TB

Question 1

describe the primary infection process with TB

Answer 1

• mycobacterium tuberculosis (MTB) causes an inflammatory response in hosts immune system
• macrophages engulf the bacteria and granuloma/tubercule (mass of tissue) is formed
• bacteria have thick waxy cell walls so resist digestion by macrophage’s lysosomes
• bacteria can survive in macrophage and person has no signs or symptoms of disease so have latent TB
• produced in response to the infection and the tissue masses are anaerobic (MTB needs oxygen to survive) and have destroyed bacteria and macrophages in the tubercules
• macrophage unable to present an antigen so no primary immune response
• after 3-8 weeks the infection is controlled and the infected region of the lungs heals

Question 2

what cells of the immune system can mycobacterium tuberculosis target and what do they do to the cells

Answer 2

• supress T cells reducing cytokine production
• B cell activation is reduced
• antibody production is reduced
• killer T cells are supressed

Question 3

what happens in the secondary (active) phase of TB

Answer 3

bacteria multiply rapidly and destroy lung tissue causing holes or cavities
reduced gas exchange due to reduced surface area of alveoli

Question 4

why does the secondary (active) phase of TB take place

Answer 4

-number of bacteria is too large
or
- immune system is weakened due to:
poor diet
age
other infections
immunosuppressive drugs

Question 5

what are the symptoms of active TB

Answer 5

• coughing up blood
• shortness of breath
• weight loss
• loss of appetite
• fever
• extreme fatigue

Question 6

what happens in glandular TB

Answer 6

TB moves to infect other parts of patients body:
bone
lymph nodes
central nervous system

Question 7

how can TB be diagnosed

Answer 7

skin tests (injecting small amounts of tuberculin)
blood tests
chest x-rays