Chronic Inflammation

Question 1

Define chronic inflammation

Answer 1

Prolonged inflammation with associated repair

Question 2

What are the characteristic of chronic inflammation

Answer 2

• delayed onset
• limits damage and initiates repair
• variable appearance (NO 5 CARDINAL FEATURES)
• duration lasts from days to years
• can cause debilitating symptoms

Question 3

How does chronic inflammation arise (3 possibilities)

Answer 3

1) Taking over acute inflammation (resolution not possible from acute)
2) Develop alongside acute inflammation (severe/persistent irritation)
3) “De novo” (without preceding acute e.g. autoimmune)

Question 4

Macrophage (describe appearance and function)

Answer 4

• appearance: large, abundant foamy cytoplasm (from phagolysosome) with occasional slipper shaped nucleus
• functions: phagocytosis, antigen presentation, synthesis and release of mediators

Question 5

Lymphocytes (describe appearance and function)

Answer 5

• appearance: smaller cells (bigger than RBCs) with spherical nucleus and thin rim cytoplasm
• function: T cells can be helper (assist inflammatory cells) or cytotoxic (destroy pathogen directly); B cells mature to plasma cells

Note: can’t distinguish between B or T cell on appearance (use immunohistochemistry)

Question 6

Plasma cells (describe appearance and function)

Answer 6

• appearance: eccentric nucleus with ‘clock face’ chromatin and peri-nuclear white clearing (golgi)
• function: produce antibodies

Question 7

Eosinophils (describe appearance and function)

Answer 7

• appearance: bi-lobbed nucleus with a granular cytoplasm that looks red (H+E stain)
• function: release variety of mediators, hypersensitivity reactions and parasitic infections

Question 8

Giant cells (describe appearance of the three types and function)

Answer 8

1) Foreign body giant cell = randomly arranged nuclei
2) Langhans giant cell = nuclei lined up around periphery
3) Touton giant cell = nuclei found in the centre forming a ring

These are multinucleate cells from fused macrophages
To increase effectiveness of phagocytosis

Question 9

What are the problematic effects of chronic inflammation?

Answer 9

1) Fibrosis - deposition of excess collagen
2) Impaired function e.g. liver cirrhosis
3) Atrophy
4) Stimulation of immune response = autoimmune

Question 10

What is granulomatous inflammation?

Answer 10

A specific chronic inflammation that involves granulomas

Question 11

What is a granuloma?

Answer 11

A collection of epithelium histiocytes (macrophages that looks like epithelial cells) with surrounding lymphocytes

Question 12

What are the causes of granulomatous inflammation?

Answer 12

1) Foreign body reaction
2) Infections e.g. TB
3) Idiopathic e.g. sarcoidosis, Crohn’s disease

Question 13

Differences between Crohn’s disease and Ulcerative colitis

Answer 13

• CD can affect all of GI; UC only affects large bowel
• CD discontinuous patches of inflammation (skip lesions); UC is continuous
• CD affects full thickness of bowel wall; UC only affects superficial bowel wall
• CD less likely for rectal bleeding; UC more likely to have rectal bleeding
• CD can find granulomata; UC no granulomata