Tuberculosis

Question 1

TB

It’s caused by the bacterium ____.

Answer 1

Mycobacterium tuberculosis

Question 2

TB

What is latent TB?

What is active TB?

Answer 2

Latent TB: Where the person is infected but does not have active disease and is NOT infectious

Active TB: Where the person is symptomatic and may be infectious.

Question 3

TB

How does it present?

Answer 3

• cough
• haemoptysis

systemic symptoms:
- fevers
- night sweats
- weight loss

Question 4

TB

What are some common Ddx?
What other more specific features may those conditions have?

Answer 4

• Pneumonia: characterised by fever, productive cough, and signs of consolidation on examination and chest X-ray
• Lung Cancer: a persistent cough, haemoptysis and weight loss are common symptoms, often in a smoker or former smoker
• COPD: characterised by chronic productive cough, dyspnoea and a history of tobacco or other inhalational exposure
• PE: characterised by acute onset dyspnoea, chest pain and haemoptysis

Question 5

TB

What is first line investigation?

What are some classic findings (but non-specific)?

Answer 5

CXR

Classic findings may include:

Apical infiltrates
Cavitation
Miliary pattern

Question 6

TB

What other scane might we do if the cxr is inconclusive?

Answer 6

HRCT

Question 7

TB

If TB is suspected and a cxr has been done, what is the other imperative investigation?

Answer 7

microbiological confirmation
sputum samples for:
- smear microscopy
- culture
- nucleic acid amplification tests (NAAT)

Question 8

TB

What is NAAT?

Answer 8

nucleic acid amplification tests

Question 9

TB

Microbiological Investigations

What is the quickest but least sensitive test?

Answer 9

Sputum smear microscopy

Question 10

TB

Microbiological Investigations

What is the gold standard? (what is the con about this test?)

Answer 10

Culture

take several weeks for results due to the slow-growing nature of Mycobacterium tuberculosis

Question 11

TB

Microbiological Investigations

NAAT, such as the Xpert MTB/RIF assay, provides a rapid diagnosis and can simultaneously detect ____ resistance.

Answer 11

rifampicin

Question 12

TB

What 2 tests are used to diagnose latent TB or when active TB is suspected, but other investigations are inconclusive?

Answer 12

Tuberculin Skin Test
Interferon Gamma Release Assays

Question 13

TB

Drug Sensitivity Testing
Once the TB bacterium is isolated, drug sensitivity testing is crucial to determine the susceptibility pattern of the Mycobacterium and to guide appropriate treatment.

The NICE guideline recommends universal susceptibility testing for ____ and ____ .

Answer 13

rifampicin and isoniazid

Question 14

TB

Pharmacological Management
For drug-sensitive TB, the initial intensive phase consists of four drugs:

Answer 14

• Isoniazid
• Rifampicin
• Pyrazinamide
• Ethambutol

These are prescribed for two months, followed by a continuation phase of four months with Isoniazid and Rifampicin.

Question 15

TB

For latent TB infection, NICE recommends a regimen of Rifinah (which is ____ and ____) for 3 months or Isoniazid alone for 6 months.

Answer 15

Rifampicin + Isoniazid

Question 16

TB

What 2 drugs does Rifinah consist of?

Answer 16

Rifampicin + Isoniazid

Question 17

TB

Monitoring during treatment includes what kinds of regular tests?

3

Answer 17

• clinical assessments
• sputum cultures
• LFTs

Question 18

TB

Monitoring during treatment includes regular clinical assessment, sputum cultures, and liver function tests.

Adverse effects are common and can include: (3)

Answer 18

Hepatotoxicity
Peripheral neuropathy
Hypersensitivity reactions.

Question 19

TB

Public Health Measures

Once a case is confirmed, what are the next steps?

Answer 19

contact tracing

Question 20

TB

Public Health Measures

What should those with latent TB be offered?

Answer 20

treatment to prevent progression to active disease

Question 21

TB

What are some factors implicated in the reactivation of latent tuberculosis?

Answer 21

• HIV co-infection
• Immunosuppressant therapy (chemotherapy/monoclonal antibody treatment), including corticosteroids
• Diabetes mellitus
• End-stage chronic kidney disease
• Malnutrition
• Ageing

Question 22

TB

A patient with confirmed pulmonary tuberculosis is started on the standard four-drug antitubercular therapy.

What should be the duration of the intensive phase of treatment?

Answer 22

2 months

According to the NICE guideline, the intensive phase of antitubercular therapy for pulmonary tuberculosis is 2 months long. The initial or “intensive” phase typically involves a four-drug regimen of isoniazid, rifampicin, pyrazinamide, and ethambutol.

After the intensive phase, the continuation phase follows. This generally lasts 4 months (making a total standard treatment duration of 6 months) and consists of isoniazid and rifampicin. If there is drug resistance, extrapulmonary involvement or other complications, the duration of treatment may be extended.