What are the common symptoms of active tuberculosis (TB)?

Symptoms depend on the organs affected. Some people may not develop any obvious symptoms. Some common ones include:

• low-grade fever
• night sweats
• fatigue
• weight loss
• a persistent cough that lasts three weeks or longer
• chest pain
• coughing up blood or sputum

Q: When does a patient with TB become non-infectious?

A: The patient will generally become non-infectious after two weeks of TB treatment. He or she can then return to work or school.

However, he or she is not cured yet at this stage and must continue with the treatment until the whole course has been completed.

Stopping TB treatment prematurely before its entire six-to-nine months course can lead to the patient becoming infectious again or developing TB strains which are resistant to treatment.

Q: What is Latent TB Infection?

A: Initial TB infection usually goes unnoticed.

The TB bacteria can remain in the body without showing symptoms for years, sometimes decades. This is called latent TB infection (LTBI).

LTBI is not a disease. Persons with it do not spread TB to others. About 10 per cent of those with LTBI will develop active TB during their lifetime, and half of such persons do so in the first two years after acquiring the infection.

Q: How do you manage LTBI?

A: An anti-TB drug known as isoniazid is given to persons with LTBI for six to 12 months to reduce the risk of developing active TB in the future.

Isoniazid is able to reduce the risk of developing active TB by up to 90 per cent. This means that the lifetime risk of developing active TB in persons with LTBI is reduced from 10 per cent to one per cent or less.

A major side effect of taking isoniazid is hepatitis (inflammation of liver). However, the risk is very low, at less than one per 1,000 for persons under 20 years of age. It is therefore a safe drug.

Source of information: MOH website

This article was first published in November 2011 in The New Paper.