S3: chronic inflammation & introduction to histological interpretation

Question 1

Name the three different ways by which chronic inflammation can arise

Answer 1

When it takes over from acute inflammation
When it begins without any preceding acute inflammation
When it develops alongside and superimposed on acute inflammation

Question 2

What different cells are present in chronic inflammation?

Answer 2

Macrophages
Giant cells
Lymphocytes
Eoisinophils
Fibroblasts/myofibroblasts

Question 3

Name the functions of macrophages

Answer 3

Phagocytosis
Secretion of numerous susbstances that summon and activate other cells
Antigen presentation
Stimulating angiogenesis
Inducing fibrosis
Inducing fever

Question 4

Name the functions of lymphocytes

Answer 4

Processing antigens
Secreting cytokines that influence other inflammatory cells
Killing cells (done by natural killer cells)

Question 5

What are the three different types of giant cells?

Answer 5

Langhans giant cells = nuclei are arranged around the periphery of the giant cell eg. TB
Foreign body giant cells = nuclei are arranged randomly in the cell eg. when a hard to digest foreign body is present
Touton giant cells = nuclei are arranged in a ring towards the centre of the cell eg. in lesions where there is high fat content (fat necrosis & xanthoma)

Question 6

What are giant cells?

Answer 6

Giant cells are when macrophages fuse with each other to form single cells (multiple are required to remove the foreign body)

Question 7

Name unwanted effects of chronic inflammation

Answer 7

Fibrosis and impaired function = means an excess of fibrous tissue; can replace normal parenchymal tissue and impair the function of an organ
Involvement in inappropriate immune reactions = immune system can attack innocuous targets (pollen in hay fever) or inappropriate targets such as the body’s normal tissues (autoimmune diseases)

Question 8

Describe granulomatous inflammation and the causes

Answer 8

Type of chronic inflammation in which granulomas are seen
Granuloma = a collection of epithelioid histiocytes with surrounding lymphocytes
Infections (myobacterium) = thick cell wall, mycolic acids -> caseous necrosis
Chron’s disease, sarcoidosis (eg. lymph nodes, lungs, skin) = non-caseating granulomata

Question 9

What are the two types of granulomas?

Answer 9

Foreign body granuloma = destruction and removal of foreign material, few lymphocytes, develop around material that is not antigenic
Immune mediated = destruction and removal of pathogens, can undergo central necrosis, can be idiopathic, many lymphocytes

Question 10

Describe the differences between Chron’s disease and ulcerative colitis

Answer 10

Chron’s disease = can affect all of GI tract, discontinuous patches of inflammation, affects full thickness of bowel wall, sometimes find granulomata & less likely to have rectal bleeding
Ulcerative colitis = affects large bowel only, continous inflammation, affects superficial bowel wall only (mucosa & submucosa), no granulomata & more likely to have rectal bleeding

Question 11

Name two clinical examples where fibrosis in commonly seen

Answer 11

Liver cirrhosis

Chronic cholecystitis

Question 12

Name a clinical example where atrophy is commonly seen

Answer 12

Atrophic gastritis

Question 13

Name a clinical feature seen in rheumatoid arthritis

Answer 13

Painless subcutaneous lumps on the extensor aspect of the forearm and fingers = rheumatoid nodules

Question 14

What cellular components are stained by H&E?

Answer 14

Haematoxylin = nuclei (attracted to negatively charged particles)
Eosin = cytoplasm (attached to postively charged particles)