Equine Med - Optho

drraythe's version from 2017-09-10 05:02


Question Answer
most common reason horse holding eye shutpain
check CNs for eyes....which nerves?Menace= II & VII....Palpebral= V & VII.....PLR= II & III....Eye position= III, IV and VI
eye position which CNs?3,4,6 make the eyes twitch
if youre gonna nerve block, do what first?CN test
sedation drugs for eye exam?prolly xylazine or detomidine or sthing
what are the 3 equine regional nerve blocks for the eye?frontal n block, auriculopalpebral n block, lacrimal n block
frontal nerve block does what?blocks sensory to upper lid
auriculopalpebral nerve block does what?blocks Motor to orbicularis oculi (upper eyelid)
lacrimal nerve block does what?block sensory to lower eyelid
FIRST things you should do with an eye examCheck PLR, before you put in drops check tear production/ do culture
what do you dilate the eye with? what DON'T you dilate the eye with?DO: tropicamide. DONT: atropine. can cause GI stasis
all horses with squinty eyes have ___ until proven otherwisekeratitis (corneal ulcer)
analgesia for eye exam?Topical proparacaine
how common is IOP taken?not commonly- refer for this. No set normals. Changes with head position and sedation
why stain with fluorescein?look for ulcers and nasolacrimal duct patency (in nasal passage within 5 min)
If you suspect fungal keratitis, which stain?rose bengal
if you try to dilate pupil and its still miotic after ___(time), what do you suspect?takes at least 20min, suspect uveitis
what does the optic disk look like with the fundic exam?Large pink horizontal ellipse/oval, check the blood vessels too
why would you US the eye?look for detached retina
what should you know about the speed of the horse PLR?smaller than small animals
what is the hangy-down awning part that partially covers the horse pupil?Corpora nigrans (shades pupil from light)
why are foals predisposed to keratitis?foals are REALLY predisposed bc no menace and dec corneal sensitivity
white cornea means?abscess, necrosis, hypopyon
red cornea means?(1) vessels: Superficial (tree-like) and deep vessels (bush). (2) Hemorrhage
superficial vs deep corneal vessels look like?superficial looks tree like and deep looks like hedges
blue cornea means?edema
black cornea means?BAD- prolly iris trying to pop out
do horses do well with enuclations?yes! owners are the ones with the prob
melting corneal ulcer is called? why does this happen/ what is usually to blame?keratomalacia, Said in class: usually strep or pseudomonas-- and make proteases or elastaces. this is protein degradation. not much we can do by this stage. prevent routine corneal ulcer from becoming this. if tons of neuts on ulcers, pre-melting phase
corneal ulcer can lead to..anterior uveitis
things you look for on cytology of an ulcerStain for organisms, cell types present, If lots of neutrophils & bacteria might start melting
if you need to get meds into a horses eye mult times, you might consider what kinda system?Subpalpebral Lavage System
what can you give to reduce pain from uveitis?atropine
what kind of analgesia should you use on the eye if there is an ulcer?NO STEROIDS!!! consider Systemic flunixin meglumine and Topical NSAIDS (Flurbiprofen or diclofenac)
sx you can try to do to tx corneal ulcer?Conjunctival flap surgery
What are some antiproteases which you can give for severe ulcers?EDTA, N-acetylcysteine, Systemic doxycycline
If the horse's eye is painful but the eye isn't taking up any stain, it can be..(1) Desmetocele (too deep to take up stain) (2) Stromal abscess (see a white spot) (3) Anterior uveitis (equine recurrent uveitis) (4) glaucoma
Equine recurrent uveitis is aka? what is happening? CSs?“Periodic ophthalmia” or “Moon blindness” (moon bc symptoms wax and wane) (Acute and chronic quiescent clinical phases). It's an autoimmune dz with a suspected leptospirosis role (could be other bact/viruses/etc). Dx: Uveitis with no ulcer that recurs. On exam you will see: Painful - tearing, conjunctivitis, Miotic pupil; hypotony, Negative fluorescein retention, Hypopyon, flare, hyphema, Retinal degeneration, butterfly lesions
what is this/ what dz do you suspect? Butterfly lesion from equine recurrent uveitis
infection probably implicate in ERU which breaks blood-ocular barrier? How can you try to confirm it's there?lepto (screw into your eye). Immune system of eye on alert--so abs present in aqueous humor. If aqueous humor Abs > serum Ab titers, or you can isolate organisms from humor. However not a direct relationship, but if there is lepto, it tends to be more severe
*who is genetically predisposed to equine recurrent uveitis?appaloosas. German Warmbloods also have heritable form)
can you tell if an appaloosa might get ERU by just looking at them?sort of-- The less pigment, the more ERU.
what gross sign might you see of the eye with ERU?corpora nigrans atropy
what should your treatment pan be like with ERU? Things you should know about how you give these drugs?(1) REDUCE INFLAMMATION: Can give systemic flunixin, if you suspect lepto, can also give Doxycycline PO for 28d (best to get it in the eye if you can tho). (2) For the eye itself: topical NSAIDs, topical corticosteroids (MAKE SURE NOT KERATITIS), atropine (pupil relax--> pain relief) *****TAPERING IS ESSENTIAL*****
What is the fancy new special effective tx for ERU which is expensive but seems to be quite effective? Suprachoroidal cyclosporine sustained release device (effective for 3-5 years in 70% of horses. so far most effective thing to date. super expensive tho.)
what is prog of ERU like?should consider if it is One or both eyes. Each episode causes progressive damage. Prog depends on: Inciting cause, Age of the animal, Number of previous episodes, tx. Prog for long term vision is guarded.
What do you think this is? what do we know about it? Probably sarcoid- they like to pop up around the eyes. It is a fibroelastic benign tumor, potentially linked to bovine papilloma virus.
what are the two types of sarcoid tumors?Type A stays in the SQ tissue.... Type B goes to the surface.
how should you treat a sarcoid, what should you keep in mind about tx?Can be locally invasive-- esp if you try to treat the and it comes back angrier. so leave alone unless causing a prob. If it is, freeze it off, BCG vx, creams (bloodroot abstract) and drugs like extera-- work good, but not good idea to put near eye. and sx debulk- if really good margins might go away.
what do you think this is? what do we know about it? Tx? MELANOMA!! IT IS A GREY HORSE!! with a black lump on it. It isn't very metastatic in horses tho. Most of the time they don't cause a prob, but they can, so keep an eye on it. tx options-- basially same- cut if off, freeze, etc...most of the time dont do much unless causing a prob. Can be locally invasive. if good margins can sx debride- but prolly not around the eye
what do you tihnk this is? what do we know about it? Tx? SCC. This is a nasty one. In horses usually on eyelids or 3rd eyelids. This is the one where you look out for metastasis. uncommon but should def keep close eye on it- make sure LNs not involved. prolly super painful. how to tx? lots of sthing to try- sx, radiation, freezing, laser.... and no one thing works all the time.
What drug might help reduce the spread of an scc?piroxicam is a kinda nsaid which works on SCC cascade- can help reduce how much they spread.
what is the tumor that actually is most likely to metastasize and cause probs in horses?SCC
parasite that can affect AROUND the eye? Explain it a bitOCULAR habronemiasis. eyeball itself not effected but nasty SQ nodular ulcers in medial canthus of horses face- and white ocular discharge- and its gritty- pathognomonic for hab.
habronema life cycleAdult worm in stomach, horse poops eggs, fly eats eggs, fly deposits larvae inside it near mouth where horse swallows it-- except for when they instead deposit them in wounds or around the medial canthus of the eye
pathognomonic for ocular habronemiasis?white gritty material discharging.
how do you tx habronemiasis?ivermectin. predose with some NSaidS too bc if kill off larvae fast lesons can get worse. treat topically and systemically. but eye itself isnt involved!!
what do you know about where habronema affects the eye?actually medial canthus/SQ NOT the globe itself
parasite that affects tissues around eye? parasite that affects the globe itself?around= habronema. Globe= onchocerca
what is this? Explain it a bit (lifecycle) onchocerciasis. in horses body live in nuchal ligament. produce microfilariae which migrate SQ around horse and eye is accidental location where infection occurs. severe ocular lesions, edema, uveitis.