Keratitis Flashcards
Name three types of non-infective keratitis
- CLPU
- Marginal keratitis
- Keratitis secondary to exposure
What is the pathogen that is responsible for protozoal keratitis?
Acanthamoeba
What are corneal signs of corneal disease (there are seven)?
-Punctate keratitis
- Superior limbic keratitis
- Corneal infiltrates
- Scaring (from trachoma)
- Corneal ulcer
- Vascularisation
- Hypopyon (accumulation of inflammatory material)
What are associated adnexal and conjunctival signs of corneal disease?
-Skin lesions (respects midline)
-Follicles (adenoviral)
-Conjunctival pseudo membrane (adenoviral)
-Conjunctival scaring (trachoma)
What are symptoms of corneal disease?
- Pain/discomfort (due to lots of pain receptors)
- Reduced VA
- Photophobia
What are two corneal diseases that are similar?
CLPU and MK
What causes the ulcer in CLPU and infilt?
Staphylococcus produces toxins and the ocular surface responds to these toxins.
What are some symptoms of CIE?
- Mild FB sensation
- Can be asymptomatic
- Mid pain
- Mild photophobia
- Mild epiphora
What does CIE stand or?
Contact lens infiltrative events this includes CLPU and CL-associated infiltrative keratitis- in these conditions bacteria does not cause progression to an infection (its an inflammatory response)
What are clinical signs of CIE?
- Mild conjunctival hyperamia
- Stromal infiltrate
- No AC activity
- Overlying epithelium may stain
What does flare represent ?
Breakdown of the blood aqueous barrier and there is protein in aqueous which leads to light scatter
Is microbial keratitis a sight threatening condition?
YES
Which contact lens wearers are at most risk of MK?
Extended contact lens wearers
Which is the most common bacteria to cause MK in contact lens wearers?
Gram negative psuedonomas
What are symptoms of MK?
Severe pain with a rapid onset, redness, photophobia, discharge, blurred vision, more pronounced photophobia
What are signs of MK?
- Loss of epithelium
- Stromal infiltrate + oedema (seen from a hazy cornea)
- Reduced VA
- AC activity (cells and flare)
- Fungal lesions deeper and feathery edges
BOWMANS MEMBRANE NOT INTACT
How is MK managed?
Emergency referral to an ophthalmologist, contact lenses should not be discarded as they are required for culture, they will be given intensive day and night therapy
Why is MK so serious?
It is sight threatening as they can penetrate the cornea which can lead to corneal scarring
What is the 123 that ophthalmologists use after a referral of suspected MK?
If there is the presence of AC inflammation (6-15 cells in a 1mm by 1mm SL beam),
2mm> in size or adjacent lesions or
3mm> from centre of cornea then a corneal scrape is formed to see what organisms is causing this immediately
What happens to patient who to no meet the 123 criteria from a suspect MK referral?
They are given antibiotic therapy straight away every hour
Is an corneal infiltration an infection?
No it is an inflammatory response to a toxin
What is another name for blepharitis?
Marginal keratitis
What are some signs and symptoms of marginal keratitis?
Lacrimination, red eye, photophobia, stromal infiltrate where the lid margin is in contact with the cornea, Hypereamia of adjacent conjunctiva,
What is a major RF of marginal keratitis?
Long standing conjunctivitis
What is the treatment of marginal keratitis?
Combination of topical steroids and antibiotics are used (MAKE SURE IT IS AN INFLAMMATION AND NOT AN INFECTION)
What is another name for inflammatory keratitis?
Sub-epithelial infiltrates in adenoviral conjunctivitis
Describe what is seen in inflammatory keratitis.
Begins with small microcysts then to focal punctate epithelial lesions which can then progress into sub epithelial infiltrates which occurs after viral conjunctivitis
What is the normal treatment for inflammatory conjunctivitis?
Let is self heal, if not then topical steroids can be used in some cases
What is causes acanthamoeba keratitis?
Acanthamoeba in contact lens wearers mostly which can be caused by exposure to soil or contaminated water
What are the early and late signs of acanthoemba infective keratitis?
Early= Epithelial or sub epithelial infiltrates, pseudodendrities, infiltrates along corneal nerves
Late= Central or paracentral ring infiltrate, stromal thinning
What is the management of infective keratitis caused my acanthamoeba ?
Emergency referral to ophthalmologist where they will be on intensive topical disinfective treatment
What can acanthamoeba infective keratitis be misdiagnosed for and why?
Herpes simplex infective keratitis because of the dendritic ulcer
What are the symptoms of herpes simplex keratitis?
- Pain
- Burning
- Irritation
- Photophobia
- Reduced VA - based on severity
- Redness
State the epithelial and stromal (sight threatening) signs of herpes simplex keratitis
Epithelial = initially punctate lesions which coalesce into a dendritic form which could lead to a geographic ulcer
Stromal= stromal infiltrate,vascularisation, necrosis, scarring
What is the management of herpes simplex keratitis?
Emergency referral, topical antiviral given to epithelial level, combination of antiviral and steroidal for stromal level
What causes exposure keratitis?
When corneal surface becomes dehydrated due to dry eye or inadequate lid closure
What causes photokeratitis?
Exposure to UV radiation and no eye protection worn when exposed- mild irritation and severe pain
How is photokeratitis managed?
Lubricant and/or prophylactic topical antibiotics
