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Tuberculosis: Types, Causes, Treatment and Prevention

Introduction

Infectious diseases are a significant health concern in the Indian subcontinent, with tuberculosis (TB) frequently seen in clinical practice. Despite ongoing efforts and numerous initiatives by the Indian government and medical organisations to control TB, it remains a major public health challenge. 

The World Health Organization report 2024 estimates that there is a 17.7% decline in TB incidence from the earlier report1; however, India still has the highest TB burden globally (26% of the global total)2, which is rather alarming. 

One of the key challenges with TB is that it can affect nearly any part of the body. In India, the most commonly diagnosed form is pulmonary TB, which specifically affects the lungs. 

In this article, we will briefly explore TB, its causes, symptoms, various types of TB, and how it is managed in India. 

What Is Tuberculosis?

Did you know? 

Types of Tuberculosis

TB can be classified in several ways: 

Based on Infection Status

Based on Site of Infection

Based on Response to Drugs

What Causes Tuberculosis?

Risk Factors for Tuberculosis

Understanding how TB spreads and risk factors for TB can help with early detection and timely treatment of this disease. 

Transmission of TB

Risk factors for TB

What Are the Clinical Symptoms and Signs of Tuberculosis?

TB can present with a range of symptoms, depending on whether the infection is in the lungs or in other parts of the body. The symptoms of different forms of TB are as follows13

1. Pulmonary Tuberculosis

The most common symptom of TB of the lungs is prolonged low-grade fever (that rarely crosses 100°F) in the evening with intermittent spikes that may occasionally exceed 100°F. Generally, patients may not always notice a fever; however, they often experience night sweats, malaise (a general feeling of being unwell), and unexplained fatigue and weight loss in the absence of dietary changes or increased exercise. 

Individuals with advanced lung TB may experience a persistent cough accompanied by thick phlegm, which may be blood-stained. 

2. Pleural Tuberculosis

When TB involves the pleura (the thin lining around the lungs), it can lead to a buildup of fluid between the two layers. This condition is known as pleural effusion. 

In some cases, the fluid accumulation may compress the lung beneath it (lung atelectasis), making it difficult for the lung to expand fully during breathing. This leads to breathlessness, which is a common symptom in pleural TB affects the pleura or causes significant lung damage. Other general symptoms like fever, unexplained weight loss, and fatigue are usually also present. 

In rare cases, the pleural fluid becomes infected and thickens into a pus-like material, a condition called empyema. Empyema requires urgent medical attention, including drainage of the infected fluid and a prolonged course of anti-TB medication. 

3. Skeletal Tuberculosis

Skeletal TB occurs when the TB bacteria spread to the bones and joints. The spine is the most commonly affected site, and TB of the spine is referred to as Pott’s disease. The most common symptom of Pott’s disease is pain, especially along the spine. As the infection progresses, surrounding muscles may become irritated, leading to spasms and back stiffness. If left untreated, the infection can damage the spinal cord, leading to neurological complications such as numbness, weakness, or even paralysis. These complications are serious and not uncommon in advanced, untreated cases. Early detection is key to avoiding lasting damage. 

Other areas like the hip or knee joints may also be involved in skeletal TB with symptoms including swelling, tenderness, and restricted movement. 

As with other forms of TB, general symptoms such as weakness, fatigue, and fever are often present in skeletal TB. 

4. Brain Tuberculosis

When TB spreads to the brain and central nervous system, it is referred to as brain TB, which can take several forms. The most common and severe type is TB meningitis (inflammation of the membranes surrounding the brain), but other forms include tuberculomas (localised granulomas) and other central nervous system (CNS) complications. 

In TB meningitis, patients often experience a persistent headache, fever, vomiting, and stiffness in the neck. As the condition progresses, there may be changes in mental state, such as confusion or erratic behaviour, which are often first noticed by family members. These changes can start subtly and worsen over time. If not treated promptly, the person may deteriorate further and may slip into a coma, a complication that can be extremely difficult to manage. 

5. Bladder and Kidney Tuberculosis

TB can affect the urinary system, a condition known as genitourinary TB. It often begins in the kidneys (renal TB) and may later involve the bladder (TB cystitis). 

Renal TB typically presents with pain in the flanks, blood in the urine (haematuria), increased frequency of urination, and malaise. When the infection spreads to the bladder, it may cause dysuria (pain or burning during urination) and the presence of pus cells in the urine, even though no bacteria grow in the urine culture. This specific finding is known as sterile pyuria, and it is a hallmark sign of genitourinary TB. 

Early detection is important for avoiding complications that affect kidney and bladder function. 

6. Joint Tuberculosis

TB can sometimes affect the joints, a condition known as TB arthritis. It usually involves large weight-bearing joints, particularly the hip and knee. 

Symptoms may include joint pain, restricted mobility, swelling, stiffness, and sometimes, a low-grade fever. There may also be swelling of nearby soft tissues and general symptoms such as weight loss or night sweats. 

Because the symptoms can resemble those of regular arthritis, maintaining a high level of suspicion is important, especially in individuals with persistent joint symptoms unresponsive to routine treatment. 

7. Gastrointestinal Tract Tuberculosis

TB can affect the gastrointestinal (GI) tract, although it most commonly involves the ileocecal region (where the small intestine meets the large intestine). 

Gastrointestinal TB can present with symptoms like abdominal pain, weight loss, diarrhoea or constipation, low-grade fever, and generalised fatigue. Some patients may experience signs of intestinal obstruction or GI bleeding. Although ulcers can form, they are typically deeper and result from chronic inflammation. 

Difficulty swallowing (dysphagia) is a rare symptom and typically occurs only when the oesophagus (food pipe) is involved, which is uncommon. Malabsorption may occur but is less prominent compared to other GI diseases. 

8. Miliary Tuberculosis

Miliary TB is a serious type of TB where the infection spreads through the blood to different parts of the body. Tiny spots of infection can appear in the lungs and other organs and the lungs may be extensively involved. Symptoms may include persistent fever, weight loss, tiredness, and night sweats. 

Diagnosis of Tuberculosis

The diagnosis of TB can sometimes be challenging as TB can be active, with obvious symptoms, or latent, where the bacteria are present in the body but do not cause illness and may not be seen in the sputum. 

The first step in diagnosis is taking a detailed clinical history to check whether the person’s symptoms suggest TB and physical examination. This can be challenging, as the symptoms may be vague or overlap with other conditions. 

If TB is suspected, further tests will be done to confirm it. In people with pulmonary TB, a sputum test is often used to check for TB bacteria. Advanced tests, such as nucleic acid amplification tests (e.g., GeneXpert), can now detect the bacteria’s DNA directly without needing to grow it in a laboratory. Traditional culture tests are still used, but they take longer to provide results14

Diagnostic tests for TB include the following. 

1. Mantoux Test

One of the common tests used to check for TB infection is the Mantoux test, also known as the tuberculin skin test. In this test, a small amount of a substance called Purified Protein Derivative (PPD), made from TB proteins, is injected just under the skin. If the person has been exposed to TB bacteria earlier, their immune system reacts with a firm, raised swelling (induration) at the site within 48 to 72 hours. The size of the induration is carefully measured to determine if the test is positive. 

A positive result may suggest TB infection but does not confirm it as other conditions may lead to a positive result. On the other hand, people with weakened immune systems may have a negative test result even if they have TB. 

The Mantoux test is considered a supportive tool as it must always be interpreted by someone trained in reading the results correctly and needs further testing to confirm a positive result15

2. Chest X-Ray

Chest x-rays are an important tool in detecting pulmonary TB, especially for active TB. However, a chest x-ray can sometimes appear normal even in people with TB. 

Abnormalities typically appear in the upper parts of the lungs on an X-ray as infiltrates, small nodules, or cavities. In miliary TB, the infection is more widespread and presents as numerous tiny, uniform nodules scattered throughout both lungs. 

If TB affects the lining of the lungs (the pleura), fluid may collect in the space between the lung and chest wall (pleural effusion) and is often clearly visible on a chest x-ray. In such cases, a sample of this fluid is checked for TB using methods like bacterial culture or DNA-based PCR test. If the test results are unclear, a biopsy of the pleural lining may be needed14.

3. Blood Tests

Blood tests can sometimes help support the diagnosis of TB, but they are not definitive on their own. Routine blood tests, such as a complete blood count (CBC), may sometimes appear normal even in the presence of TB. The erythrocyte sedimentation rate (ESR) may be elevated in TB, however, it is not specific to TB as ESR rises in many infections and inflammatory conditions. 

For TB affecting certain organs, blood tests for those organs may show changes. For example, liver function tests may be abnormal if the liver is involved and kidney function tests may show changes if the kidneys are affected16

A more targeted test called adenosine deaminase (ADA) can be helpful in diagnosis, however, it is not a blood test. Instead, it analyses the fluids collected from the body, such as pleural fluid, spinal fluid, or abdominal fluid, for ADA levels and may support the diagnosis of TB affecting these areas17

4. Ultrasound Scan of the Abdomen

Ultrasound scans may often be used to evaluate the abdomen when TB is suspected. This painless and non-invasive test can help identify signs of a possible infection in organs like the liver and other vital structures. It is particularly useful in detecting a fluid collection, organ enlargement, or masses that may indicate the presence of TB in the abdomen. 

However, the ultrasound does not directly detect TB or confirm an infection. Instead, it helps identify structural changes that may suggest the need for further testing18

5. Urine Test

In bladder TB, a urine test may show pus cells, indicating inflammation. However, when a urine culture is done, it often shows no bacterial growth. This condition is called sterile pyuria and is commonly seen in TB of the bladder. However, sterile pyuria is not specific to TB and may also be seen in conditions like kidney stones or certain infections19

6. CT Scan of the Brain

When TB affects the brain, a CT scan can help determine the extent to which it is affected. Sometimes, an MRI scan may be required20

Tuberculosis Treatment in India

Once TB is confirmed, it’s essential to begin treatment promptly. India has specific national guidelines on how to manage TB. If a person also has HIV, both conditions are treated at the same time. 

TB treatment plans fall into two broad categories: 

For new pulmonary TB cases, the standard treatment begins with an intensive phase of two months. This involves taking four medicines: 

This is followed by a continuation phase of four months, where usually isoniazid and rifampicin are continued. In some complex or extrapulmonary TB cases, a third drug may be added during this phase. 

In previously treated patients, tests for drug resistance may be performed before treatment. In the absence of drug resistance, a similar treatment plan to that used for new patients may be followed. However, if resistance is detected, the treatment approach is adjusted accordingly. 

Note: During treatment, liver function tests must be monitored closely, as TB medications may affect liver function. 

India follows the DOTS strategy (Directly Observed Treatment, short-course) to ensure treatment adherence, in which a trained healthcare worker or volunteer watches the patient take their medication daily. This helps ensure that doses are not missed as it may lead to complications. 

Treatment Duration: TB treatment usually lasts 6 months, although certain forms of extrapulmonary TB may need 9 to 12 months. After treatment, follow-up tests, such as a chest x-ray or urine test, may be done to ensure the infection is fully cleared. 

MDR-TB is usually resistant to at least isoniazid and rifampicin and requires taking second-line medicines for 9 to 24 months. Treatment regimens for MDR-TB may include oral drugs and occasionally injections and require expert supervision21

Diet and Nutrition for Tuberculosis

Also Read: Pneumonia: Types, Symptoms, Characteristics & More!

Is Tuberculosis Manageable With Treatment?

Yes, TB can be successfully managed if diagnosed early and managed with strict adherence to the prescribed regimen; however, taking steps to avoid the infection is always better than having to undergo treatment. TB treatment usually lasts 6 to 9 months, and completing the full course without missing any doses is essential for full recovery. 

Tuberculosis Prevention

TB can be avoided through several measures. In children, the BCG (Bacille Calmette-Guérin) vaccine is given to help protect against TB infection. 

Other steps include taking proper precautions if someone in the household has TB of the lungs or airways as they can spread the infection through the air, usually by coughing or sneezing. Here are some precautions that can be taken to avoid the spread of TB from a family member: 

TB in other parts of the body, such as the bladder, is not contagious. 

Also Read: Does Masturbation Cause Weight Loss? Debunking Sexual Health Misconceptions

Prognosis of Tuberculosis

TB is a widespread health concern in India and can present with various symptoms, making diagnosis challenging at times. However, once diagnosed, it is usually treatable with standard medications, provided there are no complications or drug resistance. 

Most individuals who receive timely treatment and complete the full course without missing doses recover well. The recurrence rate of TB is generally low, however, the long-term outcome may be poorer in those who experience reactivation of TB or reinfection, particularly if they had incomplete prior treatment or developed drug-resistant TB. Similarly, elderly patients and individuals with weakened immunity, such as those with HIV or undergoing chemotherapy, often require closer monitoring23

Conclusion

Tuberculosis is a serious health condition, but early identification of the infection and timely medical care can help manage it effectively. Preventive steps, good hygiene practices, and adequate nutrition may play a role in overall health during recovery. Ongoing medical supervision is especially important in cases where drug resistance or other complications are present. 

References

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Disclaimer: The information provided here is for educational/awareness purposes only and is not intended to be a substitute for medical treatment by a healthcare professional and should not be relied upon to diagnose or treat any medical condition. The reader should consult a registered medical practitioner to determine the appropriateness of the information and before consuming any medication. PharmEasy does not provide any guarantee or warranty (express or implied) regarding the accuracy, adequacy, completeness, legality, reliability or usefulness of the information; and disclaims any liability arising thereof. 

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