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.     

Effect of Breed and Body Weight on Echocardiographic Values in Four Breeds of Dogs of Differing Somatotype

Eighty normal dogs of four morphologically disparate breeds (Pembroke Welsh Corgi, Miniature Poodle, Afghan Hound, Golden Retriever) (twenty of each breed), were studied by echocardiography to determine the importance of breed and weight in establishing normal echocardiographic reference ranges. Echocardiographic measurements included left-ventricular chamber dimension at systole and end-diastole, right-ventricular chamber dimension at end-diastole, interventricular septal thickness at systole and end-diastole, left-ventricular free wall thickness at systole and end-diastole, E-point septal separation, aortic root dimension at end-diastole, left atrial dimension, and fractional shortening. Analyses of covariance indicated that for all measurements except right-ventricular chamber dimension, the means were significantly different among breeds, after the differences in weight were taken into account. Echocardiographic measurements are variable even within the same breed. Breed must be considered in establishing echocardiographic measurement reference ranges. Echocardiographic values for each breed are presented.     

Detachable Coils for Occlusion of Patent Ductus Arteriosus in 2 Dogs

OBJECTIVE: To describe the use of a detachable coil for transcatheter closure (TCC) of patent ductus arteriosus (PDA) in 2 dogs. STUDY DESIGN: Clinical study. ANIMALS: Two female Pembroke Welsh Corgi dogs with PDA. METHODS: Using fluoroscopic guidance, an 8-mm-diameter coil stent with 5 loops (detachable coils for PDA closure) was inserted via catheterization of the femoral artery. The catheter was passed through the PDA into the pulmonary artery. The coil was withdrawn so that 1.5 loops remained on the pulmonary side of the orifice of the ductus. The rest of the loops were pushed out from the catheter into the ductus. After confirming the correct placement of the coil and the effectiveness of the occlusion, the delivery wire was detached from the coil. RESULTS: Insertion of the coil was easily performed, even without previous experience. Immediate and marked decrease of the cardiac murmur was auscultated. Only slight residual flow was detected by angiography conducted 3 months' postoperatively. The dogs experienced quick and uneventful recovery after coil placement and required minimal postoperative care. Follow-up evaluation of the dogs showed no functional clinical signs of PDA, and no cardiac abnormalities were detected on electrocardiographic, phonocardiographic, and echocardiographic examination. In dog 1, the residual flow had disappeared on the color-flow Doppler echocardiographic examination at 18 months' postoperatively. CONCLUSION: TCC using a detachable coil was easy, safe, and effective in 2 dogs with PDA. The minimal residual shunting observed only by echocardiography seemed hemodynamically insignificant. CLINICAL RELEVANCE: This method can be used as an alternative to traditional surgical methods.     

Nasal adenocarcinoma metastatic to bone in two dogs

Diagnosis of nasal adenocarcinoma was made in a 6-year-old 35-kg neutered Golden Retriever and a 6-year-old 8-kg spayed mixed-breed dog with chronic bilateral nasal discharge unresponsive to antibiotics. Treatment for the Golden Retriever consisted of bilateral rhinotomy, curettage, and postoperative fractionated 48-Gy orthovoltage irradiation. The mixed-breed dog was treated with cisplatin. After complete remission of the primary neoplasm, the dogs were reevaluated because of acute lameness. Radiography of the right stifle of the Golden Retriever revealed soft tissue swelling, extensive bony destruction of the distal femoral metaphysis and epiphysis, and pathologic fracture involving the medial condyle. Radiography of the left scapula of the mixed-breed dog revealed lysis of the glenoid cavity and subchondral scapular bone. Diagnosis of metastatic carcinoma was made in both dogs. With treatment improvements and longer survival time of affected dogs, sinonasal neoplasia may be observed to develop in similar life-threatening metastatic sites.     

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.     

Opinions of veterinarians regarding aggression in different breeds of dogs

Aggression in 108 dog breeds and six crosses was ranked by 185 members of the Companion Animal Society of the New Zealand Veterinary Association. The Rottweiler and German Shepherd were categorised as extremely aggressive and the Akita, Basengi, Chihuahua (long-coated and short-coated), Chow Chow, Cocker Spaniel, Shar pei and Welsh Corgi (Cardigan and Pembroke) were classified as very aggressive. A chi-squared test of data from the twenty most popular breeds showed that significant differences were perceived between the breeds. Cocker Spaniels, Pembroke Welsh Corgis, German Shepherds and Rottweilers were more aggressive than Staffordshire Bull Terriers, Border Collies and Doberman Pinchers, which were more aggressive than Cavalier King Charles Spaniels, Bichon Frise, English Springer Spaniels, German Shorthaired Pointers, Weimaraners, Labrador Retrievers, Golden Retrievers, Newfoundlands, Dalmatians, Boxers, Bulldogs, Bull Mastiffs and Rough Collies.     

Prevalence of primary breed-related cataracts in the dog in North America

The objective of the study was to determine the prevalence of cataracts in dogs presented to veterinary medical teaching hospitals in North America between 1964 and 2003. A retrospective study of all dogs presented with cataracts to veterinary medical teaching hospitals in North America between 1964 and 2003 was conducted to determine cataract prevalence. The different decades, breeds, gender, and age at time of presentation with cataract were compared. The prevalence of dogs presented with cataract varied by decade and ranged from 0.95% (1964-73), 1.88% (1974-83), 2.42% (1994-2003), to 3.5% (1984-93). The total number of dogs presented with cataracts over the 40-year period was 39,229. From 1964 to 2003 the prevalence of cataract formation in this patient population increased by about 255%. Fifty-nine breeds of dogs were affected with cataracts above the baseline prevalence of 1.61% seen in mixed-breed/hybrid dogs. The breeds with the highest cataract prevalence included: Smooth Fox Terrier (11.70%), Havanese (11.57%), Bichon Frise (11.45%), Boston Terrier (11.11%), Miniature Poodle (10.79%), Silky Terrier (10.29%) and Toy Poodle (10.21%). The breeds with the largest number of cataractous dogs during the entire four decades were the Boston Terrier (11.11%), Miniature Poodle (10.79%), American Cocker Spaniel (8.77%), Standard Poodle (7.00%), and Miniature Schnauzer (4.98%). Gender ratios of cataractous dogs seemed to affect limited breeds. Age of presentation with cataract diagnosis varied among several breeds. In the mixed-breed/hybrid baseline population, cataract formation appeared to be age related with a higher frequency of cataract formation in dogs after 4-7 years. Cataract formation is one of the most prevalent eye diseases in the dog population, and in about 60 breeds of dogs the prevalence of cataract exceeds that of the baseline mixed-breed/hybrid group. The prevalence of cataract is also influenced by age in most purebred dogs and affects 16.80% of the 7-15+-year-old mixed-breed/hybrid dog population. Total and age-related cataract prevalence in dogs seems very similar to that in man.     

Evaluation of canine heat shock transcription factor 4 (HSF4) as a candidate gene for primary cataracts in the Dachshund and the Entlebucher Mountain dog

OBJECTIVE: Testing of the cataract-causing insertion/deletion mutation in the canine HSF4 gene for its linkage and association with primary cataracts (CAT) in Dachshunds and Entlebucher Mountain dogs. MATERIALS: Exon 9 with flanking intronic regions of the canine HSF4 gene was sequenced in 24 Dachshunds and 20 Entlebucher Mountain dogs. The HSF4 cDNA sequence of lens tissue was analyzed in a CAT-unaffected mixed-breed dog and in three CAT-affected dogs of different breeds, including a Wire-haired Dachshund, a Dachshund-mix and a German Shepherd dog. RESULTS: In all dogs investigated here, the previously reported CAT-causing mutation did not exist. We found a single nucleotide polymorphism (SNP) in intron 9, which was neither associated nor linked with the CAT phenotype in the two dog breeds. CONCLUSION: The CAT phenotype in the two dog breeds investigated here was not caused by the same mutation found to be associated with early-onset CAT in the Staffordshire Bull Terrier and Boston Terrier. The intronic SNP may be useful to test HSF4 for linkage with CAT in further dog breeds.     

Echocardiographic detection of pulmonic valve rupture in a horse with right-sided heart failure

Pulmonic valve rupture was determined to be the cause of severe right-sided heart failure in a 20-year-old Thoroughbred gelding. A flail in the intermediate pulmonic valve cusp was detected by 2-dimensional echocardiography. Significant pulmonic and tricuspid valvular regurgitation were confirmed by Doppler echocardiography. Despite treatment, the horse's condition deteriorated, and euthanasia was performed. At necropsy, a tear in the pulmonary artery extending into the right valve cusp and a tear at the base of the intermediate valve cusp were identified at the junction of the right and intermediate pulmonic valve cusps. Careful echocardiographic evaluation of the pulmonic valve is warranted for horses with right-sided heart failure, for which more common causes cannot be found.     

Successful surgical treatment of mitral valve stenosis in a dog

OBJECTIVE: To report the successful surgical management (open mitral commissurotomy, OMC) of mitral stenosis (MS), incorporating heart-beating cardiopulmonary bypass (CPB), in a 1-year-old dog. STUDY DESIGN: Clinical case. ANIMALS: One-year-old Cairn Terrier with MS. MATERIALS AND METHODS: Diagnosis of MS was confirmed by means of 2-dimensional, continuous-wave and color-flow Doppler echocardiography. Surgery was performed through a left intercostal thoracotomy. CPB was initiated and the heart was kept beating. The fused commissures of the mitral valve were incised to free the cusps of the valve. RESULTS: Left intercostal thoracotomy allowed easy observation of the mitral orifice during heart-beating OMC. Persistent bleeding from the atriotomy site required a second surgical procedure after which the dog had an uneventful recovery. Echocardiography at 2 weeks and 1 year postoperatively indicated substantial improvement in left ventricular filling (pressure half-time=187 ms before surgery, 105 ms [2 weeks] and 110 ms [1 year] after surgery). Enlargement of the left atrium resolved; however, moderate mitral valve regurgitation was still present. CONCLUSIONS: MS can be successfully treated by OMC, facilitated by use of CPB. Substantial improvement in cardiac function was evident by ultrasound and Doppler examination postoperatively. CLINICAL RELEVANCE: OMC under heart-beating CPB should be considered for the treatment of MS in the dog.     

Beating heart mitral valve replacement with a bovine pericardial bioprosthesis for treatment of mitral valve dysplasia in a Bull Terrier

OBJECTIVES: To describe an open, beating heart surgical technique and use of a bovine pericardial prosthetic valve for mitral valve replacement (MVR) in the dog. STUDY DESIGN: Clinical case report. ANIMALS: Male Bull Terrier (17-month-old, 26 kg) with mitral valve dysplasia and severe regurgitation. METHODS: A bovine pericardial bioprosthesis was used to replace the mitral valve using an open beating heart surgical technique and cardiopulmonary bypass. RESULTS: Successful MVR was achieved using a beating heart technique. Mitral regurgitation resolved and cardiac performances improved (left ventricular end-diastolic diameter decreased from 57.6 to 48.7 mm, and left atrium/aorta ratio returned to almost normal, from 1.62 to 1.19). Cardiopulmonary by-pass time and total surgical duration were decreased compared with standard cardioplegic techniques. Surgical recovery was uneventful and on echocardiography 6 months later valve function was excellent. CONCLUSION: Considering the technique advantages (no cardiac arrest, ischemic reperfusion injury, and hypothermia, or the need for aortic dissection and cannulation for administration of cardioplegic solution), short-term mortality and morbidity may be reduced compared with standard cardioplegic techniques. CLINICAL RELEVANCE: Based on experience in this dog, beating heart mitral valvular replacement is a seemingly safe and viable option for the dog and bovine pericardial prosthesis may provide better long-term survival than mechanical prostheses.     

Doppler echocardiography-derived evidence of pulmonary arterial hypertension in dogs with degenerative mitral valve disease: 86 cases (2001-2005)

OBJECTIVE: To determine the prevalence of Doppler echocardiography-derived evidence of pulmonary arterial hypertension (DEE-PAH) in dogs with mitral valve disease (MVD) classified according to the International Small Animal Cardiac Health Council (ISACHC) heart failure classification scheme and various echocardiographic and Doppler indices of MVD severity. DESIGN: Retrospective case series. ANIMALS: 617 dogs examined from 2001 to 2005 with MVD in ISACHC classes I to III. PROCEDURES: Dogs were examined echocardiographically. Criteria used for systolic and diastolic DEE-PAH were detection of high tricuspid (> or = 2.5 m/s) and telediastolic pulmonic (> or = 2.0 m/s) valvular peak regurgitant jet velocities, respectively, by use of continuous-wave Doppler echocardiography. RESULTS: 86 (13.9%) dogs with MVD had a diagnosis of DEE-PAH. Severity and prevalence of DEE-PAH increased with ISACHC class (3.0%, 16.9%, 26.7%, and 72.2% prevalences for ISACHC classes Ia, Ib, II, and III, respectively). A significant correlation between systolic or diastolic pulmonary arterial pressure and left atrial-to-aortic diameter ratio (LA/Ao) was detected. Doppler echocardiography-derived evidence of pulmonary arterial hypertension was detected in 18 dogs with values of LA/Ao within reference range, all of which had moderate (n = 2 dogs) or severe (16) mitral valve regurgitation on color Doppler imaging. CONCLUSIONS AND CLINICAL RELEVANCE: The prevalence and degree of DEE-PAH were related to the severity of MVD. Changes associated with DEEPAH may be detected in early stages of the disease, but only in dogs with severe mitral valve regurgitation.     

Localized pulmonary histiocytic sarcomas in Pembroke Welsh Corgi

Nineteen cases of histiocytic sarcomas in Pembroke Welsh Corgi were examined histopathologically. Focal or multiple masses were detected in the lung or in regional lymph nodes, or in both lung and nodes. All neoplastic lesions had common histological features characterized by the proliferation of pleomorphic histiocytic cells combined with various inflammatory cells. Most of the pleomorphic neoplastic cells were immunopositive for human leukocyte antigen (HLA)-DR and Iba-1. The median survival time for all dogs was 133 days. In the present study, several prognostic factors, such as gender, age, single or multiple lesions, lymph node involvement at the time of diagnosis, surgical resection status and additional chemotherapy, were examined, although none of these factors approached statistical significance. Histiocytic sarcoma must be considered in the differential diagnosis of dogs with pulmonary masses, especially in the canine breed.     

The clinical and morphologic features of nonepidermolytic ichthyosis in the golden retriever

A scaling disorder specific to Golden Retriever dogs has been recognized by both dermatologists and pathologists, but to date has not been well characterized. At the University of Pennsylvania's Laboratory of Toxicology and Pathology, 46 cases of ichthyosis were diagnosed histologically in Golden Retriever dogs from January 2004 to January 2007. A total of 22 dogs had skin lesions documented at younger than 1 year of age; 3 dogs between 1 and 2 years of age; 13 dogs developed lesions at older than 2 years; and the time of onset was unknown for 8 dogs. A total of 25 dogs were female, and 21 were male. All dogs had strikingly similar histopathologic changes that consisted of mild to moderate laminar orthokeratotic hyperkeratosis with an absence of epidermal hyperplasia and dermal inflammation. Ultrastructural analysis using a ruthenium tetroxide fixation method was performed on punch biopsy samples from 5 dogs and compared with 2 control dogs (1 clinically and histologically normal sibling of an affected dog and 1 Cairn Terrier). All affected dogs had retained and convoluted membranes with crystalline structures in the stratum corneum. Scattered keratinocytes in the granular cell layer had prominent, clear, membrane-bound, cytoplasmic vacuoles. Pedigree analysis of 14 dogs was compatible with autosomal recessive inheritance, but incomplete dominance could not be ruled out. This unique hyperkeratotic/scaling disorder in Golden Retrievers has distinctive clinical, histologic, and ultrastructural features, which are consistent with a primary cornification defect.     

Tissue Doppler assessment of diastolic and systolic alterations of radial and longitudinal left ventricular motions in Golden Retrievers during the preclinical phase of cardiomyopathy associated with muscular dystrophy

OBJECTIVE: To quantify radial and longitudinal left ventricular free wall (LVFW) velocities in dogs during the preclinical phase of Golden Retriever muscular dystrophy (GRMD)-associated cardiomyopathy by use of tissue Doppler imaging (TDI). ANIMALS: 9 dogs with GRMD and 6 healthy control dogs. PROCEDURE: All dogs (< 3 years old) were examined via conventional echocardiography and 2-dimensional color TDI. Myocardial velocities in the LVFW were recorded from right parasternal ventricular short-axis (radial motion) and left apical 4-chamber (longitudinal motion) views. Cardiac assessments via TDI included maximal systolic and early and late diastolic LVFW velocities in the endocardial and epicardial layers (for radial motion) and in the basal and apical segments (for longitudinal motion) (for longitudinal motion), RESULTS:-No notable ventricular dilatation or alteration of inotropism was detected in dogs with GRMD via conventional echocardiography. Compared with healthy dogs, endocardial velocities were significantly decreased in dogs with GRMD, resulting in marked decreases in radial myocardial velocity gradients during systole and early and late diastole. Similarly, basal and apical velocities were significantly decreased in systole and the former also in early diastole, resulting in significant decreases in the 2 corresponding longitudinal myocardial velocity gradients. The radial epicardial and longitudinal late diastolic velocities were comparable in the 2 groups. CONCLUSION AND CLINICAL RELEVANCE: Results indicated that GRMD-associated cardiomyopathy in dogs is associated with early marked dysfunction of both radial and longitudinal LVFW motions. These combined regional myocardial abnormalities might be useful criteria for detection of dilated cardiomyopathy at the preclinical stage of the disease in dogs.     

Canine congenital aortic stenosis: A review of the literature and commentary

Congenital aortic stenosis usually affects the subvalvular region, and occurs mainly in Newfoundland, Golden Retriever, German Shepherd, and Boxer dogs. The disorder is inherited as a dominant trait with variable penetrance in Newfoundland dogs.

The prevalence of subaortic stenosis-like heart murmurs in Golden Retriever dogs appears to be very much greater than previously suspected.

Most cases of aortic stenosis represent mild lesions, are detected as incidental findings, and result in no loss of longevity or quality of life. Moderate or severe stenosis may result in exertional weakness, syncope, or sudden death. Signs of congestive heart failure are rare unless mitral valve insufficiency is present.

Generally, electrocardiography and radiography are unrevealing in this disorder. Doppler echocardiography may be the best diagnostic tool to detect even mild cases of aortic stenosis.

At present, therapy is limited due to the technical expertise and expense required. The prognosis depends on the severity of the lesion.

     

Cytology of canine malignant histiocytosis

Cytologic features of bone marrow, tissue, and abdominal fluid in seven cases of malignant histiocytosis in dogs are described, and histopathology, hematology, and serum biochemistry of the cases are reviewed. Diagnosis of malignant histiocytosis was confirmed by tissue morphology and immunohistochemistry; neoplastic cells in all cases had positive immunoreactivity to lysozyme. This stain can be used to definitively establish the diagnosis of malignant histiocytosis on cytology specimens as well as tissue sections. Cytologic findings included numerous pleomorphic, large, discrete mononuclear cells with abundant, lightly basophilic, vacuolated, granular cytoplasm. Nuclei were round to oval to reniform with marked anisocytosis and anisokaryosis; nucleoli were prominent. Mitotic figures, often bizarre, were occasionally seen. Multinucleated giant cells and phagocytosis of erythrocytes and leukocytes were prominent features in cytologic preparations in four cases. Four dogs were anemic, five dogs were thrombocytopenic, and three dogs were hypercalcemic. Breeds affected included Doberman Pinscher (1), Golden Retriever (2), Flat Coated Retriever (3), and mixed-breed dog (1).     

Aneurysmal dilatation of the right auricle in two dogs

An 8-year-old sexually intact male Golden Retriever with a history of collapse during exercise underwent an examination during which tachydysrhythmia was identified. At another institution, a 12.5-year-old spayed female Lhasa Apso was referred because of a cough and for evaluation of a heart murmur. In the Golden Retriever, radiographic examination revealed bulging of the craniodorsal aspect of the cardiac silhouette and echocardiography revealed right atrial dilatation. In the Lhasa Apso, a cranial mediastinal mass was suspected on the basis of radiographic findings, but no abnormalities were detected echocardiographically. In both dogs, nonselective angiography and contrast-enhanced computed tomography revealed a markedly enlarged, thin-walled right auricle. Exploratory thoracotomy in the Golden Retriever revealed a defect in the pericardium through which the right auricle and part of the atrium had herniated. In dogs, a right auricular aneurysm should be considered in differential diagnoses of a cranial mediastinal mass (detected radiographically) adjacent to the cardiac silhouette.     

Breed distribution of dogs with diabetes mellitus admitted to a tertiary care facility

OBJECTIVE: To determine which dog breeds are at low and high risk for developing diabetes mellitus (DM). DESIGN: Cohort study. ANIMALS: Hospital population of 221 dogs with DM and 42,882 dogs without DM during 5.5 years. PROCEDURE: 165 breeds (including a mixed-breed category) were represented in the hospital population. Breed-specific expected numbers of dogs with DM were calculated by multiplying the proportion of all dogs admitted to the hospital that were determined to have DM during the study period by the breed-specific totals during the study period. Breeds or breed groups evaluated in the analysis (n = 20) were restricted to those that had a combined observed and expected count > 5 to document breeds at low and high risk for developing DM. Proportionate changes in the risk of developing DM by breed were calculated and presented using exact odds ratios, 95% confidence intervals, and P values. Mixed-breed dogs were chosen as the reference breed. RESULTS: Samoyeds, Miniature Schnauzers, Miniature Poodles, Pugs, and Toy Poodles were at high risk for developing DM. Dog breeds found to be at low risk for developing DM were German Shepherd Dog, Golden Retriever, and American Pit Bull Terrier. CONCLUSION AND CLINICAL RELEVANCE: The finding that certain dog breeds are at low or high risk for developing DM suggests that some genetic defects may predispose dogs to development of DM, whereas other genetic factors may protect dogs from development of DM.