Chronic Inflammation 2 Flashcards
What is granulomatous inflammation characterised by?
presence of granulomas in tissues and organs
What is granulomatous inflammation stimulated by?
indigestible antigen that the body can’t get rid of
Why are granulomatous inflammatory diseases important on a global scale?
granulomatous inflammatory diseases are infectious and idiopathic
What are granulomas?
aggregates of epithelioid macrophages
may contain giant cells, neutrophils, eosinophils
may surround dead material and be surrounded by lymphocytes
When are granulomas made?
in response to indigestible antigen
many due to type IV hypersensitivity reactions
What are epithelioid macrophages?
macrophages that look like epithelial cells
What are giant cells?
comprised of epithelioid histioytes (macrophages)
? fusion of macrophages to form larger cells
have large cytoplasm; multiple nuclei
What are Langerhans type giant cells?
classically found in TB
peripheral rim of nuclei
large eosinophilic cytoplasm
What are foreign body type giant cells?
often associated w/ pyogenic granulation tissue (acutely inflamed, neutrophils, pus, organisation, giant cells), e.g. pilonidal abscess
How would you get a silicone associated giant cell?
ruptured silicone implants
usually but not always breast, vacuoles contain leaked silicone
classically small bubbles in giant cells
When would you find a Warthog-Finkeldy type giant cell? and what does it look like?
In appendices of children w/ measles
Has central cluster of nuclei, cytoplasm on outside
Give examples of granulomatous diseases.
mycobacterium tuberculosis - tuberculosis
mycobacterium leprae - leprosy
treponema pallidium - syphilis
Describe granulomas found in lung of TB patients.
most primary infections of TB occur in the lung
lumps of white material are granulomas
What is caseous necrosis?
dead tissue surrounded by macrophages, giant cells, lymphocytes
In what disease is TB a common secondary infection?
HIV
Give examples of non-infectious granulomas.
Rheumatoid disease - tissue specific autoimmune disease
sarcoidosis
Crohn’s disease - chronic inflammatory bowel disease
What is a rheumatoid nodule formed of?
Degenerate collagenous material in the middle, macrophages at edge of area
What does Crohn’s disease look like?
Ulceration of surface of bowel, cobble stoned appearance
Muscosa lost completely and patients bowel lining is swollen, sore and raw and bleeds heavily
What are the four stages of wound healing?
phase of acute inflammation
granulation tissue formation
local angiogenesis - new vessels grow
fibrosis and scar formation
What is healing by primary intention?
occurs when tissue surfaces have been closed, e.g. surgical wounds w/ stitches or skin glue
very little tissue loss, small amount of granulation tissue
creates small linear scar
What is healing by secondary intention?
healing of larger wounds
involves loss of lots of tissue, lots of granulation tissue ingrowth
contraction and scarring
Describe in detail the events that occur from injury to scar formation.
injury, blood clot, acute inflammation, fibrin
many growth factors and cytokines involved
granulation tissue growth and angiogenesis
phagocytosis of fibrin
myofibroblasts move in and lay down collagen
contraction of scar
re-epithelialisation
What conditions favour wound healing?
Cleanliness - no debris, germs etc. apposition of edges (no haematoma) sound nutrition metabolic stability and normality normal inflammatory and coagulation mechanisms note local mediators
What conditions would inhibit wound healing?
dirty, gaping wound, large haematoma
poorly nourished, lack of vitamins A and C
abnormal carb metabolism, diabetes, corticosteroid therapy
inhibition of angiogenesis
Fracture healing follows same principles as healing at any site, how is the situation modified in bone?
have to repair bony structure as well as soft tissue
Describe the sequence of events that occur 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 is callus formation in bone?
the bony healing tissue which forms around the ends of broken bone
How are calluses formed?
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 is angiogenesis?
formation of new blood vessels from capillary buds
What growth factor stimulates angiogenesis (proliferation of blood vessel cells)? and where is the growth factor released from?
Vascular Endothelial Growth Factor (VEGF)
released by hypoxic cells (oxygen deficient)
–> enables blood supply to enter damaged tissue
What does angiogenesis and organisation in thrombosis limit and allow?
limits thrombus propagation
reinstates flow
What does angiogenesis in malignant tumours allow?
Angiogenesis occurs as tumour grows
–> potential for therapeutic control
Fibrosis and scarring in atherosclerosis
(similarities with chronic inflammation)
