The Basics Of Tuberculosis (TB)

Dr. Jade Mogambery, Specialist Physician at Melomed Richards Bay Hospital
FCP(SA) CertIDPhys(SA)

Tuberculosis (TB) is a disease caused by the pathogen mycobacteria tuberculosis (MTB). MTB is a bacterium that can be spread from person to person by droplet transmission. This means an infected individual can spread the organism to others by coughing, singing, shouting or sneezing.

If I am in contact with someone who has TB, will I definitely get it?
No. Whether an individual develops TB is dependent on the load of TB in the environment, and the immune system of the exposed individual. If the person who has TB has a low concentration of MTB in the sputum, or has been on treatment for over two weeks, the risk of transmission is very low. If the load of MTB in the environment is high, an individual may become infected. However, the body’s immune system often halts the infection and TB does not ensue. If the immune system is compromised, the infection will progress to disease.

How can a person get TB without a recent contact?
Sometimes MTB lies dormant in the lung (latent). When the immune system becomes compromised, MTB is activated and the person develops TB. What are the symptoms of pulmonary TB?
Common symptoms are coughing, night sweats, fever, loss of weight, loss of appetite, and chest pain.

Should you be worried about asymptomatic TB?
Yes. More than half (58%) of people in South Africa who are already sick with tuberculosis (TB) may not realise it because they don’t have any of the symptoms often linked with the disease, such as coughing and weight loss. They may even say that they feel well and that they’ve been continuing with their daily lives as usual, completely unaware that their bodies are fighting a TB infection. This category of TB is called subclinical, or asymptomatic TB. Researchers don’t yet know to what extent people with asymptomatic TB spread the disease. It’s also unclear whether people with symptomless disease will necessarily fall ill.

How do people get extra-pulmonary TB (TB of organs other than the lung)?
This can happen if MTB moves to other organs, usually by blood or lymph spread. This type of TB can be harder to diagnose, but because South Africa has a high burden of TB, doctors are vigilant and run tests that make the diagnosis easier.

How can a diagnosis of TB be made?
The most common way is by examining sputum. A good sample of sputum must be expectorated (coughed up) and this is sent to the lab. Sometimes the MTB can be seen with special staining, but more recently laboratories run a test looking for MTB DNA, which is more sensitive. Blood tests can assist in making the diagnosis. Imaging of the chest by X-rays or CT scans are also useful. Doctors often want a biopsy of the affected organ to confirm TB if the diagnosis is not easy to make, as one needs to be sure before starting TB treatment.

What does TB treatment consist of?
Four drugs are used simultaneously for two months. Following this phase, two drugs are removed and two are continued for a further four months. In total, an individual with TB is on treatment for six months. Treatment is extended in cases of TB meningitis and TB spine.

What are the common side-effects of TB treatment?
• Rifampicin: Orange urine and body fluids, liver injury
• Isoniazid: Liver injury, vitamin B6 deficiency
• Ethambutol: Visual disturbances, rash
• Pyrazinamide: Joint pain, liver injury

What is drug-resistant TB?
This is when one or more of the usual drugs used to treat TB do not work. This often develops when individuals do not complete TB treatment. These individuals harbour MTB that has mutated in the presence of low concentrations of TB treatment. They can then transmit the resistant MTB to others.

Is there treatment for drug-resistant TB?
Yes. There have been great strides made in the treatment of multi-drug resistant TB, but it remains a big problem owing to the duration of therapy and high pill-burden.

How can I protect myself and others from getting TB?
Try to be as healthy as possible. Eat healthy foods, exercise and manage chronic conditions, especially HIV and diabetes mellitus. Try to avoid crowded spaces and keep to well- ventilated areas. Ensure there is good ventilation at home and work, and especially in crowded spaces. Cross-ventilation is best (where windows are opened opposite each other). Air conditioning does not equate to good ventilation. As we learnt during the Covid-19 pandemic, cough hygiene is key and should be practised by all. Simple measures, like coughing into one’s arm or tissue and using a mask when one has a cough, help prevent transmission.

If you think that you or one of your loved ones may have TB, you should immediately consult a healthcare practitioner, who can conduct a clinical assessment, send away sputum for testing and possibly refer you for further x-ray testing. If you had close exposure to TB, please also talk to your healthcare provider, who will screen and test you, and may offer you TB preventive therapy which includes antibiotics to prevent you from becoming ill with TB.

TB remains a massive problem in South Africa, but with increased awareness and early detection, we can prevent the spread of this treatable infectious disease.