Search

Abstract A 10‐year‐old male neutered crossbreed dog and an 8‐year‐old female neutered greyhound presented after peracute onset of cerebellar dysfunction. The crossbreed dog had anisocoria with the left pupil being mydriatic, spontaneous conjugate rotatory nystagmus with fast phase to the left and delayed postural reactions on the left side. The greyhound had anisocoria with the left pupil being mydriatic, right positional ventral strabismus, absent menace response in the left eye and postural reaction deficits on the left side. For both dogs, the neuroanatomical localization was left cerebellum with paradoxical vestibular syndrome. Magnetic resonance imaging identified a left cerebellar ischemic territorial infarct of the rostral cerebellar artery, involving the region of the left interposital nucleus. Both dogs were given supportive care and at 2‐week follow‐up the anisocoria had resolved. Anisocoria with mydriasis can be a clinical sign in dogs with naturally‐occurring cerebellar ischemic infarcts in the region of the ipsilateral interposital nucleus.

Abstract Pituitary‐dependent hypersomatotropism is rarely diagnosed in dogs and surgical treatment is not reported. A 6‐year‐10‐month male neutered Patterdale Terrier presented with polyuria, polydipsia, progressive pharyngeal stertor, excessive hair growth and widened facial features and paws. Serum insulin‐like growth factor‐1 concentration via radioimmunoassay was consistent with hypersomatotropism (1783 ng/mL). A pituitary mass was identified on magnetic resonance and computed tomography imaging. Six weeks later, glucosuria, starved hyperglycemia and serum fructosamine above the reference range (467.6 μmol/L, RI 177‐314) were documented, consistent with diabetes mellitus. Transsphenoidal hypophysectomy was performed under general anesthesia without complications. Pituitary histopathology identified an acidophil neoplasm, with positive immunostaining for growth hormone. Postoperatively, there was rapid resolution of clinical, biochemical and morphologic changes of hypersomatotropism with persistence of diabetes mellitus. This case demonstrates successful resolution of hypersomatotropism with ongoing diabetes mellitus in a dog after surgical treatment by transsphenoidal hypophysectomy.

Intervertebral disc degeneration in dogs occurs in an accelerated way and involves calcification, which is associated with disc herniation or extrusion. The degenerative process is complex and involves the transformation of collagen fibres, loss of proteoglycans and notochord cells and a reduction in water content; however, how these processes are linked to future disc extrusion remains unknown. We have employed techniques including Fourier Transform Infra-red Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Uniaxial Compression Loading and Atomic Force Microscopy (AFM) in an attempt to gain a greater understanding of the degenerative process and its consequences on the physical properties of the disc. FTIR verified by TEM demonstrated that calcium phosphate exists in an amorphous state within the disc and that the formation of crystalline particles of hydroxyapatite occurs prior to disc extrusion. AFM identified crystalline agglomerates consistent with hydroxyapatite as well as individual collagen fibres. SEM enabled the identification of regions rich in calcium, phosphorous and oxygen and allowed the visualization of the topographical landscape of the disc. Compression testing generated stress/strain curves which will facilitate investigation into disc stiffness. Ongoing work is aimed at identifying potential areas of intervention in the degenerative process as well as further characterizing the role of calcification in disc extrusion.

Abstract Background Thoracolumbar intervertebral disc extrusion (TL‐IVDE) is the most common cause of acute paraparesis and paraplegia in dogs; however, guidelines on management of the condition are lacking. Objectives To summarize the current literature as it relates to diagnosis and management of acute TL‐IVDE in dogs, and to formulate clinically relevant evidence‐based recommendations. Animals None. Methods A panel of 8 experts was convened to assess and summarize evidence from the peer‐reviewed literature in order to develop consensus clinical recommendations. Level of evidence available to support each recommendation was assessed and reported. Results The majority of available literature described observational studies. Most recommendations made by the panel were supported by a low or moderate level of evidence, and several areas of high need for further study were identified. These include better understanding of the ideal timing for surgical decompression, expected surgical vs medical outcomes for more mildly affected dogs, impact of durotomy on locomotor outcome and development of progressive myelomalacia, and refining of postoperative care, and genetic and preventative care studies. Conclusions and Clinical Importance Future efforts should build on current recommendations by conducting prospective studies and randomized controlled trials, where possible, to address identified gaps in knowledge and to develop cost effectiveness and number needed to treat studies supporting various aspects of diagnosis and treatment of TL‐IVDE.

Abstract Acquired cervical scoliosis previously has been reported in dogs as a clinical sign associated with Chiari‐like malformation and syringomyelia but has not been described with inflammatory central nervous system disease. A 9‐month‐old Flat‐Coated Retriever was presented with an acute onset of cervical scoliosis with no other neurological deficits. Magnetic resonance imaging identified a focal, poorly defined intramedullary lesion within the cranial cervical spinal cord. Cerebrospinal fluid (CSF) analysis indicated mononuclear pleocytosis consistent with a diagnosis of meningomyelitis of unknown etiology. A second dog, a 3‐year‐old female spayed German Shepherd, developed an acute onset of cervical scoliosis with mild generalized proprioceptive ataxia 2 months after commencing immunosuppressive corticosteroid treatment for presumed steroid‐responsive meningitis‐arteritis. Magnetic resonance imaging at the time of diagnosis disclosed a similar intramedullary lesion within the cranial cervical spinal cord, with a neutrophilic pleocytosis on CSF analysis. Both dogs were treated with immunosuppressive dosages of prednisolone, along with cytosine arabinoside in the first dog, with resolution of cervical scoliosis seen in both. To our knowledge, this is the first report of acute onset acquired, reversible cervical scoliosis in dogs with presumed immune‐mediated meningomyelitis.

Abstract Background Acquired narcolepsy has rarely been reported in veterinary medicine. Objective To describe the presentation, clinicopathological features, diagnostic imaging findings, and management of dogs with suspected‐acquired narcolepsy. Animals Eight dogs with clinical features consistent with acquired narcolepsy. Methods A call for suspected cases of acquired narcolepsy was made online, followed by a retrospective review of detailed medical records of potential cases. Dogs were included if episodes consistent with cataplexy were present during examination by a board‐certified veterinary neurologist and diagnostic work‐up included magnetic resonance imaging of the brain and analysis of cerebrospinal fluid. Results Seven French Bulldogs and 1 Chihuahua (age range, 9‐66 months) were included. Meningoencephalitis of unknown origin was diagnosed in 2 dogs, extracranial foci of inflammation were identified in 2 dogs (aspiration pneumonia, esophagitis, otitis media), and no abnormalities were found on diagnostic investigations in 4 dogs. Prednisolone was used in the management of all dogs, 6 dogs received imipramine, and 2 received cytosine arabinoside. An initial remission of signs was observed in all dogs, but a subsequent relapse of clinical signs was recorded for 4 dogs, of which 3 responded to adjustment or resumption of treatment. Conclusions and Clinical Importance The presence of cataplexy episodes should prompt a thorough diagnostic work‐up to exclude the presence of intracranial (and extracranial) pathology. The potential for both remission and relapse of signs in suspected acquired cases is important for clinicians and owners to be aware of.

Abstract Background Hypersomatotropism (HST) is an increasingly recognized endocrinopathy in cats and is mostly described associated with diabetes mellitus (DM). Objectives To evaluate the efficacy and safety of transsphenoidal hypophysectomy in treating HST and DM in cats. Animals Sixty‐eight client‐owned cats with HST and DM treated by transsphenoidal hypophysectomy. Methods Retrospective cohort study. Medical records were reviewed for glycemic control and serum insulin‐like growth factor‐1 (IGF‐1) concentrations. Postoperative complications, death within 4 weeks, and proportion achieving diabetic remission were recorded. Survival times and DM‐free intervals were calculated. Results Fifty‐eight cats (85.3%) were alive 4 weeks postoperatively with 10 (15%) postoperative deaths. Complications included hypoglycemia (n = 9), electrolyte imbalance (n = 9), and transient congestive heart failure (n = 5). Fifty‐five cats (95% of 58 surviving cats [81% of all cats undergoing surgery]) had improved control of diabetes. Diabetic remission occurred in 41 cats (71% of 58 surviving cats [60% of all cats]) with insulin administration discontinued after a median of 9 days (range, 2‐120). Postoperative 4‐week serum IGF‐1 concentration nadir was significantly lower in cats achieving diabetic remission (median 20 ng/mL [15‐708] than those that did not (324 ng/mL [15‐1955]; P = .03). All cats received long‐term levothyroxine and hydrocortisone PO, alongside desmopressin (conjunctival) in 38 of 53 cats (72%). Recurrence of DM occurred in 5 of 41 cats (12%) after a median of 248 days (range, 84‐1232). Median survival time of all cats was 853 days (range, 1‐1740). Conclusions and Clinical Importance Transsphenoidal hypophysectomy is an effective treatment for cats with HST and DM, with a long‐term outcome that compares favorably to existing options.

ObjectiveHypophysectomy in dogs is a difficult surgery that requires specific learning and training. We aimed to evaluate the accuracy of a 3-dimensional printed patient-specific surgical guide to facilitate choosing the entry point in the basisphenoid bone before approaching the sella turcica during transsphenoidal hypophysectomy in dogs.MethodsTwo canine cadavers and 8 dogs undergoing transsphenoidal hypophysectomy for Cushing's disease treatment, involving design and fabrication of a 3-dimensional printed guide. The ideal entry point in the basisphenoid bone outer cortical layer was determined in each dog pre-operatively; its anatomical location was described with a set of measurements then compared to post-operative computed tomography measures describing the location of the outer cortical window created in the basisphenoid bone.ResultsSeveral guide designs were proposed, and a consensus reached based on surgeons' experience performing hypophysectomy. The device chosen could be applied to the size and shape of skulls encountered in this case series. The pre-planned measurements were comparable to post-operative measurement (there was also no statistical difference), with median of differences

Abstract Background Retrospective research recently identified a possible relationship between duration of surgery and outcome in severely affected dogs treated surgically for acute thoracolumbar intervertebral disk herniation (TL‐IVDH). Hypothesis That increased duration of surgery is associated with poorer outcome in dogs with absent pain perception treated surgically for TL‐IVDH. Animals Two hundred ninety‐seven paraplegic dogs with absent pain perception surgically treated for acute TL‐IVDH. Methods Retrospective cohort study. Medical records of 5 institutions were reviewed. Inclusion criteria were paraplegia with absence of pain perception, surgical treatment of TL‐IVDH, and 1‐year postoperative outcome (ambulatory: yes or no). Canine data, outcome, and surgery and total anesthesia duration were retrieved. Results In this study, 183/297 (61.6%) dogs were ambulatory within 1 year, 114 (38.4%) dogs failed to recover, including 74 dogs (24.9%) euthanized because of progressive myelomalacia. Median anesthesia duration in dogs that regained ambulation within 1 year of surgery (4.0 hours, interquartile range [IQR] 3.2‐5.1) was significantly shorter than those that did not (4.5 hours, IQR 3.7‐5.6, P = .01). Multivariable logistic regression demonstrated a significant negative association between both duration of surgery and total anesthesia time and ambulation at 1 year when controlling for body weight and number of disk spaces operated on. Conclusions and Clinical Importance Findings support a negative association between increased duration of anesthesia and outcome in this group of dogs. However, the retrospective nature of the data does not imply a causal relationship.

Abstract Background Crossmatching is used to prevent life‐threatening transfusion reactions in horses. Laboratory methods are laborious and technically challenging, which is impractical during emergencies. Hypothesis/Objectives Evaluate agreement between a stall‐side crossmatch kit (KIT) and a laboratory method (LAB) in horses with known and unknown blood types. Animals Twenty‐four blood‐typed and alloantibody‐screened healthy adult horses (Aim 1) and 156 adult horses of unknown blood type (Aim 2). Methods Prospective, blinded study. Expected positive (n = 35) and negative (n = 36) crossmatches among 24 antibody and blood‐typed horses were used to determine sensitivity and specificity of KIT and LAB against the reference method. Agreement in 156 untyped horses was evaluated by reciprocal crossmatch (n = 156). Results Sensitivity (95% confidence interval [CI]) for LAB and KIT compared with expected reactions was 77.1% (59.9%‐90.0%) and 91.4% (77.0%‐98.2%), and specificity 77.8% (60.9%‐89.9%) and 73.5% (55.6%‐87.1%), respectively. The KIT was 100% sensitive for Aa reactions; LAB was 100% sensitive for Qab; and both were 100% sensitive for Ca. Cohen's κ agreement for LAB and KIT with expected positive and negative reactions (n = 71) was moderate (0.55 [0.36‐0.74]) and substantial (0.65 [0.47‐0.82]), respectively. Agreement was fair comparing LAB with KIT in Aim 1 (0.30 [0.08‐0.52]) and in untyped horses in Aim 2 (0.26 [0.11‐0.41]). Conclusions and Clinical Importance Agreement between KIT and LAB with expected reactions was blood type dependent. Performance of both methods depends on blood type prevalence.

Spinal cord injury in companion dogs can lead to urinary and fecal incontinence or retention, depending on the severity, and localization of the lesion along the canine nervous system. The bladder and gastrointestinal dysfunction caused by lesions of the autonomic system can be difficult to recognize, interpret and are easily overlooked. Nevertheless, it is crucial to maintain a high degree of awareness of the impact of micturition and defecation disturbances on the animal's condition, welfare and on the owner. The management of these disabilities is all the more challenging that the autonomic nervous system physiology is a complex topic. In this review, we propose to briefly remind the reader the physiology of micturition and defecation in dogs. We then present the bladder and gastrointestinal clinical signs associated with sacral lesions (i.e., the L7-S3 spinal cord segments and nerves) and supra-sacral lesions (i.e., cranial to the L7 spinal cord segment), largely in the context of intervertebral disc herniation. We summarize what is known about the natural recovery of urinary and fecal continence in dogs after spinal cord injury. In particular we review the incidence of urinary tract infection after injury. We finally explore the past and recent literature describing management of urinary and fecal dysfunction in the acute and chronic phase of spinal cord injury. This comprises medical therapies but importantly a number of surgical options, some known for decades such as sacral nerve stimulation, that might spark some interest in the field of spinal cord injury in companion dogs.

Imaging is integral in the diagnosis of canine intervertebral disc disease (IVDD) and in differentiating subtypes of intervertebral disc herniation (IVDH). These include intervertebral disc extrusion (IVDE), intervertebral disc protrusion (IVDP) and more recently recognized forms such as acute non-compressive nucleus pulposus extrusion (ANNPE), hydrated nucleus pulposus extrusion (HNPE), and intradural/intramedullary intervertebral disc extrusion (IIVDE). Many imaging techniques have been described in dogs with roles for survey radiographs, myelography, computed tomography (CT), and magnetic resonance imaging (MRI). Given how common IVDH is in dogs, a thorough understanding of the indications and limitations for each imaging modality to aid in diagnosis, treatment planning and prognosis is essential to successful case management. While radiographs can provide useful information, especially for identifying intervertebral disc degeneration or calcification, there are notable limitations. Myelography addresses some of the constraints of survey radiographs but has largely been supplanted by cross-sectional imaging. Computed tomography with or without myelography and MRI is currently utilized most widely and have become the focus of most contemporary studies on this subject. Novel advanced imaging applications are being explored in dogs but are not yet routinely performed in clinical patients. The following review will provide a comprehensive overview on common imaging modalities reported to aid in the diagnosis of IVDH including IVDE, IVDP, ANNPE, HNPE, and IIVDE. The review focuses primarily on canine IVDH due to its frequency and vast literature as opposed to feline IVDH.

Spinal cord injury (SCI) in dogs is commonly attributed to intervertebral disc extrusion (IVDE). Over the last years substantial progress was made in the elucidation of factors contributing to the pathogenesis of this common canine disease. A detailed understanding of the underlying histopathological and molecular alterations in the lesioned spinal cord represents a prerequisite to translate knowledge on the time course of secondary injury processes into the clinical setting. This review summarizes the current state of knowledge of the underlying pathology of canine IVDE-related SCI. Pathological alterations in the spinal cord of dogs affected by IVDE-related SCI include early and persisting axonal damage and glial responses, dominated by phagocytic microglia/macrophages. These processes are paralleled by a pro-inflammatory microenvironment with dysregulation of cytokines and matrix metalloproteinases within the spinal cord. These data mirror findings from a clinical and therapeutic perspective and can be used to identify biomarkers that are able to more precisely predict the clinical outcome. The pathogenesis of progressive myelomalacia, a devastating complication of SCI in dogs, is not understood in detail so far; however, a fulminant and exaggerating secondary injury response with massive reactive oxygen species formation seems to be involved in this unique neuropathological entity. There are substantial gaps in the knowledge of pathological changes in IVDE with respect to more advanced and chronic lesions and the potential involvement of demyelination. Moreover, the role of microglia/macrophage polarization in IVDE-related SCI still remains to be investigated. A close collaboration of clinical neurologists and veterinary pathologists will help to facilitate an integrative approach to a more detailed understanding of the molecular pathogenesis of canine IVDE and thus to identify therapeutic targets.

Intervertebral disc disease (IVDD) has been recognized in dogs since the 1800s, when the first descriptions of extruded disc material within the vertebral canal were published. In the intervening time our understanding of intervertebral disc pathology in dogs and cats has increased dramatically, with many variations of IVDD described. Whilst the volume of literature and collective understanding of IVDD has expanded, there has also been scope for confusion as the definition of intervertebral disc disease, with its myriad different manifestations, becomes more complicated. A large volume of literature has aimed to combine the use of histopathology, diagnostic imaging and clinical findings to better understand the various ways in which IVDD can be classified. Much of this research has focused on the classification of mechanisms of intervertebral disc degeneration, centering around the differences between, and overlaps in, IVDD in chondrodystrophic and non-chondrodystrophic dog breeds. However, with the increasing availability of advanced imaging modalities allowing more accurate antemortem diagnosis, the concept of IVDD has expanded to include other clinical presentations that may not fit into traditional models of classification of IVDD. This review aims to provide an up to date overview of both historical and current systems of IVDD classification, highlighting the important findings and controversies underpinning them.

Some dogs do not make a full recovery following medical or surgical management of acute canine intervertebral disc herniation (IVDH), highlighting the limits of currently available treatment options. The multitude of difficulties in treating severe spinal cord injury are well-recognized, and they have spurred intense laboratory research, resulting in a broad range of strategies that might have value in treating spinal cord-injured dogs. These include interventions that aim to directly repair the spinal cord lesion, promote axonal sparing or regeneration, mitigate secondary injury through neuroprotective mechanisms, or facilitate functional compensation. Despite initial promise in experimental models, many of these techniques have failed or shown mild efficacy in clinical trials in humans and dogs, although high quality evidence is lacking for many of these interventions. However, the continued introduction of new options to the veterinary clinic remains important for expanding our understanding of the mechanisms of injury and repair and for development of novel and combined strategies for severely affected dogs. This review outlines adjunctive or emerging therapies that have been proposed as treatment options for dogs with acute IVDH, including discussion of local or lesion-based approaches as well as systemically applied treatments in both acute and subacute-to-chronic settings. These interventions include low-level laser therapy, electromagnetic fields or oscillating electrical fields, adjunctive surgical techniques (myelotomy or durotomy), systemically or locally-applied hypothermia, neuroprotective chemicals, physical rehabilitation, hyperbaric oxygen therapy, electroacupuncture, electrical stimulation of the spinal cord or specific peripheral nerves, nerve grafting strategies, 4-aminopyridine, chondroitinase ABC, and cell transplantation.

There is a clear need for new methods of treatment of acute disc herniation in dogs, most obviously to address the permanent loss of function that can arise because of the associated spinal cord injury. Clinical trials form the optimal method to introduce new therapies into everyday clinical practice because they are a reliable source of unbiased evidence of effectiveness. Although many designs are available, parallel cohort trials are most widely applicable to acute disc herniation in dogs. In this review another key trial design decision—that between pragmatic and explanatory approaches—is highlighted and used as a theme to illustrate the close relationship between trial objective and design. Acute disc herniation, and acute spinal cord injury, is common in dogs and there is a multitude of candidate interventions that could be trialed. Most current obstacles to large-scale clinical trials in dogs can be overcome by collaboration and cooperation amongst interested veterinarians.

Intervertebral disc extrusion (IVDE) is one of the most common neurologic problems encountered in veterinary clinical practice. The purpose of this manuscript is to provide an overview of the literature related to treatment of acute canine thoracolumbar IVDE to help construct a framework for standard care of acute canine thoracolumbar IVDE where sufficient evidence exists and to highlight opportunities for future prospective veterinary clinical research useful to strengthen care recommendations in areas where evidence is low or non-existent. While there exist a number of gaps in the veterinary literature with respect to standards of care for dogs with acute thoracolumbar IVDE, recommendations for standard care can be made in some areas, particularly with respect to surgical decompression where the currently available evidence supports that surgery should be recommended for dogs with nonambulatory paraparesis or worse. While additional information is needed about the influence on timing of decompression on outcome in dogs that are deep pain negative for longer than 48 h duration, there is no evidence to support treatment of the 48 h time point as a cut off beyond which it becomes impossible for dogs to achieve locomotor recovery. Surgical decompression is best accomplished by either hemilaminectomy or mini-hemilaminectomy and fenestration of, at a minimum, the acutely ruptured disc. Adjacent discs easily accessed by way of the same approach should be considered for fenestration given the evidence that this substantially reduces future herniation at fenestrated sites. Currently available neuroprotective strategies such as high does MPSS and PEG are not recommended due to lack of demonstrated treatment effect in randomized controlled trials, although the role of anti-inflammatory steroids as a protective strategy against progressive myelomalacia and the question of whether anti-inflammatory steroids or NSAIDs provide superior medical therapy require further evaluation.

Acute thoracolumbar spinal cord injury (SCI) is common in dogs frequently secondary to intervertebral disc herniation. Following severe injury, some dogs never regain sensory function to the pelvic limbs or tail and are designated chronically “deep pain negative.” Despite this, a subset of these dogs develop spontaneous motor recovery over time including some that recover sufficient function in their pelvic limbs to walk independently without assistance or weight support. This type of ambulation is commonly known as “spinal walking” and can take up to a year or more to develop. This review provides a comparative overview of locomotion and explores the physiology of locomotor recovery after severe SCI in dogs. We discuss the mechanisms by which post-injury plasticity and coordination between circuitry contained within the spinal cord, peripheral sensory feedback, and residual or recovered supraspinal connections might combine to underpin spinal walking. The clinical characteristics of spinal walking are outlined including what is known about the role of patient or injury features such as lesion location, timeframe post-injury, body size, and spasticity. The relationship between the emergence of spinal walking and electrodiagnostic and magnetic resonance imaging findings are also discussed. Finally, we review possible ways to predict or facilitate recovery of walking in chronically deep pain negative dogs. Improved understanding of the mechanisms of gait generation and plasticity of the surviving tissue after injury might pave the way for further treatment options and enhanced outcomes in severely injured dogs.