Real Neuro Exam 3

Epiphora - puncta aplasia - common in ______ and may impact

cocker spaniels, golden retrievers, mini poodles, horses, llamas, alpacas
may effect superior, inferior, or both puncta, unilateral or bilateral

Dacryocystitis

mucopurulent dischage, epiphora, swelling or draining fistulas in medial canthal region
usulaly secondary to foreign bodies but rarely find them
cytology and culture, dacryocystorhinography (can also remove)

Dacrocyocystitis - tx

flsuhing and culutirng of nasolacrimal duct
dacryocystotomy to remove foreign body
placemnt of temporary nasolacriaml stent and topical antibiotic drops

Virteous humor - made of

elastic hydrogel
99% water, 1% collagen fibrils adn hyaluronic acid
very few cells (hyalocytes)

Vitereous - fucntion

75% volume of eye
some role in refraction
attahments formed by condensations of fibrils (located at ora ciliaries retinae and pars palan ciliaris (posterior ciliaray body), posterior lens capusle, around optic nerve
supports lens anteriorly, retian posteriorly

Virteous developmental abnormailites - persistent hyaloid artery

fialure of hyaloid artery to regress, usually small dense white or reddish string of tissue extending posteriorly from lens, may or may not have cataract

Persistent tunica vasculoas lentis

fine wite strands extending from posterior lens capusle, remnants of embryonic blood suppply

Persistent hyperplastic tunica vasculosa lentis/persistent hyperplastic primary viterous - breeds

dobermans, staffordshite terriers
sporadic in other breeds

Persistent hyperplastic tunica vasculosa lentis/persistent hyperplastic primary viterous - s/s

varies from small retrolentally located fibrovascular dots to malformation of lens and anterior viterous
posterior cataracts, fibrovascular plaque on posterior lens, lenticonus, viterous or intralenticular hemmorrhage

Vitreal degenerations

syneressi-liquefaction of viterous due to age or inflammation, may predispose to retinal detachement
asteroir hyalosis-small white or pigemnted particles consisting of ca or phsophlipids, move with eye movement

What is this

Asteroid hyalosis

Asteroid hyalosis - etiology

usually incidnetal
maye due to age or inflammation
often appears as small glsitening particles (asteroids) in viterous body cositing of ca and phospholipids
age related changes with no impact on vision

viterous is best evaluated through

a dilated pupil by indirect illumination

Viterous - opacities

asteroid hyalsos - bening aging change “snow globe”
hyaitis - inflammation of the viterous appears hazy
blood - secondary to retinal detachemnts, clotting disorders, hypertension or trua

Viterous - congenital abnormailites

PHPV/PHTVL (associated with lens changes)

Layers of the retina

1) sclera
2) choroid
3) tapetum
4) RPE (lacks pigment in blue eye dogs)
5) Neuosensory retina

Reitnal morphology

potential space between RPE and photoreceptors
axons from ganglion cells from optic nerve (exit at optic disk)
area centralis - temporal to disk, area of higher cone density, devoid of blood vessels, usually blood vessels branching around it
in doemstic animals mostly rod based

Path of light sensation to optic nerve then goes to

optic chaism, optic tracts, lateral geniculate body of thalamus, optic radiations, occipital cortex (vision)

how to test vision

behavioral - owner, maze testing in light and dark, cotton bal
menace - retina, optic nerve, optic radiations, visual cortex, then CN VII for blink reposne

Testing for retian/optic nerve functiong

PLR - retian, optic nerve, parasympathetic anteromedian nucleus, then CN III to iris
dazzle reflex - withdrawal respose, subcortical

How to test retinal funciton directly

electroretinogram (ERG) light stimulation reuslt in electral repsosne measures photoreceptor acitivty
(usually prior to cataract sx and in cases of blindness espcially with normal ophthalmic exam)

Assesing a hidden retina - ultrasonogrpahy

useful when canot visualzie posterior segment, can dx retinal detachemnt, vitreal abnormalities, tumors

Fundus - what is it and layers

strucutres of posterior segment visualized during exam
divided into tapetal fundus, non-tapetal fundus, optic nerve head (optic disc), vascualture

Fundus - opthalmoscopy indirect vs direct

indirect - larger field of view, inverted image, lower mag, good for exam of entire fundus
direct - smaller field of view, high mag, upright image, for closer exam of leison, inspection of opitc nerver

Sytematically assess the fundus

evaluate - blood vessels (attenuated, large, tortuous)
tapetal reflectiivty (increased, decreased)
retinal hemorrhage
detachments

Tapetal fundus

variablly traingular, located in superior fundus
cats - usually yellow to green
dogs - green, yellow, orange, blue
color of funds related to coat color, color dultue animals especialy merles may lack tapetum
small dogs = small tapteum and vice versa

Non tapetal fundus

largest area of fundus
junction between tapetal/nontapetal area highly variable (distinc demaracation to transitional area)
tan to dark brown (reuded pgiement (albinoitc animals) allows choroidal vasculature to be seen)

Choroidal vessels vs retianl vessesl

larger, straighter, birhgter, orange
decreased pigmentation in choroid allows choroidal vessels to be seen

Retinal vessel pattterns - holangiotic retina

dogs, cats, ruminants
etesive (visible retinal vascular supply)
usually 3-4 major venules, variable number of arterioles
arterioles smaller and lighter in color

Retinal vessel patterns - paurangiotic retina

horses
small retinal vessels extending only a short distance from optic disc
usually 30-60 fine vessels radiating from disc

Dog optic head variation

located in tapetum, quite variable myelination
varaitoin in myelination causes variation in nerve shape, round oval, triangular, polygonal
pinkish white to deep pink

Cats - optic head variaitons

located in tapetum not myelinated
circular, graysih color, conus-perpapillary hyperreflectivity

Generalized progressive retinal atrophy (PRA) - 2 subdivisions

photoreceptor dysplasia- severe structual alterations of rods before retina completely developed (rate of progress and fate of cones varies)
photorrecepotr degenerations - degeneration of photorecepotrs after normal differentiation (slower and later onset of disease)

most are autosomal recessive

Photoreceptor dysplaisa - signalment

first year of life
irish setters, norwegian elkhounds, collies, mini schanuzers, belgian shepherds

Photorreceptor degenerations - signalment

middle aged or older dogs
usually rods affecred first and most severely
mini poodle,s mini schanuzers, cocker spainels, collies
alaskan malamute - cone degeration (day blindness but retain night vision throughout life)

Progressive retinal atrophy - s/s

both type have simialr s/s
bilateral and leads to blindness
decreased night vision (nyctalopia) usually first signs (since rods usually affected first)
progressive decrease in PLR, but may be present even when dog clinically blind
latger resting pupillary size than normal
cataract formation in very late stages

Progressive retinal atrophy - fundic exam findings (early, moderated, advanced)

early - subtle altred tapetal relfectiivty, usually peripheral, mild vascular attenuation
moderate - increase in tapetal reflectiivty and vascular attenuations, slight decrease in pigmentation of non-tapetal funds, decreased myelination of optic nerve head, optic nerve head atophy
advanced - maker hyperreflecivitiy, decreased pigmentation of non-tapetal fundus, maked vascualr attenuaiton, pale, demyelinated optic disk

What is wrong with the fundus on the right

Advanced PRA - small vessels, optic nerve atrophy, hyperreflectivity

Sudden acquired retinal degernation syndrome (SARDS) - what is it and signalment

acute photorecptor death
middle aged dogs, femlaes predisposed, all breeds affected

Sudden acquired retinal degeneration syndrome - s/s

weight gain, polyuria, polydispia, polyphagia for weeks or months prior to vision loss (cushing’s like signs)
Acute vsision los often over 24 hours, dilated pupils, minimal PLR, normal fundic exam

Sudden acquired retinal degeneration syndrome (SARDS) - diagnosis, tx

dx - electrotinogram (ERG) to confirm loss of photoreceptor function, may have elevated ALK phos or other cushing’s like changes on bloodwork but rarely positive for cushing’s
tx -none permanent blindness
fundus will develop opthalmoscopiacally visible s/s of degernation voer time, simialr to PRA

Retinal dysplasia

linerar folding of sensroy retina with formation of rosettes, abnormal formation of full thickess areas of retina
may have involvemnt of other strucutres of eye
visual deficit depends on severity (mild cases = no s/s)

Retinal dysplasia - signlament and etiology

signalment - labs, springer spaniels, sealyham terriers, bedington terriers, beagles, cocker spaniels
etiology - heredity (most common, autosomal recessive), herpes, vit A deficiency, radiation, trauma, toxins

Retinal dysplasia - clincial apperance

focal or mutifocal retinal folds or rosettes, appear as reduced tapetal reflectiivty, gray or green dots or linera V or Y areas, usually superior to disk
more severe - geogrpahic irregualr or horseshoe-shaped area usually in superior fundus, usually hypereflective with variable pigmentation, may have focal retinal detachemnts

Retinal dysplasia is more common in what breed

Lab with ocualr and skeletal defects (oculochondrodyplasia)
ocular cataracts, complete retinal detachemnt and skeltal retareded growth of raidus, ulna and tibia, hip dysplasia, hypoplasia of anconeal/coronoid processes

collie eye anomlay - etiology and signlament

etiology - simple autosomal recessive - variable expression
signlaemnt - collies, shetland sheepdogs, aussies, border collies

Collie eye anomaly - what is it, choroidal hypoplaisa, intraocualr hyphema

abnormal mesodermal differentiation - defects in sclera, choroid, optic disk, retina, retinal vasculature
choroidal hypoplaisa - palte to white area temporal or superiotemporal to disk, associated with abnormal tortuous choroidal/retinal vessels
s/s - usually none
intraocular hyphema - usually associated with retinal detachment and colobomas blindness

collie eye anomaly - posterior colobomas and retinal detachemnt

usually involve optic disk or just adjacent to disk, gray or pink indentations of variable depth, varibale s/s
retinal detachemnt - often associated with colobomas, blindness

s/s of inflammatory disease of retina acitve lesions

fuzzy or indistinct borders, hyporeflective tapetum, raised areas

Chorioretinits vs retinochoroiditis

Chorioretinits - choridal extneds to retina
retinochoroidiits - retina to chorioids (uncommon)

Chorioretinal inflamations and infections s/s

may have none, if severe may have red eye, signs of uveitis (panuveiits), vision loss if extensive

s/s of chorioretinal inflamations and infections - acute

irregular margins of lesions
often riased - extensive subretinal exudates may cuase local or extensive retinal detachment
edema - grya irregular borders
retinal blood vessles - go over exudate, edeuma
tpaetal - indistinct grayish/borwnish areas, white, perivascular opacities (WBC accumualtion/granulomas)hyporeflective areas, obscured/inflamed
non-tapetal - grayish to white areas, white, perivascular opacities

Chorioretinal inflammations and infections -s/s chornic/inactive

distinc margins, flat not raised
tapetal- hyperreflective areas (retina overlying tapetum is thinner) may have pigmented clumping, blod vessel attenuation in area of lesion
non tapetal - depigmentation areas with variable pigment clumping/proliferation, blood vessel attenuation
optic nerve - pale atrophied in some cases

DDX - choriretinits (infective)

viral - distemepr, herpes, feLeuk, FIP, FIV in cats
bacteria - septicemia
rickettsial-enhrilchia canis or platys, rickettsia rickettsii (especially retinal hemorrhage, vasculitis)
fungal - blastomyces, cryptococcus, coccidiodes, geotrichum, aspergillus (esp chorioretinal exudates)
algal - protheca spp (rare)
protozoal - toxoplasma, neospora, leishmainia
parasitic - toxocara and balisacaris (ocular larval migrans), diptera (opthalmonyiasis interna)

dx - chorioretinits

minmum datapase
titers by geography, BP, fecal
if extensvie retinal detachemnt or vitreal inflammation, could do viteral or subretinal tap

Chorioretinal inflammations and infections - tx

treat primary cuase and associated uveal inflammation (systemic anti-inflammatories)

Retinal hemorrhages apperance

reflects anatomicla locatoin
subretinal - large, dark
intraretinal - punctate
superficial - flame shaped
pre-etinal - globular, boat-keel

Retual detachemnts happen when____ and small vs large detachemnts

usually neurotetina sperates form underlying reitnal pigmented epithelium (RPE) (embryologic basis
small detachemnts - no visual deficits
large - visual deficit or blindness

Retinal detachments - non-rhematogenous retinal detachments/exudative

remian attached at ora ciliaris retinae (periphery) and at optic nerve
bullous detachemnts, edudative retinal detachemnts “morning lgory” inflammatory or exudative fluid displacing retina
can also be due to vitreal traction bands - secondary to vitreal inflammation or hemorrhage resulting in fibrous bands that contract and pull retina off RPE

Retianl detachments - ophthalmoscopic apperance - exudative/bullous detachemnts

anteiro displacment of retina
focal -may be an area of retina out of focus

Retinal detachemnts - optalmoscopic apperance - complete bullous attachemnt

retinal vessels may approach back of lens capsule often can see with transilluminatory (penlight diagnosis)

Bullous (fluid) often associated with

systemic disease

retinal detachemnts -tx

systemic workup in animals with bullous or exudative retinal detachemnts
tx - treat underlying cuase

Retinal detachemnts - rhematogenous retinal detachments -

retinal tear of break present which allows liqufied viterous to enter subretinal space (between retina and RPE)

Retinal detachments - dialysis

refers to separation of peripheral retina from attachments, also called “disinsertional”

Retinal detachemnts - ophthalmoscopic apperance - dialysis

retina hanfs in grayish folds, obscuring optic nerve, tapetum is hyperreflective with no visible vessel

rhematogenous retinal detachments are cuased by

congenital abnormalities (collie eye anomaly, optic nerve colobomas allow viterous in subretinal space)
shih tzus/lhasa - may have a primary viterous abnormailty that predisposes to RRD
maybe secondary to inflammation or trauma
post cataract sx?
surgical repair difficult

retinal detachemnts - sx repiar

rhematogneous or traction bands only (focal, non inflammatory)
simplest is laser retinopexy-rows of burns around detachment to create adhesions to prevent further detachemnt
more complicated sx involve entering viterous chamber, removing viterous and replacing with various oils or gases, along with retinopexy

Hypertensive retinopathy - signalmnet, etiology, location

acute vision loss in older cats
s/s due to precapillary vascocontriciton of retinal arteriols (autoregulation) → smooth muscle necrosis, vascular dialtion and leakge
may occur in choroid as well leading to retinal detahcemnts

hypertensive retinopathy - s/s

hyphema, intraviteral hemorrhage, retinal vessel tortuosity, retinal hemorrhages, varying degress of retinal detahcment (sudden blindness)

Hypertensive retinopathy - dx

BP measurement, systmeic work up (associated with cardiac, renal abnormalities and hyperthyroidism)

Hypertensive retinopathy - tx and prognosis

tx - treat primary disease and lower BP
prognosis - quick retinal reattahcment may result in regianing vision but retina may slwoly degenerate over time

Retianl detachemnts cuases in cats

hypertension, hyperviscosity syndromes, infectious (toxoplasmosis, cryptococcosis, blastomycosis, histoplasmosis, FIP) neoplasia

Nutiritional retinal degeneration

traurine deficiency and it isessentia to photorecepotr function
tuarine defifecy retinal degenration = feline cnetral retinal degeneration

Nutritional retinal degneration - stages

increased granulairty to area centrali
elipsoid hyperreflective region
development of seocnd hyperreflective lesion nasal to disk
two leisons coalesce to form horizontal band over disk
end stage - generalized retinal degeneration

Nutritional retinal degenration - dx and tx

dx - measure taurine lvels and caridac function
tx - none to reverse damage but supplementation will prevent progression

Retinal dysplaisa - feline

associated with FeLV and panleukopenia along with impaired devlopement of cerebral and cerebellar tissues

Chorioretinal inflammation in cats

opthalmoscopic s/s similar to dogs
causes - viral FeLV, FIP, FIV, bacterial fungal (crytococcosis, histoplasmosis, blastomycosis, parasitic)

Optic nerve what is it

extension of brain
axonal projection of the retinal ganglion cells
coalesce at optic nerve head (where myelinated)
pass through lamina cribrosa of sclera to retrobulbar space
surrounded by meninges where exit eye

Optic nerve divisions

intraocular - retinal ganglion cell layer, nerve fiber layer, optic nerve head, intralaminar (scleral) region
intraorbital - posterior to globe
intracanalicular - nerve within the canal
intracranial nerve - from canal to optic chiasm

micropapilla/optic nerve hypoplasia/optic nerve aplasia

decreased number of retinal ganglion cells
unilateral or bilateral
visual deficit depends on severity, PLR variably affected

Micropapilla/optic nerve hypoplasia/nerve aplaisa - aperance

small, round and gray round due to lack of myelin, nromal retinal vessels

Optic nerve colobomas

pits on or withinnevere
part or all of disk may be involed
in collie eye anomaly other breeds afected
may predipose to retinal detachemnt

coloboma

defect or absence of ocualr strucutre

Optic nerve inflammation

opitc neuritits
unilateral or bilateral
can involve any segment of optic nerve
associated with sudden blindness, fixed and dialted pupils

Optic nevre inflamamtion - intraocualr ivovlement vs retobulbar invovlemt

intraocular - disk appears swollen, elevated, and hyperemic, margins become indistinct
retrobulbar - optic disk will appear normal
ERG nromal

optic nerve inflammaiton -ddx

infectios (distemper, blastomyosis, cryptococcosis, histoplasmosis, toxoplasmosis)
trauam, toxins, vit a defieicney, neoplasia - reticulsis/GME
idiopathic

optic nerve inflammation - dx

CBC, chem, uA, 3 view chest, titers,
MRI or CT
CSF tap
think as a neuro disease

optic nevre inflammation - tx

treat primary cuase
systemic steorids especially if cannot determine pirmary cuase and have ruled out infectious disease
often poor prognosis for vision

Optic nerve atrophy

pale nerve, myelin loss (becoes round)
assoicated with PRA, chronic glaucoma, optic neuritis

Trauamtic optic neuropathy

traumaitc proprtosis - optic enrve shearing, laceration or avulsion (immediate vision loss with PLR deficit)
may have damage further awya from globe or ischemic damage
if optic nerve intact steroids may help

Seizure has an anatomic diagnosis of

prosencephalon

seizure definition

a sudden and transient abnormal phenomenon of a motor, sensory, autonomic or psychic nature resulting from transient dysfunction of the brain

GABA effect

hyperpolarize that sends inhibitory impulses

Glutamate effect

depolarize - excitatory impulses
50% of impulses

3 types of seizures

generalized, focal, focal with secondary generalization

Simple partial seizures vs complex partial seuizres

simpe have normal responsiveness while complex has abnormal

Post ictal phase

variable period of time after the seizures (minutes - day)

Post ictal phase - s/s

abnormal mental state (aggressive, attention seeking or hiding), blind, change in appetite/thirst

Pre-ictal (prodromal) phase

variable period of time prior the seizures (mins-day)