A Clinical Case from the Archives : 17/09/2004

Posted on September 17, 2004 by davidwilliams

[tab name=”The Case”]What is the lesion in this ten year old cat’s eye and what prognosis would you give for the eye and the animal?[/tab][tab name=”David’s view”]The differential diagnosis of such pigmented lesions in the cat iris is between a benign naevus and a malignant iris melanoma. The velvety appearance of the surface of the pigmented area suggests that latter rather than a more benign iris freckle. Notice how you can see iris detail in this cat with a benign naevus This finding is not good news for the cat with the tumour, especially given the extension of the lesion to the edge of the iris. Glaucoma may supervene as the tumour occupies the iridocorneal angle, and research has shown that once a malignant melanoma in the cat has reached the periphery of the iris, death from metastatic disease is likely to occur (Kalishman et al: A matched observational study of survival in cats with enucleation due to diffuse iris melanoma. Vet Ophthalmol. 1998;1:25-29) while survival after enucleation in a cat where the tumour is less extensive is the same as an unaffected cat..[/tab][end_tabset] 

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A Clinical Case from the Archives : 17/09/2004

Posted on September 17, 2004 by davidwilliams

[tab name=”The Case”]What is the likely cause of these eyelid masses in a domestic rabbit. What influences the disease profile that may be associated with such lesions?[/tab][tab name=”David’s view”]While such masses could be inflammation or tumour of many different sorts, the vast majority in domestic rabbits are associated with myxomatosis. The relation between the myxoma virus and the host rabbit is a fascinating story (very well reviewed in Zuniga MC: A pox on thee! Manipulation of the host immune system by myxoma virus and implications for viral-host co-adaptation. Virus Res. 2002 88:17-33) with viral virulence factors and host resistance in a major host-virus battle. This rabbit had been vaccinated and thus was not as severely affected as an unvaccinated animal such as this poor rabbit.
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A Clinical Case from the Archives : 17/09/2004

Posted on September 17, 2004 by davidwilliams

[tab name=”The Case”]This 12 year old Cocker Spaniel has for some time had mucoid discharge from both eyes and some mild ocular discomfort. What is the problem (or problems) and how may it (or they) be ameliorated?
[/tab][tab name=”David’s view”]The obvious problem here is upper eyelid entropion with trichiasis (eyelash hairs contacting the cornea) with mucoid discharge and corneal vascularisation, commonly seen in ageing Cocker spaniels. The problem can be rectified using the Stades procedure shown in these line drawings (Stades FC: A new method for surgical correction of upper eyelid trichiasis-entropion: operative method. J Am Anim Hosp Assoc 1987 23: 603-606, Stades FC: A new method for surgical correction of upper eyelid trichiasis-entropion: results and follow-up in 55 eyes. J Am Anim Hosp Assoc 1987 23: 607-610), these days also called a forced granulation technique since it removes the eyelashes and leaves a margin of granulation tissue preventing eyelid hairs contacting the cornea. A Schirmer tear test should also be undertaken in any dog with this sort of mucoid discharge – in this dog tear production was only 2mm of test strip wetting in a minute (normal around 15-20mm/min), showing that ocular surface drying was also a factor in the corneal pathology and ocular discharge. Topical cyclosporine increased tear wetting to 8mm in three weeks, giving a better lubricated ocular surface. Combining these medical and surgical treatment routes improved this dog’s ocular health immeasurably. The Stades Procedure: an ellipse of skin is excised including the eyelashes and then the supraincisional skin is mobilised and sutured to leave a 5mm margin of granulation tissue next to the lid margin.[/tab][end_tabset] 

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A Clinical Case from the Archives : 17/09/2004

Posted on September 17, 2004 by davidwilliams

[tab name=”The Case”]This ten year old male entire Border Collie is presented with gradually developing visual disturbance but suddenly a painful right eye. What is the obvious corneal condition in both eyes, why might it be leading to ocular pain and what can be done about it?[/tab][tab name=”David’s view”]This dog has severe corneal oedema. The possible causes of this are (in order of importance to the eye not prevalence) glaucoma, CAV-1-associated uveitis, endothelial degeneration or dystrophy, though the latter is less likely given the age and breed of the animal. Intraocular pressure was normal and thus with the age of the animal and the gradual onset of the condition, endothelial degeneration is most likely. The endothelium is vital in maintaining the correct level of corneal hydration and thus dystrophy, degeneration or damage through increased intraocular pressure or endothelitis in CAV-1-induced uveitis can curtail its function leading to corneal oedema. Norice the irregular light reflection from the right cornea. Here stromal water has resulted in subepithelial bullae which have burst giving painful corneal ulceration. The best treatment for such bullous keratopathy is thermokertoplasty where a hot wire is used to scar the central cornea, thus preventing formation of further bullae (Michau et al: Use of thermokeratoplasty for treatment of ulcerative keratitis and bullous keratopathy secondary to corneal endothelial disease in dogs: 13 cases (1994-2001). J Am Vet Med Assoc. 2003 222(5):607-12).[/tab][end_tabset] 

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A Clinical Case from the Archives : 17/09/2004

Posted on September 17, 2004 by davidwilliams

[tab name=”The Case”]What are the white lesions at the limbus in this 5 year old guinea pig? What is the likely pathogenesis that underlies them and are they a problem to the animal?[/tab][tab name=”David’s view”]These are so-called heterotopic bone formation, well recognised at this site in guinea pigs. The likely pathogenesis centres around the movement of vitamin C into the aqueous at the ciliary body. Excessive ascorbic acid at this site can lead to new bone formation at the limbus in the same way in which it is important in bone deposition more generally (Kipp et al: Long-term low ascorbic acid intake reduces bone mass in guinea pigs. J Nutr. 1996 126:2044-9). These lesions are probably of little consequence to the animal, and while they might interfere with aqueous drainage, glaucoma is not a common consequence of heterotopic bone formation here. The condition used to be termed oseous choristoma, hence two useful case reports are Brooks et al Heterotopic bone formation in the ciliary body of an aged guinea pig. Lab Anim Sci. 1990 40:88-90 and Griffith et al Osseous choristoma of the ciliary body in guinea pigs. Vet Pathol. 1988 25:100-2.[/tab][end_tabset] 

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A Clinical Case from the Archives : 17/09/2004

Posted on September 17, 2004 by davidwilliams

[tab name=”The Case”]This 9 year old female Shire horse was referred as the veterinary surgeon was concerned about this lesion in the eye. What is it, is there any reason to worry and what measures might be taken to deal with it if it were a problem?[/tab][tab name=”David’s view”]This an iris cyst, in this case probably developing from one of the corpora nigra given its position. Such lesions rarely cause a problem to the animal although may be associated with headshaking or visual impairment if large. Deflation with an Nd-YAG laser has been reported (Gilger et al: Neodymium:yttrium-aluminum-garnet laser treatment of cystic granula iridica in horses: eight cases (1988-1996). J Am Vet Med Assoc. 1997 211:341-3) although aspiration with a wide-bore needle is also readily acheieved. The only problem there is that more often than not these are attached to the iris, a situation not seen in the dog were these are common and, when present in large numbers, can lead to glaucoma. Solitary ones as shown here can happily be left well alone (note also the darker melanocytoma ventrally here, a possible differential diagnosis for an iris cyst and the posterior polar subcapsular cataract at the confluence of the suture lines in the background.[/tab][end_tabset] 

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A Clinical Case from the Archives : 17/09/2004

Posted on September 17, 2004 by davidwilliams

[tab name=”The Case”]This twelve week old Cavalier King Charles Puppy is presented with these eyelid lesions. What is the likely diagnosis, what steps would you take to confirm it and what treatment should be implemented?[/tab][tab name=”David’s view”]These irregularly thickened lids are typical of pyogranuloamtous inflammationcentred around the meibomian glands and associated with juvenile cellulitis or ‘head-gland’ disease. The question and the image were a little unfair, as in real life you would see the whole head of the animal with the classical dermatological lesions. Although the lesions suggest an infectious problem no agents were cultured from samples taken from the dog. Cytology from a fine needle aspirate showed a mixed inflammatory cell reaction with no agents visible on Gram stain. Systemic steroid is the recommended treatment, although I am always concerned enough that infection might possibly be present to give a cephalosporin antibiotic concurrently. The two most useful reviews are Reimann et al: Clinicopathologic characterization of canine juvenile cellulitis. Vet Pathol. 1989 26(6):499-504 from a pathological perspective and White SD et al: Juvenile cellulitis in dogs: 15 cases (1979-1988). J Am Vet Med Assoc. 1989 Dec 1;195(11):1609-11 as a significant case series. [/tab][end_tabset] 

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A Clinical Case from the Archives : 17/09/2004

Posted on September 17, 2004 by davidwilliams

[tab name=”The Case”]This little kitten was one of a litter presented to the RSPCA in this sorry state. What is the diagnosis, what are the potential infectious causes, how would you make a definitive diagnosis and what treatment might be employed in this case?[/tab][tab name=”David’s view”]This is feline keratoconjunctivitis, most probably caused by Feline Herpes Virus type 1 although Chamydophila is another possible cause (Nasisse et al: Clinical and laboratory findings in chronic conjunctivitis in cats: 91 cases (1983-1991). J Am Veterinary Med Assoc 203: 834-7.). Diagnosis is best achieved by PCR as shown here, but treatment is very difficult in the UK. We have recently shown that acyclovir can be effective when used topically five times daily but trifluorothymidine is probably the best antiviral, although difficult to obtain in the UK. Initial treatment with topical chlortetracycline would be sensible to exclude Chlamydophila as an aetiological agent. Prognosis for full return to vision and ocular comfort is poor.[/tab][end_tabset] 

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A Clinical Case from the Archives : 17/09/2004

Posted on September 17, 2004 by davidwilliams

[tab name=”The Case”]The owner of this young bull terrier has asked you to snip out this ‘cherry eye’ under local anaesthetic – that’s what she’s always had done before with other puppies. Is that an acceptable therapeutic option and if not what should be done?[/tab][tab name=”David’s view”]This is the prolapsed gland of the third eyelid or nictitatns gland which accounts for about 25-30% of the aqueous tear production in the eye ( Saito A et al The effect of third eyelid gland removal on the ocular surface of dogs.Vet Ophthalmol. 2001 4:13-8). Removing the gland may predispose to keratoconjunctivitis in the future. Replacement of the gland can be acheieved by the orbital rim anchoring techinque of Kaswan (Surgical correction of third eyelid prolapse in dogs. J Am Vet Med Assoc. 1985 186:83) or the mucosal pocket technique reported by Morgan (Prolapse of the gland of the third eyelid in dogs: a retorspective study of 89 cases (1980 to 1990). J Am Anim Hosp Assoc 1993 29:56-60).
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A Clinical Case from the Archives : 17/09/2004

Posted on September 17, 2004 by davidwilliams

[tab name=”The Case”]What clinical signs are visible in this polydypsic polyuric twelve year old male neutered Yorshire Terrier which has become blind over a few days. Can you explain its sudden loss of sight and what treatment could restore vision?[/tab][tab name=”David’s view”]The dog has a mature cataract with evidence of water clefts. These total lens opacities are seen in diabetes mellitus in the dog where the buildup of the insoluble glucose metabolite sorbitol can suddenly caus an osmotic cataract, hence the rapid loss of vision in this dog. Other signs include iris atrophy, seen as polycoria (multiple small holes in the iris appearing as ‘many pupils’. The iris is somewhat dark which may indicate developing lens induced uveitis. The diabetic cataract is intumescent, that is to say enlarged in size (Williams DL: Lens morphometry determined by B-mode ultrasonography of the normal and cataractous canine lens. Vet Ophthalmol. 2004 7:91-5) and microfractures in the lens capsule allow lens protein into the aqueous humour, elliciting an inflammatory reaction with iridal darkening. Such change worsens the prognosis for a successful surgery to remove the cataract, but this is the only treatment option which will restore vision after diabetes has been stabilised.
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