Tuberculosis

Question 1

What are some bacterial species responsible for TB?

3

Answer 1

M. tuberculosis
M.africanum
M. bovis (“bovine TB”, BCG strain)

Question 2

When a lab AAFB test (ZN stain) is positive (+). What could this mean?

Answer 2

active TB +

or could have other disease:
Leprosy
NTM-infections

Question 3

Why is TB antibiotic resistant?

Answer 3

the bacteria has a thick, lipid membrane

Question 4

How is TB spread?

Answer 4

airborne (pulmonary TB) except Bovine TB

Question 5

How does TB become latent?

Answer 5

Mycobacteria becomes enclosed in granulomas made up from infected macrophages, normal macrophages, B/T-lymphocytes etc.

Question 6

What is the name given to disseminated TB that spreads from entering the blood stream?

Answer 6

miliary TB

Question 7

Which parts of the body tend to be unaffected by TB?

Answer 7

pancreas*
heart
skeletal muscles
thyroid

Question 8

What happens in the centre of the granulomas containing the TB mycobacterium?

Answer 8

caseous necrosis

Question 9

Which patient group is at an increased risk of developing active TB?

Answer 9

HIV positive/immunocompromised

Question 10

What is the primary site of infection in the lungs known as?

Where in the lungs is this site?

Answer 10

Ghon focus

lower part of upper lobe or;
upper part of lower lobe

Question 11

TB infection of the lungs from the blood stream is known as what?

Where in the lungs is this site of infection?

Answer 11

Simons focus

top of the lung

Question 12

What are the symptoms of TB?

5

Answer 12

may be asymptomatic at first, rarely any chest signs

chronic cough with bloody mucus
haemoptysis
fever
night sweats
weight loss

Question 13

How is TB diagnosed/investigated?

Answer 13

• CXR - lung apices, soft ‘fluffy/nodular upper zone, cavitation in 10-30%, mediastinal lymphadenopathy (mainly unilateral, 15% bilateral), pleural effusion
• CT
• AAFB test
• sputum sample (x3)

Question 14

Which drugs are used to treat active TB?

What is the duration of drug therapy?

Answer 14

Rifampicin
Isoniazid
Pyrazinamide
Ethambutol

6 months

Question 15

Which drugs are given for the first 2 months?

Answer 15

Rifampicin
Isoniazid
Pyrazinamide
Ethambutol

Question 16

Which drugs are given for the last 4 months?

Answer 16

Rifampicin

Isoniazid

Question 17

What drug might be used if a patient developed resistance to isoniazid?

Answer 17

levofloxacin (fluoroquinolone)

Question 18

How many weeks into therapy can a patient can be considered ‘uninfective’?

Answer 18

2 weeks

Question 19

What are some side effects to TB therapy drugs?

5

Answer 19

hepatitis
'irn bru' coloured urine (Rifampicin) 
peripheral neuropathy (Isonazid)
gout (Pyrazinamide)
optic neuropathy (ethambutol)
rash

Question 20

How do you treat latent TB infection?

4

Answer 20

Treatment of LTBI – always rule out active TB!

• Rifampicin & Isoniazid for three months, or
• Isoniazid only for six months, or
• Rifampicin only for six months, or
• Rifapentine & Isoniazide once weekly for 12 weeks (underserved population)