Tuberculosis

Question 1

What causes tuberculosis?

Answer 1

Mycobacterium tuberculosis

Question 2

What is the course of a primary TB infection?

Answer 2

• A non-immune host who is exposed to M. tuberculosis may develop a primary infection of the lungs
• small lung lesion known as a Ghon focus develops.
• immunocompetent people, the initial lesion usually heals by fibrosis.
• immunocompromised may develop disseminated disease (miliary TB)

Question 3

What is secondary TB?

Answer 3

*If the host becomes immunocompromised the initial infection may become reactivated. Reactivation generally occurs in the apex of the lungs and may spread locally or to more distant sites

Question 4

Where can extra-pulomonary infection occur with TB?

Answer 4

• CNS
• Vertebral bodies
• cervical lymph nodes
• renal
• GI tract

Question 5

What investigation is used to diagnose latent TB?

Answer 5

Mantoux test

Question 6

What is latent TB?

Answer 6

Been infected with TB but do not have the symptoms of active infection

Question 7

What investigations diagnose active TB?

Answer 7

*CXR
>upper lobe cavitation
>bilateral hilar lymphadenopathy

• Sputum culture
• Nucleic acid amplification test (NAAT)

Question 8

What is the treatment of active TB?

Answer 8

First 2 months (RIPE)

• Rifampicin
• Isoniazid
• Pyrazinamide
• Ethambutol

Continuation phase (next 4months)
*Rifampicin*Isoniazid

Question 9

What is the treatment of latent TB?

Answer 9

3 months of isoniazid + pyridoxine and rifampicin

or

6months of isoniazid + pyridoxine