Pulmonary Tuberculosis

Introduction and Transmission Dynamics

Pulmonary tuberculosis is a chronic, infectious bacterial disease that primarily targets the lung parenchyma. The causative organism is Mycobacterium tuberculosis, an aerobic, acid-fast bacillus with a remarkably slow growth rate. Transmission occurs almost exclusively through the airborne route. When an infected person coughs, sneezes, speaks, or sings, they expel microscopic droplet nuclei containing the bacteria into the air. These droplets remain suspended for hours, and nearby individuals inhale them into the terminal alveoli, establishing the initial site of infection.

Pathophysiology and Infection Stages

Once inhaled bacilli reach the alveoli, resident alveolar macrophages phagocytize them. However, Mycobacterium tuberculosis resists intracellular destruction by blocking phagosome-lysosome fusion. The bacteria multiply locally, prompting a cell-mediated immune response. Lymphocytes and macrophages wall off the infection, forming a microscopic nodule called a tubercle. Over time, the center of this tubercle undergoes caseous necrosis. If the immune system fails to contain the bacteria, liquefaction occurs, allowing bacilli to rupture into the airways and spread throughout the lungs or via the bloodstream.

Clinical Manifestations

Active pulmonary tuberculosis presents with systemic and localized respiratory symptoms that develop gradually over weeks or months.

• Persistent cough: Lasting longer than two weeks, initially dry and non-productive, later progressing to productive sputum.
• Hemoptysis: Coughing up blood, resulting from tissue destruction and vessel erosion in pulmonary cavities.
• Drenching night sweats: Profuse nocturnal sweating that often requires changing bedclothes.
• Progressive weight loss: Caused by catabolic state, anorexia, and metabolic changes driven by chronic inflammation.
• Low-grade afternoon fevers: Typical fever pattern that spikes in the late afternoon or evening.

Diagnostic and Screening Methods

Primary healthcare settings rely on a combination of clinical evaluation, laboratory tests, and imaging to confirm tuberculosis.

1. Sputum Smear Microscopy: Direct staining for acid-fast bacilli using the Ziehl-Neelsen technique remains widely accessible in resource-limited settings.
2. GeneXpert MTB/RIF: A rapid automated molecular test that detects Mycobacterium tuberculosis DNA and rifampicin resistance simultaneously within two hours.
3. Chest Radiography: Reveals patchy or nodular infiltrates, cavitary lesions, and lymphadenopathy, predominantly in the upper lung zones.
4. Mantoux Tuberculin Skin Test: Injects purified protein derivative intradermally to measure delayed-type hypersensitivity, though it does not distinguish active from latent infection.

Directly Observed Therapy Short-Course (DOTS)

The cornerstone of tuberculosis control is the DOTS strategy, recommended by the World Health Organization. Treatment failure and drug resistance often stem from patient non-adherence due to the lengthy duration of therapy. Under DOTS, a trained healthcare worker or designated community observer watches the patient swallow every single dose of anti-tuberculosis medication. The standard regimen typically involves an intensive phase of two months using multiple drugs, followed by a continuation phase of four months to eradicate persistent dormant bacilli.

Nursing Care and Complications

Nurses play a vital role in managing patients with active tuberculosis, balancing infection control with holistic patient support. Airborne precautions, including placing the patient in a negative pressure room and enforcing N95 respirator use, are critical during the infectious phase. Nurses monitor for severe adverse drug reactions, such as hepatotoxicity from isoniazid and pyrazinamide, or optic neuritis from ethambutol. Nutritional counseling is equally essential, as chronic wasting is common and robust nutritional intake aids tissue healing.