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TUBERCULOSIS. Definition: chronic infective granuloma affecting nearly all body systems but mainly the lungs . Predisposing factors : A) Environmental b) Personal factors Causative Agents : T.B. bacilli. Structure o f T.B. bacilli : Carbohydrate, lipid and protein (tuberculoprotein)
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Definition: chronic infective granuloma affecting nearly all body systems but mainly the lungs. • Predisposing factors: A) Environmental b) Personal factors • Causative Agents:T.B. bacilli
Structure o f T.B. bacilli: Carbohydrate, lipid and protein (tuberculoprotein) • Types of TB Bacilli: • Human type • Bovine type
Primary tuberculosis(childhood type) • Methods of infections: 1- Inhalation. 2- Ingestion 3- Direct contact. • Sites of primary complex: 1- lung. 2- Intestine 3- Tonsils 4- Skin 5- Nose (rare site).
Reaction of the body against bacilli Proliferative reaction (tubercle formation)
N/E of tubercle: Small, 1-3 mm, with central yellow caseation and grey periphery. • M/E of tubercle: Central caseating material (structureless eosinophilic material, epithelioid cells, macrophages, Langhan’s giant cells, lymphocytes and peripheral fibroblastic reaction.
The constituents of primary complex: • Parenchymatous lesion • Tuberculous lymphangitis • Tuberculous lymphadenitis
Fate of primary complex: 1- Good fate: Healing 2- Bad fate: spread: • Local. • Lymphatic. • Hematogenous • Natural passage.
Secondary tuberculosisAdult hood type • Methods of infection: • Endogenous by reactivation of dormant focus. • Exogenous by inhalation or ingestion. • Sites: Any site, mainly the lung & intestine are affected.
Reaction of the body against bacilli in secondary infection. • Proliferative reaction in solid organs. • Exudative reaction in serous sacs and sometimes in soft parenchymatous organs.
Fate of secondary T.B: 1. Good fate: Healing. 2. Bad fate: Extension and spread: • Local. • Natural passages. • Blood (rare) • Lymphatic.
Tuberculoma • Definition:Tumor-like tuberculous lesion formed of inspissated caseating material surrounded by fibrous capsule • Sites:Lung, brain, kidney, and spinal cord.
Miliary Tuberculosis • Definition:acute hematogenous dissemination of large dose of T.B bacilli with wide spread involvement of multiple organs. • NAKED EYE EXAMINATION: Multiple, scattered, uniform, small size (3mm) tubercles separated from each other by normal tissue and not surrounded by area of congestion and present on outer and cut surface of organs.
MICROSCOPIC EXAMINATION: They are related to blood vessels are poorly developed tubercle with central necrosis and absent giant cells.
Lung is a favorable site for T.B. (easy inhalation and aeration). • Predisposing Factors: • Decrease immunity • contact with patients • Silicosis • congenital heart diseases.
Primary Pulmonary Tuberculosis • Primary pulmonary complex: Consists of 3 parts: • Parenchymatous lesion (Ghon’s focus). • Tuberculous lymphangitis. • Tuberculous lymphadenitis.
Fate: • Good fate: Healing. • Bad fate: Spread.
SECONDARY PULMONARY T.B • Sources of Infection: • Reactivation of dormant focus. • Exogenous by inhalation. • Site: • Apical or subapical • More in Rt. Lung than left lung.
The Morphological Feature: Simon’s focus (Assman- Simon’s focus) Chronic apical lesion formed by fusion of many tubercles. Not associated with lymphangitis or lymphadenitis.
The Fate: A. Regression (good fate) B. progressive lesion (Bad Fate) 1. Cavitary Tuberculosis 2. Chronic fibrocaseous pulmonary tuberculosis 3. Acute tuberculous bronchopneumonia & acute caseous pneumonia.
Chronic fibrocaseous pulmonary tuberculosis • Naked Eye and Pathogenesis: 1. Mother cavity. 2. Daughter cavities (acinar lesions). 3. Insignificant hilar lymphadenopathy. • Microscopic examination: Extensive caseation necrosis form multiple Caseating tubercles healing by fibrosis, epithelialization of cavities, calcification.
Complications: 1- Local tissue destruction: • Hemoptysis. • Spontaneous pneumothorax. • Pyopneumothorax. • 2ry Amyloidosis.
2- Peptic ulcer: 20% of cases; related to stress. 3- Fibrosis: of the lung, bronchus & pleura leads to bronchiectasis and pulmonary hypertension and cor- pulmonale. 4- Spread.