Overview
Tuberculosis (TB) is a contagious infectious disease caused by Mycobacterium tuberculosis. It most commonly affects the lungs (pulmonary tuberculosis) but can also involve almost any organ in the body, including the lymph nodes, bones, kidneys, spine and brain (extrapulmonary tuberculosis).
The disease spreads through tiny airborne droplets released when a person with active pulmonary tuberculosis coughs, sneezes, speaks or sings. People with latent tuberculosis infection (LTBI) carry the bacteria without symptoms and cannot transmit the disease, although the infection may become active later if the immune system becomes weakened.
Despite being both preventable and curable, tuberculosis remains one of the world’s leading infectious causes of illness and death. Early diagnosis, laboratory confirmation, prompt treatment and completion of therapy are essential for reducing transmission and improving patient outcomes.
Disease Summary
- Category
- Infectious Disease
- Cause
- Mycobacterium tuberculosis
- Transmission
- Airborne respiratory droplets
- Body System
- Respiratory System
- Preventable
- Yes
- Curable
- Yes
Symptoms
Common Symptoms
Most people with active pulmonary tuberculosis experience one or more of the following symptoms.
Persistent Cough
A cough lasting two weeks or longer is one of the most common symptoms of pulmonary tuberculosis. It may initially be dry before becoming productive.
Fever
Low-grade fever, particularly in the evenings, commonly occurs during active tuberculosis.
Night Sweats
Excessive sweating during sleep is a classic symptom of tuberculosis and may soak clothing or bedding.
Weight Loss
Unintentional weight loss often develops gradually due to chronic infection and reduced appetite.
Fatigue
Persistent tiredness and reduced energy are common constitutional symptoms of active tuberculosis.
Danger Signs
Seek urgent medical attention immediately if any of the following symptoms develop.
Coughing Up Blood
Coughing up blood (haemoptysis) may indicate advanced pulmonary disease and requires immediate medical evaluation.
Severe Shortness of Breath
Difficulty breathing may indicate extensive lung involvement or another serious complication.
Confusion
Confusion, drowsiness or reduced consciousness may suggest tuberculosis affecting the brain or severe systemic illness.
Persistent Chest Pain
Persistent or worsening chest pain should be evaluated promptly as it may indicate pleural disease or other complications.
Diagnosis
Clinical Assessment
Diagnosis begins with a detailed medical history and physical examination. Healthcare professionals assess symptoms, duration of illness, exposure to tuberculosis, previous infection, HIV status and other risk factors.
Physical Examination
The examination may reveal fever, weight loss, enlarged lymph nodes or abnormal breath sounds. However, physical findings alone cannot confirm tuberculosis.
Chest Imaging
Chest radiography helps identify abnormalities suggestive of pulmonary tuberculosis, including infiltrates, cavitary lesions and pleural disease. Imaging findings must always be interpreted alongside laboratory investigations.
Laboratory Confirmation
Microbiological testing remains essential for confirming tuberculosis and identifying drug resistance where appropriate.
Laboratory Tests
Sputum Smear Microscopy
Sputum smear microscopy detects acid-fast bacilli (AFB) using Ziehl-Neelsen or auramine staining. It is inexpensive and widely available but less sensitive than molecular methods.
GeneXpert MTB/RIF
The GeneXpert MTB/RIF assay rapidly detects Mycobacterium tuberculosis DNA and identifies rifampicin resistance, allowing earlier diagnosis and treatment decisions.
Mycobacterial Culture
Culture remains the reference standard for confirming tuberculosis and allows comprehensive drug susceptibility testing to guide treatment.
Tuberculin Skin Test (TST)
The tuberculin skin test detects immune sensitisation to tuberculosis antigens and is commonly used to identify latent tuberculosis infection, particularly in contact tracing.
Interferon-Gamma Release Assay (IGRA)
IGRAs are blood tests that detect immune responses to tuberculosis-specific antigens. They are used to diagnose latent tuberculosis infection and are not affected by prior BCG vaccination.
Treatment
Standard First-Line Therapy
Standard treatment for drug-susceptible tuberculosis consists of an initial two-month intensive phase using isoniazid, rifampicin, pyrazinamide and ethambutol, followed by a four-month continuation phase using isoniazid and rifampicin. Completion of the full course is essential.
Treatment for Drug-Resistant Tuberculosis
Drug-resistant tuberculosis requires longer treatment with second-line agents. Newer regimens including bedaquiline and pretomanid have improved outcomes for multidrug-resistant tuberculosis.
Treatment for Latent Tuberculosis Infection
Individuals with latent tuberculosis infection who are at high risk of progression may receive preventive therapy, such as isoniazid for six months or a shorter rifampicin-based regimen.
Prevention
BCG Vaccination
The Bacille Calmette-Guerin (BCG) vaccine is recommended for infants in high-burden countries and provides protection against severe forms of tuberculosis in children, including tuberculous meningitis.
Ensure good ventilation
Good ventilation in homes, healthcare facilities and congregate settings reduces the concentration of airborne tuberculosis bacteria and lowers the risk of transmission.
Identify and treat latent tuberculosis infection
Screening high-risk groups and treating those with latent tuberculosis infection prevents progression to active disease and reduces ongoing transmission.
Complete tuberculosis treatment
Completing the full course of treatment is one of the most important ways to prevent drug resistance and protect both the individual and the community.
Risk Factors
High Risk
These individuals are most likely to develop active tuberculosis.
- People living with HIV
- Individuals on immunosuppressive therapy
- People with a recent tuberculosis infection (within the past two years)
Increased Risk
These groups have a higher chance of acquiring or developing tuberculosis.
- Healthcare workers in high-burden settings
- Contacts of people with active pulmonary tuberculosis
- People with diabetes, chronic kidney disease or malnutrition
- People who use tobacco or alcohol heavily
Exposure and Social Factors
Environmental and social conditions that increase the risk of tuberculosis.
- Living in overcrowded or poorly ventilated settings
- Living or working in prisons, shelters or congregate facilities
- Living in or migrating from high-burden countries
Complications
Tuberculous Meningitis
Tuberculosis affecting the brain and its surrounding membranes is a life-threatening complication that can cause severe neurological damage, disability or death if not treated promptly.
Respiratory Failure
Extensive lung disease can lead to respiratory failure, particularly in patients with delayed diagnosis or drug-resistant tuberculosis.
Drug-Resistant Tuberculosis
Incomplete or inappropriate treatment can lead to multidrug-resistant tuberculosis (MDR-TB), which is significantly more difficult and expensive to treat.
Pericarditis
Tuberculosis can infect the pericardium (the sac surrounding the heart), causing inflammation and fluid accumulation that may compromise cardiac function.
When to Seek Medical Care
Cough Lasting More Than Two Weeks
A persistent cough lasting two weeks or more, especially when accompanied by fever, night sweats or weight loss, should be evaluated for tuberculosis.
Coughing Up Blood
Any amount of blood in the sputum requires prompt medical evaluation.
Difficulty Breathing
Worsening shortness of breath may indicate significant lung involvement and requires urgent assessment.
Confusion or Neurological Symptoms
Confusion, severe headache or neck stiffness may suggest tuberculosis affecting the brain and require emergency medical care.
Prognosis
Excellent with Early Diagnosis and Full Treatment
Most people with drug-susceptible tuberculosis recover fully when treatment is started early and completed in full.
Poorer Outcomes with Drug Resistance or Delayed Treatment
Drug-resistant tuberculosis requires longer, more complex treatment and is associated with higher rates of treatment failure and mortality.
Follow-up and Monitoring
Patients require monitoring throughout treatment to assess response, detect side effects and confirm cure at completion of therapy.
Differential Diagnosis
Community-Acquired Pneumonia
Bacterial pneumonia commonly presents with cough, fever and abnormal chest imaging findings that may resemble pulmonary tuberculosis.
Lung Cancer
Lung cancer can produce similar symptoms including chronic cough, haemoptysis and weight loss, and may show overlapping radiological findings.
Non-Tuberculous Mycobacterial Infection
Infections caused by other mycobacterial species can mimic tuberculosis clinically and radiologically and require microbiological distinction for appropriate management.
Chronic Fungal Infections
Conditions such as histoplasmosis and aspergillosis may present with chronic respiratory symptoms and chest imaging changes similar to tuberculosis.
References
World Health Organization (WHO)
World Health Organization guidance on tuberculosis epidemiology, diagnosis, treatment and prevention.
Centers for Disease Control and Prevention (CDC)
Clinical guidance, public health recommendations and educational resources on tuberculosis.
MSD Manual Professional Edition
Evidence-based medical reference covering tuberculosis and other infectious diseases.
Ghana Health Service , National Tuberculosis Control Programme
National tuberculosis policies, treatment guidelines and public health recommendations for Ghana.
Frequently Asked Questions
Can tuberculosis be cured?
Yes. Most cases of drug-susceptible tuberculosis can be cured with a full six-month course of first-line antibiotics when treatment is started early and completed consistently.
Is tuberculosis contagious?
Active pulmonary tuberculosis is contagious and spreads through airborne droplets. Latent tuberculosis infection is not contagious. Patients on effective treatment typically become non-infectious within a few weeks.
What is the difference between active and latent tuberculosis?
Active tuberculosis causes symptoms and can be transmitted to others. Latent tuberculosis infection means the bacteria are present in the body but are inactive, causing no symptoms and no risk of transmission. Latent infection can progress to active disease if the immune system becomes weakened.
Can tuberculosis come back after treatment?
Yes. Tuberculosis can relapse, particularly if treatment was not completed. Reinfection is also possible. Follow-up after treatment is important to monitor for any signs of recurrence.
Can tuberculosis be prevented?
Yes. BCG vaccination, good ventilation, early identification and treatment of latent infection, and completion of treatment for active disease are all effective preventive measures.