A Clinical Case from the Archives : 06/05/2006

Posted on May 6, 2006 by davidwilliams

[tab name=”The Case”]This 7 year old horse presents with a slowly growing firm medial canthal mass. What might your differentials be and how would you determine which was correct?
[/tab][tab name=”David’s view”]Well top of my list would be a sarcoid, next another neoplasm with a lacrimal sac lesion further down the list. So I was surprised on performing a fine needle aspirate, to be able to draw of several mls of this clear brown fluid. The cyst (for that’s what I guess this is) slowly filled up over the few few hours. So now my question is, should we resect the cyst or can we inject a sclerosing fluid to adhere the walls of the collapsed cyst together?
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A Clinical Case from the Archives : 23/03/2006

Posted on March 23, 2006 by davidwilliams

[tab name=”The Case”]This cat is presented because the right eye has changed to a yellow-brown from the blue-green of the fellow eye. What could the cause of this be? How would you determine what the true cause is?[/tab][tab name=”David’s view”]To my mind the differentials are development of uveitis, iris naevi (benign pigmented lesions) or frank melanoma. This picture shows little light brown areas in the iris characteristic of naevi, but there are also keratic precipitates on the back of the cornea like a grey haze, demonstrating uveitis. My only worry is that some of these are pigmented (particularly on the right) and that the intraocular pressure is 14mmHg in both eyes, rather than being lower in this one as we might expect from an inflamed eye. A paracentesis might yield cells that would give you a definitive diagnosis but removing aqueous in that manner would exacerbate any inflammation so at present I’ve chosen to watch and wait, wimp that I am![/tab][end_tabset] 

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A Clinical Case from the Archives : 12/03/2006

Posted on March 12, 2006 by davidwilliams

[tab name=”The Case”]This horse is presented with a sore eye of some month’s standing. What is the likely diagnosis and what therapeutic measures would you suggest?[/tab][tab name=”David’s view”]This is likely to be a squamous cell carcinoma and surgical resection, as shown here, is required ideally with ajunctive radio or cryotherapy. Long term prognosis with such an advanced lesion is not particularly brilliant.[/tab][end_tabset] 

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A Clinical Case from the Archives : 04/03/2006

Posted on March 4, 2006 by davidwilliams

[tab name=”The Case”]What species are we looking at here and what condition? What treatment would you suggest?[/tab][tab name=”David’s view”]This is a cat with a prolapsed nictitans gland, a so-called cherry eye. While not unheard-of (see Chahory et al Three cases of prolapse of the nictitans gland in cats. Vet Ophthalmol. 2004;7:417-9 and three other papers suggesting a breed predisposition of the Burmese) the condition is seen much more commonly in the dog. As in that species, replacement, here using the mucosal pocket technique is advisable.[/tab][end_tabset] 

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A Clinical Case from the Archives : 26/02/2006

Posted on February 26, 2006 by davidwilliams

[tab name=”The Case”]This young labrador is brought to you with persistently dilated pupils but apparently no deficiency with her sight. The owner happens to mention that the dog seems overly interested in a small number of amphibians (she doesn’t know if they are frogs or toads) at the bottom of the garden. Could that have anything to do with this abnormality?[/tab][tab name=”David’s view”]The pupils do seem fixed and dilated – there is no constriction with a bright light. Glaucoma worried me but the dog is normally sighted and the intraocular pressures were normal at 16mmHg. This is then an efferent pupillary defect and might well be related to a pharmacological pupil dilation. Amphibians like this common British toad are known to excrete anti-cholinergic toxins from their skin (Tsuneki et al Alkaloids indolizidine 235B’, quinolizidine 1-epi-207I, and the tricyclic 205B are potent and selective noncompetitive inhibitors of nicotinic acetylcholine receptors.
Mol Pharmacol. 2004;66:1061-9 is a recent report but one I don’t expect you have come across in your ophthalmology reading!) so this is a possible cause of mydriasis but the dog has no other signs of parasympatholytic activity – we await the owner presenting the toad to us as well as the dog![/tab][end_tabset] 

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A Clinical Case from the Archives : 16/02/2006

Posted on February 16, 2006 by davidwilliams

[tab name=”The Case”]Here’s one I have to say I am pretty pleased about! Lucky seems rather a sad name for this little 4 week old kitten that comes in from a rehoming centre where he has been left, just about blind. What is happening and what can be done to help him?[/tab][tab name=”David’s view”]After 3 months and surgery to open up the adhered conjunctiva causing a symblepahron that has obscured the eye, here is Lucky, living up to his name and ready to be rehomed. Not a brilliant picture I know but I wanted to show you the advert rehoming him – you can see his eyes are fine now! The key to stopping the conjunctiva readhering is, in my opinion, the fact that we controlled his herpesviral infection with systemic Famvir at 30mg/kg. This is rather an empirical dose, 1/8th of a 125 tablet, the smallest one can get, but it seems to work. We could have used topical penciclovir, the antiviral which is produced as the breakdown product of the oral prodrug famciclovir, but the preparation available, Vectavir, stings in the ulcerated eye, so we didn’t use it in Lucky.[/tab][end_tabset] 

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A Clinical Case from the Archives : 11/02/2006

Posted on February 11, 2006 by davidwilliams

[tab name=”The Case”]Claude, a delightful Tonkinese cat presents to you because his owner is concerned at a difference in colour between the two irises. Intraocular pressure is 15mmHg in both eyes. What is happening here and what might be the reason for the difference between this eye and the other where the iris is uniformly blue?[/tab][tab name=”David’s view”]Here is the eye as it was a month ago with slightly less in the way of focal iris neovascularisation, the cause of the colour change. This could be rubeosis iridis (iris neovascularisation in response to ischaemic change in the iris or retina) but the similarity in iop between the eyes suggests no inflammatory process here and the retina is unremarkable. The other possibility is a neoplastic process in the iris or the ciliary body behind it. Ultrasonography shows a moderately thickened iris but no ciliary body mass. What would your next diagnostic step be? Give me an e-mail and let me know please![/tab][end_tabset] 

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A Clinical Case from the Archives : 01/02/2006

Posted on February 1, 2006 by davidwilliams

[tab name=”The Case”]This aged cat in a rehoming rescue centre is seen to have differently sized pupils but nobody has noted a vision problem. One eye has this appearance in the fundus, while the other has a diffuse retinal greying – I’m sorry you might think this photo is a bit out of focus but the other side really was – it was difficult to focus on the ‘fuzzy’ image of both retina and disc….oh whoops -maybe I’ve given the game away! What is happening here and what might be causing it?[/tab][tab name=”David’s view”]This looks to me like a pretty severe optic neuritis, which would explain the anisocoria perhaps. With limited financial resources I’ve limited my work-up request to a Toxoplasma titre but what else could be causing this?[/tab][end_tabset] 

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A Clinical Case from the Archives : 31/01/2006

Posted on January 31, 2006 by davidwilliams

[tab name=”The Case”]What is the ocular abnormality in this delightful Silkie bantam? What might be causing it and should we be concerned?[/tab][tab name=”David’s view”]Here’s a closer picture – the bluey-greyness is corneal oedema, ocurring bilaterally and I guess the key differential here is to decide whether the diagnosis is glaucoma or uveitis. The intraocular pressure was 8mmHg and so uveitis is the diagnosis – there’s a pretty miotic pupil too though its difficult to see it here. Topical steroid would be of value but of course atropine wouldn’t work as a mydriatic, since birds have a striated muscle iris. The real concern is over a systemic disease. Avian flu, very topical at present, gives oedema in the eyelids and conjunctiva not cornea, and anyway the bird was fine systemically. Newcastle disease can give uveitis(Obaldia and Hanson: Effect of Newcastle disease virus on ocular and paraocular tissues in experimentally inoculated chickens. Avian Disease 1989;33:285-90) as can E coli (Nakamura and Abe: Ocular lesions in chickens inoculated with Escherichia coli. Canadian Journal of Veterinary Research 1987 51:528-30) and even Marek’s disease (Smith et al: Ocular manifestations of Marek’s disease.Investigative Ophthalmology 1974 13:586-92) although this latter agent causes it through iridal lymphoid neoplasia. I must admit to being at a bit of a loss to explain the relatively sudden bilateral uveitis and corneal oedema here – any ideas?![/tab][end_tabset] 

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A Clinical Case from the Archives : 30/01/2006

Posted on January 30, 2006 by davidwilliams

[tab name=”The Case”]This cat is presented with an uncomfortable eye but its really the owner who is uncomfortable with the appearance of the cat – the eye is enlarged. We’ll come to the reason for that in the next image, but why is the eye uncomfortable?[/tab][tab name=”David’s view”]There is corneal oedema but notice also the blackish spots from about three o’clock to seven o’clock ventrally. These are keratic precipitates (deposits of inflammatory cells from the aqueous on the back face of the cornea) showing that the cat has uveitis. The iris is muddy and reddened too supporting that diagnosis. This could be related to FeLV, FIV, FIP or Toxoplasma but the owner decines further work-up, happy to go for topical anti-inflammatory treatment alone. Go to the next question to see how the eye looks compared to the contralateral side.[/tab][end_tabset] 

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