Tuberculosis (pulmonary) - Symptoms, Causes, Treatment & Prevention

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Overview

Pulmonary tuberculosis (TB) is an infectious disease caused by the bacterium Mycobacterium tuberculosis that primarily affects the lungs. It spreads through the air when a person with active lung disease coughs, sneezes, speaks, or sings, releasing tiny droplets that contain the bacteria.

TB can affect anyone, but certain groups are disproportionately impacted:

• People living in high‑burden countries (India, Indonesia, China, the Philippines, Pakistan, Nigeria, South Africa)
• Individuals with weakened immune systems (e.g., HIV infection, diabetes, malnutrition)
• Close contacts of someone with active TB
• People who use tobacco, alcohol excessively, or substances that impair lung function

According to the World Health Organization (WHO), in 2022 there were an estimated 10.6 million new cases of TB worldwide, and about 1.3 million deaths—making it the leading cause of death from a single infectious agent, surpassing HIV/AIDS.<sup>1</sup> In the United States, the Centers for Disease Control and Prevention (CDC) reports roughly 8,000–9,000 new pulmonary TB cases each year.<sup>2</sup>

Symptoms

Symptoms of pulmonary TB usually develop gradually over weeks to months. People with early disease may be asymptomatic, which is why screening is important for high‑risk individuals.

• Persistent cough lasting > 2 weeks, often with sputum production.
• Hemoptysis (coughing up blood) – usually small amounts but can be alarming.
• Fever – low‑grade, often worse in the evening.
• Night sweats – soaking the bedclothes.
• Unexplained weight loss – “consumption” was historically used to describe TB.
• Fatigue and weakness – may limit daily activities.
• Chest pain – sharp or dull, sometimes worsening with deep breaths.
• Shortness of breath – especially if disease involves extensive lung tissue.

Children may present with non‑specific symptoms such as persistent fever, poor growth, or abdominal swelling (due to lymph node involvement).

Causes and Risk Factors

How TB spreads

The bacterium is transmitted via airborne droplet nuclei that remain suspended for several hours. A single infectious person can release thousands of organisms per cough.

Key risk factors

• Close, prolonged exposure to an untreated, smear‑positive case (e.g., household members, coworkers in poorly ventilated settings).
• Immunosuppression – HIV infection raises the risk of progression from latent infection to active disease by 20‑30 times.<sup>3</sup>
• Chronic lung disease such as COPD or silicosis.
• Diabetes mellitus – triples the risk of active TB.<sup>3</sup>
• Malnutrition – protein‑energy deficiency impairs cell‑mediated immunity.
• Substance use – smoking, alcohol, illicit drugs.
• Age – children < 5 years old and adults > 65 years have higher susceptibility.
• Living/working in congregate settings – prisons, homeless shelters, refugee camps.

Diagnosis

Accurate diagnosis combines clinical assessment, imaging, and microbiologic testing.

Initial clinical evaluation

• Detailed history (symptom duration, exposure, travel, immunization, HIV status).
• Physical exam focusing on lung fields, lymph nodes, and signs of extrapulmonary disease.

Laboratory and imaging studies

• Chest radiograph (CXR) – the most common first‑line imaging; typical findings include upper‑lobe infiltrates, cavitation, or nodular lesions.
• Sputum smear microscopy – Ziehl‑Neelsen or fluorochrome staining to detect acid‑fast bacilli (AFB). Quick but less sensitive.
• Sputum culture – gold standard; grows M. tuberculosis on solid (Lowenstein‑Jensen) or liquid media (MGIT). Results take 2‑6 weeks.
• Rapid molecular test (e.g., Xpert MTB/RIF) – detects DNA of M. tuberculosis and rifampin resistance within hours.<sup>4</sup>
• Interferon‑γ release assays (IGRAs) or Tuberculin Skin Test (TST) – identify latent infection; not diagnostic for active disease but useful for screening.
• Drug‑susceptibility testing (DST) – essential for guiding therapy, especially in areas with multidrug‑resistant TB (MDR‑TB).

Treatment Options

Standard therapy for drug‑susceptible pulmonary TB lasts 6 months and is highly effective when taken correctly.

First‑line medication regimen

Phase	Drugs (Daily)	Duration
Intensive (2 months)	Isoniazid (INH) + Rifampin (RIF) + Pyrazinamide (PZA) + Ethambutol (EMB)	8 weeks
Continuation (4 months)	Isoniazid + Rifampin	16 weeks

All drugs should be taken under direct observation (DOT) when possible to ensure adherence.

Drug‑resistant TB

• MDR‑TB (resistant to INH and RIF) requires at least 5 drugs, including a fluoroquinolone (e.g., levofloxacin) and a second‑line injectable (e.g., amikacin) for 18–24 months.
• XDR‑TB** (extensively drug‑resistant) adds resistance to any fluoroquinolone and at least one second‑line injectable. Treatment is individualized, often involving newer agents such as bedaquiline, delamanid, and linezolid.

Adjunctive measures

• Corticosteroids – recommended for TB meningitis and pericarditis; not routine for uncomplicated pulmonary disease.
• Nutrition support – high‑calorie, protein‑rich diet to counteract weight loss.
• Smoking cessation – improves treatment outcomes.

Lifestyle considerations during therapy

• Take medication on an empty stomach (usually morning) with a full glass of water.
• Separate INH from antacids, calcium, or iron supplements by at least 2 hours.
• Report side effects promptly: liver inflammation (jaundice, dark urine), visual changes (ethambutol), joint pain (PZA), rash.

Living with Pulmonary Tuberculosis

Adhering to treatment and making small daily adjustments can reduce transmission risk and speed recovery.

• Medication adherence – use pillboxes, alarms, or a treatment partner.
• Isolation precautions – stay at home until sputum smear‑negative (usually 2 weeks of therapy). Open windows and use fans to improve ventilation.
• Nutrition – aim for 2 ,300–2,500 kcal/day (more if weight loss >10 %). Include lean protein, fruits, vegetables, and whole grains.
• Hydration – at least 8 glasses of water daily; helps thin sputum.
• Exercise – light activity (walking) as tolerated; avoid exhaustive workouts that may worsen fatigue.
• Vaccinations – keep flu and COVID‑19 vaccines up to date to prevent co‑infection.
• Follow‑up appointments – monthly sputum checks in the first 2 months, then as directed.
• Psychosocial support – counseling, support groups, and, where needed, financial assistance programs can mitigate stigma and economic burden.

Prevention

Primary prevention (prevent infection)

• Identify and treat infectious cases promptly with effective therapy.
• Improve indoor ventilation in homes, workplaces, and congregate settings.
• Use respiratory hygiene – cover mouth/nose when coughing, dispose of tissues.
• Screen high‑risk populations (e.g., HIV‑positive, close contacts) with IGRA or TST.

Secondary prevention (prevent progression from latent to active TB)

• Isoniazid preventive therapy (IPT) – 6–9 months of INH for those with latent infection and no active disease.
• Rifampin or Rifapentine regimens – shorter (4 months or 12 weekly doses) alternatives for individuals unable to tolerate INH.
• Vaccination: the BCG vaccine offers protection against severe childhood TB; its efficacy in adults varies.

Complications

If left untreated or inadequately treated, pulmonary TB can lead to serious complications:

• Cavitary lung disease – permanent holes that predispose to chronic infections and hemoptysis.
• Fibrosis and restrictive lung disease – reduced lung capacity, chronic shortness of breath.
• Secondary bacterial pneumonia – due to damaged airway defenses.
• Bronchiectasis – irreversible airway dilation causing chronic cough and sputum production.
• Spread to other organs (miliary TB), including meningitis, pericarditis, and osteoarticular disease.
• Drug‑induced toxicity – hepatotoxicity, optic neuritis, peripheral neuropathy.
• Increased mortality – especially in those co‑infected with HIV or with multi‑drug resistance.

When to Seek Emergency Care

References

1. World Health Organization. Global Tuberculosis Report 2023. Accessed May 2026.
2. Centers for Disease Control and Prevention. Tuberculosis (TB) Data and Statistics. Updated 2024.
3. CDC. Tuberculosis Transmission and Risk. 2023.
4. CDC. Molecular Tests for TB (Xpert MTB/RIF). 2022.
5. Mayo Clinic. Tuberculosis (TB) – Symptoms and Causes. Reviewed 2024.
6. National Institutes of Health. Management of Drug‑Resistant Tuberculosis. 2023.

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