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Objective: Episodic mandibular tremor (EMT), manifested as teeth chattering, is not well described in dogs. The aim of this study was to describe clinical signs, MRI findings, and outcome of dogs with EMT., Animals: 11 dogs retrospectively and 31 dogs in an online survey., Methods: A retrospective multicenter study of dogs with EMT between 2018 and 2023 and prospective online questionnaire open to owners of pets with teeth chattering., Results: All dogs had rapid and short-lasting (< 1 minute) episodes of EMT in the absence of other neurological signs. Lip smacking occasionally accompanied the tremor in 5 of 11 (45.5%) hospital dog cases. Excitement was a common trigger in 14 of 31 (45.2%) dogs from the survey. Cavalier King Charles Spaniel was the most common breed in both clinical and survey populations. Median age at presentation was 3 years for both hospital cases and the survey dogs. A concurrent medical condition was present in 8 of 11 (72.7%) hospital cases and 20 of 31 (64.5%) survey dogs. In 3 hospital dogs that underwent further investigations, no brain disease was present., Clinical Relevance: EMT and its clinical features are presented for the first time, shedding light on a clinical sign that might resemble an idiopathic movement disorder or a manifestation of pain in dogs.

Case Description: Three dogs were presented for investigation of chronic nasal discharge and epistaxis 141, 250, and 357 days after undergoing transfrontal craniotomy to treat an intracranial meningioma (2 dogs) or a meningoencephalocele (1 dog)., Clinical Findings: CT findings were consistent with destructive rhinitis and frontal sinusitis in all 3 dogs, with results of histologic examination and fungal culture of samples obtained during frontal sinusotomy confirming mycotic infection. Frontal sinusotomy revealed fungal plaques covering a combination of bone and residual surgical tissue adhesive at the site of the previous craniotomy in all 3 dogs. Aspergillus spp were identified in all 3 dogs, and Chrysosporium sp was also identified in 1 dog., Treatment and Outcome: Surgical curettage was followed by antifungal treatment (topical clotrimazole in 2 dogs and oral itraconazole for 3 months in 1 dog). Nasal discharge improved in the short-term but recurred in all dogs 99, 118, and 110 days after frontal sinusotomy. One dog received no further treatment, 1 dog received an additional 8.5 months of oral itraconazole treatment, and 1 dog underwent 2 additional surgical debridement procedures. At last follow-up, 2 dogs were alive 311 and 481 days after frontal sinusotomy; the third dog was euthanized because of status epilepticus 223 days after frontal sinusotomy., Clinical Relevance: Sinonasal mycosis should be considered as a potential complication in dogs developing persistent mucopurulent nasal discharge, intermittent epistaxis, and intermittent sneezing following transfrontal craniotomy. The pathophysiology may be multifactorial, and potential risk factors, including use of surgical tissue adhesive in the frontal sinus, require further investigation.

Objective: To evaluate whether concurrent analysis of CSF samples from 2 collection sites (cerebellomedullary cistern [CMC] and lumbar subarachnoid space [LSS]) versus only 1 site could improve the diagnostic sensitivity of CSF analysis for dogs with suspected steroid-responsive meningitis arteritis (SRMA)., Animals: 111 client-owned dogs with SRMA diagnosed at 3 veterinary referral hospitals between 2011 and 2017., Procedures: Only dogs with CSF collected from both sites (CMC and LSS) and with no previous history of corticosteroid administration were included. Medical record data and logistic regression were used to identify factors associated with having a total nucleated cell concentration (TNCC) within the reference interval in a CSF sample from 1 collection site., Results: The TNCC was within the reference interval (TNCC < 5 cells/μL) in the CSF sample from 1 collection site for 8 of 111 (7%) dogs and was only slightly high (TNCC, 5 to 9 cells/μL) in the sample from 1 or both sites for 10 (11%) other dogs. For each of these 18 dogs, results for samples from 1 site were consistent with SRMA. The proportion of CSF samples that had a TNCC within the reference interval was comparable between sites. As age increased, so did the risk of having an unremarkable TNCC in the CSF sample from 1 site, albeit only slightly (OR, 1.08; 95% confidence interval, 1.01 to 1.16)., Conclusions and Clinical Relevance: CSF samples from both the CMC and LSS should be analyzed when evaluating dogs with suspected SRMA to improve the chance of detecting a high TNCC.

Objective: To evaluate signalment, clinical findings, and outcomes of dogs with congenital hydrocephalus treated medically with orally administered prednisolone or surgically by ventriculoperitoneal shunt placement., Design: Retrospective case series., Animals: 40 client-owned dogs., Procedures: Medical records from 2005 to 2016 were searched to identify dogs with congenital hydrocephalus confirmed by MRI examination. Patients were categorized by treatment (medical vs surgical). Signalment, clinical signs, neurologic examination findings, results of diagnostic tests, duration of hospitalization, complications potentially related to treatment, and follow-up information were recorded. Outcome was categorized on the basis of clinical (neurologic) signs as improved, stabilized, or deteriorated. Variables of interest were compared between groups by Fisher exact or Mann-Whitney U tests., Results: 28 and 12 dogs had surgical and medical treatment, respectively; 3 medically treated dogs subsequently underwent ventriculoperitoneal shunt placement. No significant differences were noted in clinical or imaging findings between surgically and medically treated dogs. Median follow-up time was 9 months and 15.5 months for medically and surgically treated dogs, respectively. Of 12 medically treated dogs, 6 improved and 6 deteriorated. Of 26 surgically treated dogs with data available, 14 (54%) improved, 1 (4%) stabilized, and 11 (42%) deteriorated; 4 (15%) had known postoperative complications., Conclusions and Clinical Relevance: Approximately half of the dogs treated with prednisolone in this population had neurologic improvement at last follow-up; results of surgical treatment were comparable to those in previous studies. Further research is needed to assess factors associated with acceptable outcomes for dogs with congenital hydrocephalus.

OBJECTIVE To characterize outcomes following nonsurgical treatment of congenital thoracic vertebral body malformations causing neurologic deficits in dogs. DESIGN Retrospective case series. ANIMALS 13 client-owned dogs treated nonsurgically for congenital thoracic vertebral body malformations at 3 veterinary referral hospitals from June 2009 through May 2016. PROCEDURES Data were extracted from the medical records regarding dog signalment, duration and type of clinical signs before referral, general physical and neurologic examination findings, radiographic and MRI findings, and treatments provided after diagnosis. Follow-up data were obtained from records of recheck examinations and via a standardized owner questionnaire. RESULTS All included dogs were screw-tail brachycephalic breeds with a median age of 6 months. All dogs had ambulatory paraparesis and ataxia, and in 1 dog, signs of spinal hyperesthesia could be elicited. Nonsurgical treatments consisted of restricted exercise without (n = 5) or with (3) physiotherapy, physiotherapy without restricted exercise (3), and no exercise modification (2). Seven dogs received additional nonsurgical treatment consisting of prednisolone (n = 5) or gabapentin (2). Four dogs were eventually euthanized because of progressive neurologic deterioration, 2 underwent surgery for the same reason, and the remaining 7 dogs survived for ≥ 170 days after diagnosis, despite progressive neurologic deterioration. CONCLUSIONS AND CLINICAL RELEVANCE Nonsurgical treatment of congenital thoracic vertebral body malformations was associated with an unfavorable outcome in this group of dogs. Despite this treatment, all dogs had progression of clinical signs.

CASE DESCRIPTION A 16-month-old neutered male Continental Giant rabbit (Lepus curpaeums) was referred for evaluation of a 7-day history of acute-onset, progressive, symmetric paraparesis. CLINICAL FINDINGS On initial examination, the rabbit was nonambulatory, and results of neurologic examination were consistent with a lesion affecting the T3-L3 spinal cord segments. Thoracic radiography showed irregular widening of the left T11-12 articular process joint. Marked dorsolateral and lateral extradural spinal cord compression with contrast enhancement of the adjacent epaxial muscles was evident on MRI images of the spine. TREATMENT AND OUTCOME A left-sided T11-T12 hemilaminectomy was performed, which revealed an abnormal and hypertrophic T11-12 articular process joint and an osteolytic lesion communicating with the vertebral canal. Copious purulent material causing marked spinal cord compression was evident, and the surgical site was lavaged extensively with sterile (0.9% NaCl) saline solution. Results of aerobic, anaerobic, and enriched bacteriologic cultures of swab specimens obtained from the surgical site were negative. Histologic analysis of biopsy samples revealed chronic purulent osteomyelitis, myositis, and fasciitis with necrosis, fibrosis, and dystrophic mineralization. The rabbit was discharged 48 hours after surgery. Ten weeks after surgery, the rabbit was ambulatory with mild paraparesis. On telephone follow-up 21 months after surgery, the owners indicated that the rabbit was healthy and expressed satisfaction with the treatment and outcome. CLINICAL RELEVANCE Paraspinal abscess with vertebral canal involvement should be considered as a differential diagnosis for rabbits with clinical signs of progressive T3-L3 myelopathy. Outcome for the patient of the present report suggested that surgical treatment including decompression and debridement can result in a favorable long-term outcome.

OBJECTIVE To compare clinical signs and outcomes between dogs with presumptive ischemic myelopathy and dogs with presumptive acute noncompressive nucleus pulposus extrusion (ANNPE). DESIGN Retrospective study. ANIMALS 51 dogs with ischemic myelopathy and 42 dogs with ANNPE examined at 1 referral hospital. PROCEDURES Medical records and MRI sequences were reviewed for dogs with a presumptive antemortem diagnosis of ischemic myelopathy or ANNPE. Information regarding signalment, clinical signs at initial examination, and short-term outcome was retrospectively retrieved from patient records. Long-term outcome information was obtained by telephone communication with referring or primary-care veterinarians and owners. RESULTS Compared with the hospital population, English Staffordshire Bull Terriers and Border Collies were overrepresented in the ischemic myelopathy and ANNPE groups, respectively. Dogs with ANNPE were significantly older at disease onset and were more likely to have a history of vocalization at onset of clinical signs, have spinal hyperesthesia during initial examination, have a lesion at C1-C5 spinal cord segments, and be ambulatory at hospital discharge, compared with dogs with ischemic myelopathy. Dogs with ischemic myelopathy were more likely to have a lesion at L4-S3 spinal cord segments and have long-term fecal incontinence, compared with dogs with ANNPE. However, long-term quality of life and outcome did not differ between dogs with ischemic myelopathy and dogs with ANNPE. CONCLUSIONS AND CLINICAL RELEVANCE Results revealed differences in clinical signs at initial examination between dogs with ischemic myelopathy and dogs with ANNPE that may aid clinicians in differentiating the 2 conditions.

Objective: To assess the anatomic distribution of thoracolumbar and lumbar intervertebral disk extrusions (IVDEs) in English Cocker Spaniels as compared with findings in Dachshunds and to characterize clinical findings in English Cocker Spaniels with thoracolumbar or lumbar IVDEs affecting various regions of the vertebral column., Design: Retrospective observational study., Animals: 81 English Cocker Spaniels and 81 Dachshunds with IVDEs., Procedures: Signalment, clinical signs, neurologic examination findings, and affected intervertebral disk spaces (IVDSs) were recorded for both breeds. Management methods and outcomes were recorded for English Cocker Spaniels. Lesions were categorized as thoracolumbar (IVDSs T9-10 through L1-2), midlumbar (L2-3 through L4-5), or caudal lumbar (L5-6 through L7-S1)., Results: Midlumbar and caudal lumbar IVDEs were significantly more common in English Cocker Spaniels than in Dachshunds. English Cocker Spaniels with caudal lumbar IVDEs had a longer median duration of clinical signs before evaluation and more commonly had unilateral pelvic limb lameness or spinal hyperesthesia as the predominant clinical sign than did those with IVDEs at other sites. Those with caudal lumbar IVDEs less commonly had neurologic deficits and had a higher median neurologic grade (indicating lesser severity), shorter mean postoperative hospitalization time, and faster mean time to ambulation after surgery than those with other sites affected. These variables did not differ between English Cocker Spaniels with thoracolumbar and midlumbar IVDEs., Conclusions and Clinical Relevance: Caudal and midlumbar IVDEs were more common in English Cocker Spaniels than in Dachshunds. English Cocker Spaniels with caudal lumbar IVDE had clinical signs and posttreatment responses that differed from those in dogs with midlumbar or thoracolumbar IVDE.

Objective: To compare clinical signs of dogs treated medically or surgically for degenerative lumbosacral stenosis (DLSS) and assess outcome after medical treatment., Design: Retrospective case series., Animals: Client-owned dogs treated medically (n = 49) or surgically (49) for DLSS., Procedures: Medical records from 2004 to 2012 were reviewed. Dogs were included if they had clinical signs, clinical examination findings, and MRI abnormalities consistent with DLSS. Several variables were compared between surgically and medically treated dogs: age, sex, duration of clinical signs, presence or absence of neurologic deficits, urinary and fecal incontinence, concurrent medical conditions, and medical treatment before referral. Medical treatment after obtaining a final diagnosis of DLSS consisted of restricted exercise in combination with anti-inflammatory and analgesic drugs. Surgical treatment consisted of dorsal lumbosacral laminectomy. Outcome for medically treated dogs was obtained via a standardized questionnaire., Results: Neurologic deficits were observed significantly more often in surgically treated dogs. Surgically treated dogs had unsuccessful medical treatment before referral significantly more often than did medically treated dogs. Thirty-one of 49 (63.3%) medically treated dogs were available for follow-up evaluation. Of these 31 dogs, 17 (55%) were managed successfully, 10 (32.3%) were managed unsuccessfully and underwent surgical treatment, 3 (9.7%) were euthanized because of progression of clinical signs, and 1 (3.2%) was alive but had an increase in severity of clinical signs after medical management., Conclusions and Clinical Relevance: Clinical signs differed in dogs treated medically or surgically for DLSS. Medical treatment for dogs with DLSS was associated with a fair prognosis.

Case Description: A 4-year-old sexually intact male mixed-breed dog was evaluated because of clinical signs of acute-onset pelvic limb ataxia, rapidly progressing to paraplegia with severe spinal hyperesthesia., Clinical Findings: General physical examination revealed pyrexia, tachycardia, and tachypnea. Neurologic examination demonstrated severe spinal hyperesthesia and paraplegia with decreased nociception. Magnetic resonance imaging revealed extradural spinal cord compression at T13-L1 and hyperintense lesions on T1- and T2-weighted images in the epaxial musculature and epidural space., Treatment and Outcome: Decompressive surgery, consisting of a continuous dorsal laminectomy, with copious lavage of the vertebral canal was performed. Cultures of blood, urine, and surgical site samples were negative. Histologic examination results for samples obtained during surgery demonstrated suppurative myositis and steatitis. These findings confirmed a diagnosis of sterile idiopathic inflammation of the epidural fat and epaxial muscles with spinal cord compression. The dog's neurologic status started to improve 1 week after surgery. After surgery, the dog received supportive care including antimicrobials and NSAIDs. The dog was ambulatory 1 month after surgery and was fully ambulatory despite signs of mild bilateral pelvic limb ataxia 3 years after surgery., Clinical Relevance: Although idiopathic sterile inflammation of adipose tissue, referred to as panniculitis, more commonly affects subcutaneous tissue, its presence in the vertebral canal is rare. Specific MRI findings described in this report may help in reaching a presumptive diagnosis of this neurologic disorder. A definitive diagnosis and successful long-term outcome in affected patients can be achieved by decompressive surgery and histologic examination of surgical biopsy samples.

Objective: To evaluate the evolution of clinical signs and their correlation with results of magnetic resonance imaging (MRI) and transcranial magnetic stimulation (TMS) and to assess potential prognostic variables after conservative medical treatment for disk-associated cervical spondylomyelopathy (DA-CSM) in dogs., Design: Prospective cohort study., Animals: 21 client-owned dogs with DA-CSM., Procedures: After neurologic grading, dogs underwent low-field MRI and TMS with measurement of onset latencies and peak-to-peak amplitudes from the extensor carpi radialis and cranial tibial muscles. Dimensions calculated from MRI images were remaining spinal cord area, spinal cord compression ratio, vertebral occupying ratio, vertebral canal height-to-body height ratio, vertebral canal height-to-body length ratio, and vertebral canal compromise ratio. Intraparenchymal signal intensity changes were graded. Dogs were reevaluated 1, 3, 6, 12, and 24 months after initial diagnosis., Results: Outcome was successful in 8 of 21 dogs. Negative outcomes were characterized by rapid progression of clinical signs. All dogs with more severe clinical signs of DA-CSM 1 month after diagnosis had unsuccessful outcomes. Outcome was associated with the remaining spinal cord area and vertebral canal compromise ratio. Prognosis was not associated with severity of clinical signs or results of TMS. There were no significant correlations among clinical signs, MRI findings, and TMS results., Conclusions and Clinical Relevance: Conservative medical treatment of DA-CSM was associated with a guarded prognosis. Selected MRI variables and clinical evolution 1 month after diagnosis can be considered prognostic indicators. The lack of correlation among clinical signs, results of diagnostic imaging, and results of electrophysiologic evaluation in dogs with DA-CSM warrants further investigation.

Objective: To determine intraobserver, interobserver, and intermethod agreement for results of myelography, computed tomography-myelography (CTM), and low-field magnetic resonance imaging (MRI) in dogs with disk-associated wobbler syndrome (DAWS)., Design: Prospective cross-sectional study., Animals: 22 dogs with DAWS., Procedures: All dogs underwent myelography, CTM, and low-field MRI. Each imaging study was interpreted twice by 4 observers who were blinded to signalment and clinical information of the patients. The following variables were assessed by all 3 techniques: number, site, and direction of spinal cord compressions; narrowed intervertebral disk spaces; vertebral body abnormalities; spondylosis deformans; and abnormal articular facets. Intervertebral foraminal stenosis was assessed on CTM and MRI images. Intraobserver, interobserver, and intermethod agreement were calculated by κ and weighted κ statistics., Results: There was very good to good intraobserver agreement for most variables assessed by myelography and only moderate intraobserver agreement for most variables assessed by CTM and low-field MRI. There was moderate to fair interobserver and intermethod agreement for most variables assessed by the 3 diagnostic techniques. There was very good or good intraobserver, interobserver, or intermethod agreement for the site and direction of the worst spinal cord compression as assessed by all the imaging modalities; abnormal articular facets and intervertebral foraminal stenosis were the least reliably assessed variables, with poor interobserver agreement regardless of imaging modality used., Conclusions and Clinical Relevance: There was considerable variation in image interpretation among observers and between use of various imaging modalities; these imaging techniques should be considered complementary in assessment of dogs with DAWS.

Objective: To evaluate the use of transcranial magnetic stimulation for differentiating between clinically relevant and clinically irrelevant cervical spinal cord compression on magnetic resonance imaging (MRI)., Design: Validation study., Animals: Clinically normal Doberman Pinschers without (n = 11) and with (6) spinal cord compression on MRI and 16 Doberman Pinschers with disk-associated wobbler syndrome (DAWS)., Procedures: After dogs were sedated, transcranial magnetic motor evoked potentials were recorded from the extensor carpi radialis muscle (ECRM) and cranial tibial muscle (CTM). Onset latencies and peak-to-peak amplitudes were measured. Magnetic resonance imaging was performed to identify spinal cord compression., Results: There were significant differences in ECRM and CTM onset latencies between Doberman Pinschers with DAWS and each of the 2 groups of clinically normal dogs, but there were no significant differences in ECRM and CTM onset latencies between the 2 groups of clinically normal dogs. There were significant differences in CTM peak-to-peak amplitudes between Doberman Pinschers with DAWS and each of the 2 groups of clinically normal dogs, but there were no significant differences in ECRM peak-to-peak amplitudes among groups or in CTM peak-to-peak amplitudes between the 2 groups of clinically normal dogs. There was a significant correlation between severity of spinal cord compression and ECRM onset latency, CTM onset latency, and CTM peak-to-peak amplitude., Conclusions and Clinical Relevance: Results suggested that transcranial magnetic stimulation may be a useful diagnostic tool to differentiate between clinically relevant and clinically irrelevant spinal cord compression identified on MRI alone.

Objective: To determine interobserver and intraobserver agreement for results of low-field magnetic resonance imaging (MRI) in dogs with and without disk-associated wobbler syndrome (DAWS)., Design: Validation study., Animals: 21 dogs with and 23 dogs without clinical signs of DAWS., Procedures: For each dog, MRI of the cervical vertebral column was performed. The MRI studies were presented in a randomized sequence to 4 board-certified radiologists blinded to clinical status. Observers assessed degree of disk degeneration, disk-associated and dorsal compression, alterations in intraspinal signal intensity (ISI), vertebral body abnormalities, and new bone formation and categorized each study as originating from a clinically affected or clinically normal dog. Interobserver agreement was calculated for 44 initial measurements for each observer. Intraobserver agreement was calculated for 11 replicate measurements for each observer., Results: There was good interobserver agreement for ratings of disk degeneration and vertebral body abnormalities and moderate interobserver agreement for ratings of disk-associated compression, dorsal compression, alterations in ISI, new bone formation, and suspected clinical status. There was very good intraobserver agreement for ratings of disk degeneration, disk-associated compression, alterations in ISI, vertebral body abnormalities, and suspected clinical status. There was good intraobserver agreement for ratings of dorsal compression and new bone formation. Two of 21 clinically affected dogs were erroneously categorized as clinically normal, and 4 of 23 clinically normal dogs were erroneously categorized as clinically affected., Conclusions and Clinical Relevance: Results suggested that variability exists among observers with regard to results of MRI in dogs with DAWS and that MRI could lead to false-positive and false-negative assessments.