MOD 3 Chronic Inflammation

Question 1

What are the clinical signs of chronic inflammation?

Answer 1

Swelling and pain persist but heat and redness resolve.

Question 2

When does chronic inflammation arise?

Answer 2

1. After acute inflammation
2. A chronic insult e.g. TB (without acute inflammation first)
3. Alongside acute inflammation e.g. in a bacterial infection.

Question 3

What is the predominant cell type in chronic inflammation?

Answer 3

Macrophages

Question 4

What are macrophages called before they leave the blood?

Answer 4

Monocytes

Question 5

How do macrophages differ from neutrophils?

Answer 5

Kidney bean shaped nucleus
Larger in size
Can divide
Can make more granules

Question 6

What are the functions of macrophages?

Answer 6

1. Phagocytosis
2. Antigen-presentation
3. Cytokine production
4. Stimulating angiogenesis e.g. via VEGF secretion
5. Induction of fibrosis
6. Induction of acute phase response and cachexia and fever

Question 7

What are the functions of lymphocytes?

Answer 7

Plasma cells make antibodies
Making cytokines
Killing cells e.g. cytotoxic T cell

Question 8

What are the functions of myo/fibroblasts?

Answer 8

1. To secrete collagen and lay down extracellular matrix
2. To contract and reduce wound size

Fibroblasts also respond to chemotaxins, moving towards them.

Question 9

What are the three types of giant cell?

Answer 9

Langhans - seen in TB
Touton - seen in fat necrosis
Foreign Body - seen where foreign bodies are present e.g. silicone breast implants leaking

Question 10

Why and how do giant cells form?

What are they made of?

Answer 10

Form in response to FRUSTRATED PHAGOCYTOSIS. They are made of many macrophages grouped together.
Giant cells can be seen in areas of granulomatous inflammation.

Question 11

How do the different giant cells look under the microscope?

Answer 11

Toulon - Nuclei in central cluster
Langhans- Nuclei around periphery of giant cell
Foreign Body - Nuclei randomly arranged

Question 12

What is meant by fibrosis?

Answer 12

The deposition of excess fibrin caused as a response to injury.

Question 13

What is granulomatous inflammation?

Answer 13

Chronic inflammation with granulomas present

Question 14

What is a granuloma?

Answer 14

A group of epithelioid histiocytes that are immobilised, with associated lymphocytes and giant cells roughly 1mm in diameter.

Question 15

What causes granulomatous inflammation?

Answer 15

Frustrated phagocytosis of difficult objects e.g. thorns or ‘tough’ bacteria e.g. mycobacterium tuberculosis / leprae

Question 16

What are the two main types of granuloma?

Answer 16

FOREIGN BODY
Don't have many lymphocytes.
HYPERSENSITIVITY/IMMUNE
Have many lymphocytes.
Have an area of central necrosis e.g. in TB

Question 17

How can TB be distinguished from sarcoidosis? Microscopy & clinical tests acceptable.

Answer 17

Caseous necrosis in TB with Langhans cells
Using acid fast stain, Mycobacterium may be seen in TB
Mycobacterium can be cultured in TB from sputum
Hypercalcaemia / elevated ACE in sarcoidosis