Chronic Inflammation Flashcards Preview

ESA2 - Mechanisms Of Disease > Chronic Inflammation > Flashcards

Flashcards in Chronic Inflammation Deck (51)
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1
Q

What are the dominant cell types in acute and chronic inflammation?

A
  • ACUTE - neutrophil

- CHRONIC - macrophage

2
Q

How can chronic inflammation arise from injury?

A
  • Prolonged injury where the injurious agent is not removed quickly will cause chronic inflammation after a few hours
  • Such agents include microorganisms, necrotic tissue, foreign bodies and antigens produced during an autoimmune disease
3
Q

In what ways can chronic inflammation arise? (3)

A
  • Takes over from acute inflammation
  • Begins without any preceding acute inflammation
  • Develops alongside of and is superimposed on acute inflammation
4
Q

Describe one event where chronic inflammation could develop alongside and superimpose on acute inflammation

A

Ongoing bacterial infection

5
Q

State 3 events where chronic inflammation can occur without a preceding acute inflammation

A
  • TUBERCULOSIS
  • Rheumatoid arthritis
  • Prolonged exposure to some toxic agents e.g. Silica
6
Q

What are macrophages derived from and where are the derived cells produced?

A
  • BLOOD MONOCYTES
  • Produced in the bone marrow and circulate in blood for ~6 days
  • Enter tissues and become macrophages (remain dormant until activated and can live for months)
7
Q

What are the main functions of macrophages?

A
  • Phagocytosis
  • Presentation of antigens to T lymphocytes
  • Secretion of substances to activate other cells
  • Stimulate angiogenesis
  • Induce FIBROSIS
8
Q

Name 3 properties of macrophages that neutrophils do not have

A
  • Can replicate
  • Presentation of antigens to immune cells
  • Induce fever by producing PYROGENIC CYTOKINES
9
Q

Name the types cells that are seen in chronic inflammation (5)

A
  • Macrophages
  • T and B Lymphocytes
  • Myo/fibroblasts
  • Giant cells
  • Eosinophils
10
Q

What are the roles of T and B lymphocytes in chronic inflammation?

A
  • Killer cells (cytotoxic T cells and natural killer)
  • Processing antigens
  • Produce antibodies (B lymphocytes that differentiate into plasma cells)
  • Secretion of cytokines to influence other inflammatory cells
11
Q

Where are eosinophils found and what is their function?

A
  • Normally present scattered throughout tissues

- Attack large parasites and are involved in hypersensitivity immune response (asthma)

12
Q

What is the role of fibroblasts in chronic inflammation?

A
  • Secrete extracellular matrix consisting of collagen, GAGs and elastin
  • Can differentiate into myofibroblasts and contract which is important in wound healing
13
Q

How are fibroblasts similar to leucocytes?

A

Both can respond to chemotacic stimuli and move to sites where most needed

14
Q

What are giant cells and where are they usually seen?

A
  • Under certain circumstances, macrophages fuse together to form large single multinucleate cells
  • Seen in granulomatous inflammation
15
Q

Name the 3 types of giant cells and state where you would find them

A
  • Langhans giant cells - tuberculosis
  • Foreign body giant cells - when a hard to digest foreign body is present
  • Touton giant cells - fat necrosis or xanthomas
16
Q

Describe the appearance of a Langhans cell

A
  • Large cell with multiple nuclei arranged in a horseshoe shape at the periphery
  • Seen in TUBERCULOSIS
17
Q

Describe the appearance of a foreign body giant cell and state its function

A
  • Large cell with multiple nuclei randomly arranged

- Phagocytose small foreign bodies and stick to surface of larger foreign bodies

18
Q

Describe the appearance of touton giant cells and where they are commonly found

A
  • Nuclei arranged in a ring towards the centre of the cell
  • Form in LESIONS where there is a high lipid content (fat necrosis)
  • Lesions may contain FOAM CELLS where macrophage cytoplasm appears foamy due to phagocytosis of lipids
19
Q

Which of the 4 signs of acute inflammation persist in chronic inflammation?

A
  • TUMOR (swelling) and DONAR (pain) persist

- Ruber (redness) and Calor (heat) both resolve

20
Q

What is fibrosis and how does it occur?

A
  • Excess of fibrous tissue
  • Fibroblasts stimulated by cytokines to produce excess collagen
  • Helpful at first but if excessive this could impair the function of the organ
21
Q

Describe how fibrosis can lead to impaired function of an organ

A
  • Excessive fibrosis may lead to replacement of parenchymal tissue and impair function
  • Myofibroblasts if parent in excess may cause further problems by slowly contracting, which may restrict blood flow to organ
22
Q

How can the immune system cause chronic inflammation which results in a disease?

A
  • AUTOIMMUNE response
  • Immune system begins attacking inappropriate targets such as body’s normal tissues, so resulting inflammation becomes disease process (e.g. Graves’ disease)
23
Q

What is granulomatous inflammation?

A

Type of chronic inflammation where granulomas are seen

24
Q

Describe the appearance of a granuloma

A
  • Large pale stained structure containing free or phagocytised foreign bodies/bacteria at centre
  • Eosinophilic cytoplasm, high proportion of macrophages (giant cells) and epithelioid cells
25
Q

What are the two types of granulomas that are typically seen?

A
  • Foreign body granulomas

- Hypersensitivity or immune type granulomas

26
Q

How do immune type granulomas differ from foreign body type granulomas microscopically?

A
  • Immune type granulomas contain LYMPHOCYTES
  • Have more prominent epithelioid cells
  • Form around antigenic insoluble material that cause cell mediated immunity
27
Q

Describe the contents of a foreign body granuloma

A
  • Develop around NON-ANTIGENIC material e.g. surgical threads
  • Cells, including macrophages, foreign body giant cells, epithelioid cells, some fibroblasts at periphery
  • NO LYMPHOCYTES
28
Q

How can immune type granulomas be harmful?

A

Can impair organ function as they can develop in parenchymal tissue and occupy parenchymal space within the organ

29
Q

Name 4 diseases where immune type granulomas may be seen

A
  • Tuberculosis
  • Crohn’s disease
  • Sarcoidosis
  • Wegener’s granulomatosis
30
Q

What cell types are present in immune type granulomas?

A
  • Macrophages
  • Langhans type giant cells
  • Epithelioid histiocytes
  • Lymphocytes
  • Some fibroblasts
31
Q

What are epithelioid histiocytes?

A
  • MODIFIED MACROPHAGES
  • Elongated and tightly packed so resemble epithelia
  • Contain eosinophilic cytpplasm and are present in granulomas
32
Q

What are immune type granulomas capable of which doesn’t occur in foreign body granulomas?

A
  • Can undergo CENTRAL NECROSIS

- Particularly seen in granulomas associated with tuberculosis

33
Q

Name 3 idiopathic diseases associated with chronic inflammation

A
  • Crohn’s disease
  • Sarcoidosis
  • Wegener’s granulomatosis
34
Q

What is chronic cholecystitis and how does it occur?

A
  • Chronic inflammatory disease of the gall bladder
  • Caused by repeated obstruction of the cystic duct by gall stones, causing repeated acute inflammation which can progress to chronic
  • Fibrosis of the gall bladder wall can occur
35
Q

Name 3 structures that can be affected in sarcoidosis

A
  • Lungs
  • Lymph nodes
  • Skin
36
Q

Name 2 entities that may be present in the lungs in milliary tuberculosis

A
  • Ghon lesions

- Ranke complexes

37
Q

Where can TB commonly spread from the lung?

A

Lymph nodes

38
Q

List 3 differences between ulcerative colitis and Crohn’s disease

A
  • UC affects mucosa and submucosa; CD is transmural
  • UC affects mainly distal colon and does not affect anus; CD affects the anus and can affect more than one section of bowel
  • CD can present with cobblestone mucosa, strictures and/or fistulae
39
Q

What is a systemic consequence of rheumatoid arthritis?

A

AMYLOIDOSIS of organs

40
Q

Describe how atrophy of the gastric mucosa commonly occurs

A

Accumulation of lymphocytes due to cell mediated immunity leads to destruction of the gastric wall

41
Q

Explain how gastric ulceration occurs

A

Imbalance between the production of gastric acid and mucus defence leads to ulceration of the gastric wall

42
Q

Name one acute and one chronic cause of gastric ulceration

A
  • ACUTE - alcohol/NSAIDS

- CHRONIC - Helicobacter pylori

43
Q

Describe the appearance of a cirrhotic liver

A

Hard, shrunken liver with nodules of attempted regeneration surrounded by bands of collagen, where excessive fibrosis has occurred

44
Q

How does mycobacterium tuberculosis cause disease?

A
  • PERSISTENCE

- Induces cell mediated immunity which can cause damage to normal tissue

45
Q

Name 8 examples of diseases where granulomas may be present

A
  • TB
  • Leprosy
  • Crohn’s disease
  • Sarcoidosis
  • Cat scratch disease
  • Wegener’s granulomatosis
  • Chronic granulomatous disease
  • Syphyllis
46
Q

What are the two types of granuloma that can form? Give examples of when these may occur

A
  • Hypersensitivity/immune type (develop around insoluble but antigenic material triggering cell mediated immunity e.g. TB)
  • Foreign body type (develop around material that is non-antigenic e.g. surgical thread)
47
Q

Describe the significance of granuloma formation in removal of foreign bodies/tough bacteria

A
  • Granuloma forms around the foreign body and walls it off from the surrounding parenchymal tissue (minimises tissue injury)
  • Concentrates mononuclear cells at its centre to destroy the particle
48
Q

When do granulomas form?

A
  • When the body attempts to deal with particles which are poorly soluble or difficult to eliminate
  • May also be idiopathic (have no known cause)
49
Q

What are epithelioid histiocytes?

A
  • Immobile modified macrophages with eosinophilic granular cytoplasms, usually found within granulomas
  • Assist in phagocytosis and destruction of foreign bodies
  • Elongated and appear tightly packed (similar to appearance of epithelia)
50
Q

What is a germinal centre?

A

Accumulation of B lymphocytes within lymph nodes which are undergoing proliferation, differentiation and maturation of antibodies

51
Q

What are eosinophils? Describe their appearance and action

A
  • Bright pink granular cytoplasm with a bilobar nucleus

- Attack large parasites and are involved in hypersensitivity reactions