uveitis, hyphaema and lens luxation Flashcards
(18 cards)
What is uveitis and how is it classified anatomically and temporally?
Uveitis is inflammation of the uveal tract: iris, ciliary body, and choroid. It is classified anatomically as anterior, posterior, or panuveitis, and temporally as acute, subacute, or chronic.
What are the clinical signs of acute anterior uveitis?
Signs include blepharospasm, photophobia, tearing, enophthalmos, conjunctival hyperemia, episcleral injection, corneal edema, aqueous flare, hypopyon, hyphaema, miosis, and iris changes. Posterior involvement may show retinal edema, hemorrhage, granulomas, or detachment.
How does intraocular pressure (IOP) change in acute uveitis and what does this indicate?
IOP is usually decreased (<10 mmHg) due to reduced aqueous production and increased uveoscleral outflow. A normal or increased IOP in an inflamed eye may indicate impending secondary glaucoma.
What is the diagnostic approach to identifying the cause of uveitis?
Includes full physical and ocular exam, CBC, biochemistry, coagulation panel, urinalysis, infectious disease testing, thoracic imaging, and ocular/abdominal ultrasound. Cytology or histopathology may be indicated. Differentials include trauma, neoplasia, infection, immune-mediated and idiopathic causes.
List common causes of uveitis in dogs and cats.
Dogs: trauma, lens-induced uveitis, corneal ulceration, neoplasia, infections (e.g., Leptospira, Toxoplasma), immune-mediated diseases. Cats: trauma, FeLV, FIV, FIP, toxoplasmosis, fungal infections, neoplasia (e.g., lymphoma, melanoma).
What are the primary goals of treating anterior uveitis?
Control inflammation, relieve pain, and prevent complications like synechiae or glaucoma. Topical corticosteroids (prednisolone acetate, dexamethasone) and NSAIDs are commonly used. Corneal ulcers must be ruled out first.
How are parasympatholytic drugs used in anterior uveitis?
Atropine (q8–24h) induces cycloplegia and mydriasis, reducing pain and preventing synechiae. Tropicamide may be used in borderline-high IOP cases. Atropine is contraindicated in secondary glaucoma except in early iris bombé.
What systemic treatments are used for uveitis?
Systemic NSAIDs or corticosteroids are indicated for severe anterior or posterior uveitis. Corticosteroids should be delayed until diagnostics are completed. Treat underlying cause when identified (e.g., infection, immune-mediated, neoplasia).
What are the complications of untreated or severe uveitis?
Complications include synechiae, glaucoma, cataracts, lens luxation, retinal detachment or scarring, and phthisis bulbi.
What is hyphaema and what are the main causes?
Hyphaema is blood in the anterior chamber. Causes include trauma, uveitis, neoplasia, coagulopathies, systemic hypertension, congenital ocular disease, glaucoma, and retinal detachment.
What is the diagnostic approach to a case of hyphaema?
Perform history and physical exam, coagulation profile, blood pressure assessment, and ocular ultrasound if needed. Imaging may be required for trauma. Evaluate for uveitis, neoplasia, and systemic causes.
How is hyphaema treated?
Treat underlying cause. Topical corticosteroids (if no corneal ulcer), systemic anti-inflammatories if vitreous hemorrhage present. Atropine to prevent synechiae. TPA may be used intracamerally if fibrin clots elevate IOP—refer to ophthalmologist.
What are the common complications of hyphaema?
Posterior synechiae, secondary glaucoma, cataract formation, corneal blood staining, and phthisis bulbi.
What is the prognosis for hyphaema?
Variable, depending on cause and complications. Good if no posterior segment damage or glaucoma. Poor prognosis associated with absent dazzle/PLR reflexes, complete hyphaema, or high IOP.
How is lens luxation classified and diagnosed?
Classified as congenital, primary (inherited zonular defect), or secondary (due to uveitis, glaucoma, cataracts). Diagnosed by visualizing anterior or posterior lens displacement, aphakic crescent, iridodonesis, or phacodonesis.
What are the clinical signs of anterior versus posterior lens luxation?
Anterior: lens in anterior chamber, corneal edema, pain. Posterior: deep anterior chamber, iridodonesis, lens on ventral retina.
How is anterior lens luxation treated acutely?
Measure IOP. Begin topical CAIs; mannitol if needed. Avoid PGAs. Refer for surgical lens removal. If surgery not possible, reposition lens posteriorly and use PGAs long-term to maintain position.
What is the long-term prognosis for lens luxation?
Guarded due to risks of glaucoma, retinal detachment, uveitis, and cataracts. Prognosis improves significantly with early diagnosis and surgical management.
