TB in this region increases the pretest probability of the disease in patients presenting with compatible symptoms and radiological findings (3). Pulmonary TB is usually a disease having a gradual onset. Fever is the most common observed constitutional symptom which characteristically develops in the late afternoon. There may be other manifestations in up to 75% of cases of pulmonary TB, such as malaise, weakness, unusual fatigue, headache, night sweats and weight loss. This is usually accompanied by caseous necrosis and concomitant caseous liquefaction and cough and purulent sputum which is often associated with mild hemoptysis (4).Sputum smear microscopy and culture are commonly used for the diagnosis of pulmonary TB. However, it’s essential to recognize the limitations of these tests (5, 6). Smear microscopy has a sensitivity ranging from 36.9% to 55.6% and specificity of around 99%, while culture has higher sensitivity (approximately 80-90%) but takes longer for results (7, 8). Importantly, negative smear and culture results do not exclude the diagnosis of TB, especially in cases of paucibacillary disease or extrapulmonary involvement (8).