The truth about TB

BREATHE EASY

Villain in your lungs: Tuberculosis is a disease caused by Mycobacterium.  PIC GETTY IMAGES

Despite recent progress, tuberculosis (TB) remains an important global public issue. One-third of the world’s population is currently infected with Tubercle Bacillus, nearly 9 million new cases occur each year and more than one-and-a-half million deaths are due to tuberculosis.

Tuberculosis is one of the oldest of human diseases and has a history as old as mankind itself. In India, it is a major public health problem and the most common cause of death due to a single infectious agent in adults. Nearly one percent of the world’s population is infected with tuberculosis every year.

What is tuberculosis?

Tuberculosis is a bacterial infection caused by Mycobacterium Tuberculosis. The disease usually affects the lungs, but can spread to other parts of the body in full blown cases. An individual gets infected with tuberculosis when the patient coughs, sneezes or spits. However, not all people who get infected with tuberculosis develop the symptoms. Those who do not become ill have latent tuberculosis and cannot spread the disease to others.
The clinical symptoms of pulmonary tuberculosis are low-grade fever (with evening rise of fever and night sweats), loss of appetite and weight, weakness, fatigue and cough for a duration greater than 3 weeks and blood streaks in phlegm. A patient may have all or a few of these symptoms. The common findings on chest x-rays of infected people are cavities, pleural effusion or fibrosis. Histopathology shows necrosis with acid-fast bacilli (AFB). A patient with active tuberculosis will have at least 2 out of 3 sputum smears positive for AFB.

HIV positive individuals have a very high lifetime risk of developing active tuberculosis (30%) as compared to HIV negative persons (5-10%). Diabetics and immuno-compromised patients also frequently develop pulmonary tuberculosis. The disease also kills more young people than any other disease. Nearly one lakh children die of tuberculosis every year.

Treatment

Decades ago, it was compulsory to admit a tuberculosis patient in a sanatorium, for up to a year. Patients were confined to beds in airy, well ventilated, clean wards. Later, the Madras study showed that sanatorium treatment was in no way superior to home (domiciliary) treatment. Despite good accommodation, nursing, rich diet and prolonged bed rest, sanatorium patients showed little difference from patients treated in overcrowded homes with poor ventilation and diet and very little rest. Also it was very difficult to keep a patient in the sanatorium away from his family for a whole year. Hence domiciliary treatment of tuberculosis prevailed.

Tuberculosis is curable only with a combination of chemotherapy, in which a medley of three or four anti-tubercular drugs (ATT) is administered. The first line ATT drugs are Isoniazid, Rifampicin, Ethambutol, Pyrazinamite, Streptomycin. This treatment is streamlined over a period of six months. The patient receives four drugs during the first two months and two drugs for the rest four months, depending on his clinical improvement. In rare cases of spinal tuberculosis or TB meningitis, the treatment is extended up to nine months or a year.

DOTS (Directly observed treatment short course) has been very effective in controlling the spread of tuberculosis. Under the scheme, the government provides free ATT to all tuberculosis patients in the country, irrespective of their age, socio-economic status or type of TB. Patients fall under one of the following categories —Category A is smear positive pulmonary TB; Category B is smear negative but x-ray positive pulmonary TB; and Category C includes extra-pulmonary cases. The patient has to report to the primary health centre thrice a week (on alternate days) and take his medicines in the presence of the social worker. The DOTS strategy is known as revised national TB central program (RNTCP) in India. Surgery is indicated in MDR-Tuberculosis for removal of a diseased lobe (lobectomy) or a destroyed lung (pnuemonectomy). The aim of surgery in tuberculosis is to remove all the disease-bearing lung tissue, preserving as much of the normal lung as possible.

Newborns receive BCG vaccine which may protect against tuberculosis in infancy. However, this does not guarantee immunity against the disease after they grow up. Therefore, all those who come in close contact with a tuberculosis patient must be screened and given INH prophylaxis.

For instance, if a mother is on ATT, all her children must be given INH prophylaxis in a dose of 5 mg/kg daily for 6 months.

A patient with active smear positive TB must be taught proper sputum disposal in a phenyl can. He must cover his mouth with a tissue/ kerchief while coughing/sneezing.
There are two new and dreaded forms of tuberculosis known as MDR-TB & XDR-TB.  
MDR-TB or multi-drug resistant tuberculosis is when mycobacteria develop resistance to at least two of the first line drugs, namely Isoniazid and Rifampicin. XDR-TB or extensively drug resistant tuberculosis is when mycobacterium develops resistance to even the second line drugs.

The social stigma associated with tuberculosis in India earlier is no more evident now. People are aware that tuberculosis is  curable.

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