wk4: AED - Allergy [DG] Flashcards
What is the main cause of allergic conjunctiva presentations?
Contact lens wear
In regards to type 1 immune-mediated inflammation:
- when does it occur?
- is it an immediate or delayed response?
- occurs on second or later exposures (after primary exposure)
- immediate
In regards to type 4 immune-mediated inflammation:
- when does it occur?
- is it an immediate or delayed response?
- occurs on second or later exposures
- delayed
In regards to non-immune-mediated inflammation:
- what would cause this?
- when does it occur?
- is it immediate or delayed?
Direct injury/pharm effect (i.e. cell damage)
First exposure
Can be either immediate or delayed
In regards to type 1 immune-mediated inflammation:
- What cells and mediators are involved? (3)
- is it mainly cell or chemical mediators driving the response?
Mast cells
Eosinophils
Histamine
Response is mainly chemical mediators released from mast cells
In regards to type 4 immune-mediated inflammation:
- what cells and/or mediators are involved? (3)
- is the response mainly driven by cellular or chemical mediators?
Mainly cell mediators
Lymphocytes, Macrophages, Others
In regards to non-immune mediated inflammation:
- what cells and/or mediators are involved? (2)
- is the response driven by mainly cell or chemical mediators?
Chemical mediators from tissue and cells (usually neutrophil/macrophage)
In regards to type 1 immune-mediated inflammation:
- what kind of stimuli are responsible? (4)
usually pollen, dust mites, soft CLs, very rarely drugs
In regards to type 4 immune-mediated inflammation:
- what kind of stimuli are responsible? (4)
cosmesis, drugs, other biological FBs, ‘autoantigens’
In regards to non-immune-mediated inflammation:
- what kind of stimuli are responsible? (2)
drugs, chemicals
In regards to type 1 immune-mediated inflammation:
- how can this present in the eyelids? (1)
papillae
In regards to type 4 immune-mediated inflammation:
- how can this present in the eyelids? (3)
papillae, follicles, phlyctenules
In regards to non-immune mediated inflammation:
- how can this present in the eyelids? (1)
papillae
Name 4 kinds of allergic conjunctivitis
seasonal/perennial
vernal keratoconjunctivitis (VKC)
atopic keratoconjunctivitis
giant papillary conjunctivitis (GPC)
Which of the 4 kinds of allergic conjunctivitis are sight threatening? (2)
VKC and atopic
Which of the 4 kinds of allergic conjunctivitis are about px comfort?
seasonal/perennial conjunctivitis
Which of the 4 kinds of allergic conjunctivitis are associated with soft CLs?
GPC
Seasonal/Perennial conjunctivitis:
- how common?
- when might symptoms persist all year?
common
if px allergic to perennial allergen
Seasonal/Perennial conjunctivitis:
- what type of hypersensitivity? What mediates it?
- what proportion of population affected?
pure type 1 hypersensitivity (IgE mediated)
affects 5-20% of population, 80% under 30yrs
Seasonal/Perennial conjunctivitis:
- list its clinical features (7)
usually bilateral
conj papillae
hyperaemia (injection)
oedema (chemosis)
lids may also be oedematous
serous + mucus discharge
cornea unaffected
List the symptoms of seasonal/perennial conjunctivitis (3)
itchy eyes (hallmark)
watery eyes
associated sneezing etc.
What does the mast cell do in terms of the inflammatory response?
doesn’t do much other than alerting other cells to cause inflammation
What mediators and factors are released by mast cells? (6ish)
Histamines, Leukotrienes, Chemokines, LTB4, Proinflammatory cytokines, IL-4, IL-5, Tryptase
What cell and mediator is responsible for activating mast cells?
IgE from B cells
What mediators are released from mast cells to cause bronchospasm? (4)
histamines
leukotrienes
chemokines
LTB4
What mediators are released from mast cells to recruit neutrophils? (1)
tryptase
What mediators are released from mast cells to recruit eosinophils? (1)
IL-5
What mediators are released from mast cells to recruit T cells? (2)
pro-inflammatory cytokines
IL-4
In regard to the histamine response of mast cell activation:
- what symptoms does this cause? (2)
- how can we tx? (3)
red, itchy eye
Lubricant, antihistamine, mast cell stabilisers
In regard to the cellular response of mast cell activation:
- what 2 cells and factors are involved?
- how can we tx? (1)
- when might we treat? (1)
eosinophil and neutrophil chemotatic factors (ECF, NCF)
cyclosporin (a steroid)
steroids can block these cell responses while waiting for the mast cell stabiliser to kick in
In regard to the cytokine production from mast cell activation:
- What does heparin do? (3)
anti-coagulant, chemosis, swell
In regard to the cytokine production from mast cell activation:
- what does tryptase do? (3)
- how can we tx?
COX-2, PG production and fibroblast proliferation
Use NSAIDs
In regard to the cytokine production from mast cell activation:
- what does chymase do? (2)
increase vascular permeability via angiotensin II, chemosis
In regard to the cytokine production from mast cell activation:
- name 2 ways we can tx?
Steroids (all)
NSAIDs (for tryptase)
Which type of drug is the best choice to use to tx Type 1 allergic response?
Steroids (if side effects can be handled)
What DDx exist for seasonal conjunctivitis? (3)
other allergic conjunctivitis
dry eye related surface disease
mechanisms of conjunctivitis
How can we assess seasonal conjunctivitis? (4)
hx, slit lamp, fluoroscein, lid eversion
Why is lid eversion crucial when assessing seasonal conjunctivitis?
lid eversion can diagnose or rule out seasonal conjunctivitis among the list of ddx
How can we treat/manage seasonal conjunctivitis? (8)
Allergen avoidance
Cold compresses
Tears
Topical vasoconstrictors/antihistamines
Topical antihistamines/mast cell stabilisers
Topical NSAIDs
Topical steroids
Topical cyclosporin A
When should we prescribe topical vasoconstrictors for a patient with seasonal conjunctivitis?
do not prescribe unless absolutely needed in an acute situation
What does chronic use of topical vasoconstrictors cause?
oversaturation of alpha receptors, blocking them, which will cause vasodilation instead and prompt the patient to put in more drops, which won’t work
What is the most common vasoconstrictor used?
Naphazoline (e.g. naphcon, vizine)
How fast do vasoconstrictors tx seasonal conjunctivitis?
instantaneous relief of redness of eyes
Name an example of an S4 and S3 topical antihistamine/MCS. Are these examples covered by PBS?
Patanol (olapatidine) - S4
Zatiden (ketoifen) - S3
no
What is the difference between S4 and S3 drugs?
S3 - over the counter, needs a pharmacist to dispense
S4 - needs a script
How effective is patanol in treating seasonal conjunctivitis?
very
Why are no anti-allergy drugs covered by PBS?
b/c they are palliative tx and don’t protect or prevent anything
How often do you take patanol to tx conjunctivitis? Why is this?
twice a day. b/c once a day is ineffective b/c you need to maintain a therapeutic dose (for this reason, px compliance is very important)
How long do livostin and opticrom antihistamines/MCS take to have a therapeutic effect? What does this suggest?
4-6 weeks, which makes them useless as antihistamines, can only use as mast cell stabilisers. However, can be good as a maintenance dose in perennial conjunctivitis
How high are the side-effects of patanol? What does this suggest?
Very low, so can be used on patients as young as 3 years
How do NSAIDs compare to steroids?
Have the advantages of steroids without the adverse effects
How often are NSAIDs used for the following:
- anterior eye disease
- macular oedema
- post cataract surgery
Not often
often
often
Name 2 examples of NSAIDs used to tx seasonal conjunctivitis
Ketorolac, Diclofenac
What is the difference between fluoromethalone and flarex steroids? (6)
Fluoromethalone: alcohol version. Good for allergic conjunctivitis. Almost immediate effect
Flarex: acetate version. Good for iris + deeper corneal changes. Effects absorption
Is a seasonal allergy a surface problem or is it deeper? How does this affect mx?
surface problem, so we want a drug that doesn’t get absorbed systemically
Name 2 major side effects of steroid use
IOP rise
Risk of Cataract
How might we use steroid and patanol together?
Add together than slowly reduce steroid as patanol kicks in
If using patanol and steroid together, how long must you wait before putting the other drug in?
wait 5 minutes between the two so one drug doesn’t wash out the other
Is it easy to overdose on patanol and FML?
No
When using steroids, how should we hit the condition?
Hit it hard and early. A lot at the start then quickly withdraw
Is topical cyclosporin available in Australia?
No
If mast cells don’t work to tx conjunctivitis, what might you suspect? And how will you manage?
Due to eosinophil activity then, use steroids concurrently with MCS/anti-histamine for 2 weeks
- steroid (FML) 2 weeks, IQID week, then IBD week
