Right diagnosis key to treating TB

India leads the world in its burden of TB-related morbidity, mortality and drug resistance. India has over 2 million new TB cases every year and TB kills nearly 1,000 people every day. The emergence of drug resistant TB has made things worse.

Multidrug-resistant TB refers to TB that is resistant to isoniazid and rifampicin, two of the most important first-line antibiotics used to treat TB.

TB is a disease caused by bacteria that are spread from person to person through the air. Chronic cough (for more than 2 weeks) and fever are the most important symptoms of TB. When a person with TB coughs, TB bacteria get ejected into the air.

They can then get inhaled by another person who can become newly infected.TB usually affects the lungs, but it can also affect other parts of the body, such as the lymph nodes, abdomen,brain, bone and joints.

TB can affect adults and children, and can affect people from all walks of life. Persons with HIV infection are particularly prone to getting TB.

The good news is that TB is treatable and curable. However, unlike most common infectious diseases that require a few days of antibiotic treatment, TB requires several antibiotics and long-term treatment for cure. Otherwise, TB bacteria can become resistant to the common, first-line drugs that are used.

Early diagnosis

Because TB is a highly curable disease, it is very important to accurately diagnose the disease and to do it early, before severe lung damage occurs, and before other people in the community are infected.

All individuals with cough for more than 2 weeks must seek care early and get their sputum tested for TB. Indeed, this is the key message behind an ongoing media campaign called “BulgamBhai”.

Sputum testing can involve microscopic examination for the TB bacteria, culture to grow the bacteria in a lab, or “PCR” tests that look for TB DNA. GeneXpert is a newly available, accurate, 2-hour PCR test that has been endorsed by the World Health Organisation.

Sputum testing is available free via thousands of designated microscopy centers run by India’s National TB Control Programme. If patients seek care in the private sector, they must demand sputum testing over blood tests for TB.

Many private doctors in India order blood tests for TB. Unfortunately, these are highly inaccurate and can provide misleading results. The WHO has discouraged these tests, and, in June 2012, the Government of India banned the use of TB blood tests.

Laboratories in India should comply with the recent ban and stop offering antibody blood tests. Furthermore, laboratories should not replace antibody TB tests with equally bad or worse alternatives such as “TB Gold” (which is meant for latent TB infection), and PCR on blood samples.

TB disease cannot be diagnosed by any currently available blood test. Testing the sputum for TB bacteria is the only valid approach for accurately detecting pulmonary TB.

If TB is diagnosed, the most important thing a person can do to is to take all of their medications exactly as prescribed by their health care provider. No doses should be missed and treatment should not be stopped early. Patients who cannot afford to buy drugs in the private market must seek treatment in the public sector where drugs are given free.

Doctors have an important role to play in ensuring that their TB patients are treated correctly. Doctors must follow recommended treatment guidelines, monitor patients’ response to treatment, and make sure therapy is completed. Doctors should also avoid starting anti-TB drug treatment without doing any laboratory testing to confirm the disease. If TB is confirmed, they should start treatment promptly and follow WHO or National TB programme guidelines.

For drug-sensitive TB, a standard 4-drug treatment must be started, and the total duration of treatment must not be less than 6 months. Drug-resistance usually happens when patients do not complete their full course of treatment; when doctors prescribe the wrong treatment, the wrong dose, or length of time for taking the drugs; when the supply of drugs is not continuous; or when poor quality drugs are used.

If drug-resistance is suspected, it should be confirmed using laboratory tests such as culture or molecular tests. For drug-resistant TB, second-line drug treatment must be started, and the total duration of treatment must be at least 2 years.

In all forms of TB, providers must counsel their patients about the importance of adherence.Pharmacies and drug stores must not dispense TB drugs without a valid allopathic doctor’s prescription, and TB drugs must not be sold indiscriminately like cough syrups or placebo pills.
With correct diagnosis and complete treatment, TB can be cured and patients’ health can be restored. Importantly, this will also reduce the number of infectious patients and help control this deadly epidemic in India.
(The writer is a professor at dept. of epidemiology, McGill University, Montreal, Canada)