tuberculosis

Question 1

what impact does HIV have on TB?

Answer 1

it promotes it because they dont have CD4+ t-cells and so they fail to tolerate it

Question 2

what is the shape of mycobacterium tuberculosis?

Answer 2

rod shaped gram positive bacillus

slow growing member of the genus

Question 3

why is it’s size important?

Answer 3

2-5 microns so it can be transferred by droplets eg sneezing or singing

Question 4

who gets TB?

Answer 4

young people, babies, elderly people

Question 5

what are the symptoms of TB?

Answer 5

• persistant cough > 3 weeks
• occasional haempotysis
• pleuritic pain
• hoarseness
• upper zone crackles
• night sweats fever
• weight loss

Question 6

how do you diagnose TB?

Answer 6

• history and examination
• simple blood tests = no specific one for TB
• radiology/imaging = swollen lymph glands, cavity in lungs
• microbiology and histology

Question 7

what is the microbiology and histology of TB?

Answer 7

• specimens = sputum x3, early moring urines x3
• procedures
• culture = solid phase, liquid phase, drug sensitivities
  histology = granulonata with central caseous necrosis

Question 8

how do we treat active TB?

Answer 8

• 4 drugs for 2 months
  = rifampicin, isoniazid, pyrazinamide, ethambutol

2 drugs for a further 4 months = rifampicin, isoniazid

Question 9

how do we treat latent TB?

Answer 9

2 drugs for3 months

• rifampicin, isoniazid
• or 1 drugs for 6 months = isoniazid

Question 10

what is the immune response for TB?

Answer 10

• the macrophage is the intial intracellular primary niche of MTB
  1. phagocytosis
  2. immune recognition
  3. slow onset of Th-1 biased adaptive immunity
  4. enhanced effector mechanisms

Question 11

what do you look for in the cell structure for TB?

Answer 11

granulomas - they can keep the disease at bay from weeks to years (latent)

Question 12

does TB involve caseous necrosis?

Answer 12

yes - cheese like

Question 13

what happens after exposure to TB?

Answer 13

• 90% remian well

- 10% have lifetime risk of disease

Question 14

what is the pathology of TB?

Answer 14

• type IV hypersensitivity eg granulomas and necrosis

Question 15

what is primary TB?

Answer 15

1st exposure and up to 5 years after te disease

- ghon focus in mid zone periphery, large hilar nodes

Question 16

what is secondary TB?

Answer 16

reinfection of disease in person with some immunity (fibrosis and cavititating apical lesion)

Question 17

why does TB become reactivated?

Answer 17

• decreased T cell function due to age, HIV, immunosuppressants like steroids or chemo
• reinfection at high dose or more virulent organism

Question 18

what are the side effects of rifampicin?

Answer 18

orange fluids

Question 19

what are the side effects of isoniazid?

Answer 19

neuropathy

Question 20

what are the side effects of pyrazinaide?

Answer 20

joint pain

Question 21

what are the side effects of ethambutol?

Answer 21

colour blindness

Question 22

why is there a caution with anti TNF therapy?

Answer 22

it may reactive latent TB