Tuberculosis

Question 1

Define

Answer 1

DEFINITION: Granulomatous disease caused by Mycobacterium tuberculosis

• Primary TB: initial infection may be pulmonary or (more rarely) gastrointestinal
• Miliary TB: results from haematogenous dissemination of TB
• Post-Primary TB: caused by reinfection or reactivation

Question 2

Causes

Answer 2

Pathophysiology – immune reposes to mycobacterium causes caeseating granulomas (necrotic regions)

• M. tuberculosis is an acid-fast bacilli
• Mycobacterium tuberculosis is an intracellular organism
• It survives after being phagocytosed by macrophages

Question 3

Epidemiology

Answer 3

• Annual mortality is 3 million (with 95% in developing countries)
• Incidence in Asian immigrants >30 times native white UK population

Question 4

Symptoms

Answer 4

→ Cough, weight loss, fevers, night sweats, haemoptysis

Classic EMQ – long standing cough (>2 weeks) and Asian ethnicity Weight loss, anorexia, night sweats, fever
HIV, travel, homeless

Primary TB:

• Mostly ASYMPTOMATIC
• Fever
• Malaise
• Cough
• Wheeze
• Erythema nodosum
• Phlyctenular conjunctivitis

Miliary TB

• Fever
• Weight loss
• Meningitis
• Yellow caseous tubercles spread to other organs

Post-Primary TB

• Fever/night sweats
• Malaise
• Weight loss
• Breathlessness
• Cough
• Sputum
• Haemoptysis
• Pleuritic chest pain
• Signs of pleural effusion
• Collapse
• Consolidation
• Fibrosis

Question 5

Signs - system review

Answer 5

• Non-Pulmonary TB - occurs mainly in the immunocompromised
• Lymph Nodes
  
  • Suppuration of cervical lymph nodes leading to abscesses or sinuses
• CNS - meningitis, tuberculoma
• Skin - lupus vulgaris (jellylike reddish-brown glistening plaques)
• Heart - pericardial effusion, constrictive pericarditis
• GI
  
  • Subacute obstruction
  • Change in bowel habit
  • Weight loss
  • Peritonitis
  • Ascites
• Genitourinary
  
  • UTI symptoms
  • Renal failure
  • Epididymitis
  • Endometrial or tubal involvement
  • Infertility
  • Adrenal insufficiency
• Bone/Joint - osteomyelitis, arthritis, vertebral collapse (Pott’s disease), spinal cord compression from an abscess

Question 6

Investigations

Answer 6

1. Red Ziehl-Nielson stain (as fast-acid)
2. CXR
   
   1. Primary Infection
      
      • Peripheral consolidation
      • Hilar lymphadenopathy
   2. Miliary Infection
      
      • Fine shadowing
   3. Post-Primary
      
      • Upper lobe shadowing
      • Streaky fibrosis and cavitation
      • Calcification
      • Pleural effusion
      • Hilar lymphadenopathy
3. HIV Testing
4. CT, lymph nodes, pleural biopsy, sampling of other affected systems
5. Sputum sample – microscopy and culture in Lowstein Jensen medium for 4-6 weeks

Question 7

Management

Answer 7

RIPE
Rifampicin, isoniazid, pyraminazide, ethambutol *note side effects

• Rifampicin – flu-like symptoms, hepatitis, stains contacts orange
• Isoniazid – hepatitis, neuropathy
• Pyrazinamide – hepatitis, arthralgia, gout
• Ethambutol – ocular toxicity + colour vision loss