Mycobacterium tuberculosis

Question 1

Describe the transmission of mycobacterium tuberculosis bacteria

Answer 1

Mycobacterium tuberculosis is a droplet infection, so entry route is through respiratory tract
– MB bacteria are inhaled in water droplets and lodge in the lungs

Question 2

Describe what happens in the primary infection (latent TB) phase

Answer 2

• mycobacterium tuberculosis bacteria are inhaled
  – the bacteria multiply
  – inflammatory response provoked
  – bacteria engulfed by macrophage, bacteria lie dormant in macrophages
• a mass of tissue develops, forming a nodule called a tubercule which is anaerobic
• MBT need oxygen to survive so most die inside the tubercules
• Macrophages are unable to present antigen, the immune system is suppressed

Question 3

Describe what happens in the secondary phase of TB

Answer 3

• bacteria are rapidly multiplying and destroying the lung tissue, creating holes
• Bacteria are unable to leave tubercules and potentially spread around the body

Question 4

Why does the secondary phase take place?

Answer 4

If the immune system cannot contain the disease
- This may be due to number of bacteria being too great or weakened immune system

Question 5

What are the symptoms of active TB?

Answer 5

Coughing (sometimes with blood)
Shortness of breath
Loss of appetite
Weight loss
Fever
Extreme fatigue

Question 6

What happens in glandular TB?

Answer 6

• The bacteria moved to infect other parts of the body, e.g. blood, lymph nodes and central nervous system
• Lymph nodes in the neck or armpits can enlarge

Question 7

State the ways in which TB can be diagnosed

Answer 7

• Skin and blood tests, by injecting small amount of tuberculin
• Identification of bacteria and sputum
• Chest x-rays to identify tubercules