TUBERCULOSIS: PREVENTION AND TREATMENT

Medically Reviewed and Updated by Dr. Sony Sherpa (MBBS) - September 25, 2024

What Is Tuberculosis? 

Tuberculosis (TB) continues to claim lives globally despite being preventable and treatable. Tuberculosis (TB) is a disease that affects the lungs. According to the American Lung Association, it is caused by a type of bacteria called Mycobacterium tuberculosis.[1]

It is more common for a person to become infected with it if they have recently traveled to another country or have spent time in a hospital, nursing home, or prison.

Facts and Figures

According to the World Health Organization (WHO), there were an estimated 10.6 million people who fell ill with TB in 2022. This is an increase from 10.3 million in 2021 and 10.0 million in 2020. The TB incidence rate (new cases per 100 000 population per year) is estimated to have increased by 1.9% between both 2020–2021 and 2021–2022. COVID-19 significantly hindered TB diagnosis and treatment efforts, leading to an increase in TB cases. [2]

Common Causes

Tuberculosis is a highly contagious disease that is airborne. So, how do you get tuberculosis? People become infected with tuberculosis when they are exposed to the microscopic water droplets from an infected person's sneeze or cough.[3] These water droplets contain Mycobacterium tuberculosis bacteria. So, whenever they are inhaled, the other person's lungs may also get affected.

Risk Factors for Tuberculosis

Tuberculosis can affect anyone, but certain factors increase the risk of contracting the disease. The key risk factors include:

• HIV/AIDS: People living with HIV are at a significantly higher risk of developing tuberculosis because their weakened immune systems make them vulnerable to infection. TB is a major cause of death among individuals with HIV.[4]
• Malnutrition: Poor nutrition can compromise the immune system, making it difficult for the body to fight off TB infections. Malnourished people, especially in developing countries, are at greater risk.
• Diabetes: Diabetes reduces immune function, increasing the likelihood of developing active TB after infection. Individuals with diabetes have a two to four-fold increased risk of developing tuberculosis compared to those without diabetes. [5]
• Tobacco Use: Smoking damages the lungs, increasing susceptibility to TB. It is estimated that 20% of TB cases worldwide are attributable to smoking.[6]
• Old Age: Aging weakens the immune system, increasing the risk of developing TB, particularly in long-term care settings or among the elderly population.
• Other Vulnerable Populations: Those with compromised immune systems, such as organ transplant recipients, cancer patients undergoing chemotherapy, HIV patients, or people on certain medications, are more prone to TB.

Areas and Settings with Increased Risk

• Geographical Locations: People living in regions with high TB prevalence, such as sub-Saharan Africa, Southeast Asia, and Eastern Europe, are at a greater risk of contracting TB.
• Crowded and Poorly Ventilated Environments: Settings such as prisons, refugee camps, and homeless shelters are breeding grounds for TB transmission due to close contact and poor air circulation.
• Healthcare Workers: Healthcare workers, particularly those who interact with patients with tuberculosis, are at a higher risk of exposure to the disease, especially if they do not take appropriate precautions.

Tuberculosis Symptoms

The signs and symptoms of active tuberculosis can vary but often include:

• Persistent cough lasting three or more weeks
• Coughing up blood
• Chest pain, or pain with breathing or coughing
• Unintentional weight loss
• Fatigue
• Fever
• Night sweats
• Chills
• Loss of appetite

Symptoms in Infants and Children

TB can present differently in infants and children compared to adults. Symptoms of tuberculosis in younger patients may be more subtle, and early diagnosis can be challenging. Specific symptoms in infants and children include:

• Failure to thrive or inadequate weight gain
• Irritability or persistent crying
• Persistent fever not linked to other causes
• Lethargy or unusual sleepiness
• Swollen lymph nodes, particularly in the neck
• Difficulty breathing or wheezing in severe cases

Types of Tuberculosis

The following are the types of tuberculosis [7]:

• Latent Tuberculosis

Some people who are exposed to Mycobacterium tuberculosis bacteria become infected with it, but they do not develop any symptoms. In such cases, they are diagnosed with latent tuberculosis, also referred to as inactive TB. This form of the disease is not active, so those who have it are not contagious.

• Miliary Tuberculosis

If the Mycobacterium tuberculosis bacteria spreads to other organs besides the lungs, then a person will be diagnosed with miliary tuberculosis. Although this condition is rare, it is usually fatal because of the widespread damage that it does to the body in a relatively short period of time.

• Active Tuberculosis

Active tuberculosis is a condition wherein the Mycobacterium tuberculosis bacteria rapidly reproduces in the lungs. Whenever a person is in this stage of the disease, they can spread it to other people. Because of this, they are often kept in a quarantined hospital room until they are deemed no longer contagious.

Other Types of Tuberculosis

• Primary Tuberculosis

Primary tuberculosis occurs when an individual is initially exposed to tuberculosis bacteria and gets infected. Most people will fight off the infection, but in some cases, the bacteria remain in the body, leading to latent TB or progressing to active disease. There are different forms of primary TB, such as progressive primary TB, where the infection spreads quickly without becoming latent.

• Drug-Resistant Tuberculosis

Drug-resistant tuberculosis develops when the bacteria become resistant to one or more of the standard tuberculosis medications, making treatment more challenging. Multi-drug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) are the two most serious forms. These arise due to incomplete treatment, improper drug use, or a pre-existing resistant strain. Drug-resistant TB requires longer treatment with second-line drugs, that may have more side effects.

• Tuberculosis in Children

Diagnosing tuberculosis in children can be challenging as the symptoms are often non-specific, such as weight loss, fever, or a persistent cough. Children are at a higher risk of developing severe forms of tuberculosis, including miliary tuberculosis or tuberculosis meningitis. Early diagnosis and immediate treatment are crucial for preventing long-term complications in children.

• Tuberculosis in Pregnancy

Pregnant women with TB are at an increased risk of complications, including preterm labor, low birth weight, and fetal distress. Managing TB during pregnancy requires careful consideration of both the health of the mother and the unborn child. Pregnant women should receive appropriate TB treatment to prevent the spread of the disease and to protect the pregnancy.

• Bovine TB

Bovine tuberculosis, caused by Mycobacterium bovis, primarily affects cattle but can be transmitted to humans through direct contact with infected animals or unpasteurized dairy products. While bovine TB is less common, it poses a risk to people working in close proximity to livestock. Human cases are typically treated similarly to TB caused by Mycobacterium tuberculosis.

Diagnosis of Tuberculosis

Accurate diagnosis of tuberculosis is essential for effective treatment and preventing the spread of the disease. Several tests are available to diagnose TB, depending on whether the infection is latent or active.

Testing for TB

• Rapid Molecular Diagnostic Tests: These tests, such as GeneXpert, detect TB bacteria and assess resistance to drugs like rifampicin. They provide quick results, often within a few hours, and are highly recommended for initial testing, especially in high-risk populations.
• Interferon-Gamma Release Assay (IGRA) Blood Test: This blood test measures the immune response to TB bacteria and is often used to detect latent TB. Unlike the skin test, IGRA is not affected by prior BCG vaccination, making it a more reliable option for those who have been vaccinated.
• Sputum Smear Microscopy: For active TB, sputum samples are examined under a microscope to detect TB bacteria. This test is particularly useful for diagnosing pulmonary TB.
• Chest X-rays: Chest X-rays can reveal characteristic lung damage caused by TB, helping to identify active disease. However, X-rays alone cannot confirm TB and are usually used alongside other diagnostic methods.
• Purified Protein Derivative (PPD) Test/ Tuberculin Skin Test (TST): This test is used to identify latent TB infection. A small amount of tuberculin protein (PPD) is injected intradermally, and the reaction is assessed 48-72 hours later. A positive result indicates TB exposure, but it does not differentiate between active and latent infection. Mantoux tuberculin skin test is a specific technique used to administer the tuberculin skin test. This test is also commonly referred to as the TB skin test or PPD. While these terms are often used interchangeably, Mantoux specifically describes the method of administering the test.
• Breath Test: Though less commonly used, breath tests are being researched as non-invasive ways to diagnose TB. These tests aim to detect biomarkers in the breath of TB patients.

How the Testing Process Works

• Positive Blood or Skin Test: A positive result in either the IGRA or the PPD test suggests the presence of TB bacteria in the body. However, further tests are required to determine whether the infection is active or latent.
• Follow-Up Testing: For those with a positive blood or skin test, follow-up testing such as chest X-rays, sputum tests, or rapid molecular diagnostic tests is conducted to confirm active TB or identify latent TB.
• Vaccine Influence: It is important to note that the BCG vaccine, commonly administered in countries with a high prevalence of TB, can affect the accuracy of skin tests, leading to false positives. Conversely, some people may show false-negative results due to immune suppression, making accurate diagnosis more challenging.

Treatment of Tuberculosis

Treating tuberculosis (TB) effectively requires a comprehensive approach tailored to the type of TB and the patient’s overall health. Here’s an expanded look at treatment options, phases, and additional considerations.

Treatment Options for Latent Tuberculosis

Latent tuberculosis (LTBI) is treated to prevent progression to active TB, especially in those at high risk. Current treatment options include:

• Isoniazid (INH) for 9 Months: This is a common treatment regimen that reduces the risk of developing active TB. It is typically prescribed for those with a high risk of progression, such as those with HIV or close contacts of active TB patients.
• Rifapentine (RPT) and Isoniazid for 3 Months: This regimen is known as 3HP. It is an alternative to the 9-month INH regimen and is preferred for its shorter duration and effective results.
• Rifampin (RIF) for 4 Months: This option is used in some cases, particularly where INH resistance is a concern. It is effective but requires adherence to the regimen to prevent drug resistance.

Treatment for latent TB should be considered for people with a positive TB test but without symptoms of active TB, and who are at increased risk of developing the disease.

Treatment of Active Tuberculosis

Active TB requires a more intensive treatment approach to eradicate the bacteria and prevent transmission. The treatment generally involves:

• Intensive Phase: This initial phase involves taking a combination of antibiotics for 2 months. The standard regimen includes:
  • Isoniazid (INH)
  • Rifampin (RIF)
  • Ethambutol (EMB)
  • Pyrazinamide (PZA)
• Continuation Phase: After the intensive phase, treatment continues for 4 to 7 months with fewer drugs, typically:
  • Isoniazid (INH)
  • Rifampin (RIF)

The duration of the continuation phase may vary depending on the patient's response to treatment and the presence of drug-resistant strains.

Importance of Completing the Course of Treatment

Completing the full course of TB treatment is essential for several reasons:

• Preventing Drug Resistance: Incomplete treatment can lead to drug-resistant TB strains, which are more difficult and expensive to treat.
• Ensuring Cure: Strict adherence to the treatment regimen ensures that all bacteria are eradicated, reducing the risk of relapse and preventing further transmission.
• Protecting Public Health: Properly treated TB helps in controlling outbreaks and safeguarding community health.

Side Effects of Treatment

TB medications can have side effects, including:

• Isoniazid: Liver toxicity, neuropathy
• Rifampin: Liver toxicity, orange discoloration of urine and sweat
• Ethambutol: Visual disturbances, joint pain
• Pyrazinamide: Liver toxicity, joint pain

Patients should be monitored regularly for side effects, and any adverse reactions should be reported to a healthcare provider.

TB Complications

Tuberculosis, if left untreated or inadequately treated, can lead to several serious complications. These complications may result from the disease itself or as a side effect of the treatments. Some of the most common complications include:

• Lung Damage: Active TB can cause permanent lung damage, including scarring and reduced lung function, which can lead to chronic respiratory problems and increase the risk of future lung infections.
• Meningitis: When tuberculosis spreads to the brain and spinal cord, it can cause tuberculosis meningitis, an inflammation of the membranes surrounding the brain or spinal cord. When TB spreads to the brain and spinal cord, it can lead to TB meningitis, an inflammation of the membranes around the brain. This condition is life-threatening and requires urgent medical attention.
• Spinal Pain: TB of the spine, known as Pott's disease, can cause severe back pain, and if left untreated, it can lead to paralysis due to damage to the spinal cord.
• Heart Problems: TB can affect the tissues surrounding the heart, causing a condition known as tuberculous pericarditis. This can lead to fluid buildup around the heart, hindering its ability to pump blood effectively.
• Liver and Kidney Issues: TB can also affect the liver and kidneys, leading to impaired function of these vital organs.

Individuals with weak immune systems, such as those living with HIV, are at a higher risk of developing severe complications from tuberculosis. 

Living with Tuberculosis

Managing life with TB involves adhering to treatment, making lifestyle adjustments, and seeking support:

• Adherence to Treatment: Adhere strictly to the treatment plan and attend regular check-ups to monitor progress and adjust treatment if needed.
• Healthy Lifestyle: Maintain a balanced diet, get adequate rest, and avoid smoking and alcohol to support your immune system.
• Support Systems: Seek emotional and psychological support from groups or counseling to navigate the challenges of living with tuberculosis.
• Regular Monitoring: Continuous medical check-ups are essential to ensure the effectiveness of treatment and to catch any potential complications early.
• Public Health Measures: Inform close contacts and take precautions to prevent spreading TB to others.

Prevention

Preventing the spread of tuberculosis (TB) is essential in managing the disease and protecting vulnerable populations. Key prevention strategies include:

• Quarantine and Isolation: The most effective way to prevent TB transmission is to isolate those diagnosed with active TB. Quarantining them until they are no longer contagious can help protect others from infection. Those exposed to TB patients, including household members, should also be tested and monitored closely.
• Protective Measures: Healthcare workers, teachers, prison guards, and others who work in environments where TB exposure risk is higher should take protective measures. Wearing masks, practicing good hygiene, and maintaining well-ventilated spaces can reduce transmission. Those in high-risk jobs may also consider receiving preventive TB treatment if they test positive for latent TB.
• Vaccination: The Bacillus Calmette-Guérin (BCG) vaccine is the most widely used TB vaccine. While it provides protection against severe forms of TB in children, such as miliary and meningeal TB, it does not fully protect against pulmonary TB, which is the most common form in adults. In regions where TB is prevalent, the BCG vaccine is given to infants to reduce the severity of the disease. The BCG vaccine is not routinely given in the United States.[8] It is primarily used in countries with high rates of tuberculosis.
• Vaccines in Development: In addition to the BCG vaccine, researchers are actively developing novel TB vaccines with the aim of providing more comprehensive protection against the disease. [9] These vaccines are designed to address the limitations of BCG, such as its variable efficacy in adults and its inability to prevent latent TB infection. Some of the promising candidates currently in clinical trials include:
  • Inactivated vaccines: These vaccines use whole or fragmented, lysed forms of MTB to induce an immune response. While they have shown promise in clinical trials, their duration of protection is limited.
  • Live attenuated vaccines: These vaccines use weakened forms of MTB to stimulate a strong immune response. However, there are concerns about their safety, particularly in immunocompromised individuals.
  • Recombinant BCG vaccines: These vaccines are engineered versions of BCG that express additional antigens from MTB, potentially enhancing their efficacy.
  • Subunit vaccines: These vaccines use specific antigens from MTB, often combined with adjuvants, to target the immune response.
  • Viral vector vaccines: These vaccines use a harmless virus as a carrier to deliver MTB antigens into the body.
  • DNA vaccines: These vaccines introduce DNA encoding MTB antigens into the body, stimulating the immune system to produce the corresponding proteins.

Tips to Prevent the Spread of Tuberculosis

• Cover your mouth when coughing or sneezing, especially if you have a persistent cough.
• Ventilate rooms well, as TB bacteria spread more easily in closed spaces.
• Wear a mask if you suspect you have TB or are in close contact with someone who has it.
• Complete your treatment: People with active TB must take their full course of prescribed medications to avoid developing drug-resistant strains of TB and to prevent spreading the disease.
• Test and monitor: If you have been in close contact with someone who has active TB, regular testing and monitoring are essential.

Frequently Asked Questions

Is Age a Risk Factor for Tuberculosis?

Yes, age is a significant risk factor for tuberculosis. Children, especially infants, are at higher risk of severe forms of TB due to their underdeveloped immune systems. Older adults are also at increased risk because aging can weaken immune defenses and exacerbate TB-related complications.

How is Tuberculosis Transmitted?

Tuberculosis is primarily spread through airborne droplets from an individual with active TB when they cough, sneeze, or talk. Only those with active TB, particularly pulmonary TB, can transmit the bacteria to others. Latent TB, in contrast, is not contagious.

What is the Life Expectancy of Someone with Tuberculosis?

Life expectancy for people with tuberculosis largely depends on the effectiveness of treatment. Those receiving timely and appropriate therapy generally have a normal life expectancy. However, drug-resistant TB or severe comorbidities can complicate treatment and potentially reduce life expectancy.

What is the Prognosis for TB After Treatment?

The prognosis for tuberculosis after treatment is typically favorable if the patient adheres to the full course of therapy, with most recovering fully and no longer being infectious. Drug-resistant TB presents a more challenging prognosis due to the need for prolonged and intensive treatment, which may increase the risk of complications.

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