Chronic Inflammation Flashcards
Can chronic inflammation occur without acute inflammation ?
Yes
What is organisation ?
Replacement of destroyed tissue by granulation tissue.
Which factors favour resolution ?
Rapid destruction of causal agent
Rapid removal of fluid and debris by good drainage
Minimal cell death
Occurrence in tissue or organ with regenerative capability
What factors favour organisation ?
Presence of large amounts of fibrin
Consequential necrosis
Exudata and debris cannot be drained away
Which cells are present to replaces inflammatory exudate in chronic inflammation ?
- Sprouting capillaries
- Proliferation of fibroblasts
- Infiltration of macrophages (rather than neutrophils as in acute inflammation)
- Deposition of collagen
- Presence of multinucleate giant cells and plasma cells
- Layer of lymphocyte around vessels where new capillaries sprouting
Why is the appearance of a skin bruise undergoing chronic inflammation red and moist ?
Redness due to sprouting capillaries
Moist due to exudate
Who is responsible for regulating organisation ?
Growth factors (e.g. Tumour Necrosis Factor, Epidermal Growth Factor)
What different kinds of chronic inflammation exist ?
Primary and Moving from Acute Inflammation
What are examples of situations in which it is primary chronic inflammation. Give examples of conditions for these situations.
- Resistance of infective agent to phagocytosis and intracellular killing (tuberculosis, leprosy, brucellosis, viral infections)
- Foreign body reactions to endogenous materials (gout, in which metabolism is not getting rid of uric acid causing it to deposit in joints, resulting in arthritis.
- Foreign body reactions to exogenous materials (asbestos)
- Some autoimmune diseases including R. arthritis
- Specific diseases of unknown aetiology (ulcerative colitis, causing damage to gut)
- Primary granulomatous diseases (sarcoidosis, where large amounts of typically macrophages accumulate in organ/tissue and outside)
Which factors favour the progression from acute to chronic inflammation ? Give an example of a condition for each factor.
- Indigestible substances
- Deep seated suppurative inflammation without inadequate drainage by vascular or lymphatic system (possible abscess wall, granulation tissue, organisation of pus, fibrous scar). E.g. Osteomyelitis, chronic abscess in bone
- Recurrent episodes of acute inflammation and healing E.g. chronic cholecystitis (wall replaced by fibrous tissue, macrophages and lymphocytes predominate over neutrophils)
What are diagnostic symptomatic features of chronic inflammation ? Give examples of each.
- Chronic ulcer (e.g. mucosa breached)
- Chronic abscess cavity (e.g. enpyema thoracic in pleural cavity)
- Thickening of wall of hollow viscus
- Granulomatous inflammation (e.g. tuberculosis)
- Fibrosis
Which cells are present in chronic inflammation ?
Sprouting capillaries
Fibroblasts
Collagen (granulation tissue resulting in fibrosis)
Macrophages and plasma cells and lymphocytes
What are the microscopic features of :
- Macrophages
- Lymphocytes
- Plasma cells ?
- Macrophages- Either appears to have single, or lobed or bilobed. Larger armount of cytoplasm that other two. Can fuse to form granuloma/multinucleate giant cells. In chronic inflammation, may find something cause the damage in the center of those multinucleate cells.
- Lymphocytes- Not activated (naive). Large nucleus and small cytoplasm. When activated, vastly increased cytoplasm (nucleus also a little larger) to allow for antibody production.
- Plasma cells- eccentric nucleus. Activated version of B lymphocyte.
What is an example of leukocytes communicating ? How do they achieve such communication ? Why is this important ?
Macrophages with T cells and B cells to
i. activate them, so they form antibody secreting cells and/or cytokine secreting T cells)
ii. inactivate them to limit damage
Do so through direct cell contact or secretion of agents
Important to modulate and down-regulate immune response
What is the function of macrophages ?
- Phagocytosis
- Producing cytokines
How can bacteria immunoevade macrophages ?
Myobacterium tuberculosis hides inside the macrophage (wishes to be phagosytosed), then is resistance to lysosomal enzymes so become intracellular parasites.
How do microphages get activated ?
Activated on migration to area of inflammation by cells including macrophage activation factor, and migration inhibition factor which let them stay in site of inflammation.
What is the path onwards from haemoatopoietic stem cell ?
Haemoatopoietic stem cell (in bone marrow) –> promonocyte (in bone marrow) –> monocyte (in bone marrow) –> monocyte (in blood) –> different kinds in different tissues for instance Kupffer cells (liver), melanocyte (skin), osteoclast (bone), microgial cell
What is a granuloma ? A histiocyte ?
Aggregate of epithelioid macrophages
Macrophage in CT
What is the granuloma’s main function ?
Turn off phagocytic activity and instead have secretory function.
What does granuloma appear like ?
Central mutli-nucleate giant cells surrounded by epithelioid histiocytes with a peripheral rim of activated lymphocytes. In center may find caseation (necrotic center) due to infective agent or pus resulting in necrosis.
What are the usual causes of granulomatous disease ?
- Specific infections (causative agent indigestible)
- Foreign bodies (causative agent indigestible)
- Specific chemicals
- Drug
- Unknown
Give specific examples of histiocytic giant cells.
Langan’s giant cells
Foreign body type giant cell
What are distinguishing factors between acute and chronic ?
-ACUTE V CHRONIC
Neutrophil V macrophage
Quick and early V slower at later stage
Rapid full resolution V long term problems
What are distinguishing factors between exudate and transudate ?
In exudate, increased vascular permeability, net flow, and high plasma protein content
What are distinguishing factors between granulation tissue and granuloma ?
Granulation tissue: Tissue important in healing process with connective tissue and small blood vessels
Granuloma: Aggregate of macrophage-like cells (and other immune cells such as lymphocytes around)
What is the difference between fibrin and fibrous ?
Fibrin is deposited in acute inflammation
-Fibrous is a typical scar tissue with collagen
