Chronic Inflammation Flashcards
(37 cards)
1
Q
What are the key characteristics of acute inflammation?
A
- Rapid response to any injury
- Macroscopic: redness, swelling, heat, pain and loss of function
- Microscopic: vascular dilatation, exudate into tissues and neutrophils emigrate
- Controlled by short-term chemical mediators
- Neutrophils
- fast acting
- short-lived phagocytes that engulf & degrade bacteria
- Phagocytosis by enhanced opsonisation
- Oxygen-dependent bacterial killing
- Defects in the system lead to sever susceptibility to infection
2
Q
What is chronic inflammation?
A
“Chronic response to injury with associated fibrosis”
- Different timescale to acute response but the same effectors are used
- Overlaps with host immunity
- Heavily associated with fibrosis
3
Q
What are the two routes to chronic inflammation?
A
- Acute insult -> Acute inflammation -> Severe damage -> Chronic inflammation
- Chronic insult -> Chronic inflammation
Both result in repair and fibrous scarring.
4
Q
How does Chronic Inflammation arise?
A
- May follow from acute inflammation if damage is too severe to be resolved (most common)
- De novo
- from autoimmune conditions e.g. RA
- chronic infections e.g. viral hepatitis
- “chronic low-level irritation”
- Develops alongside acute inflammation e.g. ongoing bacteria infection
- in severe persistent or repeated inflammation
5
Q
What does chronic inflammation look like?
A
Characterised microscopically which are much more variable than acute inflammation.
- Macrophages
- Lymphocytes
- Plasma cells
- Eosinophils
- Fibroblasts/ Myofibroblasts
- Giant Cells
- Langhans type giant cells (TB)
- Foreign body type giant cells
- Touton giant cell
6
Q
What are macrophages?
A
- phagocytic cells with a bean-shaped nucleus and abundant cytoplasm
- derived from blood monocytes
- become macrophages when in tissue
- in acute and chronic inflammation
7
Q
What are the functions of macrophages?
A
- Phagocytosis
- Antigen presentation
- Synthesis of:
- cytokines
- complement components
- blood clotting factors
- proteases
- Control of other cells by cytokine release
- Stimulating angiogenesis
- Inducing fibrosis
- Inducing fever, actue phase reaction and cachexia (wasting of the body)
8
Q
What are lymphocytes?
A
- Predominat cells of the immune system
- Characterised into B and T lymphocyte s
- Presence in tissue they are normally absence in indicates that some antigenic material is or has been there
9
Q
What are the functions of lymphocytes?
A
- Processing of antigens
- Secreting antibodies (carried out by differentiated B lymphocytes)
- Secreting of cytokines which influence other inflammatory cells
- Killing of cells (through natural killer cells attacking virus infected cells or tumour cells)
10
Q
What are eosinophil and when are they normally found?
A
- Cells with a double lobed nucleus with red granules.
- Found scattered throughout the tissues
- Attack large parasites such as worms
- Present in high numbers in some immune responses:
- bronchi of asthmatics
- Hodgkins lymphoma
11
Q
What are plasma cells and how are they revelant to the immune response?
A
- Differentiated antibody producing B lymphocytes.
- Confers chronic disease
- Produces imunoglobulins
12
Q
What are fibroblast and myofibroblasts?
A
- Fibroblasts are the predifferentiated from of myofibroblasts
- Fibroblasts can response to chemotaxic stimuli and move to where they are needed
- produces collagen, elastin and glucosaminoglycans.
- Myofibroblast have the ability to contract in wound healing
13
Q
What are giant cells?
A
- Macrophages fused together to produce larger cells
- caused by foreign bodies or infection with certain bacteria are present
- Large cells with dozens to hundreds of nuclei
- Seen in granulomatous inflammation
14
Q
What are the three types of giant cell?
A
- Langhan’s Giant Cells
- Touton Giant Cells
- Foreign Body Giant Cells
15
Q
Where are Langhans giant cells normally found?
A
- nuclei are arranged around the periphery of the giant cell
- normally seen in tuberculosis
- the immune system find the TB bacteria difficult to resolve
16
Q
What do foreign body type giant cells look like and where are they normally found?
A
- nuclei are arranged randomly in the cell
- often seen when there is a hard to digest foreign body
- if the foreign body is small it can be phagocytosed by the giant cell and seen within it.
- if it is large the foreign body giant cell sticks to its surface
17
Q
What do touton giant cells look like and where are they normally found?
A
- nuclei are arranged in a ring towards the centre of the cell
- form in lesions where there is a high lipid content such as fat necrosis and xanthomas
- due to fatty tissue being avascular, large marcophages are required to clean up dead fat tissue
- lesions also contain foam cells
18
Q
What are foam cells?
A
Macrophages whos cytoplasm appears foamy from phagocyting a lot of lipid.
19
Q
How can cell types in chronic inflammation aid the diagnosis?
A
Morphology of most chronic inflammatory reaction is non specfic but there are a few exceptions:
- Rheumatoid arthiritis: mainly plasma cells
- Chronic gastritis: mainly lymphocytes
- Leishmaniasis: mainly macrophages
Giant cells types also may be helpful to diagnose e.g. langhan ginat cell in TB
20
Q
What are the effects of chronic inflammation?
A
- Fibrosis and Impaired function
- blocking off of ducts e.g. cholecystitis
- replaces normal parenchymal tissue e.g. intersitial fibrosis of the lung
- absorption in chronic inflammatory bowel disease
- Stimulation of immune response
- hayfever and rheumatoid arthiritis
21
Q
What is chronic cholecystitis?
A
Repeated damage and pain of the gall bladder due to obstruction of gall stones.
- Repeated acute inflammation leads to chronic inflammation
- Gall bladder wall becomes fibrosed
22
Q
What is inflammatory bowel diesase?
A
- Idiopathic inflammatory disease affecting the large and small bowl
- Pts present with diarrhoea and rectal bleeding
- Types include:
- Ulcerative colitis
- superficial, causes diarrhoea and bleeding
- Crohn’s disease
- transmural causing strictures and fistulae
- Ulcerative colitis
23
Q
What are the common causes of liver cirrhosis?
A
- Alcohol
- Infection with HBV and HCV
- Imunnological
- Fatty liver disease
- Drugs and toxins
24
Q
What is cirrhosis?
A
Scarring. Caused by chronic inflammation with fibrosis. Structural architecture is distrupted through attempted regneration.
25
When can chronic inflammation cause increased function?
* Thyrotoxicosis
* Graves' disease - excessive production of thyroid hormone
* Autoimmune disease characterised by autoantibodies againt thyroid hormone receptor
26
When can chronic inflammation cause atrophy?
* In the gastric mucosa inflammation reduces the number of cells and their size in a tissue.
27
How does chronic inflammatio nand immune responses overlap?
1. Immune diseases can **cause** pathology by chronic inflammation
2. Chronic inflammatory processes can **stimulate** immune responses
28
What is granulomatous inflammation?
Chronic inflammation with granulomas
29
What is a granuloma?
* Cohesive localised group of inflammatory cells
* Identified by epithelioid histiocytes
* modifed immobile macrophages at the centre
* Walls off the stubborn particle with mononuclear cells
* Normally measure 0.5-1mm in diameter
30
What are the two general types of granuloma?
1. Foreign body granulomas
2. Hypersensitivity or immune type granulomas
31
What do foreign body granulomas contain?
* non antigenic material e.g. surgical threas
* macrophages
* foreign body giant cells
* epithelioid cells
* periphery fibroblasts
* lymphocytes
32
What do hypsensitivity or immune type granumlomas contain?
* central casesous necrosis (often seen in TB associated granulomas)
* develop around insoluble but antigenic particles that cause cell mediated immunity
* Contains:
* macrophages
* giant cells
* epithelioid cells
* periphery fibroblasts
* lymphocytes
* Can be harmful if occupying the paenchymal space within an organ
33
What are the causes of granulomatous inflammation?
* mildly irritant foregin material
* infections
* mycobacteria (tuberculosis, leprosy)
* fungal
* Idiopathic
* sarcoid
* Wegener's granulomatosis
* Crohn's disease
34
What is tuberculosis?
Respiratory disease cause by mycobacteria (M. tuberculosis):
* bacteria contains wall lipids
* produces no toxins or lytic enzymes
* causes disease by persistance and induction of cell-meidated immunity
35
What is sarcoidosis?
Disease involving an abnormal collection of inflammatory cells forming granulomas mainly in the lungs, skin or lymph nodes although any organ cen be affected.
* normally found in young adult women
* granulomas are non-caseating with giant cells
36
What is Crohn's disease?
Type of inflammatory bowel disease than can affect any part of the gastrointestinal tract from the mouth to the anus.
Patchy full thickness inflammation in the bowel can cause granulomas.
37
What is Wegener's granulomatosis?
Granulomatosis with polyangiitis (GPA). Polyangiitis is the systemic inflammation of small vessels.
* Mainly affects ears, nose, sinuses, kidneys and lungs
* Affects all ages but more common in middle to older aged people
* Unknown cause
