Tuberculosis

Question 1

Define TB

Answer 1

An infectious, chronic granulomatous disease caused by Mycobacterium tuberculosis

Question 2

What body parts does it affect?

Answer 2

Typically lungs, esp upper lobes but can spread to any organ haematologically to cause extrapulmonary TB

Question 3

Describe the disease progression from primary to secondary TB

Answer 3

• M tuberculosis is dormant in many patients before it progresses to active TB
• Primary TB is asymptomatic and happens in immunocompetent individuals who become exposed to M tuberculosis - this usually heals in them
• If host becomes immunocompromised the initial infection may become reactivated into secondary TB

Question 4

Risk factors? (7)

Answer 4

• Exposure to infection
• Immunosuppression - e.g. Diabetes, Cushings, Steroid use
• Silicosis (form of lung fibrosis)
• HIV
• Malignancy
• Birth in an endemic country -
  
  • India
  • Bangladesh
  • Sub Saharan Africa
• Overcrowded areas

Question 5

Clinical features

Answer 5

• Cough → productive (may have haemoptysis), doesn’t respond to conventional antibiotic therapy
• Fever
• Weight loss
• Night sweats
• SOB
• Anorexia
• Malaise
• Pleuritic chest pain
• Cervical lymphadenopathy + hilar lymphadenopathy
• Pott’s Disease → spread to bones

Question 6

what is pott’s disease?

Answer 6

a serious infection of the spine caused by tuberculosis bacteria, leading to potential spinal deformities and neurological complications.

Question 7

1st line investigation?

Answer 7

CXR:
- Consolidation
- Bilateral hilar lymphadenopathy
- Cavitating lesion in upper lobe (Caseating granulomas)

Question 8

What is the gold standard diagnostic test?

Answer 8

Sputum culture - most sensitive and specific test

Question 9

What is a sputum acid-fast bacilli smear?

Answer 9

Uses a Ziehl-Neelson stain or auramine stain- would show Acid fast bacillus positive

Question 10

What test is offered for another disease to TB patients?

Answer 10

HIV test

Question 11

What test is usually offered for contacts of infected patients & what does it screen for?

Answer 11

Mantoux test - Screens for latent TB

Question 12

What can cause a false negative for Mantoux test?

Answer 12

Immunosuppression:
- sarcoidosis
- steroid use
- lymphoma
- AIDS

Question 13

What do we give for latent TB? (2)

Answer 13

For 3 months
- Rifampicin
- Isoniazid

Question 14

What do we give for active TB? (4)

Answer 14

RIPE
- Rifampicin
- Isoniazid
- Pyrazinamide
- Ethambutol

Question 15

When is the patient started on the drugs and for how long? (3)

Answer 15

Start all the drugs at the same time

• Rifampicin and Isoniazid for 6 months
• Pyrazinamide and ethambutol for 2 months

Question 16

SE for Rifampicin

Answer 16

Red/orange secretions

Question 17

SE for Isoniazid

Answer 17

• Drug induced lupus
• Peripheral neuropathy

Question 18

How can you prevent peripheral neuropathy?

Answer 18

Giving pyridoxine (Vit. B6)

Question 19

SE for Pyrazinamide

Answer 19

• Can cause gout due to hyperuricaemia
• most hepatotoxic out of all of them

Question 20

SE for Ethambutol

Answer 20

May cause optic neuritis

Question 21

What is needed to be done before giving BCG vaccine?

Answer 21

Tuberculin skin test to check for past exposure to TB

Question 22

Complications? (5)

Answer 22

• Transmission of TB
• ARDS
• Pneumothorax
• Haemoptysis
• Bronchiectasis