Tuberculosis

Question 1

DxT of pulmonary TB:

Answer 1

malaise + cough + weight loss ± fever/night sweats

Question 2

Features

Answer 2

Pulmonary tuberculosis may be symptomless

• and detected by mass X-ray screening.

It may be:

1. primary
2. post-primary (reactivation of latent TB) or
3. miliary.

Question 3

Natural history of TB infection

Based on WHO algorithm and Dr Grant Jenkin (personal communication).

*TST = tuberculin skin test

** IGRA = interferon gamma release assay

Answer 3

Question 4

Respiratory symptoms

Answer 4

Cough

Sputum: initially mucoid, later purulent

Haemoptysis

Dyspnoea (esp. with complications)

Pleuritic pain

Question 5

General clinical features (usually insidious)

Answer 5

• Anorexia
• Fatigue
• Weight loss
• Fever (low grade)
• Night sweats

Question 6

Physical examination

Answer 6

May be no respiratory signs or may be signs of :

• fibrosis
• consolidation or
• cavitation (amphoric breathing)

Finger clubbing

Question 7

Investigations

Answer 7

Chest X-ray (CT scan if doubtful)

Micro and culture sputum specimens or bronchial secretion (for tubercle bacilli)—3 specimens over 3 days, including one from early morning

ESR/CRP

Tuberculin skin (Mantoux) test (misleading if previous BCG vaccination): a guide only

Immunochromographic finger prick test (new and promising)

Interferon gamma release assay (IGRA)

NAAT/PCR test—less sensitive than culture

Consider HIV studies

Question 8

Management

Answer 8

Tuberculosis is a notifiable disease

Hospitalisation for the initial therapy of pulmonary TB is not necessary in most pts.

Monthly f/u is recommended, including sputum smear and culture.

Question 9

Drug therapy

Answer 9

Multiple drug therapy is initiated primarily to guard against the existence and/or emergence of resistant organisms.

• (MDR-TB is a huge issue.)

Standard initial therapy consists of:

• rifampicin + isoniazid + pyrazinamide + ethambutol daily for at least 2 m

followed by

• rifampicin + isoniazid for 4 months if the organism is susceptible to these drugs.

If isoniazid resistance is suspected,

• ethambutol or streptomycin (with care) is added.