Tuberculosis

Question 1

Define Tuberculosis

Answer 1

Infectious disease caused by mycobacterium tuberculosis

Is usually dormant before progressing to active TB where it mostly involves the lungs, but can affect any organ system

Question 2

Aetiology of Tuberculosis

Answer 2

Transmission via inhalation of aerosol droplets containing the bacteria.

Active TB: infection by Mycobacterium tuberculosis AND inadequate containment by the immune system

Latent TB: patient infected with M. Tuberculosis who have no clinical, bacteriological or radiographic evidence due to immune system containment e.g. granulomas formation

Military: lymphohaematogenous dissemination

Question 3

Risk factors for Tuberculosis

Answer 3

Exposure to infection
HIV 
Endemic countries (travel or birth): South Asia/India/Bangladesh 
Immunosuppressants
Silicosis
Apical fibrosis

Question 4

Epidemiology of Tuberculosis

Answer 4

Leading cause of death worldwide

9.6 million cases a year

Question 5

Symptoms of Tuberculosis

Answer 5

Cough (>2-3 weeks, initially dry -> productive)
Fever 
Malaise
Weight loss or anorexia 
Pleuritic chest pain
Night sweats
Haemoptysis 
Psychological symptoms (Depression, hypomania)
Dyspnoea 

Cardiac: pericardial effusion, constrictive pericarditis
Bone: Pott’s disease, spinal cord compression, osteomyelitis
Renal: Renal failure, Addison’s, Epididymo-orchid is, infertility
GI: peritonitis, ascites

Question 6

Signs of Tuberculosis on examination

Answer 6

Clubbing
Erythema nodosum (red, painful, tender, lumps fund commonly on the front calf surface)
Erythema induratum
Bronchial breath sounds or amphorae breath sounds (Distant, hollow sounds over cravity)

Question 7

Investigations for Tuberculosis

Answer 7

High suspicion - isolation at home or in a negative pressure room until 5 days to 2 weeks of therapy

Sputum smear and culture: staring for acid-fast bacilli and assess drug sensitivity (± nuclei acid amplification testing for detection)
FBC: Raised WCC
CRP: elevated
ABG: T1RF

CXR: Patchy consolidation | Bi-hilar lymphadenopathy | Upper lobe scarring | cavitation lesions | pleural effusions§

Lymph node biopsy: caseating granuloma

Mantoux/tuberculin skin test (TST): erythematous ring
Interferon-game release assay (IGRAS)

Question 8

Management for Tuberculosis

Answer 8

Rifampicin + Isoniazid 6 months

Pyrazinamide + Ethambutol 2 months