CL related pathologies 2 Flashcards
True or False- Corneal Ulcers and Contact keratitis make up most of the cases of acute eye conditions in the emergency clinic
True
Following what, may a corneal ulcer occur?
- Trauma
- Corneal surgery
- Ocular surface disease
- Systemic diseases
- Immunosuppression
- CL wear
What is telangiectasia of the lid margin?
Widening of blood vessels on lid margin
[Telangiectasia - refers to widening of blood vessels]
What signs of pathology can be seen in the following picture?
Conjunctival Redness
Telangiectasia of lid margin
White spot on cornea surrounded by Haze
What factors make you more succeptible to corneal ulcers?
Red eye
Pain
Photophobia
Watering
Visual Disturbance
[Ideally when questioning a px for their likelyhood to develop a corneal ulcer you want to be questioning them on discharge, itchiness, CL wear, POH incl surgery, medical history]
What are all the potential non-infectious causes of corneal ulcers?
- Marginal keratitis can result from hypersensitivity to staphlyoccocus
- Neutrogenic keratitis - in response to damage from the trigeminal nerve
- Allergic keratitis
- Peripheral ulcerative keratitis
- Sterile corneal infiltrates associated with CL wear
- Toxic keratitis (solution/ eye drops)
What is keratitis?
Corneal Inflammation - it includes progressing to an ulcer
What must be document about a corneal opacity/ulcer (6)?
Size
Shape
Depth
Margin (Soft, Distinct or necrotic)
Location
Colour
Why do we stain with fluorescein when we find a corneal ulcer?
Fluorescein staining can help us diffrentiate aetiology.
If dendritic structures are found then ateiology is Herpes keratitis
If there is localised punctate swelling then aetiology is acanthamoeba keratitis.
It also highlights any loose/ exposed sutures, epithelial defects or ocular surface disease presence
What is a severe anterior chambre reaction in conjunction with keratitis (an ulcer) characteristic of?
Superlative Infective Keratitis
True or False- Superlative Infective Keratitis ocurs frequently subsequently to corneal trauma
True - it may be intiated by trauma or airborne particles such as soil, sand or dust
What is our diffrential diagnosis of a corneal ulcer? (i.e. what are the different conditions that could cause it and what could it be mistaken for?)
- Microbial (bacterial or fungal) keratitis -Appearance can be similar, to CLPU (Contact lens associated Peripheral Ulcer) therefore monitor closely especially over the first 24 hours and if diagnosis remains in doubt, refer to ophthalmologist as an emergency
- Marginal keratitis
- Corneal scar
- Herpes simplex keratitis
- Adenovirus keratoconjunctivitis
If you are unsure of a diagnosis regarding a corneal ulcer what must you do?
Monitor closely for 24 hours and if in doubt still refer to an opthalmologist
In order to explore/narrow down your diffrential diagnosis what questions do you want to be asking?
Ask specifically about:
- contact with chemicals
- CL hygiene
- Previous herpetic infection
- Chronic dry eye and ocular surface problems
- Systemic history including but not limited to: diabetic status, rheumatoid arthritis, Sjögren’s syndrome, systemic immunosuppressants as well as malnutrition
Why do we closely monitor a suspected CLPU for 24 hours?
The appearance of a CLPU can be very similar to that of microbial keratitis ( which is sight threatening).
If diagnosis is unclear after 24 hours refer to an ophthalmologist
What are the different bacterial strains that cause bacterial keratitis/a corneal ulcer and how can you determine which strain is responsible?
Gram Positive - in which case there is a well circumscribed ulcer
Staphlyococcus - in which case there are round or oval lesions with dense infiltration and a distinct border
Gram Negative - in which case there are Poorly defined infiltrates with copious mucopurulent discharge
Psuedonomas - in which case there is a rapid progression, dense stromal infiltrate and corneal perforation
What are the different viral strains responsible for microbial keratitis and how do we determine their presence?
True or False - px with Microbial keratitis; Herpes Simplex or Herpes Zoster experience reduced corneal sensativity
True
What is telling about the relationship between symptoms and signs of microbial keratitis caused by acanthamoeba?
Symptoms are disproportionate to the signs - so although you may not see much sign of corneal disruption the px is in PAIN.
[This is due to irritation of corneal nerves]
Does Acanthamoeba cause an irritation of corneal nerves?
Yes
What makes CL wearers more succeptible to Acanthamoeba Keratitis?
Poor CL hygeine and/or contact with tap water (through showering and/or swimming with contacts in).
[Hence why asking questions is really important]
What are clinical signs of Acanthamoeba keratitis?
At first they are veyr subtle- including an irregular corneal surface and punctate staining (although this swelling can be dendritic - making it easily confused with Viral keratitis).
There is a gradual enlargement and coalescence of infiltrates to form a ring - which is characterisitic of Acanthamoeba Keratitis
What is one of the ways you can diffrentially diagnose Acanthamoeba Keratitis from Herpes Zoster Keratitis?
Ulcers caused by Acanthamoeba Keratitis tend to be raised ( not ulcerative liuke in Herpes Zoster) and they do not necessarily stain with fluorescein.
Is fungal keratitis associated with CL wear?
No
Is fungal keratitis common?
Not in temperate countries like the UK
What are predisposing factors to fungal keratitis?
Systemic immunosupression
Long term use of topical steroids
How can we determine ebtween the different strains of fungi that cause fungal keratitis?
Yeast based Keratitis - causes a yellow -white dense supporative infiltrate
[Supporative - undergo the formation of pus; fester]
Aspergillus/ Fusarium: yellow-white stromal infiltrate with fluffy margins ) and feathery extensions , and hypopyon.
What are the general principles for managing any kind of microbial keratitis?
Broad spectrum topical antibiotics - are used if Bacterial keratitisis present with small infiltrates or infiltrates in a peripheral location
When a central , large or deep stromal infiltrate is found - a corneal scrape is always done to diffrentially diagnose
Hospital admission is always required if px is not compliant with treatment as microbial keratitis can be sight threatening
What is empiric therapy?
Therapy based on clinical educated guesses. Empiric therapy or empirical therapy is medical treatment or therapy based on experience and, more specifically, therapy begun on the basis of a clinical “educated guess” in the absence of complete or perfect information
What are the general medications we provide for keratitis and why?
Antiobiotics for infective ulcers.
Systemic Antibiotics in severe cases
Cycloplegics for pain relief.
Debriding - taking the top layer of the cornea off - to help with penetration of eye drops - this has shown to also help in recovery as it involves getting rid of microbes.
Steriods - to reduce inflammation and increase comfort once clinical signs have improved - however some argue against this as it leads px succesptible to fungal growth
What is bacterial specific management for microbial keratitis?
Remove and retain CLs for culture
Emergency same day referral to an ophthalmologist without any intervention. Phone the department to explain what you have done.
[Any intervention we offer may cause a delay in treatment which leads to pooorer prognosis]
What is the viral specific management for microbial keratitis?
If an ulcer is not responding to treatment what should you do?
Refer for a re-scrapping to look for any other organisms that could be causing the ulcer
True or False- Ointments can interfere with the penetration of eyedrops
True
In what bacterial keratitis cases are systemic antibiotics prescribed - beyond just saying severe!
When there is scleral or intraocular extension of the bacterial infection.
Or if you suspect perforation may occur
Generally speaking if you see any stromal involvement what course of action should you take?
Same day referral
When diagnosing viral keratitis what conditions do we need to rule out?
Vasculitis
Intra-retinal haemorrhages
Vitreous Inflammation
What is the acanthamoeba specific management for microbial keratitis?
Same day ophthalmology referral
Call ahead
Advise to take CLs and case for possible culture
[Generally treatment for Acanthamoeba Keratitis is quite aggressive]
What is the fungal specific mangement for Microbial Keratitis?
Same day ophthalmology referral
Call ahead
Advise to take CLs and case for possible culture
[Same as Acanthamoeba managment]
