Tuberculosis

Question 1

What are the symptoms of primary infection TB?

Answer 1

Usually asymptomatic

Cough, fever, erythema nodosum, malaise , rarely chest pain

Question 2

in primary TB, where are most of the infections focused?

Answer 2

80% of infections are focused in the alveoli, lymph nodes and gut.

Question 3

Describe briefly what the primary infection TB can be like in a minority of patients.

Answer 3

In a minority of patients (1%) the primary focus doesnt heal and continues to enlarge causing cavitation.
The enlargement of the hilar lymph nodes compresses the bronchi causes a lobar collapse.
The hilar lymph nodes may discharge into the bronchi.
It may also develop into TB bronchopneumonia which has a poor prognosis.
6 months after infection some may develop Millard TB, meninges TB or TB pleural effusion.

Question 4

Describe what Millard TB presents like.

Answer 4

Millard TB presents with fine mottling on X ray. Shows wide spread small granulomatous and pleural effusion.
.

Question 5

What are the symptoms of post primary infection TB?

Answer 5

Cough with sputum 
Haemoptysis
Pleuritic chest pain
Breathlessness
Fever, malaise, might sweats, weight loss

Question 6

What are the clinical signs of post infection TB?

Answer 6

Usually present with no signs.

Signs may be crackles and bronchial breathing. Clubbing is rare but only in severe disease.

Question 7

What is the treatment for TB?

Answer 7

4 drugs for 2 months then 2 drugs for 4 months. Total of 6 month treatment
Rifampicin, isoniazid, ethambutol and pyrazinamide for 2 months
Rifampicin and isoniazid for 4 months

Question 8

What are the side effects of the TB treatment?

Answer 8

Rifampicin - orange ‘iron bru’ tears, urine and stains contact lenses. Hepatitis. Induces liver enzymes so makes certain drugs ineffective such as prednisolone, anti-convulsants and contraceptive pill.

Isoniazid - hepatitis and peripheral neuropathy
Ethambutol - optic neuropathy
Pyrazinamide - gout

Question 9

what species make up the mycobacterium tuberculosis complex?

Answer 9

M. Tuberculosis
M. Bovis
M. Africanum.
M. Microti

Question 10

what type of immunological response occurs when infected by M. tuberculosis?

Answer 10

T cell mediated immunological response

Question 11

Describe the granulomas present with TB.

Answer 11

granulomas contain activated macrophages and are surrounded by epitheliod cells and Lang hans giant cells
the granulomas have central caseating necrosis
there is cavitation in advanced disease

Question 12

what type of bacteria are mycobacterium tuberculosis?

Answer 12

they are facultative intracellular aerobes
they are slow growing
have high lipid content
acid fast bacilli

Question 13

why are M. tuberculosis termed as acid fast bacilli?

Answer 13

when stained with dye + phenol and washed with acid they resist decolourisation

Question 14

what is the generation time of M. tuberculosis?

Answer 14

12-18 hours

Question 15

what are the risk factors for infection from TB?

Answer 15

poverty
low socio economic background
malnourished
immigrants
sub saharan africa / asia
immunosuppressed
diabetes
HIV

Question 16

how is M. bovis contracted from and where does it deposit the infection?

Answer 16

contracted from cows milk.

the infection is usually deposited in cervical and intestinal lymph nodes

Question 17

what symptoms and signs are present with primary progressive TB?

Answer 17

usually asymptomatic
pyrexia
malaise
erythema nodosum
Ghon focus on CXR, usually found in the mid zones and/ or in regional draining lymph nodes

Question 18

describe what meningeal TB presents like.

Answer 18

high CSF protein

Question 19

what are the symptoms/ signs of post primary TB?

Answer 19

may be asymptotic for months.
respiratory: cough with sputum and/ or haemoptysis, SOB, pleuritic chest pain
malaise, pyrexia, weight loss, night sweats
Crackles and Bronchial breathing may be heard over area of consolidation.

Question 20

in latent primary TB, what can develop after 6-12 of infection?

Answer 20

Miliary TB
meningeal TB
TB pleural effusion

Question 21

what 3 investigations should be carried out for diagnosing TB?

Answer 21

sputum samples taken on 3 successive days.
- sputum culture
- sputum PCR
- sputum smear
Chest X-ray
CT scan of thorax
Bronchoscopy with bronchoalveolar lavage and transbronchial biopsy
Pleural aspiration and biopsy if pleural effusion.

Question 22

For the treatment of TB, single agent treatment leads to drug resistant organisms within how many days?

Answer 22

14 days

Question 23

when patients start treatment for TB, when are they rendered non-infectious?

Answer 23

after 2 weeks

Question 24

what is the vaccine for prophylaxis of TB infection?

Answer 24

BCG vaccine

Question 25

how is screening for TB carried out?

Answer 25

If under 16 and no BCG = Tuberculin test and CXR

If over 16 and BCG = CXR for reassurance

Question 26

In TB screening, if someone is under 16, no BCG and IGRA is positive but X ray is normal, what does this mean and what is done?

Answer 26

This means that they are at risk of disease
- chemoprophylaxis to kill mycobacterium : rifampicin + isoniazid prophylaxis therapy for 3 months and IPT for a further 6 months

Question 27

What can be used for diagnosis of latent TB?

Answer 27

IGRA

Question 28

What are the symptoms of progressive primary TB?

Answer 28

Usually none
Progressive productive cough with haemoptysis
Erythema nodosum 
Pyrexia 
Malaise 
(Ghon focus seen on mid zones on CXR)

Question 29

What are the 3 sputum tests carried out for investigation of TB?

Answer 29

Sputum culture
Sputum smear
Sputum PCR

Question 30

Where in the lungs is TB most commonly found?

Answer 30

Upper lobe

Question 31

What can miliary TB sometimes present with?

Answer 31

Pleural effusion