Valentine Martlé

Clinical evaluation of 51 dogs treated conservatively for disc-associated wobbler syndrome

OBJECTIVES To evaluate the clinical evolution and potential risk factors of 51 dogs treated conservatively for disc-associated wobbler syndrome. METHODS Medical records of dogs treated conservatively for disc-associated wobbler syndrome were reviewed, and owners were contacted regarding clinical evolution and survival of their animals. Relationships between age, treatment before diagnosis, type of neurological signs, results of medical imaging and outcome were determined. RESULTS Fifty-one dogs underwent conservative treatment for disc-associated wobbler syndrome. A successful outcome was achieved in 45 per cent (23 of 51) of the patients. Median follow-up period was 18.5 months, and median survival time was 47 months. In 85 per cent of the dogs in which euthanasia was performed because of disc-associated wobbler syndrome, this was carried out in the first year after diagnosis. Outcome score was influenced by type of neurological signs and additional radiographic and/or myelographic abnormalities. Outcome score was not significantly associated with age, number of protruded intervertebral discs, occurrence, type and results of treatment before diagnosis. CLINICAL SIGNIFICANCE Conservative treatment of disc-associated wobbler syndrome is associated with a guarded prognosis. It can be considered in cases where all four limbs are not affected and no additional radiographic and/or myelographic abnormalities are detected.

Myokymia and neuromyotonia in 37 Jack Russell terriers

The clinical and clinicopathological characteristics, treatment and outcome of vermicular muscle contractions (myokymia) and generalized muscle stiffness (neuromyotonia) in 37 Jack Russell terriers were evaluated retrospectively. Thirty dogs were affected by both disorders, whereas seven were presented with myokymia and never developed neuromyotonia. Clinical signs started at the mean age of 8 months. Except for signs of myokymia and neuromyotonia, clinical and neurological examination was normal in all dogs. Thirty dogs demonstrated typical signs of hereditary ataxia. Changes in serum chemistry included increased creatine kinase, aspartate aminotransferase and alanine aminotransferase concentrations. Electromyographic abnormalities, especially in muscles showing macroscopically visible myokymia, consisted of semirhythmic bursts of doublet, triplet, or multiplet discharges of a single motor unit. The amplitudes varied between 80 μV and 1 mV and occurred with an interburst frequency between 10 and 40 Hz and an intraburst frequency between 150 and 280 Hz. Most dogs were treated with a sodium channel blocker with variable results. Seven dogs died (most likely because of hyperthermia) or were euthanased during a neuromyotonic attack; 15 dogs were euthanased due to worsening of clinical signs, or lack of or no long-lasting effect of medication, and three were euthanased for unknown or unrelated reasons. Nine dogs were lost to follow-up and three were still alive 5-10.5 years after the start of clinical signs. In conclusion, young Jack Russell terriers with myokymia and neuromyotonia should undergo a complete blood and electrophysiological examination. Long-term prognosis is not favourable.

Dominance of chemokine ligand 2 and matrix metalloproteinase-2 and -9 and suppression of pro-inflammatory cytokines in the epidural compartment after intervertebral disc extrusion in a canine model.

BACKGROUND CONTEXT In canine intervertebral disc (IVD) disease, a useful animal model, only little is known about the inflammatory response in the epidural space. PURPOSE To determine messenger RNA (mRNA) expressions of selected cytokines, chemokines, and matrix metalloproteinases (MMPs) qualitatively and semiquantitatively over the course of the disease and to correlate results to neurologic status and outcome. STUDY DESIGN/SETTING Prospective study using extruded IVD material of dogs with thoracolumbar IVD extrusion. PATIENT SAMPLE Seventy affected and 13 control (24 samples) dogs. OUTCOME MEASURES Duration of neurologic signs, pretreatment, neurologic grade, severity of pain, and outcome were recorded. After diagnostic imaging, decompressive surgery was performed. METHODS Messenger RNA expressions of interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor (TNF), interferon (IFN)γ, MMP-2, MMP-9, chemokine ligand (CCL)2, CCL3, and three housekeeping genes was determined in the collected epidural material by Panomics 2.0 QuantiGene Plex technology. Relative mRNA expression and fold changes were calculated. Relative mRNA expression was correlated statistically to clinical parameters. RESULTS Fold changes of TNF, IL-1β, IL-2, IL-4, IL-6, IL-10, IFNγ, and CCL3 were clearly downregulated in all stages of the disease. MMP-9 was downregulated in the acute stage and upregulated in the subacute and chronic phase. Interleukin-8 was upregulated in acute cases. MMP-2 showed mild and CCL2 strong upregulation over the whole course of the disease. In dogs with severe pain, CCL3 and IFNγ were significantly higher compared with dogs without pain (p=.017/.020). Dogs pretreated with nonsteroidal anti-inflammatory drugs revealed significantly lower mRNA expression of IL-8 (p=.017). CONCLUSIONS The high CCL2 levels and upregulated MMPs combined with downregulated T-cell cytokines and suppressed pro-inflammatory genes in extruded canine disc material indicate that the epidural reaction is dominated by infiltrating monocytes differentiating into macrophages with tissue remodeling functions. These results will help to understand the pathogenic processes representing the basis for novel therapeutic approaches. The canine IVD disease model will be rewarding in this process.

Non-pharmacological treatment options for refractory epilepsy: An overview of human treatment modalities and their potential utility in dogs

Refractory epilepsy is a common disorder both in humans and dogs and treatment protocols are difficult to optimise. In humans, different non-pharmacological treatment modalities currently available include surgery, the ketogenic diet and neurostimulation. Surgery leads to freedom from seizures in 50-75% of patients, but requires strict patient selection. The ketogenic diet is indicated in severe childhood epilepsies, but efficacy is limited and long-term compliance can be problematic. In the past decade, various types of neurostimulation have emerged as promising treatment modalities for humans with refractory epilepsy. Currently, none of these treatment options are used in routine daily clinical practice to treat dogs with the condition. Since many dogs with poorly controlled seizures do not survive, the search for alternative treatment options for canine refractory epilepsy should be prioritised. This review provides an overview of non-pharmacological treatment options for human refractory epilepsy. The current knowledge and limitations of these treatments in canine refractory epilepsy is also discussed.

Surgical Treatment of a Canine Intranasal Meningoencephalocele

OBJECTIVE To report the clinical signs, diagnosis, and surgical treatment of an intranasal meningoencephalocele in a dog. STUDY DESIGN Case report. ANIMAL Female Border collie, 5 months old. METHODS A right intranasal meningoencephalocele was identified by computed tomography and magnetic resonance imaging. RESULTS The lesion was approached by a modified transfrontal craniotomy. Surgical closure of the defect at the level of the cribriform plate and removal of extruded brain tissue resulted in regression of lacrimation and coincided with absence of seizuring. Treatment with phenobarbital was gradually reduced and stopped at 7 months after surgery. At 28 months the dog remained free of seizures. CONCLUSION Meningoencephalocele, although rare, can cause seizures in dogs and can be treated surgically. CLINICAL RELEVANCE A transfrontal craniotomy with excision of the meningoencephalocele and closure of the defect can be an effective treatment for an intranasal meningoencephalocele in dogs.

High-resolution micro-SPECT to evaluate the regional brain perfusion in the adult Beagle dog

Conventional Single Photon Emission Computed Tomography (SPECT) precludes a detailed evaluation of the subcortical region. Micro-SPECT (μ-SPECT) has a higher resolution, but has not been used to evaluate the dogs brain until now. In this study, μ-SPECT of the brain was evaluated in 10 Beagle dogs. Magnetic Resonance Imaging (MRI) of the brain was used to draw a new region map containing 19 volumes of interest (VOIs). Semi-quantitative analysis of the μ-SPECT data was performed and the regional cerebral perfusion was represented by the perfusion indices (PIs). The highest perfusion was found in the parietal cortex and the lowest in the piriform cortex. An asymmetry toward the left hemisphere in general and a regional asymmetry in the frontal, temporal and parietal cortex were found. This study shows that functional imaging of the canine brain is possible using μ-SPECT and it describes the normal regional brain perfusion in the adult Beagle dog.

Magnetic stimulation of the radial nerve in dogs and cats with brachial plexus trauma: A report of 53 cases

Brachial plexus trauma is a common clinical entity in small animal practice and prognostic indicators are essential early in the course of the disease. Magnetic stimulation of the radial nerve and consequent recording of the magnetic motor evoked potential (MMEP) was examined in 36 dogs and 17 cats with unilateral brachial plexus trauma. Absence of deep pain perception (DPP), ipsilateral loss of panniculus reflex, partial Horners syndrome and a poor response to MMEP were related to the clinical outcome in 29 of the dogs and 13 of the cats. For all animals, a significant difference was found in MMEP between the normal and the affected limb. Absence of DPP and unilateral loss of the panniculus reflex were indicative of an unsuccessful outcome in dogs. Additionally, the inability to evoke a MMEP was associated with an unsuccessful outcome in all animals. It was concluded that magnetic stimulation of the radial nerve in dogs and cats with brachial plexus trauma may provide an additional diagnostic and prognostic tool.

Regional brain perfusion changes during standard and microburst vagus nerve stimulation in dogs

PURPOSE Vagus nerve stimulation (VNS) is an effective adjunctive treatment for refractory epilepsy in humans, but its mechanism of action (MOA) and optimal stimulation parameters are still unknown. Functional neuroimaging studies could provide better insight into the brain structures involved in the activity of VNS, but have not yet been described in dogs. The aim of this study was to investigate the effect of acute VNS on the regional cerebral blood flow (rCBF) in dogs using micro-SPECT (μ-SPECT). Additionally, a novel stimulation paradigm (microburst VNS) was used and compared with standard VNS. METHODS A VNS Therapy System was implanted in ten Beagle dogs. μ-SPECT was performed after sham, standard and microburst VNS in a randomized, cross-over study. Nineteen volumes of interest (VOIs) were semi-quantitatively analysed and perfusion indices (PIs) were calculated. Furthermore, a rostro-caudal gradient (R-C), an asymmetry index (AI) and a cortical-subcortical index (Co-SCo) were determined. The SPECT results after standard and microburst VNS were compared pairwise with sham stimulation. RESULTS Acute standard VNS did not cause significant rCBF alterations. Acute microburst VNS caused a significant hypoperfusion in the left frontal lobe (P=0.023) and in the right parietal lobe (P=0.035). Both stimulation paradigms did not cause changes in R-C, AI nor Co-SCo. CONCLUSIONS Microburst VNS is more potent than standard VNS to modulate the rCBF in the dog. Our results promote further research towards the antiepileptic effect of microburst VNS in dogs and humans.

Hemifacial spasm associated with an intracranial mass in two dogs

Two dogs were presented with hemifacial spasm. Computed tomography images of both the dogs revealed an intracranial mass. In the first dog, a lesion at the level of the medulla oblongata was thought to cause primary irritation of the facial nucleus, with consequently permanent contraction of the ipsilateral facial muscles. In the second dog, a mass seemingly arising from the middle cranial fossa presumably isolated the facial motor neurons from upper motor neuron control, which resulted in hemifacial spasm as a result of loss of inhibitory interneuronal activity.

Regional cerebral blood flow assessed by single photon emission computed tomography (SPECT) in dogs with congenital portosystemic shunt and hepatic encephalopathy

Regional cerebral blood flow (rCBF) in eight dogs with congenital portosystemic shunt (PSS) and hepatic encephalopathy (HE) was compared with rCBF in eight healthy control dogs using single photon emission computed tomography (SPECT) with a 99mtechnetium-hexamethylpropylene amine oxime (99mTc-HMPAO) tracer. SPECT scans were abnormal in all PSS dogs. Compared to the control group, rCBF in PSS dogs was significantly decreased in the temporal lobes and increased in the subcortical (thalamic and striatal) area. Brain perfusion imaging alterations observed in the dogs with PSS and HE are similar to those in human patients with HE. These findings suggest that dogs with HE and PSS have altered perfusion of mainly the subcortical and the temporal regions of the brain.