A Clinical Case from the Archives : 07/05/2005

Posted on May 7, 2005 by davidwilliams

[tab name=”The Case”]Here’s a cat presented by the owner who had noticed an unusual change in appearance of her 6 year old cat’s eye. What is happening here and has it any consequences for the health of the eye and the cat in general?[/tab][tab name=”David’s view”]What you are seeing here is a ballooning forward of iris tisue that is adherant at the pupil margin to the anterior lens capsule. Its what we call iris bombe and signals an anterior uveitis with posterior synechiae around the majority of the pupil margin. As far as the eye is concerned it may give glaucoma although the pressure here was 15mmHg, within normal limits. Actually I’ve been rather naughty here, since I should have told you that three weeks earlier the cat had an active anterior uveitis which we treated with atropine and steroids topically. Te inflammation has now calmed down but leaving the sequelae of this iris bombe. Treatment is quite tricky – one wants to break down the adhesions to relieve the bombe, but using atropine could be contraindicated where glaucoma may supervene and surgical intervention to breakdown the synechiae may have untoward effects in restarting the inflammation – notice the fibrin clot in the pupil showing that the eye is living on a knife edge of impending active inflammation.[/tab][end_tabset] 

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A Clinical Case from the Archives : 01/05/2005

Posted on May 1, 2005 by davidwilliams

[tab name=”The Case”]This rabbit has had an inflammatory episode of uncertain aetiology and ends up with this strange corneal appearance. I’m indebted to Alice Courtney for this great picture. What do you think might be going on here and does it shed any light on what happened to cause the problem?[/tab][tab name=”David’s view”]This white circle with a target lesion centrally in a somewhat oedematous cornea with an inflammatory ‘muddy’ loss of intraocular detail, is most probably a Wessely ring; that is to say a circle of antibody-antigen complex deposition with the antigen coming most probably from a central traumatic event and the antibody from blood vessels at the limbus. Its the same sort of deposit that gives an immunopreciptate in an agar gel preciptation assay, as here, where antigen is placed in one well and antibody in the other. While this is a classic corneal appearance it is very rare – I’ve never seen one before apart from in experimentally induced situations in textbooks. Topical anti-inflammatory and antibiotic treatment has been used here with some success but it is a shame that we don’t know which antigen(s) are involved. Suttorp-Schulten and colleagues produced a paper documenting the changes that occur in such a lesion: The fate of antigen-antibody complexes in the rabbit cornea. Current Eye Research 1991 10:773-8 and
Meyers-Elliott has documented the condition occuring with corneal herpesvirus infection in people: Viral antigens in the immune ring of Herpes simplex stromal keratitis. Arch Ophthalmol. 1980 98:897-904.
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A Clinical Case from the Archives : 21/04/2005

Posted on April 21, 2005 by davidwilliams

[tab name=”The Case”]Richard Byrne send me this picture today for a quick bit of telediagnosis with this question: This cyst has grown very fast [in a three year old male labrador] over the last 4 months and the owner is concerned – could you advise on the prognosis and any treatment options for
this case. First thanks to Richard and second what would your answer be?[/tab][tab name=”David’s view”]This is without doubt an iris cyst. There isn’t a differential list here; iris cyst is the only possibility and iris melanomas or naevi just don’t look like this pigmented sphere in the anterior chamber. Quite what to do with them is another matter. One cyst is unlikely to cause much of a problem, but where many occur, as in this second case, and especially in Golden Retrievers, glaucoma can supervene. One can remove them by aspiration under general anaesthetic or by laser surgery, as reported by Anne Gemensky-Metzler in her paper ‘The use of semiconductor diode laser for deflation and coagulation of anterior uveal cysts in dogs, cats and horses: a report of 20 cases.’ from Veterinary Ophthalmology 2004 7:360-8.[/tab][end_tabset] 

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A Clinical Case from the Archives : 21/04/2005

Posted on April 21, 2005 by davidwilliams

[tab name=”The Case”]What is this lesion on the upper eyelid of a three year old crossbred dog likely to be?[/tab][tab name=”David’s view”]While this could be inflammatory, the liklihood is that it is neoplastic. Complete excision yielded this histopathology. Note how the tumour cells hug the epithelium – their cell phenotype shows this to be a histiocytoma. Go back to the clinical picture and notice how the hairs stand erect within the body of the mass. This is another feature of this type of tumour because of the infiltration around the hair follicles.[/tab][end_tabset] 

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A Clinical Case from the Archives : 08/04/2005

Posted on April 8, 2005 by davidwilliams

[tab name=”The Case”]Diseased rabbit eyes rarely look particularly pretty, and this animal is a case in point. What are you seeing here and what is likely to be the cause of the problem?[/tab][tab name=”David’s view”]This is exophthalmos caused by a retrobulbar space occupying mass. It could be a tumour or an abscess, but in a rabbit that latter is far more likely. Here is an MRI of the head, showing pus extending up in the orbit and then down as far as the cervical area. The kindest thing in this case was euthanasia. Less severe lesions could be treated with enucleation and orbital exenteration, but even then the infection almost always recurs at some point.[/tab][end_tabset] 

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A Clinical Case from the Archives : 08/04/2005

Posted on April 8, 2005 by davidwilliams

[tab name=”The Case”]What condition is this poor rabbit suffering from? What causes it and how would you treat it?[/tab][tab name=”David’s view”]This is dacryocystitis – inflammation (and in all probability infection) or the nasolacrimal duct. The rabbit has a narrow duct with two points at which the duct bends and narrows. This, together with the likelihood of maxilary bone involvement in nutritional bone disease and dental abnormalities, leads to this build up a pus, shown well here as it leaves the single nasolacrimal punctum. Regular flushing and probably systemic antibiotic therapy too are steps to resolutin of the problem, but the road to a cure, like the nasolacrimal duct iteslf, is long and tortuous!![/tab][end_tabset] 

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A Clinical Case from the Archives : 08/04/2005

Posted on April 8, 2005 by davidwilliams

[tab name=”The Case”]Whose fundus is this? What term do we give this arrangement and why does the animal organise the back of its eye like this?[/tab][tab name=”David’s view”]This is a rabbit’s fundus – the question image was from a New Zealand White animal with a non-pigmented eye while this is from a normally pigmented Netherland Dwarf. We call this a merangiotic fundus – the rebbit has a long horizontal visual streak, giving it good vision all along the horizon, from whence might spring a hungrey fox! So it keeps its blood vessels and myelinated nerve fibres (the whiote streaks – but who knows why it has any mylelinated fibres – no other species bothers!) away from this lnie of high photoreceptor density.[/tab][end_tabset] 

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A Clinical Case from the Archives : 21/03/2005

Posted on March 21, 2005 by davidwilliams

[tab name=”The Case”]What is wrong with the eye of this young guinea pig? What inherited breed characteristic might be responsible?[/tab][tab name=”David’s view”]The eye has severe ocular surface disease, associated with the harsh hair coat of these rex guinea pigs, as shown in this wider angle photograph of the whole head. Breeders generally use KY gel to smooth the periocular hairs back right from birth and prevent irritation of the cornea.[/tab][end_tabset] 

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A Clinical Case from the Archives : 21/03/2005

Posted on March 21, 2005 by davidwilliams

[tab name=”The Case”]What is this red mass at this guinea pig’s medial canthus? Can you think of a similar condition in dogs whjich might give you a clue?[/tab][tab name=”David’s view”]This guinea pig has what cavy fanciers know as flesh eye. To tell you the truth we don’t know exactly what the tissue involved it – the cavies aren’t bothered by it so removal doesn’t exactly seem ethical, just to satify our intellectual curiosity! But this dog has a prolapsed gland of the third eyelid so we think its probably the same condition. Do let me know if you’ve had the opportunity to do histopath on one of these please![/tab][end_tabset] 

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A Clinical Case from the Archives : 21/03/2005

Posted on March 21, 2005 by davidwilliams

[tab name=”The Case”]This guinea pig is somewhat polydypsic, polyuric and polyphagic. What ocular defects are present and can these be related to the animal’s systemic condition?[/tab][tab name=”David’s view”]There is fat deposition in the lower lid conjunctiva but more importantly a mature cataract which developed bilaterally very rapidly. The cataracts are related to diabetes and the fat deposition may be linked in that the cavy was being fed a rich diet prior to being shown at a championship. Little is known about guinea pig diabetes, but it may be that obseity has been a factor in the development of diabetes in this animal.[/tab][end_tabset] 

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