Outcomes of Inflammation

Question 1

Outcomes of acute inflammation

Answer 1

Resolution (turns back to normal)…only if short lived, lack of major tissue destruction and capable of regeneration

Healing by connective tissue replacement (fibrosis, scarring)…occurs when substantial tissue destruction occured or incapable of regneeration

Abscess formation

Chronic inflammation

Question 2

Abscess formation

Answer 2

Result of suppurative inflammation from pus which is neutrophils, necrotic cell debris and exudate

Particularly from infections from pyogenic organisms (staphylococcus)

Neutrophils in pus secrete enzymes that can destroy tissue

Cavity filled iwht pus and dead microorganisms…band of neutrophils surrounds

Question 3

Outcomes of abscess

Answer 3

Collapse of cavity and scar formation

If not possible, microbes will break out of abscess and disseminate via bloodstream (sepsis)

Question 4

How can chronic inflam occur

Answer 4

From acute

OR in absense of acute which starts as low grade

Question 5

3 ways chronic inflam can start as low grade

Answer 5

Persistent infections by certain microbes…low toxicity won’t initiate acute

Prolonged exposure to certain toxins

Autoimmune dz - own tissue antigens generate abnormal, harmful immune response

Question 6

Characteristics of chronic inflam

Answer 6

Tissue infiltration by mono nucleated vs. poly from acute
Destruction caused by these cells
Healing by fibrosis

Question 7

Macrophage

Answer 7

Most important cell of chronic - tissue repair, fibrosis, secretes mediators

Question 8

Start of chronic inflammation

Answer 8

When monocyte becomes predominant cell type extravasating (about 48 hours after onset)…repleaces neutrophil

Question 9

Macrophage activated by

Answer 9

Classical pathway - inferferon gamma elaborated by T-lymphocytes…non-immunological endotoxins

Alternate pathway - cytokines other than interferon gamma

Question 10

Lymphocytes and chronic inf

Answer 10

Secrete lymphkines that activate macrophages…activated macrophages secreted monokines that activate lymphocytes…..so and so forth “vicous cycle”

Question 11

Plasma cells and chronic inf

Answer 11

Antibody productoon

Question 12

Granulomatous inflammation

Answer 12

Distinctive type of chronic inf characterized by granulomas in tissue…focal aggregate of macrophages

Question 13

Immune gradnuloma forms when

Answer 13

Macrophages phagocytose a substance they are unable to degrade (TB, syphilis)

Indigestible substance is immunogenic (induces cell-mediated immune response by T-lymphocytes)…results in transformation of macrophages into epithelioid cells

Question 14

Morephologic - immune granuloma

Answer 14

Epithelioid cells - macrophages that look like epithelial cells
Langhans giant type cells - huge cells that are fusion of epithelioid macrophages (lots of nuclei around edges)
Necrosis - granuloma may have necrotic center
Could have other cell types as well

Question 15

Foreign body granuloma

Answer 15

From substances too large to be phagocytosed in a single macrophage…substances NOT capable of eliciting T cell mediated response

Talc, asbetos, silica, surgical suture

Question 16

Morphological differences of foreign body granuloma

Answer 16

Giatn cells have nuceli arranged randomly throughout cytoplasm
May or may not have other inflammotry cell collar
Foreign body material materail can usually be visualized

Epithelioid ARE still found