Chronic Inflammation 2 Flashcards
What is granulomatous inflammation always characterised by?
Granulomas (granulomata) in tissues and organs
How is Granulomatous inflammation stimulated?
Stimulated by indigestible antigen, body cannot get rid of it
What are idiopathic diseases?
Diseases which we don’t know why they happened.
How are granulomas formed?
aggregates of epithelioid macrophages in tissue
What is epitheliod?
Looks like epithelial
What might granulomas surround?
Giant cells, dead material
What might granulomas be surrounded by?
lymphocytes
What do granulomas contain?
neutrophils, eosinophils
Granulomas are formed as a result of?
response to indigestible antigen
Many are type 4 hypersensitivity reactions
What do giant cells consist of?
A giant cell is a mass formed by the union of several distinct cells (usually macrophages)
Describe the structure of a giant cell?
large cytoplasm; multiple nuclei
- several types
Are there always granuloma for giant cells to be present?
no
Name a type of giant cell
Langhans type
What is a Langhans type giant cell classically found in?
TB
Describe the structure of Langhans type
peripheral rim of nuclei
large eosinophilic cytoplasm
What is the giant cell often associated with pyogenic granulation tissue
Foreign body type
acutely inflamed
neutrophils, pus
organisation
giant cells
What type of giant cell might you see with a ruptured silicone implant? e.g breast implant
Silicone associated giant cells
Vacuoles contain leaked silicone
Name some Infectious granulomatous diseases
Tuberculosis (Mycobacterium tuberculosis),
Leprosy Mycobacterium leprae
syphilis
Describe Caseous necrosis
Cell death in which the tissue maintains a cheese-like appearance. Dead tissue appears as a soft and white proteinaceous dead cell mass.
Dead tissue surrounded by macrophages, giant cells, lymphocytes
No neutrophils?
Feature of TB?
Give examples of Non-infective granulomas
rheumatoid disease - tissue specific auto-immune disease
sarcoidosis
Crohn’s disease – chronic inflammatory bowel disease
What is Sarcoidosis?
Development of granulomas within organs of the body
What are the common processes in chronic inflammation?
Acute inflammation
Granulation tissue formation
Local angiogenesis - new vessels grow
Fibrosis and scar formation
What is surgical wound healing?
Healing by primary intention
What are the goals of surgical wound healing?
Minimal gap, small amount of granulation tissue, small linear scar
What is healing of larger defects?
Healing by secondary intention
Describe the granulation tissue ingrowth in larger defects
Lots of it
Contraction and scarring
What is the sequence of events in wound healing?
- injury, blood clot, acute inflammation, fibrin
- many growth factors and cytokines involved
- granulation tissue growth - angiogenesis
- phagocytosis of fibrin
- myofibroblasts move in and lay down collagen
- contraction of scar
- re-epithelialisation
What conditions favour wound healing?
Cleanliness
Apposition of edges (no haematoma)
Sound nutrition
Metabolic stability and normality
Normal inflammatory and coagulation mechanisms
Note local mediators
What conditions result in impaired wound healing?
Dirty, gaping wound, large haematoma
Poorly nourished, lack of vitamins C, A
Abnormal CHO metabolism, diabetes, corticosteroid therapy
Inhibition of angiogenesis
What is the sequence of events in fracture healing?
Trauma, fracture, haematoma
Bits of dead bone and soft tissue
Acute inflammation, organisation, granulation tissue, macrophages remove debris
Granulation tissue contains osteoblasts as well as fibroblasts
What are the stages of callus formation?
Osteoblasts lay down woven bone
Nodules of cartilage present
Followed by bone remodelling:
osteoclasts remove dead bone
progressive replacement of woven bone by lamellar bone
reformation of cortical and trabecular bone
What stimulates proliferation of vessels?
Vascular endothelial growth factor, released by hypoxic cells, stimulates proliferation
What aids the process of angiogenesis?
Enzyme secretion
What is the benefit of angiogenesis?
Allows blood supply to enter damaged tissue
What is the effect of angiogenesis on thrombus
Grows vessels through the thrombus, limits its propagation
What is the effect of angiogenesis in malignant tumours
angiogenesis occurs as tumour grows,
potential for therapeutic control
