tuberculosis

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Complete course to cure TB

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Your Health - Dr. Gita Mathai

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March 24 was world tuberculosis (TB) day. Our country has 2.2 million cases of TB out of a global incidence of 8.7 million. The problem in India is compounded by irresponsible individuals who are irregular with treatment or discontinue it. This eventually results in the spread of TB bacteria that are resistant to standard inexpensive medication.

TB is caused by Mycobacterium tuberculosis. It is acquired when a person with lung tuberculosis coughs or spits out bacteria-laden sputum. Once the bacteria is inhaled or ingested, it spreads via blood. It can lodge itself in any organ - lungs, liver, kidney, lymph nodes, gastrointestinal tract, genitourinary tract, nervous system and even the eye. It can cause active infection immediately or remain dormant for a lifetime (latent TB). It can get reactivated, especially if immunity falls owing to other illnesses such as HIV infection, diabetes or cancer.

The symptoms of TB are often vague. There may be low-grade fever (especially in the evenings), sweating, weight loss and a cough, which lasts three weeks or more. There may also be blood-stained sputum or urine, white discharge, diarrhoea, lumps and bumps, enlarged lymph nodes and bony swellings, depending on the organ affected. All these signs and symptoms can occur with other diseases. Lumps may be due to tumour, fever may be due to other infections, and blood-stained sputum can occur in pneumonia, lung abscess or cancer.

If there is blood-stained sputum, it can be examined for TB bacteria. A positive result means that there is TB infection in the lungs. A negative result does not rule it out. The test needs to be repeated at least twice more. TB bacteria from the lungs can be swallowed during sleep. This can be tested by inserting a tube into the stomach and checking the early morning aspirate. Lumps and bumps can be biopsied. The diagnosis may be suspected by the appearance of the affected organs on X-rays or scans.

A skin (Mantoux) test can be done, wherein a small dose of PPD (purified protein derivative) is injected in the skin of the forearm. It is measured 48 to 72 hours later. A negative result does not rule out TB as the test may have been done too early in the disease (before immunity develops), the person may be immuno-compromised or on steroids. Other blood tests are also available like QuantiFERON-TB Gold in-Tube test and T-Spot test. They can also give false positive or negative results.

Once the diagnosis is reached, treatment is started. The duration may be anywhere from six months to one and half years depending on the site (lymph node disease requires shorter treatment whereas that in bone and meninges require longer treatment), the extent of disease, the severity and the response.

Initially, a combination of four first line drugs - Isoniazid, Rifampicin, Pyrazinamide, Ethambutol - and sometimes Streptomycin is used. After some months, the number of drugs (not the dosage) is reduced. Rifampicin needs to be taken on an empty stomach. It can colour the urine and sweat reddish-yellow.

These drugs can be purchased with prescriptions but free treatment is also provided by the government. Patients can opt for whatever suits them personally and financially.

Treatment is complicated by the fact that the bacteria multiplies slowly. If the drug dosage is inadequate or irregular, the bacteria becomes resistant and thrives even with continued administration of medication. Drug-resistant bacteria then develop which have to be treated with expensive second line medication. These unresponsive bacteria can spread in the community.

Dr Gita Mathai is a paediatrician with a family practice at Vellore. Questions on health issues may be emailed to her at yourhealthgm@yahoo.co.in