wk1: AED - Inflammation Flashcards
Name 7 causes of inflammation
Hypoxia
Chemicals and Drugs
Physical Agents
Microbiologic Agents
Immunological Agents
Genetic Defects
Nutritional imbalances
(so same as in cell injury)
Name 5 classic signs of inflammation
Redness, Heat, Swelling, Pain, Loss of function
What 3 processes can be activated by cellular injury? Can they all be activated at once?
- Mast cell degranulation
- Activation of plasma systems
- Release of cellular components
Any number of these may be activated in cellular injury (1-3). They may also activate in varying amounts (e.g. more or less mast cell degranulation)
What specific plasma systems can be activated by cellular injury? [3]
Complement system
Clotting system
Kinin system
How can cellular injury affect blood vessels?
Vasodilation
Increase vascular permeability (vessels become leaky, can result in oedema and pain)
Cellular infiltration (pus. If neutrophils)
Thrombosis (clots)
Stimulation of nerve endings (causing pain, itch)
Describe the basic immune response for the following:
A: Bacterial infection
B: Immunological/hypersensitivity injury
C: Physical trauma
D: Viral infection
A: toxins, many neutrophils
B: more eosinophil and basophil involvement
C: more oedema, haemorrhage
D: NKT cells, T cells, sometimes haemorrhagic
How might chronic inflammation arise? [2]
Failure to remove injurious agent
Failure to remove by-products of infl. response (exudate) which are now invoking infl. themselves
What is a good indicator for chronic inflammation?
Presence of lymphocytes/plasma cells and macrophages (a feature of a primary cell-mediated immune response)
In what type of inflammation might you see granuloma formation? Acute or chronic?
Chronic. A granuloma is a collection of macrophages that forms when the immune system attempts to wall off substances perceived as foreign but is unable to eliminate
In what type of inflammation might you see giant multinucleated cells? Acute or chronic?
Chronic
What happens to successful cell recovery in acute inflammation when cells cannot regrow?
Healing by repair - results in scar formation and loss of specialised function of the cells.
Describe Mast Cells in terms of their:
- appearance
- when they are prevalent
Particularly prevalent in allergy-driven hypersensitivity. Histologically similar to basophils (apart from lacking bi-lobed nucleus), characteristic blue stain, granular appearance
Describe Basophils in terms of their:
- appearance
- when prevalent
Less common than eosinophils in the eye. But demonstrated in acute allergy-driven conjunctivitis. Similar to mast cells but nucleus is bi-lobed
Describe Eosinophils in terms of their:
- appearance
- prevalence
Particularly prevalent in allergy-driven hypersensitivity and helminth infection. Like basophils, also have a bi-lobed nucleus
Describe Neutrophils in terms of their:
- prevalence
Major cell type of inflammatory response, most prevalent in bacterial infections
What is Anterior Ischaemic Optic Neuropathy? Describe its clinical features
Is a disorder of the posterior ciliary artery. Characterised by: acute oedematous reaction + haemorrhage (splinter) of papillary vessels
In hypoxia, what signs are there of acute inflammation taking place? [2]
significant loss of RGCs and retinal thinning
In trauma (lacerating injury), what signs are there of acute inflammation taking place? [4]
Swelling and redness
Extensive haemorrhage
Plasma exudation
Oedema
Do lacerating lesions always involve neutrophils as part of the acute inflammatory response?
No. Neutrophils will only get involved if the lesion becomes infected
In a bacterial corneal ulcer, what signs are there of acute inflammation taking place? [4]
inflammatory response involves neighbouring tissues (b/c no corneal blood supply)
Neutrophil exudation from iris blood vessels – forms hypopyon (that white meniscus thing)
Redness and oedema of conjunctiva – vasodilation and junctional loosening
Migration of Neutrophils
In a bacterial infection of conjunctiva, what signs are there of acute inflammation taking place? [2]
Epithelial oedema (chemosis)
Neutrophil invasion (of neutrophils from substantia propria invading into epithelial layers)
In a chemical corneal injury, what signs are there of acute inflammation taking place? [1]
Neutrophil infiltration from ocular surface vessels (driven by “chemoattractants” released by injured corneal tissue)
How might a chemical toxicity injury vary in severity?
Based on if chemical is acidic or alkaline: Acidic = milder, Alkaline = more severe
How might corneal perforation occur as a result of chemical toxicity?
Direct toxic damage exacerbated by proteases released by neutrophils may contribute to corneal perforation
What signs are there of acute inflammation taking place in membranes?
fibrinous exudate following acute inflammation - pseudomembrane is not firmly attached to underlying epithelium, while true membrane is
In anterior uveitis, what signs are there of acute inflammation taking place?
initial infl. = neutrophil exudation from uveal vessels
later stage infl = largely macrophage response
How can we differentiate between acute and chronic uveitis?
They differ in their keratic precipitates, which differ in size and colour - reflecting different cell types
How does chronic non-granulomatous anterior uveitis present pathologically? [2]
Keratic precipitates largely consisting of macrophages and lymphocytes (not neutrophils as in acute anterior uveitis)
Chronic infl. in iris leads to ischaemia + atrophy of iris stroma + dilator muscle
How common is inflammation of the episclera?
Relatively common
In episcleritis, what signs are there of chronic inflammation? [1]
infiltrate of lymphocytes/plasma cells
How does chronic granulomatous conjunctivitis present pathologically? [2]
Distinct sub-epithelial granulomatous regions - epithelioid cells and multinucleated/giant cells surround fibrous “wall” of tissue
Lymphocytes also present
What is chronic granulomatous inflammation secondary to? (i.e. what causes it?)
Blocked meibomian gland (chalazion)
What type of mediated response occurs in vernal keratoconjunctivitis?
acute, IgE mediated response
How does vernal keratoconjunctivitis affect the inner eyelid?
“cobblestone” papillae accumulations of eosinophils and some basophils (often indicative of an allergic response)
What happens to the choroid and retina following repair/healing from a case of toxoplasmosis?
Toxoplasma cysts form in choroid and retina following repair. Note: that reactivation of toxoplasmosis may occur in future
(*slide has a good retinal image showing this)
