Distal radial osteochondroma causing expansile lysis and ulna fracture in a dog.

OBJECTIVE: To describe the diagnosis, management, and outcome of a dog with a right distal radial osteochondroma that penetrated the ulna, causing expansile lysis and fracture. ANIMAL: A 9-month-old entire female German Shorthaired Pointer. CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES: The dog had a 2-month history of weight-bearing lameness of the right forelimb and a 2-week history of a progressively enlarging, firm swelling on the distolateral antebrachium. Computed tomography was used to characterize the lesion and for surgical planning. TREATMENT AND OUTCOME: A distal ulnar ostectomy removed the affected ulnar segment, and the radial osteochondroma was excised with rongeurs. The dog was sound at 2, 16, and 45 weeks postoperatively. Radiographs at 45 weeks showed a persistent ulnar ostectomy gap with irregular but smoothly marginated edges and focal cortical irregularity at the site of radial osteochondroma excision. There was no evidence of osteochondroma recurrence. CLINICAL RELEVANCE: This is a newly recognized presentation of an osteochondroma penetrating the cortex of an adjacent bone in a dog resulting in expansile lysis and cortical fracture. Computed tomography was important in diagnosis and surgical planning, and surgical treatment was successful in removing the osteochondroma and ulnar lesion. This case provides long-term radiographic and clinical follow-up after osteochondroma excision and contributes to the current knowledge on prognosis following osteochondroma excision in dogs.

Esophageal pH-monitoring in nonbrachycephalic dogs; a reference.

OBJECTIVE: To establish parameters that describe acidic gastroesophageal reflux (GER) events in nonbrachycephalic, hospitalized dogs without gastrointestinal disease following short total intravenous anesthesia, to establish upper reference limits for parameters that describe GER. STUDY DESIGN: Clinical prospective study. ANIMALS: Healthy, client-owned dogs presenting for elective orthopedic surgery. METHODS: Dogs were sedated with IM methadone (0.2 mg/kg) and medetomidine (5 ug/kg), followed by alfaxalone total intravenous anesthesia. The Digitrapper esophageal dual pH monitoring probe was placed transnasally into the esophagus. Dogs were unsedated during the subsequent recording period. A GER event was defined as esophageal pH less than 4.0. Parameters that described GER were: (1) number of GER events per hour, and (2) cumulative esophageal acid exposure (percentage of recording duration) at each sensor. Upper reference limits were calculated for each parameter. RESULTS: Thirty-five dogs were included (median age 7 years, range 1-12). The median recording duration was 21.1 h (range 13.6-29.3). Productive regurgitation was not noted in any dog. The median number of distal and proximal GER events per hour was 0.3 (range 0-4.3) and 0 (range 0-1), respectively. The median cumulative distal and proximal esophageal acid exposure was 0.2% (range 0.3-9%) and 0% (range 0%-1%), respectively. CONCLUSION: Upper reference limits for distal and proximal GER per hour was 2.4 and 0.4, respectively, and, for cumulative distal and proximal esophageal acid exposure, 2.3% and 0%, respectively. CLINICAL SIGNIFICANCE: Dogs undergoing esophageal pH monitoring in a similar hospital setting with parameters above these upper reference limits have excessive GER.

Tube cystostomy is effective for urinary outflow management in dogs with intervertebral disk extrusion and ischemic myelopathy cranial to the L3 spinal cord segment: 61 dogs (2018-2022).

OBJECTIVE: To describe the application and owner experience of tube cystostomy for management of upper motor neuron urinary bladder dysfunction secondary to intervertebral disk extrusion (IVDE) or ischemic myelopathy, and to report complications associated with cystostomy tube management. ANIMALS: 61 dogs. CLINICAL PRESENTATION: Medical records of dogs with IVDE or ischemic myelopathy cranial to the L3 spinal cord segment that underwent tube cystostomy placement via a short, caudal ventral midline celiotomy were reviewed. Days from tube placement to hospital discharge, days from placement to tube removal, and complications were recorded. An owner questionnaire was distributed to ascertain ease of use and perceived time commitment. RESULTS: 58 dogs were diagnosed with IVDE, and 3 dogs were diagnosed with ischemic myelopathy. The modal neurologic grade at cystostomy tube placement was 4 (range, 3 to 5). The median number of days from cystostomy tube placement to hospital discharge was 1 (range, 0 to 3). Follow-up data was available for 56 dogs. The median number of days from cystostomy tube placement until removal was 19 (range, 3 to 74). Fifteen minor and 6 severe postoperative complications were reported, mainly inadvertent removal (n = 11) and peristomal urine leakage (6). Twenty-seven owners responded to the questionnaire and primarily reported that cystostomy tube use was easy (22/27) and perceived time commitment was low or minimal (20/27). CLINICAL RELEVANCE: Tube cystostomy facilitates early hospital discharge and allows at-home, extended urinary management in dogs recovering from upper motor neuron urinary bladder dysfunction secondary to IVDE or ischemic myelopathy. This technique is simple for owners to use.

Early diagnosis of acute kidney injury subsequent to severe hypotension and fluid resuscitation in anaesthetized dogs.

OBJECTIVES: To document changes in urinary biomarker concentration and conventional diagnostic tests of acute kidney injury (AKI) following hypotension and fluid resuscitation in anaesthetized dogs. STUDY DESIGN: Experimental, repeated measures, prospective study. ANIMALS: A group of six male adult Greyhound dogs. METHODS: Following general anaesthesia, severe hypotension was induced by phlebotomy, maintaining mean arterial blood pressure (MAP) < 40 mmHg for 60 minutes, followed by resuscitation with intravenous gelatine solution to maintain MAP > 60 mmHg for 3 hours. Following euthanasia, renal tissue was examined by light microscopy (LM) and transmission electron microscopy (TEM). Urinary and serum concentrations of neutrophil gelatinase-associated lipocalin (NGAL), cystatin C (CysC), and gamma-glutamyl transpeptidase (GGT), serum creatinine and urine output were measured at baseline and hourly until euthanasia. Data are presented as mean and 95% confidence interval and analysed using repeated measures analysis of variance with Dunnett's adjustment, p < 0.05. RESULTS: Structural damage to proximal renal tubular cells was evident on LM and TEM. Urinary biomarker concentrations were significantly elevated from baseline, peaking 2 hours after haemorrhage at 19.8 (15.1-25.9) ng mL-1 NGAL (p = 0.002), 2.54 (1.64-3.43) mg mL-1 CysC (p = 0.009) and 2043 (790-5458) U L-1 GGT (p < 0.001). Serum creatinine remained within a breed-specific reference interval in all dogs. Urinary protein-creatinine ratio (UPC) was significantly elevated in all dogs from 1 hour following haemorrhage. CONCLUSIONS AND CLINICAL RELEVANCE: Urinary NGAL, CysC and GGT concentrations, and UPC were consistently elevated within 1 hour of severe hypotension, suggesting that proximal renal tubules are damaged in the earliest stage of ischaemia-reperfusion AKI. Measurement of urinary biomarkers may allow early diagnosis of AKI in anaesthetized dogs. Urinary GGT concentration and UPC are particularly useful as they can be measured on standard biochemistry analysers.

Analytical validation and reference intervals for a commercial multiplex assay to measure five novel biomarkers for acute kidney injury in canine urine.

Novel urinary biomarkers are increasingly utilized for the diagnosis of acute kidney injury (AKI) in dogs. Magnetic-bead based immunoassays for the simultaneous measurement of multiple biomarkers represent a potentially efficient and cost effective tool for investigators; however there is limited data to support their reliable use in dogs. Analytical validation of a commercial multiplex assay for the measurement of five AKI biomarkers: clusterin, cystatin C, kidney-injury molecule 1 (KIM-1), monocyte chemoattractant protein 1 and neutrophil gelatinase-associated lipocalin (NGAL) in canine urine was performed. The effect of pre-analytical factors including potential interfering substances and sample storage methods were investigated. Urine from 110 healthy dogs was used to determine reference intervals for each biomarker measured, according to American Society of Veterinary Clinical Pathology guidelines. Additionally, urine from 21 dogs with pyuria was used to evaluate the impact of pyuria on biomarker concentration. The assay performed with acceptable accuracy and precision for the measurement of NGAL only. Clinically relevant urine concentrations of bilirubin, haemoglobin, and synthetic colloid solutions led to interference (mean percentage difference > +/- 15% compared to control) with measurement of all or some of the biomarkers. All biomarkers were stable in urine stored at 20-22 °C for 2 h, 4 °C for 12 h, or -20 °C for 6 months. Reference intervals could not be established for KIM-1 due to unacceptable measurement imprecision (intra- and inter assay coefficient of variation 45% and 20% respectively). Urine NGAL concentration was significantly elevated in pyuria (P < 0.001).

Agreement between invasive blood pressures measured in three peripheral arteries in anaesthetized horses under clinical conditions.

OBJECTIVE: To determine agreement between invasive blood pressures measured in three peripheral arteries in anaesthetized horses undergoing elective surgery. STUDY DESIGN: Prospective balanced incomplete block design. ANIMALS: A total of 18 client-owned horses. METHODS: Invasive blood pressure (IBP) was measured simultaneously in one of the following three combinations: 1) transverse facial and facial artery; 2) transverse facial and metatarsal artery; and 3) facial and metatarsal artery. The agreement in blood pressure measured for each combination was performed in six horses. At each sample time, systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures were measured concurrently in each artery, and the mean of three consecutive measurements was recorded. The position of horse, heart rate and use of dobutamine were also recorded. Bland-Altman analysis was used to assess agreement between sites. RESULTS: A total of 54 paired measurements were obtained, with 18 paired measurements from each combination. All paired measurements showed poor and haphazard (nonsystematic) agreement. The widest limit of agreement was 51 mmHg for SAP measured in the facial artery and metatarsal artery, with a bias of -11 mmHg. The smallest limit of agreement was 16 mmHg for MAP measured in the transverse facial and metatarsal artery, with a bias of 1 mmHg. CONCLUSIONS AND CLINICAL RELEVANCE: There was poor and haphazard agreement for SAP, MAP and DAP measured in each pair of peripheral arteries in this study. These results show that blood pressure measured in different peripheral arteries cannot be used interchangeably. This has implications for studies that use IBP as an outcome variable and studies determining agreement between noninvasive blood pressure and IBP measurements in horses under general anaesthesia.

Paradoxical bradycardia during surgical caudal vena cava occlusion in an anesthetized dog.

OBJECTIVE: To describe the anesthetic management of a dog undergoing caudal vena cava (CVC) occlusion during adrenalectomy, and to discuss a reflex bradycardia that was observed during the procedure. CASE SUMMARY: General anesthesia of a 10-year-old Rhodesian ridgeback for excision of an adrenal mass and associated CVC tumor thrombus was performed. The dog was premedicated with IV methadone and anesthesia was induced with IV alfaxalone and maintained with isoflurane in 100% oxygen. An IV remifentanil infusion was administered for intraoperative analgesia. Surgical removal of the thrombus necessitated temporary complete occlusion of the CVC. During CVC occlusion an acute paradoxical bradycardia occurred, which was successfully treated with IV atropine. The cardiovascular change resembled a Bezold-Jarisch or reverse Bainbridge reflex, and was believed to be mediated by cardiac mechanoreceptors following the sudden decrease in preload. Increased myocardial contractility subsequent to increased sympathetic nervous system activity may also have contributed. A decrease in urine output was observed following CVC occlusion but had returned to normal 2 hours following the end of anesthesia. Recovery from anesthesia was otherwise uneventful. NEW OR UNIQUE INFORMATION PROVIDED: Although the mechanism is unclear, a paradoxical bradycardia may occur during complete CVC occlusion in the dog. Factors that increase sympathetic nervous system outflow, such as administration of dopamine, may have contributed to the occurrence of the reflex.

Urinary neutrophil gelatinase-associated lipocalin concentration changes after acute haemorrhage and colloid-mediated reperfusion in anaesthetized dogs.

OBJECTIVE: To determine changes in urine neutrophil gelatinase-associated lipocalin concentration (uNGAL) in anaesthetized Greyhound dogs that developed acute tubular damage following haemorrhage and resuscitation with colloid-based fluids. STUDY DESIGN: Prospective experimental study. ANIMALS: Seven healthy adult entire male Greyhound dogs. METHODS: During isoflurane anaesthesia, approximately 50 mL kg(-1) of blood was removed to maintain mean arterial pressure (MAP) ≤40 mmHg for 1 hour followed by gelatin-based colloid administration to maintain MAP ≥60 mmHg for 3 hours. Data, including oxygen extraction ratio and uNGAL, were collected before (T0) and immediately following (T1) haemorrhage, and hourly during reperfusion (T2-T4). After T4, dogs were euthanized and renal tissue was collected for histology. Statistical analysis was performed using repeated-measures one-way anova. Data are presented as means (95% confidence interval). RESULTS: Histology identified renal tubular epithelial damage in all dogs. Urine NGAL concentration increased from 12.1 (0-30.6) ng mL(-1) at T0 to 122.0 (64.1-180.0) ng mL(-1) by T3. Compared with T0, uNGAL was significantly higher at T3 (p = 0.016) and was increased 24-fold. CONCLUSIONS AND CLINICAL RELEVANCE: Despite wide individual variation in baseline uNGAL, increases in uNGAL were observed in all dogs, suggesting that this biomarker has the potential to detect renal tubular injury following haemorrhage-induced hypotension and colloid-mediated reperfusion.

Biomechanical comparison of a locking compression plate combined with an intramedullary pin or a polyetheretherketone rod in a cadaveric canine tibia gap model.

OBJECTIVE: To compare the biomechanical properties of a 10-hole 3.5 mm locking compression plate (LCP) with 2 proximal and 2 distal bicortical locked screws reinforced with either a Steinmann pin of 30-40% the medullary diameter or a poly-ether-ether-ketone (PEEK) rod of ∼75% the medullary diameter in a cadaveric tibia gap model. STUDY DESIGN: Ex vivo study. SAMPLE POPULATION: Cadaveric canine tibias (n = 8 pair). METHODS: Each construct had a 10-hole 3.5 mm LCP with 2 screws per fracture fragment using a comminuted tibia gap model. The Steinmann pin constructs had a 2.4 mm intramedullary pin whereas the PEEK-rod constructs had a 6 mm intramedullary PEEK rod placed. Biomechanical testing included non-destructive bi-planar 4 point bending, torsion testing, and destructive axial compression. Testing produced the responses of failure load (N) in axial compression, stiffness (N/mm or N/°) in axial compression, torsion, lateral-medial, and caudal-cranial 4 point bending. Screw position within the PEEK-rods was determined after explantation. RESULTS: The PEEK-rod constructs were significantly stiffer in axial compression (P < .005), lateral-medial 4 point bending (P < .001), and in torsional loading (P < .031) than the Steinman pin constructs. There was no significant difference between the constructs for stiffness in caudal-cranial 4 point bending (P = .32). The PEEK-rod constructs failed at a significantly higher load than the Steinmann pin constructs (P < .001). All constructs failed by yielding through plastic deformation. Each screw penetrated the PEEK rod in all constructs but the position of the screw varied. CONCLUSION: PEEK-rod constructs failed at significantly higher loads and were significantly stiffer in 4 point lateral-medial bending, axial compression, and torsion when compared with Steinmann pin constructs.

Glucose detection and concentration estimation in feline urine samples with the Bayer Multistix and Purina Glucotest.

The Bayer Multistix are commonly used for detection and estimation of feline glucosuria by veterinarians and cat owners. A newer product, the Purina Glucotest, utilizes the same enzymatic technology for detection of glucose, but has been designed for home use as a litter additive that allows interpretation of glucosuria over an 8-h period. The objectives of this study were to assess the sensitivity, specificity, and accuracy of the Glucotest and Multistix, and to assess the 8-h color stability of the Glucotest. Overall, the Glucotest had greater sensitivity and specificity than the Multistix, and more accurately estimated urine glucose concentration if evaluated at least 30 min after exposure to urine. A significant lack of agreement between the results obtained immediately after exposure to urine vs after 30 min and 8 h contradicts the 8-h color stability claim, but the change in urine glucose concentration estimation over time resulted in improved test accuracy at the 30 and 480 min time points.

Randomized, blinded, placebo-controlled clinical trial of N-acetylcysteine in dogs with spinal cord trauma from acute intervertebral disc disease.

STUDY DESIGN: The effect of N-acetylcysteine administration intravenously before hemilaminectomy surgery on neurologic outcome and 15F 2t isoprostane excretion in dogs was examined in a blinded, placebo-controlled trial. OBJECTIVE: To determine the effect of N-acetylcysteine administration on urinary 15F 2t isoprostane excretion and neurologic outcome following hemilaminectomy for intervertebral disc disease. SUMMARY OF BACKGROUND DATA: Oxidative stress is a mediator of secondary injury to the spinal cord following trauma. Acute intervertebral disc disease is associated with increased oxidative damage in dogs. N-acetylcysteine has preserved neurologic function following experimental spinal cord injury. METHODS: Seventy dogs with naturally occurring acute intervertebral disc disease were administered either with saline placebo or N-acetylcysteine intravenously before hemilaminectomy surgery. Serial neurologic examinations were performed before and 1, 2, 7, 14, and 42 days following treatment. Urinary excretion of 15F 2t isoprostane excretion was determined before treatment and 1 hour after surgery. RESULTS: Analysis of subjective data did not reveal any significant effect of N-acetylcysteine on neurologic outcome or rate of improvement of neurologic score in the 42 days following treatment. Urinary 15F 2t isoprostane excretion was not significantly different between treatment groups (P > 0.05). CONCLUSION: N-acetylcysteine intravenously before hemilaminectomy has no effect on urinary 15F 2t isoprostane excretion or neurologic outcome. Treatment of dogs with the antioxidant N-acetylcysteine before hemilaminectomy, while not detrimental, does not affect neurologic outcome in the 42 days following surgery.

Concentrations of 15F2t isoprostane in urine of dogs with intervertebral disk disease.

OBJECTIVE: To measure 15F(2t) isoprostane concentrations in the urine of dogs undergoing ovariohysterectomy (OHE) and dogs undergoing surgery because of intervertebral disk disease (IVDD) and to assess relationships between urinary concentrations of 15F(2t) isoprostanes and neurologic score in dogs with IVDD. ANIMALS: 11 dogs undergoing OHE and 32 dogs with IVDD undergoing hemilaminectomy. PROCEDURES: Paired urine samples were obtained at induction of anesthesia and approximately 1 hour after OHE (controls) and were collected from dogs with IVDD at induction of anesthesia (28 samples) and approximately 1 hour after hemilaminectomy (31 samples); 26 paired urine samples were obtained from dogs with IVDD. Urinary isoprostane concentrations were measured by use of a commercial ELISA, and results were adjusted on the basis of urinary creatinine concentrations. Differences in the mean isoprostane-to-creatinine ratio were analyzed. Neurologic score was determined in dogs with IVDD by use of the modified Frankel scoring system. RESULTS: Urinary isoprostane-to-creatinine ratios were significantly higher in dogs with IVDD than in control dogs before and after surgery. There was no significant difference between values before and after surgery for either group. There was a significant correlation of neurologic score and urinary isoprostane-to-creatinine ratio because dogs that had higher neurologic scores (ie, less severely affected) generally had higher isoprostane-to-creatinine ratios. CONCLUSIONS AND CLINICAL RELEVANCE: Urinary isoprostane-to-creatinine ratios were higher in dogs with IVDD before and after surgery. Analysis of these data suggests that dogs with IVDD are in a state of oxidative stress and that preemptive treatment with antioxidants warrants further investigation.

Evaluation of cutaneous analgesia after non-focused extracorporeal shock wave application over the 3rd metacarpal bone in horses.

Extracorporeal shock wave therapy is becoming increasingly used in equine practice to treat musculoskeletal disorders. Although the exact effects of extracorporeal shock waves on tissues still need to be elucidated, transient cutaneous analgesia has been observed within treated areas in humans and horses. The purpose of this study was to determine the onset, magnitude, and duration of cutaneous analgesia after non-focused extracorporeal shock wave (ESW) application by comparing the limb withdrawal reflex latency (LWRL) in treated and untreated areas on the metacarpus of horses, using a focused light source. A single treatment with non-focused ESW was applied to 3 areas over the dorsal aspect of one metacarpus in 12 horses. The LWRL was measured to assess cutaneous sensation in treated and untreated control areas of the treated metacarpus and in an untreated area on the opposite metacarpus, before and at various time points after ESW application. Most treated and control areas revealed a significant decrease in LWRL over time compared with baseline values. Although the results of our study do not suggest cutaneous analgesia after ESW application to the equine metacarpus, we advise cautious use of this treatment modality for horses in training or before competition until further research is done.

Effects of infusion of adenosine triphosphate-magnesium chloride on cardiopulmonary and clinicopathologic variables, cytokine activity, and endothelin concentration in horses administered a low dose of endotoxin.

OBJECTIVE: To evaluate systemic effects of i.v. infusion of ATP-MgCl2 subsequent to infusion of a low dose of endotoxin in horses. ANIMALS: 12 adult horses. PROCEDURE: Horses were administered endotoxin (lipopolysaccharide [LPS]) or saline (0.9% NaCl) solution i.v., during a 30-minute period. Immediately thereafter, horses in each group were infused i.v. with ATP-MgCl2 or saline solution. Two weeks later, horses were administered the opposite solution (LPS or saline solution), but it was followed by the same infusion as 2 weeks previously (ie, ATP-MgCl2 or saline solution). Cardiopulmonary and clinicopathologic variables, cytokine activity, and endothelin (ET) concentrations were recorded. RESULTS: IV infusion of ATP-MgCl2 after administration of a low dose of endotoxin failed to attenuate the cardiopulmonary, clinicopathologic, and cytokine alterations that develop secondary to endotoxin exposure. The combination of LPS and ATP-MgCl2 potentiated pulmonary hypertension, leukopenia, and neutropenia when compared with the combination of LPS and saline solution. The combination of LPS and ATP-MgCl2 resulted in thrombocytopenia. Endothelin concentration was increased in jugular venous and pulmonary arterial plasma in horses receiving LPS and ATP-MgCl2. Similar increases were not observed with LPS and saline solution. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of ATP-MgCl2 did not protect horses from systemic effects of experimentally induced endotoxemia. Furthermore, the use of ATP-MgCl2 during endotoxemia may worsen the cardiopulmonary and clinicopathologic status of affected horses. Because ATP and other adenine nucleotides are released from cells during shock, their potential role in the development of hemodynamic derangements, leukocyte adherence, and coagulopathies during endotoxemic episodes warrants further investigation.