Feline & miscellaneous conditions Flashcards
(41 cards)
What are the common conditions affecting the feline eye?
- eosinophilic keratitis
- corneal sequestrum
- feline diffuse iris melanoma (FDIM)
Eosinophilic keratitis - presenting signs
Cottage cheese deposits
- white to pale pink elevated spots on cornea
- may coalesce into a raised plaque
Eosinophilic keratitis - aetiology
- immune mediated, possible connection with FHV-1
Eosinophilic keratitis - diagnosis
- clinical appearance/cytology: mixed cellular infiltrate
Eosinophilic keratitis - tx
- topical corticosteroid (or ciclosporin) successful in most cases
- usually responds well to tx
Eosinophilic keratitis - unilateral or bilateral?
- unilateral or bilateral
Eosinophilic keratitis - problem with treatment
- tx may induce reactivation of latent FHV-1 infection
Corneal sequestrum - presenting signs
- varies from amber corneal discolouration to dark brown plaque
- variable vascularisation, lesion depth and discomfort, often associated with epithelial loss
Corneal sequestrum - aetiology
- cause remains unknown
- chronic irritation may predispose e.g. brachycephalic conformation, entropion, grid keratotomy
Corneal sequestrum - diagnosis
- characteristic clinical appearance
Corneal sequestrum - tx
- ideally keratectomy ± graft placement (may require referral)
- sometimes lesions will slough over time
Corneal sequestrum - unilateral or bilateral
- usually unilateral (may be bilateral in predisposed breeds)
FDM - presenting signs
- hyper pigmented iris spot(s)
- usually progressing to diffuse hyperpigmentation of whole iris ± abnormalities in pupil shape ± uveitis/glaucoma
FDM - aetiology
- neoplastic
FDM - diagnosis
- suspect from clinical appearance
- histopath for definitive diagnosis
FDM - tx
- enucleation with histopath if high index of suspicion
FDM - unilateral or bilateral?
- unilateral
FDM - prognosis
- guarded due to significant risk of mets
Signs that suggest FDIM
- pigmented spots with raised surface
- pupil abnormalities: anisocoria, dyscoria
- progression of hyperpigmentation
- secondary uveitis/glaucoma
FDIM - when to enucleate
- if masses growing rapidly, cells in anterior chamber, secondary glaucoma, infiltrating drainage angle
Iris melanoma - dog vs cat
Appearance
- dog: usually a discrete, focal pigmented mass
- cat: usually diffuse thickening/darkening of iris
Behaviour
- dog: 75% benign, 25% malignant on histology (up to 5% of these mets)
- cat: mets rate of up to 63%, guarded prognosis
Tx
- dog: monitoring/enucleation if painful/worrying O
- cat: monitoring/enucleation if strong suspicion of FDIM
Anatomy of Horner’s syndrome
3 neuron system
3rd order neutron is most commonly affected with Horner’s
1st order (UMN)
- neoplasia, inflammatory dz, trauma or vascular accident affecting brainstem/spinal cord
- IVDD
2nd order (pre-ganglionic, in vagosympathetic trunk)
- rostral thoracic spinal lesions
- brachial plexus lesions
- thoracic cavity pathology e.g. cranial mediastinal masses
- soft tissue neck injuries
3rd order (post-ganglionic)
- idiopathic
- middle ear dz
- orbital dz
- skull fractures
Horner’s syndrome - CS
- 3rd eyelid protrusion
- anisocoria
- ptosis
- enophthalmos
- conjunctival hyperaemia in some animals
Horners syndrome diagnosis - phenylephrine test
- to determine site of lesion
- 1 drop of 1% or 2.5% phenylephrine into both eyes
- 3rd order Horners: <20mins to pupil dilation in affected eye
- 1st or 2nd order Horners: >20mins to pupil dilation (may not dilate at all)
