Tuberculosis

Question 1

What is tuberculosis?

Answer 1

Granulomatous Disease causde by Mycobacterium tuberculosis.

Question 2

What is primary TB?

Answer 2

• Initial infection with TB
  
  • Normally pulomary (aquired by inhalation of cough of infected person)
  • occasionally GI

Question 3

What is Milliary TB?

Answer 3

Results when there is haematogenous dissemination.

Question 4

What is post-primary TB?

Answer 4

Caused by reinfection or reactivation

Question 5

What is the epidemiology of TB?

Answer 5

• Annual mortality 3 million (95% in developing countries)
  
  • 2 Billion infected worldwide
• annual UK incidence 6000
• Incidence in Asian immigrants >30 times native UK white population.

Question 6

What kind of pathogen is Mycobacterium Tuberculosis?

Answer 6

Intracellular, aerobic organism (also known as acid-fast bacilli, AFB) which survives after being phagocytosed by macrophages

Question 7

What does the primary infection with mycobacterium tuberculosis cause?

Question 8

What are risk factors of tuberculosis?

Answer 8

• Lived in endemic country (Asia, Latin America, Eastern europe, Africa) for years
• Exposure to someone with infectious TB
• HIV infection
• Immunosuppressive medication

Question 9

What is the association between immunosupression and TB?

Question 10

What are symptoms of primary Tuberculosis?

Answer 10

Mostly asymptomatic

• may have fever, malaise
• cough, wheezeerythema nodosum and phlyctenular conjunctivitis (allergic manifestations).

Question 11

What are signs and symptoms of milliary tuberculosis?

Answer 11

• Fever, weight loss, meningitis
• yellow caseous tubercles spread to other organs (e.g. in bone and kidney may remain dormant for years)

Question 12

What are signs and symptoms of Post-primary Tuberculosis?

Answer 12

• Fever/night sweats, malaise, weight loss,
• Pulmonary TB: breathlessness, cough, sputum, haemoptysis, pleuritic pain, signs of pleural effusion, collapse, consolidation, fibrosis.

Question 13

In which patient group is non-pulmonary TB particularly common?

Question 14

What are non-pulmonary sites of TB infections?

Answer 14

• Lymph nodes: Cervical/ Supraclavicular lymph nodes leading to abscesses (spread to skin) (most common extra-pulmonary manifestation)
  
  • Normally painless, rubberym firm texture
• Gastrointestinal: Subacute obstruction, change in bowel habit, weight loss, peritonitis, ascites
• Genitourinary: Urinary tract infection symptoms renal failure, epididymitis, endometrial or tubal involvement, infertility
• CNS: Meningitis, tuberculoma.
• Skin: Lupus vulgaris (jellylike reddish-brown glistening plaques).
• Heart: Pericardial effusion, constrictive pericarditis
• Adrenal: Insufficiency.
• Bone/joints: Osteomyelitis, arthritis, paravertebral abscesses and vertebral collapse spinal cord compresson from abscesses.

Question 15

Which investigations would you do in a patient with suspected Tuberculosis?

Answer 15

• Sputum(pleural,bronchial): culture, microscopy,
  
  • low sensitivity, takes up to 6 Weeks
• Tuberculin test
• Interferon C test
• Imaging
  
  • CXR
  • CT - lymoh nodes, other extra-pulmonary
• HIV testing (2% might be +ve)

Question 16

Explain the use and result of a Tuberculin test

Answer 16

• Shows antibodies against TB
  
  • positive in previous Tuberculosis or BCG vaccine
  • Mantoux test (intradermal injection) –> redness after 72hrs
  • Heaf test (drop on skin) –> redness after 3-7 days

Question 17

What are expected finding of a patient with TB on a CXR?

Answer 17

1. Primary infection: Peripheral consolidation, hilar lymphadenopathy.
2. Miliary: Fine shadowing
3. Post-primary: Upper lobe shadowing (greatest oxygenation –> aerob) , streaky fibrosis and cavitation, calcification, pleural effusion, hilar lymphadenopathy, pleural effusion