Abstract

Pulmonary tuberculosis (TB) is a contagious bacterial infection primarily affecting the lungs and caused by Mycobacterium tuberculosis. Despite being preventable and curable, it remains a major global health issue, especially in low- and middle-income countries. This report explores the epidemiology, pathophysiology, diagnostic methods, treatment protocols, and challenges associated with pulmonary TB. Early detection and adherence to treatment are key to reducing transmission and preventing drug resistance.

Introduction

Tuberculosis is a chronic infectious disease that primarily affects the lungs but can spread to other organs. It is transmitted through airborne particles released when an infected person coughs or sneezes. According to the World Health Organization (WHO), TB is one of the top 10 causes of death worldwide. Pulmonary TB accounts for the majority of TB cases and is the primary driver of its transmission.

Causative agent: Mycobacterium tuberculosis

Transmission: Airborne droplets

Risk factors: HIV infection, malnutrition, smoking, diabetes, and close contact with TB patients.

Pulmonary tuberculosis (TB) is a communicable disease caused by Mycobacterium tuberculosis, a slow-growing, aerobic bacillus that primarily infects the lungs but can also affect other organs in extrapulmonary forms. TB has afflicted humanity for centuries and remains one of the leading causes of death from a single infectious agent, surpassing even HIV/AIDS in many parts of the world.

Tuberculosis is transmitted through airborne droplets expelled when a person with active pulmonary TB coughs, sneezes, or speaks. Once inhaled, the bacilli can establish an infection in the lungs.

Methods

The diagnosis and evaluation of pulmonary tuberculosis (TB) involve a combination of clinical assessment, laboratory testing, radiological imaging, and sometimes molecular/genetic tools. Early and accurate diagnosis is essential for initiating appropriate treatment and preventing transmission. Below are the key methods used:

1. Clinical Evaluation

•Patient History and Symptoms:

•Persistent cough (>2–3 weeks)

•Hemoptysis (blood in sputum)

•Night sweats

•Fever and chills

•Weight loss and fatigue

Risk Assessment:

History of exposure to TB

HIV status

Socioeconomic and travel history

Immunosuppressive conditions (e.g., diabetes)

2. Sputum Microscopy (Ziehl-Neelsen Staining)

Description: Microscopic examination of stained sputum samples for acid-fast bacilli (AFB).

Purpose: Quick, low-cost screening method.

Limitations: Lower sensitivity, especially in early or HIV-positive cases.

3. GeneXpert MTB/RIF Test (Molecular Testing)

Description: A rapid, automated PCR-based test detecting Mycobacterium tuberculosis DNA and rifampicin resistance.

•Turnaround Time: ~2 hours.

Advantages:

•High sensitivity and specificity

•Simultaneous detection of drug resistance

•Recommended by WHO for initial diagnosis in high-risk populations

4. Sputum Culture

Types: Solid (Löwenstein-Jensen) and liquid (MGIT)culture systems.

Purpose: Definitive diagnosis and drug susceptibility testing.

Time: 1–8 weeks depending on the method.

Advantages: Most sensitive method, can detect even low bacterial load.

5. Chest X-Ray (CXR)

Findings Suggestive of TB:

•Cavitary lesions (usually in upper lobes)

•Infiltrates

•Fibrotic changes

Role: Supportive; not diagnostic alone but useful in conjunction with lab tests.

6. Tuberculin Skin Test (TST) / Mantoux Test

Description: Intradermal injection of purified protein derivative (PPD) to assess immune response.

Use: Detects latent TB infection (LTBI), not active disease.

Limitations: False positives in BCG-vaccinated individuals.

Results

TB remains a significant health burden, particularly in developing nations.

Diagnostic results often show:

•Positive sputum smear in active pulmonary TB cases.

•Abnormal chest X-rays showing cavitary lesions or infiltrates.

•Molecular testing (GeneXpert) confirms diagnosis and detects rifampicin resistance.

Treatment outcomes:

•Standard 6-month therapy (2 months intensive phase + 4 months continuation phase) is effective in most drug-sensitive TB cases.

•Cure rates improve with supervised treatment under DOTS (Directly Observed Treatment, Short-course).

•Drug resistance is rising, especially in patients with incomplete or irregular treatment histories.

Discussion

Pulmonary TB poses a dual challenge: biological and social. While the Mycobacterium tuberculosis bacterium is biologically resilient, social determinants like poverty, overcrowding, and limited healthcare access complicate eradication. The rise of HIV/AIDS has further amplified TB incidence due to immune suppression.

The emergence of multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) poses major threats to public health. Strategies such as DOTS, BCG vaccination, and global health programs (e.g., End TB Strategy) have helped curb TB rates, but challenges remain in ensuring treatment completion and reducing stigma.

Conclusion

Pulmonary tuberculosis (TB) continues to be one of the world’s most persistent public health threats, particularly in developing nations where healthcare infrastructure, socio-economic factors, and co-infections like HIV complicate prevention and control efforts. Despite being a curable and preventable disease, TB claims millions of lives each year due to delayed diagnosis, poor treatment adherence, and the emergence of drug-resistant strains.

This report highlights that effective TB control depends on early detection through improved diagnostic tools like GeneXpert and sputum microscopy, alongside prompt initiation of standardized treatment regimens. The Directly Observed Treatment Short-course (DOTS) strategy has proven instrumental in improving adherence and cure rates. However, increasing rates of multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) underscore the urgent need for continued research, drug development, and global cooperation.

In conclusion, while great strides have been made in TB diagnosis and treatment, the battle is far from over. A comprehensive, multidisciplinary approach involving governments, healthcare professionals, researchers, and communities is essential to eliminate pulmonary TB and achieve the global target of ending the TB epidemic by 2030 as outlined by the World Health Organization.

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