Tuberculosis: Symptoms, Types, Causes and Treatment

Tuberculosis (TB) is one of humanity’s oldest and deadliest diseases, continuing to claim lives and challenge healthcare systems worldwide. Despite modern advances, TB remains a major public health threat, especially in low-income and developing countries. Understanding its symptoms, the variety of forms it can take, what causes it, and how it can be treated is essential for both healthcare professionals and the general public. In this article, we break down each of these key aspects to provide a clear, detailed overview of TB, using up-to-date scientific research.

Symptoms of Tuberculosis

Tuberculosis doesn’t always look the same—its symptoms can be subtle or severe, depending on the stage of the disease and the parts of the body affected. Early detection of TB is crucial, as this can prevent complications and halt the spread to others.

Symptom	Description	Typical in	Source(s)
Chronic Cough	Lasting three weeks or more	Pulmonary TB	1, 2
Chest Pain	Discomfort or pain when breathing	Pulmonary TB	1, 6
Hemoptysis	Coughing up blood	Pulmonary TB	1, 2
Fatigue	Persistent tiredness	Pulmonary & EPTB	1
Weight Loss	Unintentional loss of body weight	Pulmonary & EPTB	1, 2
Fever	Low to high fever, recurrent	Pulmonary & EPTB	1, 2
Night Sweats	Excessive sweating at night	Pulmonary TB	1, 2
Other (site-specific)	Varies by organ affected (e.g., lymph node swelling, joint pain, skin lesions)	Extrapulmonary TB	3, 5

Table 1: Key Symptoms

Common Pulmonary Symptoms

Pulmonary TB—the most prevalent form—typically targets the lungs and presents with a group of classic symptoms:

• Chronic cough: This is often the earliest and most persistent symptom, sometimes producing sputum and occasionally blood (hemoptysis) 1, 2.
• Chest pain: Patients may experience pain or discomfort, especially when breathing deeply or coughing 1, 6.
• Systemic symptoms: Weakness, unexplained weight loss, low-grade fever, and night sweats are characteristic. These symptoms are often gradual and can be mistaken for other illnesses 1, 2.

Extrapulmonary Symptoms

TB can affect organs other than the lungs, leading to a broad range of symptoms:

• Lymph node TB: Swelling and tenderness of lymph nodes, especially in the neck 3.
• Bone/joint TB: Chronic pain, swelling, and reduced mobility in affected joints (Pott’s disease) 3.
• Cutaneous manifestations: Skin lesions, nodules, ulcers, and sinus tracts (see "Types" for more detail) 5.
• Other: Depending on the organ involved, symptoms may include abdominal pain, neurological deficits, or genitourinary complaints 3.

Systemic and Complicated Presentations

TB can induce metabolic and biochemical disturbances, such as hyponatremia and glucose intolerance, especially in severe or disseminated cases 2. These systemic complications may worsen the patient’s overall condition and complicate management.

Types of Tuberculosis

Tuberculosis is not a single disease but a spectrum, classified by the part of the body it affects and the activity of the infection. Knowing the different types helps in diagnosis, treatment, and understanding the potential complications.

Type	Description	Common Features	Source(s)
Pulmonary TB	TB of the lungs	Cough, chest pain, fever	1, 4
Extrapulmonary TB (EPTB)	TB outside the lungs	Site-specific symptoms	3, 4
Latent TB Infection (LTBI)	Non-active, non-contagious TB	No symptoms	15
Drug-Resistant TB	TB resistant to first-line drugs	Poor response to therapy	11, 14
Cutaneous TB	TB of the skin; various forms	Nodules, ulcers, plaques	5

Table 2: Major Types of Tuberculosis

Pulmonary Tuberculosis

This is the most commonly recognized form, accounting for the majority of TB cases. It primarily affects the lungs and is responsible for the classic symptoms and the airborne spread of the disease 1, 4.

Extrapulmonary Tuberculosis

Extrapulmonary TB (EPTB) occurs when TB bacteria spread outside the lungs via the bloodstream or lymphatic system. Common sites include:

• Lymph nodes: Most frequent EPTB site, causing enlarged, sometimes tender nodes 3.
• Pleura: Fluid accumulation in the chest (pleural effusion).
• Bones and joints: Especially the spine (Pott’s disease), hips, or knees, causing pain and deformity 3.
• Skin (cutaneous TB): Multiple clinical forms, such as scrofuloderma, lupus vulgaris, and others, presenting with nodules, ulcers, and plaques 5.
• Other organs: Kidneys, brain, liver, and more can be affected, each presenting with unique symptoms 3.

Latent Tuberculosis Infection (LTBI)

In LTBI, the person is infected with Mycobacterium tuberculosis but does not show symptoms and cannot transmit the disease. However, latent TB can reactivate years later, particularly if the immune system is weakened 15.

Drug-Resistant Tuberculosis

• Multidrug-resistant TB (MDR-TB): Caused by strains resistant to at least isoniazid and rifampin, the two most powerful anti-TB drugs 11, 14.
• Extensively drug-resistant TB (XDR-TB): TB strains resistant to first-line and several second-line drugs, making treatment much more difficult 14.
• These forms require longer, more complex, and often more toxic treatment regimens.

Cutaneous Tuberculosis

Cutaneous TB is uncommon but significant, particularly in children. It can present in several forms:

• Scrofuloderma: Nodules that break down to form ulcers and draining sinuses.
• Lupus vulgaris: Plaques or nodules, often scaly and slow-growing.
• Tuberculous chancre, TVC, and others: Each with distinctive skin manifestations 5.

All cutaneous forms require confirmation by biopsy and are treated with standard anti-TB therapy 5.

Causes of Tuberculosis

Understanding the root causes of TB is crucial for prevention and control. TB is primarily an infectious disease, but its development and spread are influenced by a range of biological, environmental, and social factors.

Cause	Mechanism/Context	Impact on TB Spread	Source(s)
M. tuberculosis	Airborne transmission	Primary cause	1, 6
Overcrowding	Close contact, poor ventilation	Increases risk	1, 4
Poverty	Malnutrition, poor access	Higher TB incidence	1, 4, 7
HIV/AIDS	Immune suppression	Higher activation risk	7
Drug resistance	Incomplete/incorrect treatment	Difficult control	11, 14
Latency/reactivation	Dormant bacteria reactivation	Delayed disease	15

Table 3: Main Causes and Risk Factors for TB

The Infectious Agent

TB is caused by the bacterium Mycobacterium tuberculosis, which spreads from person to person through airborne droplets released when a person with active pulmonary TB coughs, sneezes, or speaks 1, 6. The bacteria primarily infect the lungs but can travel via the blood or lymphatic system to other organs 1, 3.

Social and Environmental Factors

Several non-biological factors play a critical role in TB transmission:

• Overcrowding and poor ventilation: Living in crowded conditions and poorly ventilated spaces makes it easier for TB bacteria to spread 1, 4.
• Poverty: TB disproportionately affects those in low-income settings, where malnutrition, limited healthcare access, and lack of education compound the risk 1, 4, 7.
• Limited awareness: Lack of knowledge about TB leads to delays in seeking care and increases transmission 1.

Biological and Host Factors

• HIV/AIDS and Immunosuppression: People with weakened immune systems (especially those with HIV/AIDS) are at much higher risk of developing active TB after infection 7.
• Latent Infection Reactivation: Many people carry dormant TB bacteria without symptoms. Reactivation can occur years later, especially if immunity drops due to illness, malnutrition, or aging 15.
• Drug Resistance: Incorrect or incomplete treatment can foster drug-resistant TB strains, making disease control far more difficult 11, 14.

Treatment of Tuberculosis

Treating TB is complex, involving multiple drugs over several months. The approach varies based on drug susceptibility, disease form, and patient characteristics. Recent advances aim to shorten treatment duration and improve outcomes, but challenges remain—especially with drug-resistant forms.

Regimen/Approach	Duration/Drugs	Indication	Source(s)
Standard (Drug-Susceptible)	6 months, 4 drugs (INH, RIF, PZA, EMB)	Pulmonary and most EPTB	12, 4
DOTS	Directly observed therapy	Ensures adherence	1, 12
MDR-TB Regimens	18–24 months, tailored drugs	Multidrug-resistant TB	11, 14
Latent TB Regimens	6–9 months INH or shorter RIF-based	Latent TB	15
New/Alternative Therapies	Host-directed, novel antibiotics	Drug-resistant, severe	14, 13

Table 4: Key Tuberculosis Treatment Strategies

Standard Treatment for Drug-Susceptible TB

• First-line therapy: The classic regimen includes four drugs: isoniazid (INH), rifampin (RIF), pyrazinamide (PZA), and ethambutol (EMB) for two months, followed by INH and RIF for an additional four months—totaling six months 4, 12.
• Directly Observed Therapy, Short-course (DOTS): Healthcare workers supervise patients taking their medication to ensure completion and prevent resistance 1, 12.
• Extrapulmonary TB: Most EPTB forms use the same regimen and duration as pulmonary TB. Exceptions are TB of the central nervous system or spine, where longer treatment may be required 3, 12.

Treatment of Drug-Resistant TB

• MDR-TB: Requires longer (often 18–24 months) and more complex treatment with second-line drugs, which may have more side effects 11, 14.
• All-oral regimens: Recent guidelines recommend all-oral combinations, avoiding injectable drugs when possible to minimize toxicity and improve patient comfort 11, 14.
• XDR-TB: Treatment is even more individualized and often includes newer or repurposed drugs 14.

Latent Tuberculosis Infection (LTBI) Treatment

• Isoniazid (INH): Traditionally, 6–9 months of INH monotherapy 15.
• Shorter regimens: Four months of rifampin or three months of weekly rifapentine plus INH are effective alternatives, especially for improving adherence and reducing side effects 15.

New and Adjunctive Therapies

• Novel antibiotics and host-directed therapies: Research is focused on finding shorter, more effective regimens, especially for drug-resistant TB 14, 13.
• Surgical intervention: Occasionally necessary for severe MDR-TB or to remove localized infection 11.

Challenges in TB Treatment

• Adherence: Long courses and side effects challenge patient adherence, risking relapse and resistance.
• Drug resistance: MDR and XDR-TB require longer, more toxic, and costly regimens 11, 14.
• Special populations: Children, pregnant women, HIV-infected patients, and those with comorbidities need tailored approaches 12.

Conclusion

Tuberculosis remains a global health challenge, with a complex interplay of biological, social, and environmental factors influencing its spread and management. Understanding its key symptoms, diverse forms, root causes, and modern treatment options is essential for both prevention and care.

In summary:

• TB symptoms range from chronic cough and chest pain in pulmonary TB to a wide variety of organ-specific symptoms in extrapulmonary forms.
• TB types include pulmonary, extrapulmonary, latent, drug-resistant, and rare cutaneous forms, each with unique challenges.
• The main cause is infection with Mycobacterium tuberculosis, but transmission is fueled by poverty, overcrowding, and weakened immunity.
• Treatment requires multiple drugs over several months, with special approaches needed for drug-resistant TB and vulnerable populations. New therapies are on the horizon, but adherence and resistance remain significant hurdles.

Greater awareness, early detection, and adherence to effective treatment are crucial to controlling and ultimately eliminating tuberculosis worldwide.