Magnetic resonance imaging (MRI) is the recognized gold standard for diagnostic imaging of the central nervous system in human and veterinary patients. Information on the use of this modality and possible imaging abnormalities in captive non-domestic felids is currently limited to individual case reports or small case series. This retrospective study provides information on technique and imaging findings in a cohort of cases undergoing MRI at an academic Veterinary Medical Center. The University of Tennessee College of Veterinary Medicine MRI database was searched for non-domestic felids undergoing MRI of the brain or spine from 2008 to 2021. Medical record data were recorded, and MRI studies were reviewed. Fifty animals met the inclusion criteria. The most common brain diseases were Chiari-like malformation (n = 8) and inflammatory conditions (n = 8). Other abnormalities included pituitary lesions (n = 5), brain atrophy (n = 2), and one each of metabolic and traumatic conditions. Fourteen animals had a normal brain MRI study. The most common spinal abnormality was intervertebral disc disease (n = 7). Other disorders included vertebral dysplasia (n = 2), presumptive ischemic myelopathy (n = 1), subdural ossification causing spinal cord compression (n = 1), and multiple myeloma (n = 1). Spinal cord swelling of undetermined cause was suspected in two animals, and seven patients had a normal MRI study of the spine. MRI is a valuable tool in the diagnostic workup of non-domestic felids with presumptive neurologic disease.

COPYRIGHT © 2022 Hecht, Thomas and Pees. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Editorial: Neurology and neuroimaging in exotic and non-domestic species

OBJECTIVE To determine the prevalence of depressed pelvic limb reflexes and changes in those reflexes over time in dogs with acute thoracolumbar myelopathy. DESIGN Prospective study. ANIMALS 34 dogs. PROCEDURES Dogs with acute pelvic limb paralysis caused by acute noncompressive nucleus pulposus extrusion (ANNPE), fibrocartilaginous embolism (FCE), or compressive intervertebral disk herniation (IVDH) within the T3-L3 spinal cord segments were enrolled in the study. Dogs with depressed or absent pelvic limb withdrawal reflexes as determined by 2 examiners were classified as affected and underwent additional testing to rule out multifocal lesions. Pelvic limb reflexes of affected dogs were reassessed every 12 hours until they returned to normal. Neurologic examinations were performed at 4 and 8 weeks after initial examination for some dogs. RESULTS Compressive IVDH, ANNPE, and FCE were diagnosed in 30, 1, and 3 dogs, respectively. Nine (5 with compressive IVDH and all 4 with FCE or ANNPE) of 34 (26%) dogs were classified as affected. Patellar reflexes were depressed in 2 of 9 affected dogs. The median time required for withdrawal reflexes to return to normal was 60 hours (range, 12 to 156 hours). Onset duration of paralysis was negatively associated with the odds of a dog being classified as affected. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that dogs with focal thoracolumbar spinal cord lesions, especially those with peracute onset of paralysis, can develop transient depression of pelvic limb reflexes. Awareness of this phenomenon is important for veterinarians to accurately localize lesions and develop appropriate diagnostic plans and prognoses.

Pediatric hydrocephalus is caused by developmental abnormalities and clinical signs are usually apparent by several months of age. Toy and brachycephalic dogs are at increased risk but the condition occurs sporadically in other breeds of dogs and cats. The diagnosis of hydrocephalus is based on clinical and imaging features. Definitive treatment of hydrocephalus is directed at the underlying cause if possible. Medical therapy is used to delay surgery, to manage acute deterioration, and when surgery is not an option or not indicated. Shunt surgery has a high failure rate and requires meticulous attention to detail. Many complications are avoidable, such as intra-parenchymal placement of the ventricular catheter. Quadrigeminal diverticula are most common in small and brachycephalic breeds, with Shih Tzus being the most common. Medical therapy of quadrigeminal diverticula is the same as for hydrocephalus, although there is limited published information regarding the efficacy of medical treatment for clinically significant quadrigeminal diverticula.

A 3-yr-old male captive bobcat (Lynx rufus) presented with chronic ataxia and right-sided head tilt. Magnetic resonance imaging (MRI) revealed cerebellar crowding and compression consistent with Chiari-like malformation. The clinical signs did not improve after surgical occipital craniectomy, and 2 mo postoperatively a second MRI showed hydromyelia and continued cerebellar compression. The bobcat was euthanized, and necropsy showed chronic focal cerebellar herniation and chronic multifocal atlanto-occipital joint osteophyte proliferation. Histology confirmed the presence of a thick fibrous membrane along the caudal aspect of the cerebellar vermis, suggestive of postoperative adhesions, and axonal degeneration of the cervical spinal cord, even in sections without a central canal lesion. These lesions appear to have been complications associated with surgical correction of the Chiari-like malformation.

OBJECTIVE To evaluate the pharmacokinetics of zonisamide following rectal administration of 20 or 30 mg/kg suspended in sterile water or polyethylene glycol (PEG) to healthy dogs and determine whether either dose resulted in plasma zonisamide concentrations within the recommended therapeutic target range (10 to 40 μg/mL). ANIMALS 8 healthy mixed-breed dogs. PROCEDURES Each dog received each of 2 doses (20 or 30 mg/kg) of zonisamide suspended in each of 2 delivery substrates (sterile water or PEG) in a randomized crossover study with a 7-day washout period between phases. A blood sample was collected from each dog immediately before and at predetermined times for 48 hours after zonisamide administration. Plasma zonisamide concentrations were determined by high-performance liquid chromatography, and data were analyzed with a noncompartmental model. RESULTS Mean maximum plasma concentration, time to maximum plasma concentration, mean residence time, and elimination half-life did not differ significantly among the 4 treatments. The mean maximum plasma concentration for all 4 treatments was less than the therapeutic target range. The mean ± SD area under the concentration-time curve for the 30 mg/kg-in-water treatment (391.94 ± 237.00 h•μg/mL) was significantly greater than that for the 20 mg/kg-in-water (146.19 ± 66.27 h•μg/mL) and 20 mg/kg-in-PEG (87.09 ± 96.87 h•μg/mL) treatments. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that rectal administration of zonisamide at doses of 20 and 30 mg/kg failed to achieve plasma zonisamide concentrations within the recommended therapeutic target range. Therefore, rectal administration of zonisamide cannot be recommended as a suitable alternative to oral administration.

OBJECTIVE:To evaluate outcome and adverse events following ventral stabilization of the atlantoaxial (AA) joint in dogs with clinical AA subluxation using screw/polymethymethacrylate (PMMA) constructs in a retrospective, multi-center cohort study.STUDY DESIGN:Historical cohort study.ANIMALS:35 client-owned dogs.METHODS:Medical records from 3 institutions were reviewed to identify dogs with AA subluxation treated with ventral screw and PMMA constructs. Data on signalment, pre- and postoperative neurologic status, imaging performed, and adverse events were retrieved. Neurologic examination data were abstracted to generate a modified Frankel score at admission, discharge, and re-examination. Telephone interview of owners >180 days postoperative was conducted.RESULTS:Thirty-five dogs with AA subluxation treated with ventral screw/PMMA constructs were included. Most dogs were young (median age 1 year), small breed dogs with acute onset of neurologic signs (median duration 22.5 hours). Most dogs were non-ambulatory at the time of admission (median modified Frankel score 3). Adverse events were identified in 15/35 dogs including 9 dogs with major adverse events. Four dogs required a second surgery due to vertebral canal violation (n = 2) or implant failure (n = 2). Re-examination at 4-6 weeks postoperative reported 15/28 dogs with improved neurologic status and 19/28 dogs were ambulatory. Telephone follow-up was available for 23/35 dogs with 23/23 reported as ambulatory (median follow-up 390 days).CONCLUSIONS:Ventral application of screw and PMMA constructs for AA subluxation, as described here, is associated with clinical improvement in the majority of dog. Major adverse events are infrequent and the technique is considered relatively safe.

A 2-year-old male, intact Yorkshire terrier presented with a 1-month history of progressive paraparesis. Neurological examination revealed paraplegia with absent deep pain perception, decreased right pelvic limb withdrawal reflex, and lumbar pain consistent with an L4-S2 neurolocalization. Magnetic resonance imaging (MRI) showed a single, well-demarcated, intramedullary mass centered over the L3-4 disk space. A hemilaminectomy was performed, and the mass was removed en bloc. Histopathological evaluation was consistent with a hemangioblastoma. Follow-up MRI 9 months after surgery showed no evidence of tumor recurrence, and the dog was ambulatory paraparetic at that time. This case is consistent with a previous histopathological report of spinal cord hemangioblastoma in a dog and provides additional clinical information regarding diagnosis, treatment, and outcome associated with this tumor type.

Traumatic disc extrusions (TDE) may occur when an otherwise healthy intervertebral disc is subjected to excessive force such as during vigorous exercise or trauma. A sudden increase in intradiscal pressure can cause rapid projection of hydrated nucleus pulposus (NP) toward the spinal cord through a tear in the annulus fibrosus. Acute noncompressive nucleus pulposus extrusion (ANNPE) has been reported in several canine breeds and in a few cats. Compressive hydrated nucleus pulposus extrusion (HNPE) has been reported in dogs and has been mainly characterized by ventral midline spinal cord compression. The antemortem diagnosis of TDE is based on clinical features and MRI. Dogs with compressive HNPE have been managed conservatively or surgically depending on the severity of neurologic dysfunction and degree of spinal cord compression. Advances in the treatment of secondary spinal cord injury may also benefit dogs with TDE.

Chapter 24 Nonsteroidal Anti-inflammatory Drugs, Muscle Relaxants, Opioids, and Other Treatments for Primary and Adjunctive Medical Management of Intervertebral Disc Herniation James M. Fingeroth, James M. FingerothSearch for more papers by this authorFranck Forterre, Franck ForterreSearch for more papers by this authorNúria Vizcaíno Revés, Núria Vizcaíno RevésSearch for more papers by this authorWilliam B. Thomas, William B. ThomasSearch for more papers by this author James M. Fingeroth, James M. FingerothSearch for more papers by this authorFranck Forterre, Franck ForterreSearch for more papers by this authorNúria Vizcaíno Revés, Núria Vizcaíno RevésSearch for more papers by this authorWilliam B. Thomas, William B. ThomasSearch for more papers by this author Book Editor(s):James M. Fingeroth, James M. Fingeroth Orchard Park Veterinary Medical Center, USASearch for more papers by this authorWilliam B. Thomas, William B. Thomas College of Veterinary Medicine, University of Tennessee, USASearch for more papers by this author First published: 12 December 2014 https://doi.org/10.1002/9781118940372.ch24 AboutPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onFacebookTwitterLinked InRedditWechat Summary Corticosteroids have been the main pharmacologic agent utilized in the treatment of intervertebral disc disease (IVDD), including patients with pain only as well as those with neurologic deficits. Studies of nonsteroidal anti-inflammatory drugs (NSAIDs) in patients with intervertebral disc herniation focus primarily on inhibition of the hyperalgesia caused by the sensitization of the peripheral afferent nerve. Skeletal muscle relaxants are divided into two categories: antispastic and antispasmodic agents. Opioids are effective for ameliorating many types of pain. They interact with various types and subtypes of opioid receptors present in the central and peripheral nervous system. Regardless of analgesic protocols selected, one of the most important aspects of management for the nonsurgically treated dog with suspected IVDH is to enforce strict rest. This recommendation is somewhat at odds with current protocols for treating low back pain in humans, where controlled mobility is encouraged. Advances in Intervertebral Disc Disease in Dogs and Cats RelatedInformation