Tuberculosis

Question 1

Organism responsible for TB

Answer 1

mycobacteria

Question 2

Various species of TB responsible for human disease

Answer 2

Myobacterium tuberculosis

M Bovis (bovine TB)

Question 3

Mycobacteria

Answer 3

non-motile bacillus

very slowly growing

aerobic

Question 4

Transmission of mycobacterium tuberculosis

source

Answer 4

case of ‘open’ pulmonary TB, coughing, sneezing

respiratory droplets evaporate

remain airborne for long period of time

Question 5

Inhaled TB

Answer 5

larger droplet nuclei impact on airways

smaller droplets impact on alveoli and slowly proliferate

Question 6

Mycobacterium bovis

Answer 6

consumption of infected cows milk deposited in cervical, intestinal lymph nodes

Question 7

Immunopathology of TB

Answer 7

accumulation of macrophages, epithelial and longhand cells –> GRANULOMA

Question 8

TB elicits a …… cell mediated immunological response

Answer 8

Th1

Question 9

Th1 cell mediated response is a TWO EDGED SWORD

Answer 9

1. eliminates/ reduces number of invading mycobacteria

2. tissue destruction is a consequence of activation of macrophages

Question 10

Susceptible host to TB

Answer 10

elderly

malnutrition

Question 11

TB primary infection

Answer 11

no preceding exposure or immunity

usually children (80% infected alveolus)

mycobacteria spreads via the lymphatics to drain lymph nodes

haematogenous seeding of mycobacteria to all organs of the body (lungs, bone etc)

Question 12

TB symptoms

Answer 12

usually no symptoms

fever, malaise

Question 13

Primary infection progression

Answer 13

primary focus continues to enlarge

lobar collapse due to enlarged lymph that compress bronchi

poor prognosis

Question 14

6-12 months after TB

Answer 14

X-ray shows widespread small granulomata

Tuberculous pleural effusion

Question 15

Post primary disease (TB)

Answer 15

1. reactivation of mycobacterium from latent primary infection disseminated by the blood stream around the body
2. New re-infection from outside source, susceptible previously infected host

(different host response because of previous sensitisation)

Question 16

Post primary diseases

Answer 16

Pulmonary disease

lymph nodes

bones and joints

genito-urinary

male infertility

Question 17

Post-primary pulmonary tuberculosis clinically

Answer 17

may occur at any age - usually the reactivation of latent disease

May not be any symptoms for months

Progressive (several months)

Respiratory: Cough, sputum, haemoptysis, pleuritic chest pain, SOB

Question 18

‘index of suspicion’ for TB

Answer 18

immunosuppressed

malnutrition

Diabetes

adolescence, elderly

Question 19

TB essential investigations

Answer 19

3 sputum specimens on successive days
(sputum smear/ sputum culture)

CXR

Question 20

Further investigations if sputum is negative

Answer 20

CT scan of thorax

bronchoscopy (bronchial histology/ biopsy)

Pleural aspiration and biopsy if pleural effusion

Question 21

Treatment of TB (surgical) and old school lol

Answer 21

Collapse down the cavity, anaerobic condition, phrenic crush, artificial pneumothorax, pneumoperitoneum, thoracoplasty, lung resection

Question 22

Modern treatment of TB

Answer 22

multiple drug treatment

therapy for 6 months

Question 23

Current TB regimes

Answer 23

2 months - 4 drugs

4 months - 2 drugs

rifampicin and
isoniazid

Question 24

Likelihood of infection with TB depends on

Answer 24

duration of contact

intensity of infection

Question 25

Screening TB

Answer 25

tuberculin test