Primary Pulmonary Tuberculosis

Primary Pulmonary Tuberculosis

Write a short note on primary pulmonary tuberculosis.
Or
Write notes on Ghon’s complex.
Answer:

The infection in an individual who has not been previously infected or immunized is called primary tuberculosis or Ghon’s complex or childhood tuberculosis.

Ghon’s complex is the lesion produced in the tissue portal of entry with foci in draining lymphatic vessels and lymph nodes.

• The most commonly involved tissues for the primary complex are the lung and hilar lymph nodes. Other sites are the intestine, skin and oropharynx
• The primary complex or Ghon’s complex in the lungs consists of three components.

Ghon’s complex Pulmonary Component

The lesion in the lung is the primary focus or Ghon’s focus. It is 1-2 mm solitary area of tuberculous pneumonia located peripherally under a patch of pleurisy in any part of lung but more often in subpleural focus in upper part of lower lobe.

Microscopically: The lung lesion consists of tuberculosis granuloma with caseation necrosis.

Ghon’s complex Lymphatic Vessel Component:

The lymphatics draining the lung lesion consist of phagocytes containing bacilli and may develop beaded, miliary tubercles along the path of hilar lymph nodes.

Ghon’s complex Lymph Node Component:

This consists of enlarged hilar and tracheobronchial lymph nodes in the area drained. The affected lymph nodes are matted and show caseation necrosis.

Primary pulmonary tuberculosis

Ghon’s complex Microscopically

Microscopically lesions of primary tuberculosis consist of the following features, i.e.

• Tuberculous granulomas with peripheral fibrosis
• Extensive caseation necrosis in the center of granulomas
• Old lesions have fibrosis and calcification.

Ghon complex in TB

Ghon’s Complex Fate of Pulmonary Tuberculosis

The primary complex may have one of the following sequelae:

• The lesion of primary tuberculosis of lung commonly do not progress but instead heal by fibrosis and in time undergoes calcification and even ossification.
• In some cases, the caseous material is disseminated through bronchi to other parts of the same lung or the opposite lung. This is called “progressive primary tuberculosis.”
• At times, bacilli may enter into circulation through erosion in a blood vessel and spread to various tissue and organiser: This is called as “primary miliary tuberculosis.”
• In some cases, the heard lesion of primary tuberculosis may get reactivated causing “secondary progressive tuberculosis”.