Lecture 9.2: Pulmonary Tuberculosis

Question 1

Mycobacterium tuberculosis staining

Answer 1

• Acid fast bacilli
• Stained by Ziehl-Nielsen Method
• Auramine Stain

Question 2

How is TB spread?

Answer 2

Through Aerosol

Question 3

What are the 3 Stages of TB?

Answer 3

• Exposure
• Latent
• Active Disease

Question 4

Exposure to TB

Answer 4

• M. tuberculosis inhaled in the form of droplets
  or aerosols
• Bacilli reach the alveoli
• Macrophages launch immune response and
  phagocytose (‘swallow’) the bacilli
• Macrophage response may be sufficient

Question 5

Latent TB

Answer 5

• Asymptomatic
• Macrophages contain, but don’t kill bacilli
• If initial macrophage response is insufficient to
  contain the infection, the bacilli enter a phase
  of exponential reproduction
• Reproduction of bacilli and destruction by
  macrophages enters a phase of equilibrium
• Ghon focus formation (known as Ghon or
  Primary complex if including a lymph node)
• The bacilli are shielded from the lungs, but can
  survive for extended periods
• If immune system is strong Ghon complex will
  heal, leaving small cavity/ scarring

Question 6

What Individuals are at High Risk of infection with TB?

Answer 6

• Patients with history of inadequately treated TB
• The homeless
• Injecting drug users and some high risk users
  (eg crack cocaine)
• Health care workers with high exposure to
  TB

Question 7

TB should be considered in any
individual from a high risk group
presenting with…? (4)

Answer 7

• Unexplained cough
• Chest infection
• Febrile illness
• Resistant to simple antibiotics

Question 8

Symptoms of Pulmonary Tuberculosis (5)

Answer 8

• Cough
• Tiredness and Malaise
• Weight Loss and Anorexia
• Fever (low grade)
• Haemoptysis
• Breathless if Pleural Effusion

Question 9

Signs of Respiratory Tuberculosis (6)

Answer 9

• Pallor
• Fever
• Weight loss
• Finger clubbing in long standing disease
• Wheeze (possible)
• Palpable cervical lymph nodes in up to
  10% of patients

Question 10

What is Tuberculous Empyema?

Answer 10

A chronic, active infection of the pleural space that contains a large number of tubercle bacilli

Question 11

Investigations for Tuberculosis (6)

Answer 11

• Chest X-Ray
• Sputum test for acid-fast bacilli
• Bronchoscopy
• Lavage
• Biopsies
• More detailed imaging

Question 12

What can be seen on a Chest X-Ray of a TB patient?

Answer 12

Pulmonary Shadowing which may be:
* Patchy solid lesions
* Cavitated solid lesions
* Streaky fibrosis

Question 13

Treatment of Tuberculosis

Answer 13

• Steriods
• Antibiotics

Question 14

What is the 1st Line of Antibiotics to Treat TB?: First 2 Months (4)

Answer 14

• Rifampicin
• Isoniazid
• Pyrazinamide
• Ethambutol

Question 15

What is the 1st Line of Antibiotics to Treat TB?: * Continuation past 4 Months (2)

Answer 15

• Rifampicin
• Isoniazid

Question 16

What is MDR-TB?

Answer 16

• Multidrug-Resistant Tuberculosis (MDR-TB)
• Resistance to Isoniazid and Rifampicin

Question 17

What individuals at increased risk of drug resistant TB? (5)

Answer 17

• Contacts of patients with drug resistant TB
• Individuals from areas where prevalence of
  drug resistant TB is high
• Persons whose smears remain positive after
  therapy
• Persons receiving inadequate treatment for
  more than 2 weeks
• Patients with HIV

Question 18

What is cornerstone of TB control? Why?

Answer 18

• Contact Tracing
• Because they detect new TB cases and
  prevent future cases

Question 19

Concentric circle approach to contact investigations (3)

Answer 19

• Household
• Workplace
• Leisure

Question 20

TB Prevention and Control Measures (5)

Answer 20

• Active case management
• TB contact screening
• New entrant screening
• Treatment of latent TB
• BCG vaccination