Definition of tb disease

Tuberculosis ( tb disease)  is a communicable disease that primarily affects the lungs but can spread to other organs such as the kidneys, brain, and spine. Tuberculosis is caused by the bacterium Mycobacterium tuberculosis ( bacillus tuberculosis bacteria). This disease is preventable and curable. Tuberculosis was discovered by Robert Koch in 1882.

Tuberculosis (TB) is a significant public health challenge globally, which continues to affect millions of people each year. Community-level implications for health systems, economic stability, and social development.

How do tuberculosis bacteria enter into body? 

Bacillus tuberculosis bacteria that lead to tuberculosis by entering the body through several different pathways, including 

1- Inhalation: When any person inhales tiny droplets expelled into the air by an infected individual (through coughing, sneezing, or speaking), the bacteria can enter the lungs and begin to multiply. 

2 – Ingestion: When any person consumes unpasteurized milk or food contaminated with the bacteria, particularly from infected cattle. This can lead to TB infection in the gastrointestinal tract.

3- Inoculation:  In healthcare or laboratory settings, the bacteria may enter the body through a break in the skin or mucous membrane, especially during handling of infected material.

4-Transplacental route: Also known as the congenital Route. In this condition infected mother transfers Mycobacterium tuberculosis to her unborn baby through the placenta. Although it is rare, this form of transmission can lead to congenital tuberculosis in the newborn.

How do TB Bacteria spread in the body? 

1- Local spread

 After inhalation, the TB bacteria are taken up by immune cells called macrophages. These infected macrophages carry the bacilli to nearby lung tissues, leading to localized infection and inflammation.

2 – Lymphatic spread

The TB bacteria can travel through the lymphatic system, spreading to:

• Lymphoid tissues and follicles

• Pharynx, causing pharyngitis

• Intestines, lymph nodes, and lymphatic vessels, resulting in lymphangitis (inflammation of lymph vessels) and lymphadenitis (inflammation of lymph nodes)

This mode of spread plays a major role in extrapulmonary TB.

3 -Hematogenous spread (Through Bloodstream)

A condition called tuberculous bacillemia. When TB bacteria enter the blood circulation and they may damage the vein walls, especially near infected lymph nodes. This allows the bacteria to disseminate widely and form tiny nodular lesions (like millet seeds) in multiple organs, including:

• Lungs

• Liver

• Kidneys

• Bones

• Other tissues

This pattern is characteristic of miliary tuberculosis, a severe form of the disease.

4 –By the natural passage

(i) Tuberculous Pleurisy: Lung lesions may extend into the pleural space, causing inflammation of the pleura.

(ii) Tuberculous Laryngitis: Infected sputum may reach the larynx, causing infection and inflammation there.

( iii) Ileocecal Tuberculosis: Swallowing infected sputum may introduce the bacteria into the gastrointestinal tract, particularly affecting the ileocecal region.

( iv) Tuberculous Peritonitis: TB infection in the fallopian tubes (salpingitis) can spread into the peritoneal cavity, causing abdominal TB.

Types of Tuberculosis

Depending upon the type of tissue, response, and age, tuberculosis is divided into 2 types :

1 – Primary tuberculosis

The infection of an individual who has not been previously infected or immunized is called primary tuberculosis or on complex or childhood tuberculosis.

2 – Secondary tuberculosis

The infection of an individual who has been previously infected or sensitive is called secondary or post-primary, or reinfection, or chronic tuberculosis.

What are the symptoms of tb disease? 

The clinical features are the signs and Symptoms of tb disease, which depend on the location, extent, and type of lesions of infection.

Primary Tuberculosis 

• Chronic cough, often with hemoptysis
• Pyrexia of unknown origin
• Unresolved pneumonia
•  Exudative pleural effusion
• Asymptomatic (diagnosis on chest X-ray)
•  Weight loss, general debility
•  Spontaneous pneumothorax
• fever, night sweats, anorexia, 
• Hepatosplenomegaly 

Secondary Tuberculosis 

• Fevers or night sweats
• Supraclavicular lymphadenopathy
• The formation of a ‘collar-stud’
  abscess and sinus formation.
• TB can affect any part of the bowel, causing anorexia and weight loss. 
• Tuberculous peritonitis is characterized by abdominal distension, pain, and constitutional symptoms.
• Headache,
• Vomiting,
• Seizures
• Delirium
• Lymphocytic meningitis
  Hydrocephalus
• Space-occupying lesion
  (tuberculoma)
• Kyphosis
• Cord compression
• Abdominal mass
• Psoas abscess
• Cranial nerve palsy
• Lymph node enlargement
• Pericardial effusion
• Constrictive pericarditis
• Monoarthritic
• Hematuria/dysuria
• Infertility in women
• Epididymitis
• Anorectal ulceration

How to diagnose Tuberculosis? 

Tuberculosis is a infection ,so if you or someone is suffering from symptoms like long-lasting cough, fever, weight loss, or night sweats, it’s important to get tested as soon as possible. It is a curable disease if diagnosed earlier. 

1. Talk to a Doctor

If you have a persistent cough for more than 2 weeks, then visit a nearby clinic or hospital. The doctor will ask about symptoms and take your medical history. It helps in diagnosing tuberculosis early. 

2. Sputum Test (Cough Test)

This is a test where your cough is taken in a container and tested in lab to see if TB germs are present. It’s the most common and simple test.

3. Chest X-ray

A chest X-ray often shows white spots or shadows in the lungs, enlarged lymph nodes in the chest, or fluid in the pleural space (pleural effusion).

4. Skin Test (Mantoux Test)

When a small amount of TB protein is injected under your skin. If a bump appears
after 2–3 days, it means you’ve been exposed to TB germs.

5. Blood Test

Any infection in the body can be identified by a blood test, so the TB.

6. Other Tests (if TB is outside the lungs)

TB occurs in other parts of the body, like bones or kidneys. The doctor may take samples from those places or do scans.