Presentation on theme: "TUBERCULOSIS. Definition: chronic infective granuloma affecting nearly all body systems but mainly the lungs. Predisposing factors: A) Environmental."— Presentation transcript:
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 Human type Bovine 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: 1. Parenchymatous lesion 2. Tuberculous lymphangitis 3. Tuberculous lymphadenitis
Fate of primary complex: 1- Good fate: Healing 2- Bad fate: spread: 1.Local. 2.Lymphatic. 3.Hematogenous 4.Natural passage.
Secondary tuberculosis Adult hood type Methods of infection: 1. Endogenous by reactivation of dormant focus. 2. Exogenous by inhalation or ingestion. Sites: Any site, mainly the lung & intestine are affected.
Reaction of the body against bacilli in secondary infection. 1.Proliferative reaction in solid organs. 2.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: 1.Local. 2.Natural passages. 3.Blood (rare) 4.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). Lung is a favorable site for T.B. (easy inhalation and aeration). Predisposing Factors: Decrease immunity Decrease immunity contact with patients contact with patients Silicosis Silicosis congenital heart diseases. congenital heart diseases.
Fate: 1. Good fate: Healing. 2. Bad fate: Spread.
SECONDARY PULMONARY T.B Sources of Infection: 1. Reactivation of dormant focus. 2. Exogenous by inhalation. Site: Apical or subapical Apical or subapical More in Rt. Lung than left lung. 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. Chronic apical lesion formed by fusion of many tubercles. Not associated with lymphangitis or lymphadenitis.