Tuberculosis or TB is a highly infectious disease that is still common in developing countries around the world.
It is caused by bacteria called Mycobacterium tuberculosis which infects the body’s lungs and other parts of the body. It can cause serious complications such as intestinal obstruction, meningitis, disseminated TB and even death if left untreated.
Who Can Get It?
Anyone can get infected with tuberculosis but children, elderly and those who have lowered immune defenses have a higher risk of acquiring it. The bacteria are spread via droplet which means that the bacteria can be suspended in the air after an infected person sneezes.
Close contact with infected persons such as talking and kissing can also transmit the infection. Fomites like a handkerchief used by an infected person can also transfer the bacteria.
Since TB is highly infective, most family members who live in the same house with an infected patient will also most likely acquire TB unless proper preventive measures are taken. Health workers like doctors and nurses are also at risk for acquiring tuberculosis infection because constant exposure to patients in hospitals and health centers.
What Are The Symptoms?
The most common symptom of tuberculosis is chronic cough. Cough becomes chronic when it lasts more than 3 weeks. Cough can also be associated with sputum or phlegm, which sometimes can be blood-tinged. On and off fevers especially during the afternoon, night sweats and unexplainable significant weight loss are also common manifestations of TB infection.
How Is It Diagnosed?
Diagnosis of tuberculosis can be done using various imaging and laboratory tests. Usually a chest radiograph is requested to visualize tubercles in the lungs. However, it is possible that patients with active TB will turn up with a negative chest radiograph.
A negative chest radiograph despite clinical symptoms of TB does not eliminate the suspicion of TB. A sputum smear or Acid Fast Bacilli (AFB) smear can also be done to detect the bacteria in the sputum. It is a non-invasive test wherein patients are made to cough up sputum which is then visualized under a microscope.
It is a good test but like the chest radiograph, negative results do not rule out tuberculosis especially if the patient presents with symptoms. Another disadvantage of the AFB smear is that it is hard to perform on children and patients who are unable to cough out sputum.
The most definitive diagnostic test for TB is the sputum culture however, the results of this test only come out after 4 weeks which may delay necessary treatment. Lung biopsy can also be done to identify the infection itself but this is a invasive procedure and is almost never used.
How Is It Treated?
Patients diagnosed with tuberculosis have to undergo at least 6 months of daily medications. It is usually a combination of 4 drugs: Isoniazid, Rifampicin, Pyrazinamide and Ethambutol. Patients with multi-drug resistant tuberculosis, which means that they do not respond to these 4 medications, will need an additional drug Streptomycin.
Strict adherence to daily medications is a must to successfully treat TB which is why doctors usually require the patient to have a treatment partner to supervise daily intake of medications. This treatment partner can be a family member or a health worker working for DOTS.
DOTS or Directly Observed Treatment Short Course is a program recommended by the World Health Organization to facilitate treatment of patients infected with tuberculosis.
How Can It Be Prevented?
In developing countries and countries where tuberculosis burden is high, children are usually required to receive a BCG vaccine which can prevent TB infection. Preventing transmission of TB is primarily the responsibility of the patient.
A patient who is diagnosed with tuberculosis and who is receiving quadruple medications for less than 2 weeks is still infective. Precautions such as wearing face masks should be taken. Family members or people in close contact with these patients should also be screened for tuberculosis.