Q: I had a swelling in my neck and the doctors did a FNAC. Now they say that I have TB in the lymph node. I consulted another doctor who said that my ESR count is only 27; hence it should not be TB. How do I correctly know if I am suffering from TB? What precautions should I take and is TB contagious?

A:Tuberculosis (TB) is caused by a bacterium called Mycobacterium tuberculosis and it occurs when an individual inhales bacteria, which have been aerosolised by infected persons (droplet infection). The primary infection is of the respiratory tract due to inhalation of infected droplets. The chances of infection increase in small, enclosed spaces and in areas with poor ventilation. Following inhalation, the bacteria are ultimately deposited in the terminal part of the respiratory tract. There is also the possibility of the bacteria spreading via the blood (or lymph) to other lymph nodes and distant parts of the body like bone, brain, kidney etc. The occurrence of lung infection with involvement of the draining lymph node is called a primary complex. Most infected persons do not develop active disease and the bacillus grows slowly and may remain inert for months to years before getting reactivated and causing disease. People who have lowered immunity like children and elderly, patients on steroids or chemotherapy or diseases like HIV malnutrition etc. have a higher risk of developing TB. The definitive diagnosis of TB depends on demonstration of the organism (stained smears &/or culture) from secretions or biopsy tissues. Appropriate specimens include sputum, gastric lavage, bronchoalveolar lavage, lung tissue, lymph node tissue, bone marrow, blood, liver, cerebrospinal fluid (CSF), overnight urine, and stool, depending on the location of the disease. Automated radiometric culture methods are increasingly being used for the rapid growth of mycobacteria. X-ray of the chest is a classic diagnostic tool when evaluating patients for pulmonary TB. Tuberculous lymphadenitis is not infective (unless there is a draining sinus). Please consult your physician who will advise you about appropriate treatment, its duration, precautions to be taken, etc.