TB is an airborne infectious disease caused by Mycobacterium tuberculosis.It spreads through fine respiratory droplets expelled when a person with active pulmonary TB coughs or sneezes.

You cannot get TB from:

• Sharing cups or utensils
• Sharing cigarettes
• Kissing or saliva contact

“TB usually affects the lungs, causing pulmonary tuberculosis. However, TB can also affect other parts of the body including the brain, lymph nodes, kidneys, bones and joints. Such a form of TB is called extrapulmonary tuberculosis. If not treated properly, tuberculosis can be a fatal disease,” explains Clin Assoc Prof Low.

Latent TB vs Active TB

TB infection does not always lead to disease.

Latent TB

• TB bacteria are present but inactive
• No symptoms
• Not contagious
• Can become active later, especially if the immune system weakens

Active TB

• Bacteria multiply and cause symptoms
• Highly contagious if the lungs are affected
• Requires immediate and complete treatment

“People with latent TB don’t feel sick because they don’t have symptoms. They are also not infectious.

But 10 per cent of people with latent TB will develop active TB at some point. When their immune systems are weakened for whatever reason, the TB wakes up and starts to be active and to multiply, potentially spreading to the rest of the body,” says Clin Assoc Prof Low.

While pulmonary TB affects the lungs, the disease can spread beyond them:

Extrapulmonary TB

Also caused by Mycobacterium tuberculosis, extrapulmonary TB:

• Most commonly affects the lymph nodes in the neck, causing them to swell
  
  
• Can involve the skin, bones, muscles, kidneys, or the linings of the lungs or brain
  
  
  • Skin - Skin lesions
  • Pleural (lung lining) - Water accumulation in the lungs causing breathlessness
  • Kidney - Kidney impairment, painful urination, hematuria (blood in urine), flank pain
  • Bones - pain and swelling of affected joint
  • Brain - Low-grade fever, lethargy, headaches, giddiness, vomiting, neck stiffness, personality or behaviour change
    
    
• Is not infectious

Typical symptoms include:

• Persistent cough (≥ 3 weeks)
• Bloody sputum
• Fever
• Chills
• Night sweats
• Loss of appetite
• Unexplained weight loss

Seek medical attention promptly if these symptoms persist.

A weakened immune system increases the risk of TB infection and reactivation.

Other factors that put one at increased risk of TB include:

• Diabetes (Type 2 Diabetes Mellitus)
• End-stage kidney disease
• Certain cancers
• Chemotherapy
• Immunosuppressive drugs (e.g., post-transplant)
• HIV/AIDS

TB is curable, but requires strict adherence.

Standard treatment

• Combination of anti-TB antibiotics
• Taken for 6–9 months or longer.
  • Dr Puan explained, "Duration is dependent on factors such as whether the patient is able to tolerate the medications, age of the patient, the patient's response to treatment and organ involvement."

“Even if symptoms begin to disappear after you’ve begun taking the drugs, it is imperative to continue for the entire course to ensure all TB germs are killed,” shares Clin Assoc Prof Low.

Stopping early can lead to drug-resistant TB, which:

• Requires second-line TB drugs
• Is harder to cure
• Has a lower success rate
  • Dr Puan added, "The reported success rate for multi-drug resistant TB is approximately 60% compared to more than 95% for drug-susceptible cases." (Source: MOH)

Infectiousness of the disease upon commencing treatment

Patients are typically isolated for the first two weeks.

"Once treatment has started, infectiousness (of the disease) decreases rapidly. Hence it is most important for patient to take the medications regularly as prescribed," advised Dr Puan.

Other precautions the patient can take include:

• Practicing cough etiquette (covering his/her nose and mouth when coughing or sneezing, and wearing a surgical mask), and
• Ensuring the home is well-ventilated

As the patient would have been infectious and his or her household members exposed for some time before treatment started, it is not necessary to avoid contact with them.

However, there are exceptions to this, "If the household has family members with weakend immunity or a child under the age of 5 years old, it is best the patient avoids contact with them," Dr Puan added.

After 2 weeks of effective treatment, no special efforts need to be undertaken to avoid contact with others

“As a precaution, family members are tested for latent or active TB,” adds Clin Assoc Prof Low.

When is surgery needed?

Surgery may be necessary if the:

• TB has severely damaged the lungs
• Medication is ineffective

“In Singapore, we are still able to treat most drug-resistant TB,” Clin Assoc Prof Low adds.

If you have active TB:

• Complete the full course of medication
• Stay home for the first two weeks
• Cover your mouth when coughing or sneezing
• Wear a mask when around others
• Attend all medical appointments
• Encourage close contacts to get tested for TB

To protect yourself and others from TB:

1. Practise good hand hygiene – wash hands frequently with soap and water.
2. Cover coughs and sneezes with a tissue; dispose of it immediately.
3. Seek medical attention if you suspect TB.
4. Wear a mask when visiting crowded places.
5. Keep your immune system healthy – eat well, exercise, and get enough sleep.
6. Support family or friends undergoing TB treatment — encourage them to complete their medication.

Myth 1: Tuberculosis infection always leads to disease.

Fact: Most people infected with TB do not develop disease. The immune system usually controls it.

Myth 2: You can get TB from kissing.

Fact: TB spreads through airborne droplets, not saliva or sharing utensils.

Myth 3: There is only one kind of TB.

Fact: TB can affect many organs. Pulmonary (relating to the lungs) TB accounts for 80% of cases in Singapore.

Myth 4: You can only get TB once.

Fact: Reinfection is possible. The chance of being reinfected is about 2%.

Ref: F26