TB

Question 1

Causes

Answer 1

-Mycobaterium tuberculosis- droplet
-Mycobacterium bovis-infected milk
-aerobic, motile bacilli which move to the alveoli
- Resistant to acids, alkalis, detergents due to wall made up go lipids and peptidoglycan
-Can be stained with analine dyes
- Can be eradicated from the air by UV, extreme dilution
-

Question 2

Investigation

Answer 2

Sputum collection for 3 successive days
Chest XR : patchiness around the apices,
calcification if tissue is chronic or healed, cavitation if advanced TB
If sputum is negative:
Blood tests: WBC, CRP
CT of thorax
Pleural aspiration if there is fluid in the pleura
Bronchoscpy

Question 3

main test

Answer 3

HEAF test: insert tuberculin under the skin and if there is an inflammatory response this is caused by TB.
In TB there is built up immunity to tuberculin

Question 4

Symptoms

Answer 4

Primary:

• Fever, malaise
• Erythema nodosum

Post-primary:

• Fever, malaise
• hemoptysis
• Pleuritic pain
• Bronchial breathing if XS

Question 5

Treatment

Answer 5

2 months:
Rifampicin
Isoniazid
Pyranizamide
Ethambutol 
4 months: R+ I

Question 6

Side effects of treatment

Answer 6

R: 
-orange urine 
-overreactive pancreatic enzymes
-oral contraceptive pill inactive 
-hepatitis
I:
Hepatitis
peripheral neuropathy
P:
Gout
E: optic neuropathy- should always do blind test

Question 7

How does it resolve

Answer 7

Progressive slow: 
-cavitation 
-lobal collapse
-broncho pneumonia
-miliary TB
-meningineal TB
-Pleural effusion
Post-primary : reactivation of mycobacterium or new infection

Question 8

How does TB develop?

Answer 8

GENERAL:
Trigget Th1 cells
Triggers the macrophages> epitheloid cells > langerhans cells to proliferate
1-primary TB
TB moves to alveoli where it is surrounded by inflammatory cells to form a granuloma- causes caseous necrosis- Ghon Focus
The TB spreads to the hilarity lymph nodes
Ghon Focus + lymph node = Ghon complex
Usually broken down or latent
2- If immune system becomes compromised then TB can move to apices of the lungs where it leads to Cavitating necrosis
3- In cavitating necrosis- TB moves to other parts of the body
Lungs- bronchopneumonia
Vascular system- Miliary TB- spread to multiple systems

Question 9

How to treat a <16 with no BCG

Answer 9

Heaf test:
1-Positive: chest XR
Normal: 
-At risk:
-3 months of rifampicin and isoniazid and 6 months of isoniazid
Abnormal:
-primary TB
2-Negative: repeat after 6 weeks
-Negative: BCG 
-positive; recent infection- treat as above

Question 10

How to treat a >16 with BCG

Answer 10

chest XR:
Normal- discharge
Abnormal- investigate

Question 11

Resistant hosts- will present asymptomatic with latent disease

Answer 11

Young
Strong immune system
Good nutrition
Good balance of Th1 breakdown of TB and tissue damage

Question 12

Susceptible hosts

Answer 12

Elderly, adolescence 
Compromised immune system 
From areas with high prevalence 
Malnutrition, alcoholism 
Diabetes mellitus patients

Question 13

General guidance on treatment

Answer 13

Combination of drugs must be used to prevent resistance

Must alert of all cases

Question 14

Global distribution and in the UK

Answer 14

2 billion people affected worldwide
2 leading cause of death from infectious disease worldwide
1.3 million die each year
High incidence in the UK due to immigration from people from high incidence areas
45/100,000 people affected in the uk