Tuberculosis

1. Tuberculosis Prepared by : Dr. NehadJaser

2. Tuberculosis is an infectious disease caused by the organism Mycobacterium tuberculosis. Unlike most other bacteria, M. Tuberculosis is surrounded by an outer capsule that makes the organism very resistant to destruction. Mycobacterium tuberculosis is primarily transmitted via the airborne route. Once in the lung tissues, the organism causes an inflammatory reaction as it is attacked first by poly-morphonuclear leukocytes and later by macrophages.

3. The primary lesion that results in the lung during tuberculosis Infection is called the Ghon’s focus . If the lesion also involves regional lymph nodes, it is termed a Ghon’s complex Necrosis of infected lung tissues may result in a cheesy appearance to the tissue that is referred to as a caseousnecrosis. Liquefactionof the necrotic lesions might also occur over time

4. In an otherwise healthy individual, the immune system is usually able to contain the organism and over time will encapsulate it through calcification of the lesions. These calcifiedGhon’s complexes are readily visualized by chest radiograph for the remainder of the patient’s life . Because live M. tuberculosis is often found within these encapsulations,impairmentof immune function in the infected individual may lead to reactivationof the primary infection.

5. Testing for Tuberculosis • Mantoux test — Intradermal test for reaction against the tuberculin purifiedprotein derivative standard (PPDS) • Acid-fast staining of sputum cultures to visualize • Chest radiograph to identify Ghon’s complex

6. Manifestations of primary tuberculosis: • Productive, prolonged cough • Chest pain, hemoptysis • Chill, fever, night sweats • Anorexia, weight loss

7. Drugs for the Treatment of Tuberculosis Isoniazid Rifampicin Ethambutol