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- Author or Editor: Kate Alexander x
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Abstract
CASE DESCRIPTION A 3-year-old and a 7-year-old spayed female rabbit (Oryctolagus cuniculus) were evaluated because of digestive stasis associated with renal asymmetry.
CLINICAL FINDINGS Neoplasia of the right kidney was diagnosed via cytologic analysis in the 3-year-old rabbit. Ureterolithiasis of the left kidney was diagnosed via abdominal ultrasonography in the 7-year-old rabbit. To evaluate whether unilateral nephrectomy was indicated, evaluation of glomerular filtration rate by dynamic CT (CT-GFR) was performed on both rabbits. On the basis of the functional and morphological CT-GFR results, radical nephrectomy was recommended for the rabbit with renal neoplasia whereas a more conservative approach was recommended for the other rabbit.
TREATMENT AND OUTCOME The rabbit with renal neoplasia underwent radical nephrectomy without complication. The rabbit with ureterolithiasis underwent ureteral stent placement, and the renal pelvic dilatation resolved. Both rabbits maintained unremarkable serum urea and creatinine concentrations after surgery.
CLINICAL RELEVANCE GFR is a highly useful and reliable variable for the evaluation of renal function but is difficult to assess with routine clinical laboratory tests. The CT-GFR technique described here was quickly performed, was technically suitable for rabbits, and provided clinically relevant information. Studies are required to establish reference values for CT-GFR in rabbits.
Abstract
OBJECTIVE To measure the minimal joint space width (mJSW) in caudocranial radiographic views of orthopedically normal femorotibial joints of horses, to compare the accuracy of measurements with those of a software program designed for humans, and to identify the ideal caudocranial radiographic projection angle for mJSW measurement.
ANIMALS 12 healthy mares (22 femorotibial joints) and 3 equine cadavers (6 stifle joints).
PROCEDURES Caudocranial views of femorotibial joints were acquired in the proximodistal plane at 5°, 10°, and 15° (caudo-5°-proximal-craniodistal oblique, 10°, and 15°) and lateromedial plane (caudo-10°-proximo-5°-lateral-craniodistomedial oblique and caudo-10°-proximo-5°-medial-craniodistolateral oblique). The mJSWs of medial and lateral femorotibial joint compartments were measured manually by 2 evaluators and automatically by a digital analysis software program. Interevaluator reproducibility was assessed. Post hoc tests were used to identify the projection angle that provided the largest measurements. Validation of mJSW measurements was performed by evaluation of 6 stifle joints ex vivo.
RESULTS Excellent agreement was achieved between the 2 evaluators and between the veterinary radiologist and the analysis software for the medial and lateral compartments of femorotibial joints. Angle of caudocranial view in the proximodistal but not lateromedial plane had a significant effect on the medial compartment mJSW measurements. Mean mJSW for the medial compartment was significantly higher for the caudoproximal-craniodistal oblique projection made at 10° from the horizontal than for other angles. Angle had no significant effect on mean mJSW for the lateral compartment. Agreement between automated measurements of mJSW in the medial compartment and thickness of nonmineralized cartilage in histologic preparations of associated tissues was excellent.
CONCLUSIONS AND CLINICAL RELEVANCE Measurements of mJSW in the medial compartment of femorotibial joints, the most common site of osteoarthritis in horses, were reproducible and optimal with a caudoproximal-craniodistal oblique radiographic projection made at 10° from the horizontal. (Am J Vet Res 2016;77:127–136)
Abstract
OBJECTIVE To determine whether urolithiasis is associated with chronic kidney disease (CKD) in cats.
DESIGN Retrospective case-control study.
ANIMALS 126 cats (59 and 67 with and without urolithiasis, respectively).
PROCEDURES Medical records from June 2006 to July 2013 were searched to identify cats that underwent abdominal or focal urinary tract ultrasonography and for which serum creatinine concentration and urine specific gravity data were obtained ≤ 14 days before or after the examination. In cats with (urolithiasis group) and without (control group) urolithiasis, the presence of CKD was determined according to International Renal Interest Society guidelines. Information recorded included signalment, body weight, serum creatinine concentration, and urine specific gravity; when present, the location and number of uroliths were noted. Differences between groups and associations between group and categorical variables were analyzed statistically.
RESULTS Age, weight, sex, and breed did not differ between groups. The prevalence of CKD was significantly higher in cats with urolithiasis than in the control group. Among cats with urolithiasis, there was a negative association between CKD and presence of cystoliths. There was no association between urolithiasis and the stage of CKD or between presence of CKD and location of nephroliths in the kidney.
CONCLUSIONS AND CLINICAL RELEVANCE Results confirmed a positive association between urolithiasis and CKD in the feline population studied and suggested that cats with urolithiasis should be evaluated for CKD. Further research is warranted to assess the nature of the relationship between CKD and urolithiasis in cats.
Abstract
Case Description—A 1-year-old female spayed Labrador Retriever was admitted for evaluation of a progressive gait disturbance characterized by tetraparesis and general proprioceptive ataxia in all limbs.
Clinical Findings—Neurologic examination suggested a dysfunction of the C6-T2 spinal cord segments, which was slightly worse on the right side. Discomfort was suspected upon lateral flexion of the neck. Two magnetic resonance imaging (MRI) examinations at a 3-week interval revealed an intramedullary fluid-filled cavitary lesion adjacent to C7, containing a blood clot.
Treatment and Outcome—Following unsuccessful initial conservative management, surgical marsupialization of the lesion was performed through a dorsal laminectomy, durotomy, and myelotomy at C6 and C7. Histologic evaluation including immunohistochemistry was diagnostic for a vascular anomaly. Initially, the dog was nonambulatory with tetraparesis and became tetraplegic after surgery; movement was regained 6 days later. Four weeks after the procedure, the dog was able to walk unassisted. One year after surgery, the dog was actively running and jumping, with mild residual ataxia in the pelvic limbs.
Clinical Relevance—The intramedullary vascular anomaly in this dog was successfully treated with a surgical marsupialization technique. The combination of MRI, histologic eval-uation, and immunohistochemistry enabled lesion localization, evaluation of cavity content, and final diagnosis.
Abstract
Objective—To identify the prevalence of fragmentation of the proximal tubercle of the talus (FPTT) in a hospital population of horses, characterize the anatomic features of the affected area and fragments, and describe clinical findings, diagnosis, treatment, and outcome for horses with FPTT.
Design—Retrospective case series.
Animals—9 horses with FPTT.
Procedures—2,543 radiographic views of the tarsal region of 1,526 horses that were evaluated between June 2004 and December 2010 were reviewed. Medical case records for horses with detectable FPTT were retrieved, and signalment, history, clinical signs, diagnostic methods, treatment, and outcome were recorded for assessment.
Results—9 horses (median age, 5 years; age range, 1 to 12 years) with FPTT were identified. Seven horses were warmbloods. Diagnosis was made on the basis of radiographic findings, occasionally along with results of ultrasonography and CT. The only horse that was lame in the affected limb had a history of a prior traumatic event and resultant lateral tibial malleolus fracture. One horse underwent arthroscopy, but fragments were not found and were presumed to be extra-articular. Outcome was available for 7 horses; mean ± SD duration of stable radiographic and clinical examination findings was 3 ± 1 years (range, 1 to 4 years).
Conclusions and Clinical Relevance—FPTT appeared to occur more frequently in warmbloods and was not usually associated with lameness. Affected horses remained clinically and radiographically stable over time. These data have provided some information regarding the importance of FPTT for practitioners who perform radiographic screenings during prepurchase examinations.
Abstract
OBJECTIVES
This study aims to assess intrathecal mepivacaine for euthanasia in anesthetized horses and compare it to a traditional euthanasia method using a single intravenous injection of pentobarbital in sedated horses.
ANIMALS
Client-owned horses and horses requiring euthanasia due to involvement in concurrent research projects were used. Horses were randomly assigned to 1 of 2 groups: intrathecal mepivacaine after anesthesia or intravenous pentobarbital after sedation. All horses had normal vital parameters and no signs of infectious disease at the time of euthanasia.
PROCEDURES
The intrathecal mepivacaine group was anesthetized before the intrathecal injection of mepivacaine. The pentobarbital group was sedated, concurrently anesthetized and euthanized using intravenous pentobarbital, then received an intrathecal saline (0.9% NaCl) solution injection to a blind observer. Both groups were sedated with detomidine and the time from sedation to the cessation of vital parameters (respirations, pulse, corneal reflex, and ECG) was recorded. Euthanasias were recorded for review by a blinded anesthesiologist, using an independent scale to assess the quality of sedation, anesthesia induction, and lateral recumbency.
RESULTS
Time from detomidine administration to cessation of each vital parameter was significantly longer in the intrathecal mepivacaine group. There was no statistically significant difference in qualitative scores between groups for sedation or induction, but lateral recumbency was subjectively superior in the anesthetized intrathecal mepivacaine group.
CLINICAL RELEVANCE
Intrathecal mepivacaine provided a safe, effective, alternative method of euthanasia to intravenous pentobarbital and addresses concerns about barbiturate availability. This study also informs practitioners of what to expect (ie, longer cessation of vital parameters) when using the intrathecal mepivacaine method.
Abstract
Objective—To assess the variability in vertebral heart score (VHS) measurement induced by cardiac and respiratory cycles in dogs.
Design—Prospective observational study.
Animals—14 healthy Beagles.
Procedures—Dogs underwent fluoroscopic examination by 4 observers, and VHS was measured at end-tidal inspiration and end-tidal expiration during end systole and end diastole in left and right lateral recumbency. Mean VHS was compared within and among cardiac and respiratory phases and recumbency type, and correlation between VHS and heart rate was investigated. Interobserver variability was assessed.
Results—Mean VHS for each combination of respiratory and cardiac cycle was larger on images obtained in right lateral versus left lateral recumbency. The greatest differences were observed between VHS measured in the diastolic inspiratory phase (mean ± SD, 10.59 ± 0.49 vertebral units [VU] and 10.35 ± 0.50 VU for right and left lateral recumbency, respectively) and the systolic expiratory phase (10.11 ± 0.37 VU and 9.92 ± 0.50 VU for right and left lateral recumbency, respectively). The combination of respiratory and cardiac cycles induced a maximal difference in VHS of up to 0.97 VU and 1.11 VU in the inspiratory and expiratory phases, respectively. Heart rate was not correlated with the difference between VHS in systolic and diastolic phases.
Conclusions and Clinical Relevance—Clinicians should be aware of the potential influence of these factors when assessing VHS in dogs; in addition to allowing optimal pulmonary assessment, consistently taking radiographs at end-inspiratory tidal volume may help to limit VHS variability attributable to the respiratory cycle. Further research is needed to assess the effects of cardiac and respiratory phases on VHS in dogs with cardiac or respiratory disease.
Abstract
Objective—To develop a whole-kidney computed tomography (CT) technique that would allow 3-point Patlak plot determination of glomular filtration rate (GFR) and assess the correlation of GFR determined via CT (CT-GFR) with GFR determined via renal plasma clearance of inulin (Inu-GFR) in pigs.
Animals—6 healthy anesthetized pigs.
Procedures—Each pig underwent 3-phase whole-kidney helical CT (arterial, early, and late parenchymal phases) before and after contrast medium administration. After contrast medium administration, corrected Hounsfield unit values were determined for each kidney and the aorta. A 3-point Patlak plot for each kidney was generated, and plasma clearance per unit volume was multiplied by renal volume to obtain whole-animal CT-GFR. Correlations of mean Inu-GFR for the left and right kidneys (and combined [total] values) with the corresponding CT-GFRs were assessed via linear regression and Bland-Altman analyses.
Results—Left kidney, right kidney, and total CT-GFRs were good predictors of the respective Inu-GFR values (r 2 = 92.3%, r 2 = 85.5%, and r 2 = 93.7%, respectively). For the left kidney, no significant bias between Inu-GFR and CT-GFR was detected. Right kidney and total CT-GFRs underestimated the corresponding Inu-GFRs (mean underestimation, −8.4 mL•min−1 and −12.6 mL•min−1, respectively).
Conclusions and Clinical Relevance—Three-phase whole-kidney CT with Patlak plot analysis of GFR may underestimate right kidney and total Inu-GFRs in pigs. The Patlak plot generated may be sensitive to nonlinearity caused by temporal variation in GFR. Nonetheless, the 3-phase CT approach offers some practical advantages for simultaneous evaluation of renal morphology and measurement of GFR.
