Tuberculosis (DISEASE MECHANISMS)

Question 1

Upon exposure with T the pathogens are engulfed within ____ where they replicate

Answer 1

macrophages

Question 2

TB pathogens are kept in ‘prisons’ called

Answer 2

granulomas

Question 3

After infection _% remain well
50% __ _ ______
_% have lifetime risk of disease of which _% _______ and _% _____________

Answer 3

90%
clear TB spontaneously 
10
5% primary TB
5% reactivation of latent disease

Question 4

The symptoms of TB are _______ and have a _____ onset

Answer 4

subacute

gradual

Question 5

What are the general symptoms of TB?

Answer 5

Malaise
Weight loss
Night sweats

Question 6

What are the respiratory symptoms of TB?

Answer 6

Cough
Haemoptysis
Breathlessness
Upper zone crackles on asucultation

Question 7

What are the meningeal symptoms of TB?

Answer 7

Headaches
Drowsy
Fits

Question 8

What are the GI symptoms of TB

Answer 8

Pain
Bower obstruction
Perforation
Peritonitis

Question 9

What are the symptoms of spinal TB?

Answer 9

Pain
Deformity
Paraplegia

Question 10

What is paraplegia?

Answer 10

Impairment in motor or sensory function of the lower extremities

Question 11

How can TB in the lymph nodes be detected?

Answer 11

Lymphodenopathy

Question 12

TB can present as a cold abscess - what is a cold abscess?

Answer 12

Collection of pus without pain or acute inflammation

Question 13

What are the pericardial symptoms of TB?

Answer 13

Tamponade

Question 14

What are the real symptoms of TB?

Answer 14

Renal failure

Question 15

How can TB in the joints present?

Answer 15

Septic arthritis - cold mono arthritis or large joints

Question 16

How can TB in the adrenal present?

Answer 16

Hypoadrenalism

Question 17

How can TB be diagnosed using histology?

Answer 17

Multinucleate giant cell granulomas
Caseous necrosis
Sometimes visible mycobacteria

Question 18

What would be noticeable on a CXR of a patient with TB?

Answer 18

Upper lobe predominance
Cavity formation
Tissue destruction
Scarring and shrinkage
Heals with calcification

Question 19

How is TB treated?

Answer 19

2 months of Rifampicin, Isoniazid, Pyrozinamide and Ethambutol

4 months of Rifampicin and Isoniazid

Question 20

What are the side effect of Rifampicin?

Answer 20

Colours urine and all bodily fluids orange
Potent inducer of cytochrome enzymes causing rapid breakdown of all steroid molecules (inc. hormonal contraception) and opiate analgesics and many other drugs

Question 21

What are the side effects of ethambutol?

Answer 21

Can cause optic neuritis

Question 22

What are the different types of drug resistance?

Answer 22

Single resistance
Multi-drug resistance
Extensive resistance

Question 23

Which TB drug shows single resistance?

Answer 23

Isoniazid

Question 24

Which TB drugs show MDR?

Answer 24

Rifampicin

Isoniazid

Question 25

Which TB drugs show extensive drug resistance?

Answer 25

MDR Quinolone Injectables

Question 26

A patient with latent TB infection would present ...

Answer 26

asymptomatic | negative culture

Question 27

What is the criteria for latent TB?

Answer 27

No evidence of active TB | Evidence of previous TB infection (history before 1960 / calcification on CXR / Exposure to high prevalence areas)

Question 28

What are the two tests to determine if someone has had previous TB exposure?

Answer 28

Interferon Gamma Release Assay blood test Mantoux tuberculin skin test

Question 29

How does the Interferon gamma release assay test work?

Answer 29

Assays look for interferon gamma specific to antigens found only in M. tuberculosis

Question 30

What are the advantages of the interferon gamma release assay test?

Answer 30

High specificity Only requires 1 visit Doesn't react with BCG

Question 31

How does the mantoux tuberculin skin test work?

Answer 31

Tuberculin is a protein derived from mycobacteria culture - detects any previous TB exposure

Question 32

What are the disadvantages of the mantoux tuberculin skin test compared to interferon gamma release assay?

Answer 32

Requires 2 visits Lots of false positives and negatives Cannot distinguish BCG

Question 33

How can latent TB be treated?

Answer 33

6 months of isoniazid or 3 months of rifampicin + isoniazid

Question 34

Which drug must NOT be given to a patient with latent TB?

Answer 34

Anti-TNF

Question 35

Is it an option to simply not treat latent TB?

Answer 35

Yes

Question 36

How can TB be prevented?

Answer 36

``` Contact tracing Isolation of infected Screening (of high risk individuals) BCG immunisation Social measures (housing / nutrition) ```

Question 37

How does the BCG immunisation work?

Answer 37

Attenuated strain of M. bovid | Intradermal injection

Question 38

Where is BCG immunisation most effective?

Answer 38

Neonates of high risk families

Question 39

TB is closely associated with which disease?

Answer 39

HIV

Question 40

Which types of drugs can reactivate latent TB?

Answer 40

Steroids and other immunosuppressants

Question 41

What are the main aspects of pleural infection?

Answer 41

Increasing incidence Significant mortality Doesn't always follow pneumonia Can rapidly coagulate and organise to form fibrosis peels even w/o antibiotics

Question 42

What are the risk factor for pleural infection?

Answer 42

``` Diabetes mellitus Immunosuppression Gastro-oesophageal reflux Alcohol misses I.V. drug abuse ```

Question 43

What is are the 3 types of pleural infection?

Answer 43

1. Simple parapneumonic effusion 2. Complicated parapneumonic effusion Effusion 3. Empyema

Question 44

What distinguishes a simple parapneumonic effusion?

Answer 44

Typically respond well to antibiotics

Question 45

What distinguishes a complicated parapneumonic effusion?

Answer 45

``` Includes pus Gram-stain postive pH < 7.2 low glucose separations loculations ```

Question 46

What distinguishes empyema?

Answer 46

Pus in pleural cavity

Question 47

Typically, pleural effusions below _ cm don't need to be drained?

Answer 47

1 cm

Question 48

How are pleural effusions managed?

Answer 48

``` Antibiotics (often several weeks) Drain as needed Early discuss with surgeons if persistent sepsis Nutrition VTE prophylaxis Question role of fibrinolytic or Dnase Reassess if don't improve ```