Tuberculosis

SAKHTISWARAN RAJASEKAR, 5TH YEAR, 2010

Tuberculosis is a chronic infectious disease caused by mycobacterium tuberculosis/m.bovis, mainly affecting the lungs causing PTB and also affects other parts of the body causing EPTB.

It is characterized by cough lasting more than 3 weeks and not responding to usual antibiotics, production of sputum sometimes blood stained, temperature and night sweats, weight loss.

A third of the world's population are thought to be infected with M. tuberculosis.

In 2007 there were an estimated 13.7 million chronic active cases, 9.3 million new cases, and 1.8 million deaths

TB is the leading cause of death from a single infection in adults.

1 in 10 to 1 in 20 of the people infected with TB actually get sick.

If untreated, fatal in over 50% of cases. Untreated patients infect 10-12 people

on a yearly basis.

TB has been around since prehistoric times, Found in ancient mummies

Are rod shaped(bacilli) and sometimes they exhibit filamentous forms resembling fungal mycelium and hence they are so named.

Gram positive Non-motile, non-capsulated, non sporing Are acid fast bacilli Very slow growing This genus includes over 50 species

Transmission –air droplets, food/milk, through skin

Forms or Primary TB: TB intoxication (TBI) as an

independent disease (5%). Primary TB complex (PTBC) (25%). TB of intrathoracic lymph-nodes

(TBITLN) (70%).

paleness of the skin integument . poorly developed subcutaneous fat. node erythema (local consolidation of the skin

with cyanotic discoloration and large dermal papules).

Phlyctenular Keratoconjunctiviti, conjunctivitis, blepharitis

micropolyadenitis (increased, feebly tender, movable peripheral lymph-nodes).

enlarged liver, splenic hyperplasia. quick pulse

No evident TB intrathoracic lesions. except paraspecific reactions:- increased periradical lung pattern (congestion)- slight lung field fogging (pleural reaction)

Pneumonic stage – onset of the disease when clinical manifestations are at the height.

Bipolar stage –clinical manifestation regression in 2-3 months after onset.

Consolidation stage – lung affection capsulizing without clinical symptoms.

Ossification stage – Ghon’s focus formation.

Post-primary tuberculosis is a reinfection tuberculosis (RT) in adults

-limitation to the lung;-progression with caseous sloughing;-intrabronchial spread;-cavity formation.

Cavity TB- the caseous necrosis may be absorbed or it erodes into a bronchus and is coughed out leaving behind a cavity

Fibrocaseous TB/ Tuberculoma- Fibrosis causes restriction of the size of the caseous necrosis resulting in the formation of solid nodules called fibrocaseous tuberculosis.

Tuberculous Bronchopneumonia- the caseous material may spread in the bronchi and surrounding structures producing bronchopneumonia.

Caseous Pneumonia- when reaction spreads from alveolus to alveolus across the pulmonary acini, a large focus of consolidation by caseous necrosis occurs.

Miliary TB- hematogenous spread causing miliary TB.