TERM 1: keratitis Flashcards
What are the types of non-infective keratitis?
What are the types of infective keratitis?
-CLPU
-Marginal keratitis
-Exposure keratitis
-Photokeratitis
bacterial
fungal
viral
secondary to chlamydia (trachoma)
protozoal
What are the clinical signs of corneal disease?
punctate keratitis
superior limbic keratitis
corneal infiltrates
scaring
corneal ulcer
vascularisation
hypopyon
What are the adnexal signs of corneal disease?
skin lesions (herpes zoster opthalmicus)
conjunctival follicles (adenoviral conjunctivitis)
conjunctival pseudomembrane (adenoviral conjunctivitis)
conjunctival scarring (trachoma)
What are the general symptoms of corneal disease?
Pain/discomfort
±Reduced VA
Photophobia
What is different about inflammatory keratitis compared to infective keratitis?
- bacteria do not invade or replicate in the cornea
-there is no progression to infection
-symptoms usually resolve over 48h infiltrates resolve over 2-3 weeks
-response to bacterial toxins (usually staph.species)
What are the associations of infective MK?
What bacteria commonly cause it?
What are the symptoms?
-strong association with CL wear (soft overnight wear)
Pseudomonas
staph
strep
pain, moderate to severe (usually acute onset, rapid progression)
redness, photophobia (may be severe), discharge
blurred vision (especially if lesion on visual axis)
What are the signs of MK?
What is the management?
loss of epithelium
stromal infiltrate and oedema
reduced VA
AC activity (flare and cells)
fungal lesions tend to be deeper and often have ‘feathery’ edges
-emergency referral to an ophthalmologist
-Severe sight-threatening condition.
-warn contact lens wearers not to discard their lenses or lens cases, but to retain them for culture
-requires intensive (day and night) antibiotic therapy
What are the risk factors for developing marginal keratitis?
What are the symptoms?
What are the signs?
What is the treatment?
-presence of longstanding conjunctivitis or Meibomian gland disease
-lacrimation, red eye, photophobia
-stromal infiltrate with overlying epithelial cell loss
-hyperaemia of adjacent conjunctiva
-usually treated with a combination of topical steroids and antibiotics
What can cause inflammatory keratitis?
What are the signs?
What is the management?
keratitis typically follows adenoviral conjunctivitis
-starts with epithelial microcysts, which may progress to focal punctate epithelial keratopathy that stains with fluorescein
-in more severe cases, subepithelial/anterior stromal infiltrates develop after a span of around 2–3 weeks
inflammatory response to viral antigens
What are the associations of acanthamoeba keratitis?
What are the symptoms?
What are the early and late signs?
What is the management?
-CL wear
-Exposure to soil or contaminated water
-pain (may be severe and out of proportion to the degree of inflammation)
- visual disturbance
- epiphora
-photophobia
early : epithelial or subepithelial infiltrates, pseudodendrites, infiltrates along corneal nerves
late: central or paracentral ring infiltrate, stromal thinning
emergency referral to an ophthalmologist
Severe sight-threatening condition.
intensive (day and night) topical medical treatment with topical disnfectants (biguanide or a diamidine or a combination of the two)
What can ocular herpes simplex virus manifest as?
blepharoconjunctivitis
keratitis
anterior uveitis
acute retinal necrosis
most common form: epithelial keratitis
Keratitis caused by HSV-1 virus
What are the symptoms of HS keratitis?
What are the signs?
What is the management?
variable
pain, burning, irritation
photophobia
reduced visual acuity, redness
epithelial : initially punctate lesions, coalescing into dendriform pattern. Continual enlargement may result in a geographic ulcer
stromal: stromal infiltrates, vascularisation, necrosis, scarring,
emergency or urgent referral to an ophthalmologist
Sight-threatening condition.
topical antivirals e.g. acyclovir effective for managing epithelial keratitis
may need combination of antivirals and steroids for stromal disease
When does exposure keratitis occur?
-when the surface of the cornea (and usually adjacent conjunctiva) become dehydrated and damaged secondary to poor tear film wetting
- can also occur following incomplete lid closure
When does photokeratitis occur?
What are the signs and symptoms?
What is the management?
occurs following unprotected exposure to ultraviolet radiation (UVB or UVC) e.g. welding
-varies in severity (depending on exposure)
- mild irritation to severe pain
-conjunctival hyperaemia/ epiphora/punctate
-staining of corneal epithelium
lubricants
prophylactic topical antibiotics
