Cindy L. Shmon

Exercise-induced collapse of Labrador retrievers: survey results and preliminary investigation of heritability.

Completed surveys were obtained from owners of 225 Labrador retrievers affected by the syndrome of exercise-induced collapse. Questions addressed signalment, age of onset, description of collapse episodes, and owner perception of activities and factors associated with collapse. Most dogs were young (mean 12 months) when collapse episodes began. Retrieving was the activity most commonly associated with collapse. Owners felt that excitement (187/225; 83%) and high environmental temperatures (71/225; 31%) increased the likelihood of collapse. Analysis of pedigrees collected from 169 affected dogs was most consistent with an autosomal recessive mode of inheritance.

Urinary Obstruction Secondary to an Ossifying Fibroma of the Os Penis in a Dog

A 13-year-old, 25-kg, castrated male border collie was referred for evaluation of pollakiuria, stranguria, and a decreased urine stream. A calcified periurethral mass near the caudal aspect of the os penis was identified on survey abdominal radiographs. A retrograde contrast urethrocystogram demonstrated that the mass was compressing the penile urethra. The mass was surgically resected. A histopathological diagnosis of an ossifying fibroma of the os penis was made. This report describes an atypical presentation of a rare tumor, an ossifying fibroma, that caused a urinary obstruction in a male dog. A review of the incidence, histopathological features, and behavior of ossifying fibromas is included.

Evaluations of Labrador retrievers with exercise-induced collapse, including response to a standardized strenuous exercise protocol.

Clinical and metabolic variables were evaluated in 14 Labrador retrievers with exercise-induced collapse (EIC) before, during, and following completion of a standardized strenuous exercise protocol. Findings were compared with previously reported variables from 14 normal Labrador retrievers that participated in the same protocol. Ten of 14 dogs with EIC developed an abnormal gait during evaluation, and these dogs were significantly more tachycardic and had a more severe respiratory alkalosis after exercise compared to the normal dogs. Muscle biopsy characteristics and sequential lactate and pyruvate concentrations were normal. Genetic testing and linkage analysis excluded malignant hyperthermia as the cause of EIC. Common causes of exercise intolerance were eliminated, but the cause of collapse in EIC was not determined.

Prevalence of circumcaval ureters and double caudal vena cava in cats

OBJECTIVE To determine the prevalence of circumcaval ureters and other caudal vena cava variations in cats and determine whether circumcaval ureters were associated with macroscopic evidence of ureteral obstruction. SAMPLE 301 domestic cat cadavers obtained from an animal shelter. PROCEDURES All cat cadavers were examined, and anatomic variations of the ureters and caudal vena cava were recorded. In cadavers with a circumcaval ureter, kidney length, width, and height were measured, and the ureters were examined macroscopically to determine whether there was gross evidence of ureteral obstruction in cats with circumcaval ureters. RESULTS At least 1 circumcaval ureter was present in 106 of the 301 (35.2%) cats, with a right circumcaval ureter identified in 92 (30.6%) cats, a left circumcaval ureter identified in 4 (1.3%), and bilateral circumcaval ureters identified in 10 (3.3%). Twenty-one (7.0%) cats had a double caudal vena cava, including 2 cats in which the double caudal vena cava was the only anatomic abnormality identified. No sex predilection for anatomic abnormalities was found. Mean right kidney length was significantly greater than mean left kidney length in cats with a right circumcaval ureter. CONCLUSIONS AND CLINICAL RELEVANCE Circumcaval ureter was present in approximately a third of cats in this study. Variation in the development of the caudal vena cava is the proposed cause. The clinical relevance of this variation is unknown.

Evaluation of Dogs with Border Collie Collapse, Including Response to Two Standardized Strenuous Exercise Protocols

Clinical and metabolic variables were evaluated in 13 dogs with border collie collapse (BCC) before, during, and following completion of standardized strenuous exercise protocols. Six dogs participated in a ball-retrieving protocol, and seven dogs participated in a sheep-herding protocol. Findings were compared with 16 normal border collies participating in the same exercise protocols (11 retrieving, five herding). Twelve dogs with BCC developed abnormal mentation and/or an abnormal gait during evaluation. All dogs had post-exercise elevations in rectal temperature, pulse rate, arterial blood pH, PaO2, and lactate, and decreased PaCO2 and bicarbonate, as expected with strenuous exercise, but there were no significant differences between BCC dogs and normal dogs. Electrocardiography demonstrated sinus tachycardia in all dogs following exercise. Needle electromyography was normal, and evaluation of muscle biopsy cryosections using a standard panel of histochemical stains and reactions did not reveal a reason for collapse in 10 dogs with BCC in which these tests were performed. Genetic testing excluded the dynamin-1 related exercise-induced collapse mutation and the V547A malignant hyperthermia mutation as the cause of BCC. Common reasons for exercise intolerance were eliminated. Although a genetic basis is suspected, the cause of collapse in BCC was not determined.

Border Collie Collapse: Owner Survey Results and Veterinary Description of Videotaped Episodes.

Completed surveys were obtained from owners of 165 border collies experiencing repeated episodes of abnormal gait or collapse during strenuous exercise. Unremarkable veterinary evaluation and lack of disease progression over time made common systemic, cardiac, and neurologic causes of exercise intolerance unlikely. Survey questions addressed signalment, age of onset, description of episodes, and owner perception of factors associated with collapse. Most dogs were young adults (median 2 yr) when episodes began, and they had experienced from 2 to more than 100 episodes (median 6) prior to their owners completing the survey. Retrieving was the activity most commonly associated with episodes (112/165 dogs, 68%), followed by herding stock (39/165 dogs, 24%). Owners reported that high environmental temperatures (111/165 dogs, 67%) and excitement (67/165 dogs, 41%) increased the likelihood of their dog having an episode during strenuous activity. Veterinary evaluation of videotapes of presumed border collie collapse (BCC) episodes (40 dogs) were used to provide a description of the typical features of BCC episodes. Altered mentation, symmetrical ataxia affecting all four limbs, increased pelvic limb extensor tone and toe scuffing or knuckling, truncal swaying, and falling to the side were common features, suggesting that BCC may be an episodic diffuse central nervous system disorder.

Ex vivo evaluation of the effect of various surgical procedures on blood delivery to the patellar tendon of dogs

OBJECTIVE To determine the effect of arthrotomy alone or in combination with osteotomy of the proximal portion of the tibia on blood delivery to the patellar tendon of dogs. SAMPLE 24 canine cadavers. PROCEDURES One hind limb from each cadaver was assigned to 1 of 4 treatment groups: medial arthrotomy (MA; MA group), lateral arthrotomy (LA; LA group), MA and LA with tibial tuberosity transposition (MALA group), and MA with tibial plateau leveling osteotomy (TPLO; TPLO group). The contralateral hind limb served as the control sample. Contrast solution (barium [33%], India ink [17%], and saline [0.9% NaCl] solution [50%]) was injected through an 8F catheter inserted in the caudal portion of the abdominal aorta. Limbs were radiographed to allow examination of vascular filling. The patella, patellar tendon, and tibial crest were harvested, radiographed to allow examination of tissue vascular filling, and fixed in 4% paraformaldehyde. Vessels perfused with contrast solution were counted in sections obtained from the proximal, middle, and distal regions of each patellar tendon. RESULTS Vessel counts did not differ significantly among the 3 tendon regions. Compared with results for the control group, delivery of contrast solution to the patellar tendon was significantly decreased in the MALA and TPLO groups but was not changed in the MA or LA groups. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that surgical procedures used to treat cranial cruciate injuries (ie, TPLO) and patellar luxation decreased blood delivery to the patellar tendon of canine cadavers, at least acutely.