MOD Week 3 chronic inflammation

Question 1

Define chronic inflammation

Answer 1

Chronic response to injury with associated fibrosis

Question 2

How is chronic inflammation linked to acute inflammation

Answer 2

If damage is irreversible then chronic inflammation may occur to result in repair and scarring. This can also occur through chronic insult, such as autoimmune, hypersensitivity reactions, or chronic infections such as viral hepatitis

Question 3

What is the difference in cell types visible with chronic and acute inflammation

Answer 3

Chronic inflammation has many macrophages and lymphocytes, whereas acute inflammation is mainly neutrophils.

Question 4

Describe the role of macrophages in chronic inflammation

Answer 4

They circulate dormant in the blood until activated in an inflammation reaction, where they then travel to the site of inflammation to take over from neutrophils.
Also perform phagocytosis and are antigen presenting, stimulate angiogenesis, induce fibrosis and induce fever, acute phase reaction and cachexia (weakening and wasting of whole body).

Question 5

What two functions do T lymphocytes have?

Answer 5

Control (CD4+)
Cytotoxic function (CD8+)

Question 6

Is chronic inflammation stereotyped?

Answer 6

No. Heterogeneous.

Question 7

Where are T lymphocytes released from?

Answer 7

Thymus

Question 8

What are plasma cells?

Answer 8

Differentiated B lymphocytes with abundant cytoplasm to produce antibodies. Can be told apart by “clock-faced chromatin” down microscope.

Question 9

Are eosinophils normally seen in the body?

Answer 9

Yes, with larger numbers in chronic inflammation

Question 10

What are the roles of fibroblasts and myofibroblasts

Answer 10

Making collagen and connective tissue substances including elastin and GAGs
Respond to chemotactic stimuli to move to sites

Question 11

What does presence of plasma cells in blood samples indicate?

Answer 11

Considerable chronicity (chronic inflammation)

Question 12

What is a giant cell?

Answer 12

A cell formed when many macrophages fuse together to form a GIANT cell. They have many nuceli due to frustration of macrophages from too much phagocytosis requirement.

The type of giant cell present can help to aid diagnosis

Question 13

Describe a Langerhans giant cell and when it is most commonly seen

Answer 13

Foamy granular cytoplasm with nuclei at periphery.

Seen in TB

Question 14

Describe a foreign body giant cell and when it is most commonly seen

Answer 14

Nuclei are random within the cell.
Seen when a foreign body is present which is hard to ingest, so putting stress on macrophages. If the foreign body is small enough then it is ingested. If not, then the foreign body sticks to the cell surface.

Question 15

Describe a Touton giant cell and when it is most commonly seen

Answer 15

Nuceli are arranged in a ring towards the centre of the cell
Seen in regions of high level fat necrosis and xanthomas. In the blood sample, there will also be foam cells present as macrophages will have phagocytised a lot of lipid.

Question 16

What are the three times when acute inflammation can occur?

Answer 16

1. taking over form acute inflammation
2. without preceding acute inflammation (chronic infection or autoimmune condition) DE NOVO
3. alongside acute inflammation as an ongoing bacterial infection

Question 17

What are the possible complications of chronic inflammation?

Answer 17

Fibrosis and impaired function:

• Fibrosis is an excess of fibrous tissue
• Excess collagen produced replaces parenchymal tissue, This impairs organ function.
• If the area contains enough myofibroblasts then the area can contract to cause further problems.

Involvement of inappropriate immune responses:

• Immune system uses inflammation as non-specific weapon
• Can attack innocuous targets, such as pollen
• Can attack normal body tissue in an autoimmune reaction. The resulting chronic inflammation becomes disease.

Question 18

What is granulomatous inflammation?

Answer 18

Occuring at the same time as healing occurs, when chronic inflammation is accompanied by granulomas.

Question 19

What is a granuloma?

Answer 19

Aggregation of macrophages , adapted to look like epithelia. This means they are elongated with eosinophillic cytoplasm and are tightly packed together (hence called epithelioid cells). They form around particles which are difficult to digest and get rid of; with some walling around the edge whilst others in the centre destroy the particle.

Question 20

What are the two types of granuloma?

Answer 20

Foreign body- containing macrophages, foreign body giant cells, epithelioid cells, fibroblasts and a few lymphocytes. They develop around things which are not antigenic e.g. surgical thread.

Hypersensitivity- containing macrophages, langhan giant cells, some fibroblasts at periphery and a few lymphocytes. There is central necrosis observed (for example in TB and leprosy) and they develop around insoluble, antigenic particles, causing cell mediated immunity. This type of granuloma is seen in sarcoidosis, Wegner’s granulomatosis and Crohn’s disease. When a granuloma occupies parenchymal space in an organ it is harmful.

Question 21

Do the granuloma and type of giant cell have to match?

Answer 21

No!

Question 22

What are the effects of chronic inflammation?

Answer 22

Fibrosis (cirrhosis) , impaired function (chronic IBS) , atrophy (gastric mucosa), stimulation of immune response (macrophage-lymphocyte interactions)

Question 23

Describe chronic cholecystitis

Answer 23

Repeated obstruction by gall stones and repeated acute inflammation leads to chronic inflammation and fibrosis of gall bladder wall

Question 24

Describe gastric ulceration

Answer 24

Ulceration occurs due to imbalance of acid production and mucosal defence.
Acute gastritis is due to alcohol or drugs (such as aspirin)
Chronic gastritis is due to helicobacter pylori infections

Question 25

What is a characteristic feature of the bowel in IBS?

Answer 25

Coblestone appearance

Question 26

What is the difference between UC and Crohn’s

Answer 26

Ulcerative colitis is superficial and presents with diarrhoea and rectal bleeding
Crohn’s disease is transmural (full thickness of bowel wall) and contains strictures (narrowing) and fistulae (abnormal connection between two epithelium-lined organs).

Question 27

What are the steps leading to cirrhosis

Answer 27

Chronic inflammation with fibrosis
disorganisation of architecture and attempted regeneration
leading to cirrhosis

Question 28

What would be present in a tuberculous granuloma?

Answer 28

Langerhan's type giant cell 
Central caseous necrosis 
Lymphocytes
Epithelioid histoctyes (modified, immobile macrophages)

Question 29

Describe sarcoidosis

Answer 29

Young adult women present with persistent cough and variable other symptoms. Non-caseating granulomas, giant cells
Involving the lymph nodes and lungs