Joe Fenn

INTER- AND INTRAOBSERVER AGREEMENT FOR DIAGNOSING PRESUMPTIVE ISCHEMIC MYELOPATHY AND ACUTE NONCOMPRESSIVE NUCLEUS PULPOSUS EXTRUSION IN DOGS USING MAGNETIC RESONANCE IMAGING

Ischemic myelopathy (IM) and acute noncompressive nucleus pulposus extrusion (ANNPE) are common spinal emergencies in dogs with similar clinical presentations. Magnetic resonance imaging (MRI) criteria for a presumptive antemortem diagnosis have been reported, however inter- and intraobserver agreement for use of these criteria has not been established. The aim of this retrospective, descriptive, cross-sectional study was to describe inter- and intraobserver agreement for using previously published MRI criteria to diagnose presumptive IM and ANNPE in a sample dogs. Dogs with a presumptive diagnosis of IM or ANNPE and available MRI scan data were retrieved from medical record archives during the period of 2009 and 2013. A total of 127 dogs were identified. From this sample, MRI scans for 60 dogs were randomly selected and duplicated for intraobserver analysis, giving a total of 187 anonymized studies that were presented to two blinded assessors (one board-certified veterinary neurologist, one board-certified veterinary radiologist). Assessors were asked to diagnose lesions as IM or ANNPE based on previously published MRI characteristics. Interobserver agreement in diagnosing IM or ANNPE was moderate (Kappa = 0.56) and intraobserver agreement was moderate to good (Assessor 1 Kappa = 0.79, Assessor 2 Kappa = 0.47). Agreement was strongest for detecting presence of lesions overlying a vertebral body (94% of lesions that were diagnosed as IM) or overlying an intervertebral disk (85% of lesions that were diagnosed as ANNPE). Findings indicated that use of previously published MRI criteria yields moderate inter- and moderate to good intraobserver agreement for a presumptive diagnosis of IM or ANNPE in dogs.

Genome sequencing reveals a splice donor site mutation in the SNX14 gene associated with a novel cerebellar cortical degeneration in the Hungarian Vizsla dog breed

BackgroundCerebellar cortical degeneration (CCD) is an increasingly recognised neurodegenerative disease process affecting many dog breeds. Typical presentation consists of a progressive cerebellar ataxia, with a variable age at onset and rate of progression between different breeds. Cerebellar histopathological findings typically consist of primary Purkinje neuronal degeneration and loss, with variable secondary depletion of the granular and molecular cell layers. Causative genes have been identified associated with CCD in several breeds, allowing screening for selective breeding to reduce the prevalence of these conditions. There have been no previous reports of CCD in Hungarian Vizslas.ResultsTwo full-sibling Hungarian Vizsla puppies from a litter of nine presented with a history of progressive ataxia, starting around three months of age. Clinical signs included marked hypermetric and dysmetric ataxia, truncal sway, intention tremors and absent menace responses, with positional horizontal nystagmus in one dog. Routine diagnostic investigations were unremarkable, and magnetic resonance imaging performed in one dog revealed mild craniodorsal cerebellar sulci widening, supportive of cerebellar atrophy. Owners of both dogs elected for euthanasia shortly after the onset of signs. Histopathological examination revealed primary Purkinje neuron loss consistent with CCD. Whole genome sequencing was used to successfully identify a disease-associated splice donor site variant in the sorting nexin 14 gene (SNX14) as a strong causative candidate. An altered SNX14 splicing pattern for a CCD case was demonstrated by RNA analysis, and no SNX14 protein could be detected in CCD case cerebellum by western blotting. SNX14 is involved in maintaining normal neuronal excitability and synaptic transmission, and a mutation has recently been found to cause autosomal recessive cerebellar ataxia and intellectual disability syndrome in humans. Genetic screening of 133 unaffected Hungarian Vizslas revealed the presence of three heterozygotes, supporting the presence of carriers in the wider population.ConclusionsThis is the first report of CCD in Hungarian Vizsla dogs and identifies a highly associated splice donor site mutation in SNX14, with an autosomal recessive mode of inheritance suspected.

Associations Between Anesthetic Variables and Functional Outcome in Dogs With Thoracolumbar Intervertebral Disk Extrusion Undergoing Decompressive Hemilaminectomy

Background Outcome of acute experimental spinal cord injury is strongly associated with tissue perfusion and oxygenation. Cardiopulmonary depression could affect outcome in dogs undergoing general anesthesia for surgical treatment of thoracolumbar intervertebral disk extrusion (IVDE). Hypothesis/Objectives To evaluate the effects of general anesthesia on functional outcome in dogs undergoing surgery to treat thoracolumbar IVDE. Animals Eighty‐four client‐owned dogs with acute thoracolumbar IVDE treated by decompressive hemilaminectomy. Methods Exploratory, retrospective observational study. Medical records were reviewed for clinical presentation and anesthetic monitoring variables, including duration of anesthesia and surgery, hypotension, bradycardia, temperature, and respiratory parameters. Multivariable regression tree analysis was performed to explore associations between anesthetic variables and functional outcome scores after 6 weeks, as well as return to ambulatory status. Results Episodes of bradycardia (69%) and hypotension (57%) were frequent. Across all outcome measures, regression tree analysis highlighted functional grade at presentation as the primary determining factor, and among pain perception negative dogs, there was a possible association between increased duration of surgery and poorer outcome. In dogs with intact pain perception, duration of bradycardia, mean body temperature, and mean end‐tidal carbon dioxide were highlighted. Conclusions and Clinical Importance Exploratory statistical methods can facilitate hypothesis‐generating studies to inform prospective investigations in veterinary medicine. Although the mechanism is uncertain, increased duration of surgery might be associated with poorer outcome in pain perception negative dogs with thoracolumbar IVDE.

Acute Herniation of Nondegenerate Nucleus Pulposus: Acute Noncompressive Nucleus Pulposus Extrusion and Compressive Hydrated Nucleus Pulposus Extrusion

Acute herniation of nondegenerate nucleus pulposus material is an important and relative common cause of acute spinal cord dysfunction in dogs. Two types of herniation of nondegenerate or hydrated nucleus pulposus have been recognized: acute noncompressive nucleus pulposus extrusion (ANNPE) and acute compressive hydrated nucleus pulposus extrusion (HNPE). Spinal cord contusion plays an important role in the pathophysiology of both conditions. Sustained spinal cord compression is not present in ANNPE, whereas varying degrees of compression are present in HNPE. Although affected animals often present with severe neurologic signs, good outcomes can be achieved with appropriate treatment.

The effect of electromagnetic fields on postoperative pain and locomotor recovery in dogs with acute, severe thoracolumbar intervertebral disc extrusion: a randomized placebo-controlled, prospective clinical trial.

Spinal cord injury (SCI) attributed to acute intervertebral disc extrusions (IVDEs) is common in dogs and is treated by surgical decompression. Dogs with sensorimotor complete injuries have an incomplete recovery. Pulsed electromagnetic fields (PEMFs) reduce post-operative pain through anti-inflammatory effects and there is growing evidence for neuroprotective effects. This randomized, controlled clinical trial evaluated the effect of PEMF on post-operative pain and neurological recovery in dogs with surgically treated sensorimotor complete SCI attributed to acute IVDE. Sixteen dogs with surgically treated complete thoracolumbar SCI were randomized to receive PEMF (15 min every 2 h for 2 weeks then twice-daily for 4 weeks) or placebo starting immediately after diagnosis. The primary outcome was gait score at 2 weeks. Secondary measures of gait, pain perception, and proprioceptive function were evaluated at 2 and 6 weeks. Plasma glial fibrillary acidic protein (GFAP) concentration was measured as an SCI biomarker. Post-operative pain was quantified by measuring mechanical sensory thresholds (MSTs) at control and surgical sites. There was no significant difference in demographics or GFAP concentration between the two groups at trial entry. There was no difference in primary outcome or in secondary measures of gait, but proprioceptive placing was significantly better at 6 weeks and GFAP concentrations were significantly lower at 2 weeks in the PEMF group. MSTs were significantly higher in the PEMF-treated group. We conclude that PEMF reduced incision-associated pain in dogs post-surgery for IVDE and may reduce extent of SCI and enhance proprioceptive placing. Larger clinical trials are warranted.

Variations in magnetic resonance venographic anatomy of the dorsal dural venous sinus system in 51 dogs.

Variations in intracranial dural venous sinus anatomy have been widely reported in humans, but there have been no studies reporting this in dogs. The purpose of this retrospective study was to describe variations in magnetic resonance (MR) venographic anatomy of the dorsal dural venous sinus system in a sample population of dogs with structurally normal brains. Medical records were searched for dogs with complete phase contrast, intracranial MR venograms and a diagnosis of idiopathic epilepsy. Magnetic resonance venograms were retrieved for each dog and characteristics of the dorsal dural sinuses, symmetry of the transverse sinuses and other anatomic variations were recorded. A total of 51 dogs were included. Transverse sinus asymmetry was present in 58.8% of the dogs, with transverse sinus hypoplasia seen in 39.2%, and aplasia in 23.5% of dogs. For 70.6% of dogs, at least one anatomic variation in the dorsal sagittal sinus was observed, including deviation from the midline (33.3%) and collateral branches from either the dorsal sagittal sinus or dorsal cerebral veins (54.9%). In 5 dogs (9.8%) a vessel was also identified running from the proximal transverse sinus to the distal sigmoid sinus, in a similar location to the occipital sinus previously reported in children. Findings from this study indicated that, as in humans, anatomic variations are common in the intracranial dural venous sinus system of dogs. These anatomic variations should be taken into consideration for surgical planning or diagnosis of cerebrovascular disease.

Rapid postoperative recurrence of a cranial multilobular tumor of bone in a young dog

Although resection of multilobular tumors of bone can be associated with a good prognosis and long disease‐free intervals in dogs, osteosarcomatous transformation should be considered a cause for rapid recurrence of clinical signs.

Hypersomatotropism in 3 Cats without Concurrent Diabetes Mellitus

A 16-year-old, 6.8 kg, castrated male Domestic Short-haired cat was presented to Louisiana State University Veterinary Teaching Hospital with a 3-day history of progressive ataxia, tetraparesis, and altered mentation. The owner did not report having observed evidence of polyuria or polydipsia. The cat had been diagnosed with hypertrophic cardiomyopathy (HCM) 4 years earlier and was receiving atenolol, benazepril, and aspirin. Dull mentation, patchy truncal alopecia, and a grade III of VI systolic heart murmur were noted during the physical examination. The neurologic examination revealed ambulatory tetraparesis that was more severe in the pelvic limbs, plantigrade stance, proprioceptive deficits in all limbs, and positional vertical nystagmus. The CBC, biochemistry profile, and abdominal ultrasound were unremarkable. The blood glucose concentration measured with the chemistry analyzer was 130 mg/dL (7.2 mmol/L). Subsequent blood glucose measurements (n = 6) using a glucometer validated for use in cats ranged from 122 mg/dL (6.7 mmol/L) to 159 mg/dL (8.7 mmol/L) during the 5-day period the cat was hospitalized. These blood glucose concentrations combined with a normal serum fructosamine concentration (228 lmol/L, RI 192–288) ruled out overt diabetes mellitus (DM). Two-dimensional echocardiogram revealed severe asymmetric septal hypertrophy (8.7 mm in diastole). The left atrium was normal in size and all valves appeared normal. Continuous wave Doppler through the left ventricular outflow tract revealed dynamic outflow tract obstruction. Color Doppler demonstrated marked turbulence in the left ventricular outflow tract and a narrow eccentric jet of mitral regurgitation associated with systolic anterior motion of the mitral valve. Magnetic resonance imaging (MRI) images of the head were obtained in multiple planes prior to and following contrast administration at a dose of 0.1 mmol/kg. In the region of the pituitary gland, there was a T2 hyperintense, T1 hypointense nodule having marked uniform contrast enhancement (Fig 1). This nodule had moderate extension dorsal to the sella turcica and was increased in size compared to a normal pituitary gland: length (0.63 cm), width (0.83 cm), and height (0.85 cm). On T2* weighted (gradient recalled echo) images, some regions of reduced signal and small signal voids were present within the pituitary gland, mostly on the left side, consistent with magnetic susceptibility likely due to regions of hemorrhage within the nodule. Additionally, there was moderate dilation of the entire ventricular system with most severe ventricular enlargement occurring in the fourth ventricle, which caused dorsal elevation and compression of the cerebellum. Findings were most consistent with a pituitary macroadenoma, hydrocephalus, and hydrosyringomyelia. The degree of pituitary enlargement and severity of 4th ventricular dilation did not support obstruction due to the pituitary mass. A cystic accumulation of cerebrospinal fluid (CSF) within the 4th ventricle or obstructive hydrocephalus due to an additional lesion not visible on the MRI could not be ruled out. A clinical diagnosis of hypersomatotropism was supported by the presence of a pituitary mass and a total From the Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70810 (Fletcher, Pipe-Martin, Granger); Department of Clinical Science and Services, The Royal Veterinary College, University of London, North Mymms, AL9 7TA, Herts, UK(Scudder, Kenny, Mantis, Fenn, Niessen); Department of Pathobiology and Diagnostic Investigation, Diagnostic Center for Population and Animal Health, Michigan State University, Lansing, MI 48910 (Kiupel); Department of Pathology and Pathogen Biology, The Royal Veterinary College, University of London, North Mymms, AL9 7TA, Herts, UK(Smith); Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70810(Blair). Corresponding author: J.M. Fletcher, Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70810; e-mail: jmfletcher@lsu.edu Submitted March 31, 2016; Revised May 12, 2016; Accepted May 16, 2016. Copyright

Cerebellar cortical degeneration in Hungarian vizslas

WE are seeking cases of young Hungarian vizsla with suspected or confirmed cerebellar cortical degeneration (CCD), also known as cerebellar abiotrophy, for genetic research. We have recently seen two Hungarian vizslas full siblings that developed progressive signs of diffuse cerebellar …