Understanding Tuberculosis: Symptoms, Diagnosis and How to Prevent Its Spread

Lung tuberculosis spreads through the air if a person with lung TB coughs, sneezes or spits, releasing tiny droplets of germs of infection into the air. As they breathe in these droplets, bacteria can enter the lungs of another person, allowing the germs to enter into their lungs.

TB spreads more easily in places where people gather in crowds or live close to one another. People who have HIV/AIDS or weakened immune systems are more likely to contract TB when compared to those who have healthy immune systems.

Types of TB

• Inactive or latent TB: Latent or inactive TB is a condition where TB bacteria can stay in your body without causing any disease. Individuals with latent TB do not feel sick, have any symptoms or spread the germs to others.
• Active TB: TB bacteria start multiplying in the body if the immune system cannot stop them from growing. This is known as active TB disease. Individuals with active TB feel sick and can spread the germs to those nearby. Without treatment, active TB can be life-threatening.

Symptoms of TB

People with latent TB do not feel sick or show any symptoms, and they cannot spread the germs to others. People with TB may have one or more of the following symptoms:

A persistent cough lasting more than two weeks

• Chest pain  
• Coughing up blood or mucus
• Fatigue or weakness
• Loss of appetite
• Unexplained weight loss
• Chills
• Fever
• Night sweats

In addition to general symptoms, if TB spreads to other organs, it can cause:

• Blood in the urine and impaired kidney function if it affects the kidneys
• Back pain, stiffness, muscle spasms and spinal irregularities if it affects the spine
• Nausea, vomiting, confusion and loss of consciousness if it spreads to the brain

Causes of TB

Mycobacterium tuberculosis is a bacterium that causes TB. TB is spread through the air and most often infects the lungs, but it can also affect other parts of the body. While TB is spreadable, it does not spread easily. To get TB, you usually need to be in close contact with someone who is infected.

Spread of TB

TB can be transmitted when an individual with active TB disease releases germs into the air through actions like coughing, sneezing, talking, singing or even laughing. Only those with active pulmonary TB are contagious. Most people who inhale TB bacteria can fight off the infection, preventing the bacteria from growing. In these cases, the bacteria remain inactive, resulting in a latent TB infection.

Even though the bacteria are inactive, they remain alive in the body and could potentially become active later. Some individuals may carry a latent TB infection throughout their lifetime without it ever progressing to active TB disease.

However, TB can become active if the immune system weakens and is unable to prevent the bacteria from multiplying. This is when a latent TB infection can turn into active TB disease. Researchers are actively working on treatments to prevent this from occurring.

Risk factors of TB

Factors that can increase your risk of contracting the bacteria that causes TB include:

• Diabetes
• End-stage kidney disease
• Certain cancers
• Malnutrition
• Consumption of tobacco or alcohol for long periods of time
• HIV or another immune-system-compromising situation

Medications that suppress the immune system can increase the risk of developing active TB disease. This includes drugs used to prevent organ transplant rejection.

Other medications that may raise the risk of active TB are those prescribed for conditions like:

• Cancer
• Rheumatoid arthritis
• Crohn’s disease
• Psoriasis
• Lupus

Diagnosis of TB

TB can be screened by the following tests:

• Mantoux tuberculin skin test (TST): A small amount of purified protein derivative (PPD) called tuberculin is injected under the skin on the inside of your forearm. After 48 to 72 hours of injection, a healthcare provider will check for swelling at the injection site until the bruising is minimal. The extent of the bruising determines whether the test is positive or negative.
• Interferon-gamma release assay (IGRA): This is a blood test in which a healthcare provider collects blood samples for the analysis of TB.

Other tests include:  

• Lab tests on sputum and lung fluid
• Chest X-ray
• Computed tomography (CT) scans
• Breath test
• Urine test
• Testing the fluid surrounding the brain and spine, known as cerebrospinal fluid

TB treatment

TB is treated with specific antibiotics. It is recommended that both TB infection and active disease be treated. The most common antibiotics used are:

• Isoniazid
• Rifampicin
• Pyrazinamide
• Ethambutol

It is crucial to take all the medication your healthcare provider prescribes to ensure that all the bacteria are killed. You will need to follow your treatment plan for as long as instructed, sometimes for up to nine months.

Some sorts of TB have developed resistance to certain medications, so your doctor will likely prescribe a combination of drugs to treat it. Be sure to complete the entire course of treatment, as stopping it early can lead to the bacteria not being fully eliminated.

Medication side-effects

Most people can take TB medications without experiencing serious side effects. However, if you do have severe side effects, your healthcare provider may advise you to stop taking a particular medication or adjust the dosage.

If you experience any of the following symptoms, be sure to talk to your healthcare provider:

• Upset stomach
• Vomiting
• Loss of appetite
• Severe diarrhoea
• Pale-coloured stool
• Dark urine
• Yellowing of the skin or eyes
• Changes in vision
• Dizziness or trouble with balance
• Tingling sensations in your hands or feet
• Easy bruising or bleeding
• Unexplained weight loss
• Unexplained fatigue
• Feelings of sadness or depression
• Rash
• Joint pain

It is important to inform your healthcare provider about all the medications, dietary supplements and herbal remedies you are taking, as you may need to stop using some of them during your treatment.

Drug-resistant TB

Some strains of TB bacteria have developed drug resistance, meaning that medications that once cured the disease are no longer effective. This resistance can occur due to natural genetic changes in the bacteria. A random mutation might give a bacterium a characteristic that allows it to survive the effects of an antibiotic. If the bacterium survives, it can then multiply.

When antibiotics are not used correctly, or when they fail to eliminate all the bacteria for other reasons, the environment becomes favourable for the growth of more resistant bacteria. If these bacteria are transmitted to others, a new drug-resistant strain can emerge over time.

Factors that contribute to the development of drug-resistant bacteria include:

• Not following the prescribed treatment or stopping the medication early
• Being given an incorrect treatment plan
• Lack of access to the necessary medications
• Poor quality of the drugs
• The body not absorbing the drugs as intended

TB prevention

You typically need to be in close contact with someone who has active TB for an extended period before getting infected. Ensuring infection prevention guidelines can help, such as:

• Wash your hands thoroughly.
• Coughing in the elbow or covering the mouth when you cough can help prevent germs from spreading.
• Staying away from close contact with others can help reduce the spread of germs.
• It is essential to take all the medication exactly as prescribed by your healthcare provider.
• Avoid returning to work or school until your healthcare provider gives you the go-ahead.

Conclusion

Tuberculosis is an airborne infection that, despite being treatable, continues to cause many deaths worldwide. If you think you have been exposed to TB or are showing symptoms, be sure to reach out to your healthcare provider. If you are undergoing treatment for TB, it is important to follow the prescribed instructions carefully. Do not hesitate to ask your healthcare provider if you have any questions.