What are the Symptoms of Tuberculosis?

A person infected with TB is usually symptom free. Once the infection flares into disease the patient has symptoms like-

• Cough for 3-weeks or more. Coughing up of sputum and/or blood.
• Evening rise of temperature 
• Fever
• Chills
• Night sweats
• Loss of appetite
• Weight loss
• Chest pain
• Difficulty in breathing
• Shortness of breath
• Tiredness
• Fatigue

If the infection spreads to other organs, the symptoms depend upon the organs involved. 

How can we Diagnose Tuberculosis?

Tuberculosis symptoms can be diagnosed using sputum test, Mantoux test, chest X-ray, CT scan and blood tests.

Sputum test -

Microscopic sputum analyses or cultures can find Tb bacteria in the sputum.

Three sputum samples (2 on the spot and 1 overnight collection) are collected and tested. Based on the results the patients are classified as-

• If the sputum is positive then the patient is sputum positive TB patient.
• If the sputum is negative but the Chest X-ray shows features suggestive of active TB then the patient is a sputum negative TB patient.

Mantoux test -

The most common diagnostic test for tuberculosis is a simple skin test called the Mantoux test. This test consists of a small amount of purified protein derivative (PPD) tuberculin that is injected into the forearm.

The test results are noted after 48 to 72 hours. A hard, raised red bump at the injection site usually indicates a positive test for TB

Chest X-ray and CT-scan of lungs -

Chest x-rays and computer tomography (CT) scans of the lungs are also used to diagnose TB.

If the immune system traps the tuberculosis bacteria and creates scar tissue, this tissue and the lymph nodes may harden like stone in the calcification process. This results in granuloma i.e. rounded marble-like scars that often appear on X-rays and CT scans.

Blood tests-

Blood tests may also be used to determine whether TB is active or latent (inactive).

Other tests for diagnosing pulmonary TB are-

• Bronchoscopy
• Bronchoalveolar lavage
• MRI of lungs
• Lung biopsy
• Fundoscopy
• Biopsy of the affected tissue (rare)
• Interferon-gamma release blood test such as the QFT-Gold test to test for TB infection
• Thoracentesis

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How does Tuberculosis Spread?

Tuberculosis infection generally involves the lung tissue and is called pulmonary tuberculosis.

Pulmonary TB can be of two types based on whether the patient produces the TB germs in his sputum or not-

•  Patients who have TB germs in the sputum are called sputum positive pulmonary TB patients.

•  Patients whose sputum is negative are called the sputum negative pulmonary TB patients. 

Generally the sputum positive TB patients are the people who spread the disease in the community. A single infected untreated person can spread the disease to 10-15 individuals in his community.

Tuberculosis is transmitted from an infected person to a susceptible individual through airborne particles known as droplet nuclei. Tuberculosis bacteria are not transmitted by surface contact. This means touching cannot spread tuberculosis unless the bacteria are breathed in.

The infectious droplet nuclei, 1–5 microns in diameter, are tiny water droplets with the bacteria that are released when people with active pulmonary or laryngeal tuberculosis cough, sneeze, laugh, shout, speak etc. The droplet nuclei remain suspended in the air for up to several hours.

Infection with tuberculosis germs does not denote disease. The initial infection might not be associated with any symptoms. The germs are harbored in the body and they lie in the dormant state. 10% of the people who harbor the infection develop the disease in a time span of 60 years.

The chances of developing tuberculosis disease in such an infected person becomes higher when the person’s immunity goes down in conditions such as diabetes, cancer, chronic illness, malnutrition, HIV or treatment with immunosuppressive drugs as in after transplant surgery.

People who are at an increased risk of tuberculosis -

•  Infants
•  Elderly people
•  People with weak immune systems due to AIDS, chemotherapy, diabetes or immunosuppressant medicines.

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ABOUT TB

 Tuberculosis (TB) is a contagious bacterial infection caused by various strains of mycobacteria, usually Mycobacterium tuberculosis.

Generally, tuberculosis affects the lungs (known as pulmonary tuberculosis) but may spread to other organs including the lymph nodes, gastro intestinal tract, genito-urinary tract, brain, coverings of the brain (meninges) or heart (pericardium), bones, joints, skin, eyes or almost any other organ in the body. Only the hair and nails are not affected by TB.

When a person is infected with pulmonary tuberculosis, the bacteria in the lungs multiply and cause pneumonia along with chest pain, hemoptysis and a prolonged cough. The lymph nodes near the heart and lungs become enlarged. As the TB bacteria tries to spread to other parts of the body, the body's immune system often interrupts the process and forms scar tissue or fibrosis around the TB bacteria. This helps fight the infection and prevents the disease from spreading in the body and to other people. If the body's immune system is unable to fight the bacteria the disease returns to an active state with pneumonia and damage to kidneys, bones, and the meninges that line the spinal cord and brain.

Tuberculosis can be classified as latent or active.

Latent tuberculosis is when the bacteria in the body are in an inactive state and the person shows no symptoms. Latent tuberculosis is not contagious.

Active tuberculosis is contagious and can make a person sick.

TB is spread through the air when people with an active pulmonary tuberculosis infection cough, sneeze, shouts or spit.

The treatment can continue for several months and the patient has to take the medicines at the given time regularly for the prescribed duration. If TB medications are not taken as per the healthcare providers recommendations the infection may become much more difficult to treat and sometimes the TB bacteria may become resistant to treatment.

TB is a preventable disease. BCG vaccination is given to people in countries where there is high prevalence of tuberculosis.

Lately the incidence of tuberculosis is increasing due to increased HIV cases and appearance of drug resistant strains of TB.

In 1826 a physician Laennec said this about tuberculosis -
"Whatever the form in which the tuberculous matter develops, it begins as a grey, semi-transparent matter that little by little becomes yellow, opaque, and dense. Then it softens, and slowly acquires liquidity like pus. This pus when expelled through the airways leaves cavities, commonly called ulcers of the lung; that we will designate as tuberculous excavations."

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