The diagnosis and differential diagnosis of cataract in the dog

Cataract is a common eye condition in the dog, classified in several ways and with a varied aetiology. The clinical appearance of hereditary cataract is described in the Boston Terrier, Miniature Schnauzer, Staffordshire Bull Terrier, Cavalier King Charles Spaniel, Golden Retriever, Labrador Retriever, Large Munsterlander, English Cocker Spaniel, American Cocker Spaniel, Afghan Hound, Welsh Springer Spaniel, German Shepherd Dog, Standard Poodle. Cataracts secondary to other eye diseases, both hereditary and non-hereditary, and to systemic conditions are also discussed, as well as the differential diagnosis of cataract.     

Hereditary cataract in the dog

Hereditary cataract in the dog is described as it occurs in the Boston Terrier, the Staffordshire Bull Terrier, the Miniature Schnauzer, the Golden Retriever, the Labrador Retriever, the American Cocker Spaniel, the Afghan Hound, and the Old English Sheepdog. The mode of inheritance in each breed is also discussed and includes both dominant and recessive patterns.     

Seasonal incidence of estrus and interestrous interval for bitches of seven breeds

For 7 breeds of bitches (Toy Poodle, Cocker Spaniel, Basset Hound, Boston Terrier, German Shepherd Dog, Pekingese, and Beagle), estrous activity occurred in all seasons. Differences in seasonal incidence of estrus were not statistically significant when compared within the total group or within and between breeds. The German Shepherd Dog breed had the shortest interestrous interval (149 +/- 28.5 days), which was significantly different from that of the other breeds. Means interestrous interval in parous Beagle bitches was not significantly different from that in nonparous Beagle bitches. In Beagle bitches, the mean interval between fertile estrous periods was not significantly different from the mean interval between nonfertile estrous periods.     

Prevalence of the breed-related glaucomas in pure-bred dogs in North America

Objective To determine the prevalence of the breed‐related glaucomas in pure‐bred dogs presented to the veterinary medical teaching hospitals in North America that participate in the Veterinary Medical Data Base (VMDB). Materials and methods In this retrospective study, age of first diagnosis, breed, and gender data for all breeds of dogs were collected from the VMDB with the clinical diagnosis of primary glaucoma (glaucoma‐NOS) at 5–10 year intervals from 1964 to 2002. The prevalence for each breed (affected dogs compared to all dogs of each breed), any changes over the 38 years, and any gender differences for these glaucomas were determined. Results The prevalence of the primary breed‐related glaucomas has gradually increased from 0.29% (1964–1973); 0.46% (1974–1983); 0.76% (1984–1993); to 0.89% (1994–2002). Breeds that consistently featured among the highest 10 for glaucoma prevalence from four different periods (1964 to 2002) included American Cocker Spaniel, Basset Hound, Wire Fox Terrier, and Boston Terrier. During the last observation period (1994–2002), 22 different breeds had 1% or higher prevalence of the glaucomas. The highest prevalence of glaucomas in 1994–2002 by breed included: American Cocker Spaniel (5.52%); Basset Hound (5.44%); Chow Chow (4.70%); Shar‐Pei (4.40%); Boston Terrier (2.88%); Wire Fox Terrier (2.28%); Norwegian ElkHound (1.98%); Siberian Husky (1.88%); Cairn Terrier (1.82%); and Miniature Poodle (1.68%). A predominance of females with glaucoma occurred in the American Cocker Spaniel, Basset Hound, Cairn Terrier, Chow Chow, English Cocker Spaniel, Samoyed, and perhaps the Siberian Husky, and a predominance of males in the Australian Cattle dog and St Bernard. Age affected the time for first presentation of the glaucomas in the pure‐bred dog. In the majority of breeds the glaucomas were presented for initial diagnosis in dogs between 4 and 10 years of age. Conclusion Breed‐related glaucomas in pure‐bred dogs are frequently presented to the veterinary medical teaching hospitals in North America. The prevalence of the breed‐related glaucomas in the dog appears similar to humans, and in some breeds exceeds that in humans. In many breeds the high prevalence of the glaucomas suggests a genetic basis.     

Inherited phosphofructokinase deficiency in an American cocker spaniel.

A 3-year-old female American Cocker Spaniel with a chronic hemolytic disorder and hemolytic crises was found to have M-type phosphofructokinase deficiency. This inherited erythroenzymopathy and myopathy is commonly diagnosed in English Springer Spaniels, but the family study of this Cocker Spaniel, although supporting an autosomal recessive mode of inheritance, did not reveal any English Springer Spaniel ancestors. Molecular genetic studies did, however, identify the same mutation in this dog as we previously reported in the English Springer Spaniel breed, suggesting that this mutation originated prior to the separation of these 2 breeds.     

Congenital orbital cysts of neural tissue in two dogs

A 3-month-old English Cocker Spaniel and a 6-month-old miniature poodle presented with clinical signs related to an abnormal right eye since birth. In both dogs, the right globe could not be identified and was replaced by a fluctuant intraorbital mass covered by a vascularized mucous membrane. Ultrasonography demonstrated that both masses were cystic structures markedly larger in size than the normal contralateral globes. In both cases, surgical excision revealed a multilobular cyst filling the whole orbital cavity. Histopathologic examination and immunostaining for glial fibrillary acid protein and S100 protein supported a diagnosis of neural cysts associated with ocular dysplasia. The definitive diagnosis was congenital cystic eye and microphthalmos with cyst for the Cocker Spaniel and miniature poodle, respectively. Karyotype was normal in both dogs. Congenital cystic eye and microphthalmos with cyst result from defects in early embryonic life that arise following formation of the optic vesicle and prior to closure of the optic fissure. To the authors' knowledge neither has been reported in the canine species. They should be considered in the differential diagnosis of orbital cysts in dogs.     

Heritability of multifocal retinal dysplasia in American Cocker Spaniels

Multifocal retinal dysplasia was detected in 96 American Cocker Spaniels. Affected dogs were part of approximately 500 American Cocker Spaniels examined from 1972 to 1976 in statewide survey clinics for inherited cataracts and progressive retinal atrophy. The dysplastic retina was observable ophthalmoscopically in dogs as young as 3 to 4 weeks and as old as 7 years. Ophthalmoscopic features varied, depending on whether the dysplastic foci were in the tapetal or non-tapetal portion of the fundus. Over the tapetum, dysplastic foci appeared as multiple small irregularities of diminished and altered tapetal reflectivity. In the non-tapetal fundus, dysplasia appeared as areas of decreased pigmentation. Blindness or other apparent visual deficits were not observed in affected dogs. Histologic examination of affected eyes revealed focal dysplasia limited to the retina and optic nerve. Abnormalities included localized areas of retinal folding, rosettes, and retinal pigment epithelium hypertrophy and hyperplasia. Pedigree analysis demonstrated that 71 of the 96 affected dogs were related and could be identified in an extended pedigree. A recessive mode of inheritance was suggested, because in 5 litters (born to 10 affected parents), all 23 progeny that lived were affected. A dominant or polygenic mode of inheritance could not be ruled out.     

Spontaneous cataract resorption and lens-induced uveitis in the dog.

Spontaneous cataract resorption and the associated lens-induced uveitis occur primarily in young dogs, especially the Afghan Hound, American Cocker Spaniel, Boston Terrier, Miniature and Toy Poodle, and Miniature Schnauzer. The resorption process, if extensive, will restore vision without surgical intervention, but medical control of the lens-induced uveitis by use of mydriatics and, infrequently, topical and systemic corticosteroids is essential. The main potential complications, severe medically nonresponsive uveitis and glaucoma, necessitate immediate cataract extraction.     

Effects of risk factors and prophylactic treatment on primary glaucoma in the dog

Seventy dogs from 26 breeds were admitted with primary glaucoma between January 1979 and December 1983. Compared with mixed-breed dogs, 8 breeds were at higher risk (P less than 0.01) of developing glaucoma: Basset Hound, Beagle, Boston Terrier, Cocker Spaniel, Dalmatian, Miniature Poodle, Norwegian Elkhound, and Siberian Husky. Dogs between the ages of 5 and 10 years were at increased risk (P less than 0.001). There was no predisposition for either eye to be affected first (P greater than 0.55). Females were at twice the risk of males (P less than 0.01). Fourteen dogs had bilateral glaucoma. Among 46 dogs for which the number of months that the second eye remained normal was available, 24 were treated prophylactically and 22 were not treated or had treatment stopped. Prophylactic treatment significantly extended the interval between diagnosis in the first eye and development of glaucoma in the second eye for dogs in predisposed breeds (P less than 0.01). Prophylactic treatment did not make a difference when all breeds were considered (P greater than 0.19), nor did gender affect this interval (P greater than 0.37).     

Responses of atopic dogs to regional allergens: 268 cases (1981-1984)

Responses of atopic dogs to intradermal challenge with 60 allergens were determined and compared for 4 regions of the United States Twenty-seven allergens incited significantly higher responses in atopic dogs residing in northern Florida, when compared with dogs in Illinois; responses to 28 allergens were more significant in dogs residing in southern Florida vs Illinois. Only 1 allergen caused more responses in atopic dogs in northern Florida, compared with dogs in southern Florida. Females had a higher tendency to develop clinical signs of atopy. Dogs of the West Highland White Terrier, Cairn Terrier, English Setter, Irish Setter, Dalmatian, Lhasa Apso, Golden Retriever, and Labrador Retriever breeds were found to be predisposed to develop clinical signs of atopy. Dogs of the Poodle, Pug, German Shepherd Dog, Cocker Spaniel, Bulldog, Schnauzer, Doberman Pinscher breeds, of mixed breeding, and of terrier breeds other than the 2 aforementioned were not found to have a higher prevalence, when compared with the general hospital population. Of the atopic dogs evaluated in Florida, 79% had a significant response to flea antigen, compared with only 9% of atopic dogs evaluated in Illinois.     

Transient hypoparathyroidism following successful treatment of hypercalcaemia of malignancy in a dog

A 4-year-old, entire female, English Cocker Spaniel was presented for treatment of lymphosarcoma and secondary hypercalcaemia. After induction chemotherapy the dog became severely hypocalcaemic and showed signs of weakness, muscle fasciculation and facial pruritus. Hormone analysis confirmed inadequate production of parathyroid hormone. Although hypocalcaemia has been previously reported as a component of tumour lysis syndrome, it has not been associated with transient parathyroid hormone deficiency.     

A retrospective study on the prevalence of primary cataracts in two pedigrees from the German population of English Cocker Spaniels

Objective  Two pedigrees from the German English Cocker Spaniel population are presented to illustrate the familial occurrence of primary cataract (CAT) in single- and multicolored English Cocker Spaniels. The aim was to characterize similarities and differences in the prevalence and formation of CAT in these separately bred color variants of English Cocker Spaniels.
Materials  The study was based on the veterinary records for presumed inherited eye diseases of 1232 English Cocker Spaniels which were provided by the German panel of the European Eye Scheme for diagnosis of inherited eye diseases in animals (DOK, < http://www.dok-vet.de >). Data included information on 615 single-colored and 617 multicolored English Cocker Spaniels.
Results  CAT was diagnosed in 92 (14.96%) of the single-colored and 34 (5.51%) of the multicolored English Cocker Spaniels. The pedigree of the single-colored English Cocker Spaniels included 40 ophthalmologically examined dogs with 18 unaffected and 22 affected dogs. The pedigree of the multicolored English Cocker Spaniels contained 16 ophthalmologically examined dogs with 11 unaffected and five affected dogs.
Conclusions  In both color variants of the English Cocker Spaniels different forms of primary CAT with respect to location within the lens occurred among close relatives. Appearance of CAT was very heterogeneous without obvious sex differences. The sample pedigrees do not support the assumption of familial segregation of specific forms of primary CAT in English Cocker Spaniels.     

A gonioscopic study of the iridocorneal angle in the English and American breeds of Cocker Spaniel and the Basset Hound

Closure of the iridocorneal angle is the cause of a primary form of glaucoma which occurs in certain breeds of dog, but the precise mechanism involved in that closure is not completely understood. However, narrowness of the angle is considered to be the important predisposing factor, and in gonioscopic survey work the author has demonstrated that angle narrowness occurs with some frequency in the English Cocker Spaniel and Basset Hound breeds.     

Corneal dystrophy in the dog and cat

Two types of epithelial dystrophy have been described in dogs, one each in the Boxer and Shetland Sheepdog breeds, both of which can be associated with corneal erosions. Medical therapy is recommended when erosions or tear film abnormalities are present. Stromal dystrophies documented in dogs appear to be a primary lipid deposition in various layers of the stroma, depending on the breed. Stromal dystrophies seldom lead to loss of vision, but vision loss has been observed in middle aged Airedale Terriers and aged Siberian Huskies. Treatment is usually unnecessary. The dog demonstrates two types of endothelial dystrophy, one of which (posterior polymorphous dystrophy in the American Cocker Spaniel) does not lead to corneal edema. Endothelial dystrophy observed in the Boston Terrier, Chihuahua, and other breeds is associated with progressive corneal edema, which can lead to bullous keratopathy and corneal erosions. Stromal and endothelial dystrophies, both of which are associated with rapid progression of corneal edema, occur rarely in the cat. Treatment of dystrophies with progressive corneal edema is symptomatic and palliative.     

Cerebellar cortical degeneration in an American Staffordshire terrier

Most diseases affecting the cerebellum are congenital and three groups can be distinguished on pathogenetic grounds. In the first group, diseases are caused by intrauterine or neonatal viral infections, in the second group by malformations of genetic or unknown origin, and in the third group by degenerative disease, or abiotrophies. Familial late-onset cerebellar abiotrophy has been reported in the Gordon Setter the Old English Sheepdog, the Brittany Spaniel and more recently the American Staffordshire Terrier. This case report describes the clinical, diagnostic and pathological changes in an American Staffordshire Terrier with cerebellar cortical degeneration. This is the first case diagnosed in the Netherlands.     

Resistance and immunity of dogs against Babesia canis in an endemic area

Canine babesiosis is increasing in incidence and prevalence in some areas in France and is now a major problem for dogs. Sex and age do not have any influence on the animals' susceptibility to the disease. Some breeds are more resistant (Beagle, Fox terrier, Porcelain, Teckel, mongrel dogs) and others are more susceptible (Spaniel, Cocker, Griffon, Yorkshire terrier, Doberman, Pekinese); however, none of them is completely resistant. Dogs which live in endemic areas can synthesize antibodies against Babesia canis, sometimes at high levels, without any sign of disease.     

Neurolymphomatosis in a dog with B-cell lymphoma

Lymphoma in the left femoral nerve of a 10-year-old English Cocker Spaniel caused complete paralysis of the affected limb. Neoplastic cells were immunopositive for CD79a and Pax5 and negative for CD3. Neoplastic cells were in multiple lymph nodes and one kidney but spared bone marrow. The clinical and histologic features in this case resemble those of the rare human condition of neurolymphomatosis.     

Factor X deficiency in a Jack Russell terrier

Deficiency in factor X (Stuart-Prower factor) was identified in a 7-month-old spayed female Jack Russell Terrier following recurrent bleeding episodes. Various relatives were screened for factor X deficiency and low and subnormal levels were identified in the father and paternal grandmother, respectively. Factor X deficiency has been previously documented in a family of American Cocker Spaniels, in which the inheritance pattern appeared to be an autosomal dominant trait with variable expression. This is the first report describing this coagulopathy in the Jack Russell Terrier.     

The pathology of blindness in new-born calves caused by hypovitaminosis A

Blindness attributed to vitamin A deficiency afflicted 47 out of 197, and 15 out of 29 new-born dairy calves on 2 farms. Other clinical signs included doming of the forehead, thickening of the carpal joints, incoordination and weakness. Gross lesions in 8 of the calves examined consisted in hydrocephalus and thickened occipital and sphenoid bones. In 4 of these calves the optic nerves were constricted as a result of a reduction in size and dorsoventral narrowing of the optic canals. Microscopical changes in the optic nerves were characterized by necrosis, demyelination and fibrosis. Oedema or gliosis of the optic disc occurred in some of the calves. Retinal lesions included atrophy and gliosis of the ganglion cell layer and the nerve fibre layer. Three of the calves showed focal retinal dysplasia with occasional rosette formation.