Am I infected with TB of the chest?
Q: I am a 26 years old male. I want to know if I am infected with TB or not. In 1999, I got a TB infection in my chest. I took medicines for nine months, after which I was perfectly all right. A few days ago, in a chest X-ray some patches were seen in my chest. The doctor asked me to go for the following tests: CBC, ESR and sputum. I underwent all three in 2 different labs and got the following results: CBC – between normal range; ESR – between normal range; Sputum: No AFB seen. On showing these results to the doctor, I was asked to come one week later for the final report. Please tell me if I have this infection. I feel perfectly all right.
A:During the course of infection with TB bacteria, the inhaled bacteria enter the lungs, where they multiply and cause a local lung infection. The surrounding lymph nodes may also become involved and usually increase in size. The body's immune system tries to fight off the infection, and stop the bacteria from spreading to other parts of the body, by forming scar tissue around the TB bacteria and isolating it from the rest of the body. If the body is able to form scar tissue (also known as fibrosis) around the TB bacteria, then the infection is contained in an inactive state. Such an individual typically has no symptoms and cannot spread TB to other people. The scar tissue and lymph nodes may eventually harden, like stone, due to calcium deposition in the scar. These scars due to old healed tuberculosis lesions can be seen on x-rays. However, all cases of old treated TB may not lead to scar formation. The x-ray changes take a much longer time to resolve and do leave a scar even after successful treatment of TB. Assessment by X-ray changes alone can be very misleading. Disappearance of clinical symptoms, general well-being, ability to resume normal activities, and weight gain are all pointers to clinical progress. Persistence or reappearance of symptoms plus weight loss – indicates the need for further investigations by sputum microscopy. Erythrocyte sedimentation rate (ESR) and other tests are unreliable and unnecessary in monitoring progress. Clinical assessment is often the only means available for judging progress in extra-pulmonary and smear-negative pulmonary tuberculosis: weight gain is a valuable indicator in such cases. Since your reports are normal and you do not have any symptoms, you should not worry about the X-ray patches.