Uvea Flashcards
What are the components of the uvea?
Anterior
- iris and ciliary body
Posterior
-choroid
What is the blood supply that encircles the iris?
Major arterial circle
What are the zones of the iris?
Ciliary zone
Iris collarette (persistent pupillary membranes arise from his junction)
Pupillary zone
What is a persistent pupillary membrane (PPM) ?
Incomplete absorption of embryonic vascular tissue and mesenchymal strands
Originating form iris collarette
- iris - iris
- iris - lens (remnants can leave pigment on anterior lens capsule, often cause focal cataracts )
- iris - cornea (can see from side, transversing anterior chamber and can result from scaring where they attach)
What is the function of the uvea?
Aqueous production
Maintenance of blood-ocular barrier (clear ocular media)
Light regulation
Accommodation
What are the components of the blood-ocular barrier ?
Blood-aqueous barrier
- iris blood vessel endothelium
- ciliary body epithelium
Blood-retinal barrier
- retinal blood vessel endothelium
- retinal pigment epithelium
What is the function of the blood-ocular barrier?
Prevent passage of protein and cells into the anterior chamber and posterior segment
Allows clear media for vision
Disruption of barrier = uveitis
What is the pathophysiology of inflammation of the uvea?
Increased blood supply
Increased vessel permeability
White blood cell migration
Breakdown of the blood-ocular barrier
What do you call inflammation of the iris and ciliary body?
Anterior uveitis (iridocyclitis)
What do you call inflammation of the choroid?
Posterior uveitis ( choroiditis)
What do you call inflammation of the entire uvea?
Panuveitis
What do you call inflammation of the entire uvea and intraocular contents?
Endophthalmitits
What do you call inflammation of all the ocular and intraocular structures?
Panophtalmitis
What clinical signs are seen with uveitis?
Blepharospasm Epiphora Photophobia Red eye - ciliary flush - episceral injection Corneal edema
Miosis Aqueous flare Hyphema Hypopyon Fibrin Keratic precipitates Swollen/thickened iris Iris hyperemia Rubeosis iridis Decreased intraocular pressure Active chorioretinal lesions
What causes the miosis seen with uveitis?
Inflammation due to prostaglandins
= causes pain from ciliary body spasm
= causes iris sphincter muscle contraction
What causes an aqueous flare?
Increased turbidity due to breakdown of the blood-aqueous barrier
Protein and cells in AC cause light scattering
Detected with very focal light source close to the cornea in a dark room
What do you call blood in the anterior chamber?
Hyphema
What do you call WBC in the anterior chamber?
Hypopyon
What are keratic precipitates?
Inflammatory cells and fribrin adhered to corneal endothelium
What is rubeosis iridis?
Neovascularization of iris surface (chronic)
Why do you have a deceased ocular pressure with uveitis?
Inflammation driven by prostaglandins
Decreased aqueous humor production
Normal IOP is 10-20mmHG
Why do you see active chorioretinal lesions with uveitis?
Breakdown of blood-retinal barrier
Hyporeflective, raised, and poorly circumscribed lesions
Retinal edema
Subretinal infiltrates/glaucoma
Retinal hemorrhage
Retinal detachment
Vitreous haze
What are clinical signs of CHRONIC uveitis?
Posterior synechia
- dyscoria (abnormally shaped pupil)
- iris bombe (apposition of iris and lens prevents aqueous from flowing into posterior of anterior chamber)
Iris hyperpigmentation
Cataracts
Secondary glaucoma
Retinal detachments
Phthisis bulbi
What are the types of uveitis?
Exogenous= external to the eye
- blunt or perforating trauma
- corneal ulceration
Endogenous
-infectious, neoplasia, metabolic, auto-immune, drug-induced
What are infectous causes of canine uveitis?
Prototheca (algae)
Borrelia, brucella, lepto
Aspergillosis, blasto, crypto, histo, coccidioides
Angiostrongylus, baylisascaria, Diptera, drofilaria, toxocara
Leishmania, neospora, toxo, trypanosoma
Erhlichia, rickettsia
Adenovirus, distemper, herpes
What type of infectious uveitis has pyogranulomatous inflammation and involves the posterior segment ?
Disseminated mycotic
What type of uveitis will you see migratory tracts in retina?
Intraocular nematodiasis
What type of uveitis is associated with vasculitis and retinal hemorrhage, thrombocytopenia, platelet dysfunction, and hypervisocity?
Rickettsial disease (Ehrlichia)
What are non-infectous causes of uveitis?
Immune mediated - idiopathic most commonly
Metabolic - DM, hyperlipidemia, hypertension
Neoplastic - histiocytic proliferative disease, hyperviscocity syndome, lymphosarcoma, melanoma
Trauma
What is a lens induced uveitis?
Leakage of lens protein from a cataract
Suspect in any red eye with a cataract
What is uveodermatologic syndrome?
Autoimmune disease directed against melanocytes
Severe bilateral panuveitis
Depigmentaion of iris and or choroid
Ulceration and vitiligo of facial mucocutaneous junctions
What breed of dog gets pigmentary deposits on the lens an corneal endothelium, iris hperpigmentation, and uveal cysts ?
Golden retrievers
What are the infectious causes of feline uveitis ?
FIV, FeLV, FIP and toxo
Also fungal
Diptera
And bacterial
What is likely the cause of a chorioretintitis with concurrency URI, swelling over the bridge of the nose, and cutaneous lesions
Cryptococcosis
How will you work up a canine uveitis case?
travel history PE CBC Chem UA Thoracic rads Tick titers Fungal titers
If hyphema present:
Coag panel
BP
CBC
How will you work up a feline uveitis case?
Travel history PE CBC Chem UA Thoracic rads
FIV/FLV
Toxo titer
Fungal titers
Hyphema:
Coag
BP
CBC
What is the treatment of uveitis?
Primary cause (if known)
All required anti-inflammatories (topical steroids +/- NSAIDS)
Topical atropine
+/- systemic corticosteroids OR systemic NSAIDS
+/- systemic antimicrobials
What topical corticosteroids are appropriate for treatment of uveitis?
Prednisolone acetate
Dexamethasone (neopolydex)
What topical NSAIDS are appropriate for treating uveitis?
Flurbiprofen
Diclofenac
Ketorolac
Can be used with topical steroids
What causes of uveitis must you rule out before starting systemic corticosteroids?
Infectious causes
Prednisone (canine)
Prednisolone (cat)
What systemic NSAIDS are appropriate for treating uveitis?
Carprofen or Meloxicam (dog)
Robenacoxib (cat)
What is are the benefits to using a topical mydratics for uveitis?
Atropine
Reduce pain of ciliary body spasm
Reduces risk of posterior synechia
Stablilizes blood-ocular barrier
