A Clinical Case from the Archives : 10/01/2005

Posted on January 10, 2005 by davidwilliams

[tab name=”The Case”]This is the eye of a year old pedigree Maine Coone tom cat. What is the problem in the eye and what might be causing it?[/tab][tab name=”David’s view”]The entropion we see here is unusual in a young cat. Most lid inturning in cats is a spastic syndrome seen in older cats. Here, especially in this potential stud animal, we might well worry about an inherited form of lid defect, as we see often in several dog breeds. There is no evidence of direct inheritance here though and it seems that the lid inturning is just a function of the cat’s rather – how shall we put it – meaty jowls![/tab][end_tabset] 

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A Clinical Case from the Archives : 10/01/2005

Posted on January 10, 2005 by davidwilliams

[tab name=”The Case”]What is the problem in this Charolais’s eye and how might it be corrected?[/tab][tab name=”David’s view”]This bull, rather unusually, has entropion of the lower lid. In this case we needed to create a large skin defect to be able to evert the lid margin and stop eyelid hair abrading the cornea. Normally in a dog or cat only a ellipse of a couple of millimeters’ width would be needed and the idea is to place it as close to the eyelid margin as possible – a milimeter or so away. Here it was very difficult to evert the lid in the conscious but sedated animal even after injection of local anaesthetic into the lid tissue, so the incision is further from the lid margin than might have been wanted. Neverthless the operation was successful.[/tab][end_tabset] 

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A Clinical Case from the Archives : 10/01/2005

Posted on January 10, 2005 by davidwilliams

[tab name=”The Case”]What is the problem in this young labrador and how would you correct it?[/tab][tab name=”David’s view”]The dog has severe lower lid entropion with trichiasis (abrasion of lid hairs on the cornea) and excess lacrimation from ocular surface trauma. A number of techniques could be used to evert the lid, perhaps the most commonly used being the Hotz-Celsus technique where an ellipse of skin is removed to create tension to pull the lid margin out. In this case we used the Quickert-Rathbun technique to place a single fornix-based suture to evert the lid margin. Read about it in Entropion correction by fornix-based suture placement: use of the Quickert-Rathbun technique in ten dogs. Vet Ophthalmol. 2004 7:343-7 downloadable from the recent publications page of the website.[/tab][end_tabset] 

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A Clinical Case from the Archives : 28/11/2004

Posted on November 28, 2004 by davidwilliams

[tab name=”The Case”]This boxer is presented with a recurrence of a corneal ulcer. What classic feature is evident and what would your treatment be?[/tab][tab name=”David’s view”]These recurrent corneal ulcers, or should we say epithelial erosions, are caused because the epithelium is non-adherant to the underlying stroma because of a defecet in the epithelial basement membrane. They are seen in boxers and West highland white terriers as well as some other breeds. Here a histological section shows the non-adherant edge of the epithelium precluding further healing. Treatment involves debridement of this devitalised tissue and encouragement of healing with a grid keratotomy with protection of the healing ulcer with a third eyelid flap or contact lens. Two very useful recent papers on this condition are from Chris Murphy’s group in the States: (Morphology and immunohistochemistry of spontaneous chronic corneal epithelial defects (SCCED) in dogs. Invest Ophthalmol Vis Sci. 2001 42:2262-9, Spontaneous chronic corneal epithelial defects (SCCED) in dogs: clinical features, innervation, and effect of topical SP, with or without IGF-1. Invest Ophthalmol Vis Sci. 2001 42:2252-61)but here are two other papers which might be easier for vets to access (RG Stanley et al: Results of grid keratotomy, superficial keratectomy and debridement for the management of persistent corneal erosions in 92 dogs.
Vet Ophthalmol. 1998 1:233-238, SE Kirschner: Persistent corneal ulcers. What to do when ulcers won’t heal.
Vet Clin North Am Small Anim Pract. 1990 20:627-42[/tab][end_tabset] 

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A Clinical Case from the Archives : 28/11/2004

Posted on November 28, 2004 by davidwilliams

[tab name=”The Case”]What is evident in the cornea of this pug? What has happened, why and what is the necessary treatment?[/tab][tab name=”David’s view”]The black lesion is a descemeocoele where a corneal ulcer has perforated through the stroma to leave only descemet’s membrane bulging forward. The black appearance indicates that iris is protruding into the ulcer giving a staphyloma. The central cornea of the pug has limited sensation so that a corneral ulcer can go un-noticed until it is very severe, as in this animal. Treatment is surgical and the best operation is either a full thickness graft or more likely a corneoconjunctival transposition graft as described in the cat by Andrews and colleagues(Corneoconjunctival transposition for the treatment of feline corneal sequestra.
Vet Ophthalmol. 2001 4:107-11). This dog shows the result possible when this surgery is used in such a situation.[/tab][end_tabset] 

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A Clinical Case from the Archives : 28/11/2004

Posted on November 28, 2004 by davidwilliams

[tab name=”The Case”]What is happening to cause the lesion in this dog’s cornea? The animal was presented with acute ocular pain in the middle of August. What treatment would you prescribe and what prognosis would you give?[/tab][tab name=”David’s view”]The dog has a melting ulcer – the white uneven surface is characteristic of this lesion occurring most commonly in hot and humid conditions. Gram negative bacteria such as Pseudomonas are often responsible but as well as frequent topical antibiotic (gentamicin or fluoroquinolone every hour for the first 12-14 hours then less frequently later) anti-collagenases are vital. Serum inhibitors of matrix metalloproteinases such as alpha-2-macroglobulin make topical serum every hour for the first day an easy and effective option while EDTA chelates calcium, a vital co-factor in these collagenases. In this case such intensive treatment gave a good result as can be seen here but the prognosis should always be grave.[/tab][end_tabset] 

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A Clinical Case from the Archives : 08/11/2004

Posted on November 8, 2004 by davidwilliams

[tab name=”The Case”]What is the condition seen in this cat? What infectious agents might be causing the lesions in this 8 year old cat’s eyes? How would you differentiate betwen the two?[/tab][tab name=”David’s view”]The cat has conjunctivitis with chemosis or conjunctival oedema. The condition may be associated with Chlamydophila infection or with feline herpesvirus. Differentiating between the two is impossible by simple clinical examination of a cat such as this. A swab for polmerase chain reaction of viral or chlamydial DNA is the best method. If finances do not allow for such a test, treatment with chlortetracycline can be diagnostic; if the condition improves markedly the disaese is most likely to be chlamydial, while otherwise FHV-1 must be the more likely candidate.[/tab][end_tabset] 

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A Clinical Case from the Archives : 08/11/2004

Posted on November 8, 2004 by davidwilliams

[tab name=”The Case”]What is this black lesion in this domestic short-haired cat’s eye? What might have caused it? It is irritating the cat somewhat; how would you treat it?[/tab][tab name=”David’s view”]The lesion is a corneal sequestrum, seen only in the cat, and representing a stromal necrosis. The lesion might well be seen as a final common pathway for a number of corneal conditions; in Persian and Colourpoint breeds it occurs probably associated with corneal anaesthesia seen in these breeds; in domestic short-haired cats it can be associated with feline herpesvirus. Treatment is surgical with removal of diseased tissue by a superficial keratectomy. The lesion can slough naturally but early surgery is probably to be advised; leaving it too long can result in a very deep lesion as seen here, where removal of the superficial layers still leaves diseased tissue. A full thickness graft or deep lamellar keraectomy with tectonic graft are the only surgical options.[/tab][end_tabset] 

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A Clinical Case from the Archives : 08/11/2004

Posted on November 8, 2004 by davidwilliams

[tab name=”The Case”]This eight year old cat is affected by these corneal lesions on a reasonably regular basis. What are you seeing here, what is the cause and is it wise to use some topical steroid to solve the problem?[/tab][tab name=”David’s view”]The linear fluorescein-positive lesion is a dendritic ulcer, pathognomonic for feline herpes virus infection. These can resolve on their own, just like coild sores in people, but topical antiviral is valuable. In the States several drugs such as idocyuridine are available but in the UK only trifluorothymidine and acyclovir can be accessed. While many consider the former to be the only useful agent here, we have shown that topical acyclovir, used four or five times daily, can be effective. The key take-home message is not to use steroid. This reduces local immune responses and allows the virus to produce a stromal keratitis, as shown here.[/tab][end_tabset] 

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A Clinical Case from the Archives : 17/10/2004

Posted on October 17, 2004 by davidwilliams

[tab name=”The Case”]This Siamese cat is presented to you with the owner having been concerned about its vision since they moved house and the cat suddenly couldn’t find its way around. What is the lesion and why has the cat had this apparently acute loss of vision?[/tab][tab name=”David’s view”]This is tapetal hyper-reflectivity demonstrating that there is retinal degeneration. Inherited retinal degeneration is seen far less in the cat than in the dog where progressive retinal atrophy is common in several breeds. The Siamese is seen more commonly than other cat breeds with these signs (Giuliano and van der Woerdt Feline retinal degeneration: clinical experience and new findings (1994-1997). J Am Anim Hosp Assoc. 1999 35:511-4) but no specific mutation has been defined in this breed. This paper specifically makes the point that cats adapt very well to blindness and this is what seems to have been the case here. The retinal degeneration is a chronic not acute change; a cat with these signs may have been blind for a long time but well adapted to its surrounding. Only a change of environment showed its defective vision. The owner can be reassured that the cat will readapt quickly and show no ill effects from its blindness.
[/tab][end_tabset] 

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