Zusammenfassung der Ressource
Tuberculosis
- Cause
- Mycobacterium Tuberculosis
1. exposed by inhalation ; 2.In
most people the immune
system clears the bacteria; 3.
Recent resurgence due to HIV
- Characteristics
- 1. Tubercle --> The typical
response takes 3 weeks (time for
Type 4 Hypersensitivity reaction.
Central caseation surrounded by
epetheliod cells. Langerhans cells.
Macrophages. Lymphocytes.
Surrounded by fibrosis.
- 2. Epetheliod cells -->activated
macrophages. response to
tubercle baccilli mycolic acid. No
phagocytic fxn but secretory
- 3.Caseation Necrosis --> chalky
cheesy. Tissue destroyed with
no outline seen. Due to Type 4
hypersensitivity
- Clinical Features
- Fever; cough with bloody
sputum;chest pain;
weight loss
- Primary Tuberculosis
- AKA Ghon's lesion --> Ghon's
complex consists of 1. Ghons focus.
2. Lymphatics 3. Hilar lymph node
Also PROGRESSIVE PRIMARY
TUBERCULOSIS--> rare, involvement
of surrounding lung, invades blood
vessels and spread -->Miliary TB
- Secondary Tuberculosis
- Due to 1.reinfection 2.
reactivation. Most lesions
located at apex. CAVITY
FORMATION due to rapid
caseation. Also PROGRESSIVE
SECONDARY TB --> no healing;
direct spread to lungs, pleura,
lymph nodes ; bronchiestasis
and pleural effusion ; blood
spread --> Miliary TB
- Miliary Tuberculosis
- Millet sized granulomas
all over the lungs, liver,
spleen, brain and gut.
Occurs in primary or
secondary TB.
Mycobacterium enters
the blood and there is
hematogenous spread.
- Laboratory Tests
- Tuberculin (PPD) Test -->inject
the tubecle protein into skin.
Criteria to treat--> >5mm in
HIV+,those with recent contact,
chest Xray with old TB scar;
>10mm in IV drug users,
homeless, those born in
countries with high incidence,
healthcare workers; >15mm
everyone else
- Lab diagnosis of TB
-> mimics lung
cancer. Do a sputum
sample and
demonstrate
tubercle bacilli by
acid fast stain, pcr,
culture; fine needle
aspiration from
lymph node,; lymph
node biopsy;
bronchoscpoic
biopsy; pleural tap
- Tuberculosis in Immunocompromised patients
- EG. In pts with HIV,
steroid therapy,
lymphoma. -->poor cell
reaction so no
granulomas; extensive
necrosis not caseation; no
cavitation or fibrosis;
abundant acid fast bacilli;
other organisms such as
mycobacterium avium
intracellulare