International veterinary epilepsy task force consensus proposal: diagnostic approach to epilepsy in dogs

Measurement of Neutrophil Gelatinase-Associated Lipocalin Concentration in Canine Cerebrospinal Fluid and Serum and Its Involvement in Neuroinflammation

Neutrophil gelatinase-associated Lipocalin (NGAL) is a glycoprotein involved in inflammation acting as an acute phase protein and chemokine as well as a regulator of iron homeostasis. NGAL has been shown to be upregulated in experimental autoimmune encephalomyelitis (EAE) in mice. Increased NGAL concentration in cerebrospinal fluid (CSF) and expression in central nervous system (CNS) has been described in human neuroinflammatory disease such as multiple sclerosis and neuropsychiatric lupus as well as in bacterial meningitis. We aimed to investigate involvement of NGAL in spontaneous canine neuroinflammation as a potential large animal model for immune- mediated neurological disorders. A commercially available Enzyme-linked Immunosorbent Assay (ELISA) for detection of canine NGAL was validated for use in canine CSF. Concentration in CSF and serum of canine patients suffering from steroid- responsive meningitis- arteriitis (SRMA), Meningoencephalitis of unknown origin (MUO), different non- inflammatory CNS disease and control dogs were compared. Relationship between NGAL concentration in CSF and serum and inflammatory parameters in CSF and blood (IgA concentration, total nucleated cell count (TNCC), protein content) as well as association with erythrocytes in CSF, duration of illness, plasma creatinine and urinary leucocytes were evaluated. In dogs with SRMA and MUO, CSF concentration of NGAL was significantly higher than in dogs with idiopathic epilepsy, compressive myelopathy, intracranial neoplasia and SRMA in remission (p < 0.0001). Patients with acute SRMA had significantly higher levels of NGAL in CSF than neurologically normal controls (p < 0.0001). Serum NGAL concentrations were significantly higher in dogs with SRMA than in patients with myelopathy and intracranial neoplasia (p < 0.0001). NGAL levels in CSF were strongly positively associated with IgA concentration (rSpear= 0.60116, p < 0.0001), TNCC (rSpear= 0.65746, p < 0.0001) and protein content (rSpear= 0.73353, p < 0.0001) in CSF. It can be measured in CSF of healthy and diseased dogs. Higher concentrations in canine patients with SRMA as well as positive association with TNCC in CSF suggest an involvement in pro-inflammatory pathways and chemotaxis in SRMA. High serum levels of NGAL in serum of SRMA patients in different stages of disease might reflect the systemic character of the disease.

A cross-species approach to disorders affecting brain and behaviour

Structural and functional elements of biological systems are highly conserved across vertebrates. Many neurological and psychiatric conditions affect both humans and animals. A cross-species approach to the study of brain and behaviour can advance our understanding of human disorders via the identification of unrecognized natural models of spontaneous disorders, thus revealing novel factors that increase vulnerability or resilience, and via the assessment of potential therapies. Moreover, diagnostic and therapeutic advances in human neurology and psychiatry can often be adapted for veterinary patients. However, clinical and research collaborations between physicians and veterinarians remain limited, leaving this wealth of comparative information largely untapped. Here, we review pain, cognitive decline syndromes, epilepsy, anxiety and compulsions, autoimmune and infectious encephalitides and mismatch disorders across a range of animal species, looking for novel insights with translational potential. This comparative perspective can help generate novel hypotheses, expand and improve clinical trials and identify natural animal models of disease resistance and vulnerability.

Diagnostic value of cerebrospinal fluid analysis in a population of dogs with suspected idiopathic epilepsy

Cerebrospinal fluid (CSF) analysis is commonly used in the diagnostic investigation of seizure disorders in order to exclude possible inflammatory underlying aetiology. The medical records were searched for dogs presenting with epileptic seizures (ES) that had normal interictal neurological examination, normal complete blood count and biochemistry analysis, unremarkable MRI of the brain and had CSF analysis performed as part of the diagnostic investigation. A total of 200 dogs met the inclusion criteria. The CSF was abnormal in 30 dogs with a median total nucleated cell count of two cells/µl (IQR 1.5-6) and median protein concentration of 0.37 g/l (IQR 0.31-0.41). Pleocytosis was recorded in 14/30 dogs and the CSF protein was increased in 22/30. There was no correlation between abnormal CSF and the type or number of seizures or the time interval between the last seizure and CSF collection. A significant correlation was found between the number of red blood cells on CSF and having an abnormal CSF. The prevalence of having a diagnosis other than suspected idiopathic epilepsy (IE) was 0.5 per cent (1/200). These results suggest that performing CSF analysis in dogs with recurrent ES that have normal interictal neurological examination and unremarkable MRI has a low diagnostic value.

Open-label clinical trial of rectally administered levetiracetam as supplemental treatment in dogs with cluster seizures

Background

Treatment options for at‐home management of cluster seizures (CS) and status epilepticus (SE) are limited. The pharmacokinetics of levetiracetam (LEV) after rectal administration in both healthy and epileptic dogs has been investigated recently.

Hypothesis/Objectives

To investigate the clinical efficacy of rectally administered LEV in preventing additional seizures in dogs presented for CS and SE. We hypothesized that rectal administration of LEV in addition to a standard treatment protocol would provide better control of seizure activity as compared with the standard treatment protocol alone.

Animals

Fifty‐seven client‐owned dogs with CS or SE.

Methods

Prospective open‐label clinical trial. Patients included in the study were assigned to receive either a standard treatment protocol comprising IV/rectal diazepam and IV phenobarbital q8h (control group) or a standard treatment protocol in association with a single dose of 40 mg/kg LEV rectally (rectal LEV group). Dogs that experienced no additional seizures were defined as responders, whereas those that showed additional seizure activity were classified as nonresponders.

Results

Twenty‐one dogs were assigned to the rectal LEV group, and 36 to control group. Given the small number of cases of SE, statistical analysis was performed only on patients with CS. The response rate was 94% in the rectal LEV group and 48% in the control group (P < .001).

Conclusions and Clinical Importance

Rectally administered LEV combined with a standard treatment protocol provided good control of seizure activity in patients with CS. The validity of these results should be confirmed in a double‐blinded, placebo‐controlled clinical trial.

2-Hydroxyglutaric aciduria as a cause for seizure-like episodes in a domestic shorthair cat

Case summary

A 14-month-old male castrated domestic shorthair cat, which 2 months prior to presentation underwent hindlimb amputation following a road traffic accident, presented for investigation of four suspected generalised tonic–clonic seizures. Neurological examination was unremarkable. Routine blood work (haematology, biochemistry, ammonia, preprandial bile acids) was unremarkable. MRI of the brain identified marked symmetrical T2-weighted hyperintensities of the cerebellum and brainstem, mainly affecting the grey matter. Urine amino acid and mucopolysaccharide levels were unremarkable. Urine organic acids on two separate samples, 35 days apart, identified highly increased excretion of 2-hydroxyglutaric acid, indicative of 2-hydroxyglutaric aciduria. The cat was started on anticonvulsant therapy with phenobarbitone, which, at the point of writing, has improved seizure control, although the cat has not achieved seizure freedom.

Relevance and novel information

This case report describes the first reported case of a 2-hydroxyglutaric aciduria, an inherited neurometabolic disorder, as a cause for seizure-like episodes in a cat.

Evaluation of IL-1β levels in epilepsy and traumatic brain injury in dogs

Background

Epilepsy is a common neurological disease in dogs affecting approximately 0.6–0.75% of the canine population. There is much evidence of neuroinflammation presence in epilepsy, creating new possibilities for the treatment of the disease. An increased expression of interleukin-1 beta (IL-1β) was reported in epileptogenic foci. We hypothesized that there is an elevation of IL-1β in serum and CSF of dogs with epilepsy, as well as in serum of dogs with TBI, reflecting involvement of this cytokine in pathophysiology of naturally occurring canine epilepsy in a clinical setting.

Results

IL-1β levels were evaluated in CSF and serum of six healthy and 51 dogs with epilepsy (structural and idiopathic). In 16 dogs with TBI, only serum was tested. IL-1β concentrations in CSF were not detectable. Serum values were not elevated in dogs with TBI in comparison to healthy controls (p > 0.05). However, dogs with epilepsy had increased levels of IL-1β in serum (p = 0.003) regardless of the underlying cause of the disease (p = 0.0045). There was no significant relationship between the variables and IL-1β levels. Statistically noticeable (p = 0.0630) was that approximately 10% of dog with epilepsy (R² = 0.105) had increased seizure frequency and IL-1β elevation.

Conclusion

Increased IL-1β levels were detected in the peripheral blood in dogs with idiopathic and structural epilepsy leading to the assumption that there is an involvement of inflammation in pathophysiology of epilepsy which should be considered in the search for new therapeutic strategies for this disease. However, to better understand the pathogenic role of this cytokine in epilepsy, further evaluation of IL-1β in brain tissue is desired.

Study to determine clinical decision thresholds in small animal veterinary practice

This study aimed to determine clinical decision thresholds for six common conditions in small animal veterinary practice. Participants were provided with an online survey. Five questions described scenarios of canine patients with suspected panosteitis, hypothyroidism, urinary tract infection (UTI), mechanical gastrointestinal obstruction (GIO) and idiopathic epilepsy, and one question described a feline patient with suspected chronic kidney disease. A range of probabilities was applied to each scenario. Test and treatment threshold levels were computed for each scenario from 297 usable responses. The test and treatment thresholds were determined for UTI (test=12.8 per cent; 95 per centCI=1.1 to 20.7; treatment=82.0per cent; 95 per centCI=66.3 to 100) and GIO (test=3.2 per cent; 95 per cent CI=0 to 10.4; treatment=87.3 per cent; 95 per centCI=82.6 to 93.5). All other scenarios did not provide data that allowed interpretable test and treatment thresholds. This pilot study has used a new approach in determining clinical thresholds in small animal medicine. Thresholds were successfully determined for two common conditions-canine mechanical GIO and canine UTI. Future research should broaden investigation of methods to determine group clinical threshold levels among veterinarians, which may be used as the basis for clinical decision rules.

A double-blinded randomised dietary supplement crossover trial design to investigate the short-term influence of medium chain fatty acid (MCT) supplement on canine idiopathic epilepsy: study protocol

Background

Epilepsy is the most common brain disease in dogs. Recently, diets have been reported to have a positive impact on seizure activity and behaviour in various species including dogs with idiopathic epilepsy (IE). Historically, classic high fat ketogenic diets (KD) and medium chain triglycerides (MCT) KD have been successfully used to manage drug-resistant epilepsy. Similarly, an MCT enriched diet has been shown to improve seizure control and behavioural comorbidities in some dogs with IE. However, it is unknown whether an MCT dietary supplement (DS) may provide similar positive effects.

Methods

A 6-month prospective, randomised, double-blinded, placebo-controlled, crossover, multicentre dietary trial is designed comparing a 9% metabolic energy based calculated medium-chain triglyceride (MCT) oil supplement to a conventional ‘control’ DS. Only dogs which will have an International Veterinary Epilepsy Task Force Tier II level like diagnosis of IE which satisfied the following inclusion criteria are included: age between 6 months and ≤ 12 years; weighing between 4 and ≤ 65 kg; unremarkable interictal neurological examinations; no clinically significant findings on routine laboratory diagnostics; unremarkable brain MRI scan; have had at least 3 seizures in the previous 3 months prior to enrolment; treated with at least one ASD and being classified as resistant. All dogs are fed initially for 90 ± 2 days with either the control oil or the MCT oil alongside their normal diet, followed by 97 ± 2 days with the other supplement including a 7-day washout period. Overall, the aim is to recruit thirty-six patients at five different centres and to investigate the effect of MCTs as DS on seizure activity, tolerability, behavioural comorbidities and quality of life (QoL).

Discussion

Dietary interventions are rarely studied in a standardised form in veterinary medicine. The background diet, the cohort of animals and ASD received is standardised in this prospective diet trial to ensure representative data about the potential effect of MCT DS. If the study data confirms former findings, this would provide further evidence for the efficacy of MCTs as a management option for canine epilepsy. This publication should offer a repository of trial conditions and variable description with forecasted statistical analysis.

Electronic supplementary material

The online version of this article (10.1186/s12917-019-1915-8) contains supplementary material, which is available to authorized users.

Epileptic seizure frequency and semiology in dogs with idiopathic epilepsy after initiation of imepitoin or phenobarbital monotherapy

The aim of this study was to evaluate changes in epileptic seizures (ES) frequency and semiology in antiepileptic-medication (AEM)-naïve dogs with idiopathic epilepsy (DIE) after initiation of imepitoin (IMP) or phenobarbital (PB) monotherapy. In this observational prospective cohort study, inclusion criteria were as follows: diagnosis of idiopathic epilepsy (based on clinical, laboratory and magnetic resonance imaging investigations) in AEM-naïve dogs and presence of a detailed ES-diary. Exclusion criteria were: occurrence of cluster seizures (CS) or status epilepticus (SE) prior to treatment initiation and concurrent disease and/or treatments. Thirty-one DIE commenced IMP at 10-20mg/kg/12h and 30 dogs commenced PB at 2.50-3.30mg/kg/12h. AEM dosage was increased over time (up to IMP 30mg/kg/12h and PB 5.20mg/kg/12h). All dogs experienced generalised-tonic-clonic ES. In the IMP-group, pre-treatment median ES-frequency was 1.50ES/month (range, 1-4ES/month); post-treatment median ES-frequency was 0.95ES/m (range, 1ES/6m-3ES/m); n=21/31 (67.70%) dogs developed CS 1-18 months after initiation of treatment; n=7/31 (22.60%) dogs experienced unacceptable adverse events in the first month of treatment which required switching to an alternative AEM; and n=3/31(9.70%) dogs did not develop CS with a 3year follow-up. In the PB-group, pre-treatment median ES-frequency was 2.46ES/month (range, 1-7ES/month); post-treatment median ES-frequency was 0.36ES/month (range, 0ES/3years-1ES/month); n=11/30 (36.70%) dogs developed CS between 12-25 months after initiation of treatment. Nineteen of 30 (63.30%) dogs did not develop CS with a 3-year follow-up; three of these 19 dogs were ES free. In this study, AEM-naïve DIE receiving imepitoin-monotherapy developed CS significantly more frequently and earlier in the course of the disease, and developed aggression and required earlier discontinuation of monotherapy than AEM-naïve DIE receiving phenobarbital-monotherapy.

Seizure etiologic classification and long-term outcome for cats with juvenile-onset seizures

OBJECTIVE To identify seizure etiologic classification for cats that developed seizures at < 12 months of age and describe the long-term outcome of affected cats. DESIGN Retrospective cohort study. ANIMALS 15 client-owned cats with seizures that began at < 12 months of age. PROCEDURES Information on each cat was obtained from the medical records, veterinarians, and owners. Inclusion required an onset of seizures before 12 months of age and a complete medical record, including a final diagnosis. RESULTS 7 of the 15 cats had structural epilepsy, 4 had idiopathic epilepsy, and 4 had reactive seizures. Median age at seizure onset was 27 weeks (range, 0.4 to 41 weeks). Cluster seizures were reported in 6 cats, and status epilepticus was reported in 2. Age at the onset of seizures, presence of cluster seizures, and seizure semiology (ie, generalized vs focal seizures) were not significantly associated with seizure etiologic classification. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that cats that developed seizures at < 12 months of age were more likely to have structural epilepsy than idiopathic epilepsy or reactive seizures. Therefore, advanced diagnostic imaging is recommended in cats with juvenile-onset seizures if metabolic and toxic causes are excluded.

Seizure-precipitating factors in dogs with idiopathic epilepsy

Background

Stress, sleep deprivation, and infectious diseases are important seizure‐precipitating factors in human epilepsy patients. However, these factors have not been thoroughly studied in epileptic dogs.

Objective

Seizure‐precipitating factors are common in dogs with idiopathic epilepsy and the occurrence of these factors associate with the dogs' signalment, personality, and epilepsy‐related factors.

Animals

Fifty dogs with diagnosed idiopathic epilepsy from the hospital populations of University Veterinary Teaching Hospital of University of Helsinki and Referral Animal Hospital Aisti.

Methods

In a retrospective cross‐sectional observational study, owners were interviewed about their dogs' possible seizure‐precipitating factors according to a predefined questionnaire. The dogs were identified and selected by searching the medical records of the participating animal hospitals.

Results

The prevalence of seizure‐precipitating factors in the study population was 74% (37/50). The most frequently reported factors included stress‐related situations, sleep deprivation, weather, and hormonal factors. In dogs with focal onset seizures, the number of precipitating factors was 1.9 (95% CI 1.1‐3.4) times higher compared to dogs with generalized seizures.

Conclusions and Clinical Importance

Seizure‐precipitating factors are common in dogs with idiopathic epilepsy, and the nature of these factors is consistent with those of human patients. Aside from antiepileptic medication, acknowledging and avoiding seizure‐precipitating factors could help veterinarians achieve better treatment outcomes.

Influence of Stainless Needle Electrodes and Silver Disk Electrodes over the Interhemispheric Cerebral Coherence Value in Vigil Dogs

Electroencephalography (EEG) is an objective diagnostic tool in the evaluation of cerebral functionality, both in human and veterinary medicine. For EEG acquisition, different types of electrodes are used, as long as they have no impact on the recorded background activity. However, to date, the influence of electrode type on quantitative EEG and cerebral coherence has not been investigated. Twenty EEG traces (ten with needle electrodes and ten with disk electrodes) were recorded from ten mesocephalic vigil dogs in a monopolar montage. Values for interhemispheric coherence for each frequency band were compared between stainless needle and silver disk electrodes traces. Our results show that the values of interhemispheric coherence in vigil dogs are depending of the type of electrodes used in EEG recordings. In the frontal (FP) channel, for delta and theta frequency bands, the registered coherence is significantly higher when stainless needle electrodes are used. Our results might have important consequences in the field of canine neurology and applied neuroscience, as the frontal channel analysis is preferred in aging and behavior studies.

Comparison of electroencephalographic findings with hippocampal magnetic resonance imaging volumetry in dogs with idiopathic epilepsy

BACKGROUND

In humans, temporal lobe epilepsy (TLE), is a type of focal epilepsy occurring mainly in the mesial TLE (mTLE), commonly associated with hippocampal sclerosis (HS).

OBJECTIVES

According to recent studies, TLE might also occur in dogs and could be associated with hippocampal atrophy (HA)/HS. To date, hippocampal lesions have not been correlated with electroencephalographic (EEG) findings in epileptic dogs.

ANIMALS

An EEG examination, brain magnetic resonance imaging, and volumetric assessment of the hippocampus were performed in 16 nonepileptic and 41 epileptic dogs.

METHODS

In this retrospective study, the presence and localization of EEG-defined epileptiform discharges (EDs) was blindly evaluated. The hippocampus was measured and assessed for unilateral atrophy. The results of EEG and volumetric findings were correlated to determine whether the functional epileptic focus is equivalent to structural changes.

RESULTS

The median hippocampal asymmetric ratio (AR) in epileptic dogs was significantly greater than in the control group (P < .001). Using a cut-off threshold AR of >6%, 56% (23/41) of the dogs were characterized with unilateral HA. Of those animals, 35% (8/23) had EDs in the temporal leads and 26% (6/23) had no EDs. In 88% (7/8) of dogs with EDs in the temporal leads that had unilateral HA, the EDs correlated with the side of the decreased hippocampal volume.

CONCLUSIONS AND CLINICAL IMPORTANCE

The results indicate an association between the presence of EDs detectable on EEG and a decrease in the unilateral hippocampal volume in some cases of canine idiopathic epilepsy that might reflect features of human mTLE.

Efficacy of zonisamide on interictal electroencephalography in familial spontaneous epileptic cats

Objectives The effectiveness of zonisamide (ZNS) against spontaneous epilepsy in cats has not yet been described. The purpose of this study was to investigate the effect of ZNS on interictal paroxysmal discharges (PDs) using scalp electroencephalography (EEG) in familial spontaneous epileptic cats (FSECs). Methods Eight FSECs were evaluated (six males and two females). Scalp EEG measurements were performed once a week for 3 weeks before ZNS administration (Pre-ZNS). Thereafter, administration of ZNS was started and an adjustment period was instituted until the drug in plasma achieved the steady state. When ZNS in plasma was confirmed to be within 10-40 μg/ml, scalp EEG measurements were performed once a week for 3 weeks (Post-ZNS). The number of PDs (counts/min) were compared between Pre-ZNS and Post-ZNS treatment. Results The median number of PDs for Pre-ZNS and Post-ZNS were 0.43/min (0.13-0.82/min) and 0.28/min (0.07-0.87/min), respectively. The number of PDs Post-ZNS was significantly reduced compared with Pre-ZNS ( P = 0.02). Conclusions and relevance This study showed that ZNS, within the recommended therapeutic range suggested for use in humans and dogs (10-40 µg/ml), reduced the number of PDs recorded on EEG in FSECs that are considered a model for cats with idiopathic epilepsy. Although phenobarbital is the antiepileptic drug of choice for epileptic cats, the results of this research provide evidence to support the use of ZNS in cats with phenobarbital-resistant epilepsy or for cats that cannot use phenobarbital due to adverse side effects.

Seizure occurrence in dogs under primary veterinary care in the UK: prevalence and risk factors

Background

Primary‐care veterinary clinical records can offer data to determine generalizable epidemiological data on seizures occurrence in the dog population.

Objectives

To identify and examine epidemiologic characteristics of seizure occurrence in dogs under primary veterinary care in the UK participating in the VetCompass™ Programme.

Animals

455,553 dogs in VetCompass™’.

Methods

A cross‐sectional analysis estimated the 1‐year period prevalence and risk factors for dogs with seizures during 2013.

Results

The overall 1‐year period prevalence for dogs having at least one seizure during 2013 was 0.82% (95% CI 0.79‐0.84). Multivariable modelling identified breeds with elevated odd ratios [OR] compared with the Labrador Retriever (e.g. Pug OR: 3.41 95% CI 2.71‐4.28, P < 0.001). Males had higher risk for seizures (Male/Entire OR: 1.47 95% CI 1.30–1.66; Male/Neutered OR: 1.34 95% CI 1.19–1.51) compared to entire females. Age (3.00 ‐ ≤ 6.00 OR: 2.13 95% CI 1.90‐2.39, P < 0.001, compared to animals aged 0.50–≤ 3.00 years), and bodyweight (≥ 40.00kg, OR: 1.24 95% CI 1.08–1.41, P = 0.002, compared to animals weighing < 10.0 kg) were identified as risk factors for seizures.

Conclusion and clinical Importance

Seizures are a relatively common clinical finding in dogs. The results for breed, age, sex and bodyweight as risk factors can assist veterinarians in refining differential diagnosis lists for dogs reported with behaviors that may have been seizures. In addition, the prevalence values reported here can support pharmacovigilance with baseline data from the overall population.

Recurrent seizures in cats: Diagnostic approach - when is it idiopathic epilepsy?

Practical relevance: Seizures are one of the most common neurologic problems recognized in cats, affecting approximately 1-3% of the general population. Treatment options and prognosis are closely related to the underlying cause, so it is important that veterinarians are familiar with the diagnostic approach to cats with seizures and options for medical management. Series outline: This is the first of a two-part article series that reviews the diagnosis and treatment of seizures in cats. Part 1 outlines the classification and terminology used to describe epilepsy and epileptic seizures in cats, and discusses some of the most common and unique causes of recurrent seizures in cats. The diagnostic approach to cats with recurrent seizures is addressed, as are criteria for the diagnosis of idiopathic epilepsy.

AUDIENCE

This review of recurrent seizures in cats is intended for all veterinarians who are facing the challenges of seizure diagnosis and management in the feline patient. Evidence base: Recommendations for diagnosis and management of feline seizure disorders have historically been extrapolated from the canine and human literature. The information and guidance provided in this two-part series is based on a review of the recent published literature addressing seizure disorders and antiepileptic treatment in cats, as well as the authors' clinical experience.

Population pharmacokinetics of extended-release levetiracetam in epileptic dogs when administered alone, with phenobarbital or zonisamide

BACKGROUND

Extended-release levetiracetam (LEV-XR) has gained acceptance as an antiepileptic drug in dogs. No studies have evaluated its disposition in dogs with epilepsy.

HYPOTHESIS/OBJECTIVES

To evaluate the pharmacokinetics of LEV-XR in epileptic dogs when administered alone or with phenobarbital or zonisamide.

ANIMALS

Eighteen client-owned dogs on steady-state maintenance treatment with LEV-XR (Group L, n = 6), LEV-XR and phenobarbital (Group LP, n = 6), or LEV-XR and zonisamide (Group LZ, n = 6).

METHODS

Pharmacokinetic study. Blood samples were collected at 0, 2, 4, 8, and 12 hours after LEV-XR was administered with food. Plasma LEV concentrations were determined by high-pressure liquid chromatography. A population pharmacokinetic approach and nonlinear mixed effects modeling were used to analyze the data.

RESULTS

Treatment group accounted for most of the interindividual variation. The LP group had lower CMAX (13.38 μg/mL) compared to the L group (33.01 μg/mL) and LZ group (34.13 μg/mL), lower AUC (134.86 versus 352.95 and 452.76 hours·μg/mL, respectively), and higher CL/F (0.17 versus 0.08 and 0.07 L/kg/hr, respectively). The half-life that defined the terminal slope of the plasma concentration versus time curve (~5 hours) was similar to values previously reported for healthy dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Considerable variation exists in the pharmacokinetics of LEV-XR in dogs with epilepsy being treated with a common dose regimen. Concurrent administration of phenobarbital contributed significantly to the variation. Other factors evaluated, including co-administration of zonisamide, were not shown to contribute to the variability. Drug monitoring may be beneficial to determine the most appropriate dose of LEV-XR in individual dogs.

Investigating owner use of dietary supplements in dogs with idiopathic epilepsy

Epilepsy is the most common chronic neurological disorder in dogs. Some diets have been shown to have a positive impact upon the seizure activity in dogs with idiopathic epilepsy (IE), while other diets and dietary supplements (DS), although marketed as providing health benefits, lack conclusive scientific evidence on their actual beneficial effects. A web-based owner questionnaire was designed to assess how and why owners of dogs with IE use different dietary regimes and DS. The study cohort, with 297 valid responses, consisted mainly of pure-breed (82.5%) male neutered (52.9%) dogs. Over two-thirds of owners (67.7%) changed their dog's diet after their dog received a diagnosis of IE. Nearly half of the owners (45.8%) reported giving DS, the most common being coconut oil or derived medium-chain triglyceride oil (71.3%). Some owner justifications of DS use included improvement of seizure frequency (88.2%), seizure severity (61.8%) and protection from potential drug side effects (62.5%). Many owners give DS to their dog with IE. The pharmacokinetic properties of anti-epileptic drugs, such as efficacy, absorption and clearance can be influenced by other medications, diets and possibly by DS. We propose that use of DS should be considered and monitored by veterinary surgeons in epilepsy management.

A Review: Emergency Management of Dogs With Suspected Epileptic Seizures

Dogs with seizure disorders are commonly presented to the general practitioner for initial evaluation. The most common diagnosis provided is idiopathic epilepsy. As witnessing seizures is often traumatic for owners, it is important for the practitioner to understand seizure classification, know when to initiate antiepileptic drug therapy and be comfortable with client education regarding seizures. This review briefly discusses the most up-to-date classification of seizures, the necessity to obtain accurate histories and complete examinations, base-line diagnostics to perform, the importance of owner education, and when to start medications. This is not intended to discuss detailed differential lists, in-depth information on antiepileptic drug therapy, long-term management of epileptics or those refractory to their current treatment.

Preliminary assessment of cognitive impairments in canine idiopathic epilepsy

In humans, epilepsy can induce or accelerate cognitive impairment (CI). There is emerging evidence of CI in dogs with idiopathic epilepsy (IE) from recent epidemiological studies. The aim of our study was to assess CI in dogs with IE using two tests of cognitive dysfunction designed for use in a clinical setting. Dogs with IE (n=17) were compared against controls (n=18) in their performance in two tasks; a spatial working memory task and a problem-solving task. In addition, owners completed the Canine Cognitive Dysfunction Rating (CCDR) scale for their dog. The groups did not differ statistically with respect to age and breed. Dogs with IE performed significantly worse than controls on the spatial working memory task (P=0.016), but not on the problem solving task (P=0.683). CCDR scores were significantly higher in the IE group (P=0.016); however, no dogs reach the recommended threshold score for CCD diagnosis. Our preliminary data suggest that dogs with IE exhibit impairments in a spatial working memory task. Further research is required to explore the effect of IE on other cognitive abilities in dogs with a larger sample, characterising the age of onset, nature and progression of any impairments and the impact of anti-epileptic drugs.

Exploring the pathogenesis of canine epilepsy using a systems genetics method and implications for anti-epilepsy drug discovery

Epilepsy is a common neurological disorder in domestic dogs. However, its complex mechanism involves multiple genetic and environmental factors that make it challenging to identify the real pathogenic factors contributing to epilepsy, particularly for idiopathic epilepsy. Conventional genome-wide association studies (GWASs) can detect various genes associated with epilepsy, although they primarily detect the effects of single-site mutations in epilepsy while ignoring their interactions. In this study, we used a systems genetics method combining both GWAS and gene interactions and obtained 26 significantly mutated subnetworks. Among these subnetworks, seven genes were reported to be involved in neurological disorders. Combined with gene ontology enrichment analysis, we focused on 4 subnetworks that included traditional GWAS-neglected genes. Moreover, we performed a drug enrichment analysis for each subnetwork and identified significantly enriched candidate anti-epilepsy drugs using a hypergeometric test. We discovered 22 potential drug combinations that induced possible synergistic effects for epilepsy treatment, and one of these drug combinations has been confirmed in the Drug Combination database (DCDB) to have beneficial anti-epileptic effects. The method proposed in this study provides deep insight into the pathogenesis of canine epilepsy and implications for anti-epilepsy drug discovery.

Clinical Risk Factors for Early Seizure Recurrence in Dogs Hospitalized for Seizure Evaluation

BACKGROUND

Epileptic seizures are a common cause for neurological evaluations in dogs.

HYPOTHESIS/OBJECTIVES

To determine the timing, frequency, and risk factors for early seizure recurrence (ESR) among dogs admitted to the hospital for seizure evaluation and to facilitate rapid decision making about whether dogs should be placed in the intensive care unit (ICU) or day ward.

ANIMALS

Nine-hundred twenty-two dogs referred for seizure investigation; 214 patients were included.

METHODS

Retrospective study. Medical records between 2000 and 2017 were reviewed to determine risk factors for ESR. Findings were compared among dogs diagnosed with idiopathic epilepsy (IE), structural epilepsy (StE) and reactive seizures (RS), as well as in all selected cases together.

RESULTS

Fifty percent of dogs had a seizure while hospitalized. In the group 53.1 and 52.2% in the StE group, whereas in the RS 40.44% had ESR. The average time to ESR was 7 hours. In IE group, abnormal postictal neurological examination with prosencephalon signs predicted ESR. In StE group, a single generalized or focal seizure 72 hours before hospital admission and abnormal neurologic examination predicted ESR. In the RS group, ERS was predicted by long-term antiepileptic monotheraphy. When all dogs were analyzed together, abnormal neurological examination, the occurrence of cluster seizures, status epilepticus, or combination of them 72 hours before presentation predicted ESR.

CONCLUSIONS AND CLINICAL IMPORTANCE

Epileptic seizures recurred in 50% of patients within a mean time of 7 hours. In general, when cluster seizures, status epilepticus or both occurred 72 hours before presentation and neurological examination was abnormal upon presentation, the dog should be placed in ICU for observation.

Grey matter volume in healthy and epileptic beagles using voxel-based morphometry - a pilot study

BACKGROUND

One of the most common chronic neurological disorders in dogs is idiopathic epilepsy (IE) diagnosed as epilepsy without structural changes in the brain. In the current study the hypothesis should be proven that subtle grey matter changes occur in epileptic dogs. Therefore, magnetic resonance (MR) images of one dog breed (Beagles) were used to obtain an approximately uniform brain shape. Local differences in grey matter volume (GMV) were compared between 5 healthy Beagles and 10 Beagles with spontaneously recurrent seizures (5 dogs with IE and 5 dogs with structural epilepsy (SE)), using voxel-based morphometry (VBM). T1W images of all dogs were prepared using Amira 6.3.0 for brain extraction, FSL 4.1.8 for registration and SPM12 for realignment. After creation of tissue probability maps of cerebrospinal fluid, grey and white matter from control images to segment all extracted brains, GM templates for each group were constructed to normalize brain images for parametric statistical analysis, which was achieved using SPM12.

RESULTS

Epileptic Beagles (IE and SE Beagles) displayed statistically significant reduced GMV in olfactory bulb, cingulate gyrus, hippocampus and cortex, especially in temporal and occipital lobes. Beagles with IE showed statistically significant decreased GMV in olfactory bulb, cortex of parietal and temporal lobe, hippocampus and cingulate gyrus, Beagles with SE mild statistically significant GMV reduction in temporal lobe (p < 0.05; family- wise error correction).

CONCLUSION

These results suggest that, as reported in epileptic humans, focal reduction in GMV also occurs in epileptic dogs. Furthermore, the current study shows that VBM analysis represents an excellent method to detect GMV differences of the brain between a healthy dog group and dogs with epileptic syndrome, when MR images of one breed are used.

Glial source of nitric oxide in epileptogenesis: A target for disease modification in epilepsy

Epileptogenesis is the process of developing an epileptic condition and/or its progression once it is established. The molecules that initiate, promote, and propagate remarkable changes in the brain during epileptogenesis are emerging as targets for prevention/treatment of epilepsy. Epileptogenesis is a continuous process that follows immediately after status epilepticus (SE) in animal models of acquired temporal lobe epilepsy (TLE). Both SE and epileptogenesis are potential therapeutic targets for the discovery of anticonvulsants and antiepileptogenic or disease-modifying agents. For translational studies, SE targets are appropriate for screening anticonvulsive drugs prior to their advancement as therapeutic agents, while targets of epileptogenesis are relevant for identification and development of therapeutic agents that can either prevent or modify the disease or its onset. The acute seizure models do not reveal antiepileptogenic properties of anticonvulsive drugs. This review highlights the important components of epileptogenesis and the long-term impact of intervening one of these components, nitric oxide (NO), in rat and mouse kainate models of TLE. NO is a putative pleotropic gaseous neurotransmitter and an important contributor of nitro-oxidative stress that coexists with neuroinflammation and epileptogenesis. The long-term impact of inhibiting the glial source of NO during early epileptogenesis in the rat model of TLE is reviewed. The importance of sex as a biological variable in disease modification strategies in epilepsy is also briefly discussed.

Diffusion-weighted imaging of the brains of dogs with idiopathic epilepsy

Background

Idiopathic epilepsy is one of the most common neurological disorders in dogs. Unfortunately, up to 30% of dogs with idiopathic epilepsy show no improvement under antiepileptic drug treatment. Diffusion-weighted imaging is used in human medicine to identify epileptogenic foci in the brain to allow for more invasive treatments such as deep brain stimulation or surgical removal.

The aim of this study was to ass the feasibility of interictal diffusion-weighted MRI in dogs and to evaluate the distribution of diffusion in the brains of dogs with idiopathic epilepsy (IE) and to compare these values to previously published values from healthy beagle dogs.

Client-owned dogs with the final diagnosis of IE were included in this study. MRI examination was carried out using a 1.0Tesla superconductive magnet. Diffusion-weighted images using a single shot echo planar imaging sequence (SSh-EPI) with a b value of b = 0 s/mm² and b = 800 s/mm² were acquired in a dorsal and transverse plane with diffusion gradients in all three planes (x-, y- and z-plane). An ADC (apparent diffusion coefficient) map of the isometric image of each acquired slice was generated.

Regions of interest (ROIs) were manually drawn around the caudate nucleus, the thalamus, the piriform lobe including the amygdala, the hippocampus, the semioval center and the temporal cerebral cortex by one of the authors. ROI drawings were repeated 5 times at different time points to assess intra-obersver variability. A multi-way mixed-model analysis of variance (ANOVA) and two-way ANOVA were used during statistical analysis. A p value of p < 0.05 was considered significant.

Results

Dogs with IE showed a significantly increased ADC in the amygdala within the piriform lobe and in the semioval center (p < 0.05) compared with the healthy control group.

Conclusion

Changes in the piriform lobe in cases of epilepsy are reported infrequently in human and veterinary medicine. Similar to our results, ADC changes in the interictal phase usually include an increase in ADC due to cell loss and increased intercellular spaces. Diffusion MRI might be a promising technique for the examination of canine epileptic patients lacking other gross neuromorphological abnormalities.

Interictal cardiac autonomic nervous system disturbances in dogs with idiopathic epilepsy

Autonomic nervous system (ANS) activity in the interictal period (InIp) in dogs with presumed idiopathic epilepsy (pIE) was assessed using heart rate variability (HRV) analysis. The HRVs obtained from 28 pIE dogs with interictal epileptic discharges (InIEd; 11 with treatment and 17 without treatment) detected on electroencephalography (EEG) were compared with those obtained from 13 healthy dogs. On electrocardiographic (ECG) study, the P wave dispersion (PWD; P<0.001), P max (P=0.004) and corrected QT interval (QTc; P=0.025) were significantly increased in the pIE group. On the basis of HRV analysis, the pIE dogs had an increased activity of the parasympathetic component of the ANS, including the percentage of R-R interval (pNN50%) that differs more than 50ms (P=0.011) and high frequency band (HF; P=0.041). Administration of phenobarbitone had no influence on the ANS pattern when pIE subgroups were compared (P>0.05). In InIp, dogs elicited specific conductibility delays of the electrical impulses (increased PWD and QTc interval); these delays are considered to be risk factors for developing severe arrhythmias, such as atrial fibrillation and ventricular tachycardia. When compared with human beings, a different ANS pattern characterised by increased parasympathetic activity was observed, which may influence the therapeutic approach of IE in dogs.

Diagnostic Utility of Wireless Video-Electroencephalography in Unsedated Dogs

BACKGROUND

Poor agreement between observers on whether an unusual event is a seizure drives the need for a specific diagnostic tool provided by video-electroencephalography (video-EEG) in human pediatric epileptology.

OBJECTIVE

That successful classification of events would be positively associated with increasing EEG recording length and higher event frequency reported before video-EEG evaluation; that a novel wireless video-EEG technique would clarify whether unusual behavioral events were seizures in unsedated dogs.

ANIMALS

Eighty-one client-owned dogs of various breeds undergoing investigation of unusual behavioral events at 4 institutions.

METHODS

Retrospective case series: evaluation of wireless video-EEG recordings in unsedated dogs performed at 4 institutions.

RESULTS

Electroencephalography achieved/excluded diagnosis of epilepsy in 58 dogs (72%); 25 dogs confirmed with epileptic seizures based on ictal/interictal epileptiform discharges, and 33 dogs with no EEG abnormalities associated with their target events. As reported frequency of the target events decreased (annually, monthly, weekly, daily, hourly, minutes, seconds), EEG was less likely to achieve diagnosis (P < 0.001). Every increase in event frequency increased the odds of achieving diagnosis by 2.315 (95% confidence interval: 1.36-4.34). EEG recording length (mean = 3.69 hours, range: 0.17-22.5) was not associated (P = 0.2) with the likelihood of achieving a diagnosis.

CONCLUSIONS AND CLINICAL IMPORTANCE

Wireless video-EEG in unsedated dogs had a high success for diagnosis of unusual behavioral events. This technique offered a reliable clinical tool to investigate the epileptic origin of behavioral events in dogs.

Prevalence of neurological disorders in French bulldog: a retrospective study of 343 cases (2002-2016)

Background

French Bulldog (FB) has significantly gained in popularity over the last few years, and seems to be frequently affected by various neurological conditions. The purpose of this retrospective study was to report the prevalences of neurological diseases in a large population of FB, presented with neurological signs between 2002 and 2016, and for which a definitive diagnosis was established. A secondary objective was to identify epidemiological characteristics regarding specific diseases in this singular breed.

Results

During the study period, 533 FBs were presented for neurological signs, representing 18.7% of all admitted FBs (N = 2846). In total, 343 FBs with definitive diagnosis were included in this descriptive epidemiological study. Hansen type I intervertebral disk herniation (IVDH) was by far the most common neurological disorder (45.5% of all cases). The IVDH location was cervical in 39.8%, and thoracolumbar in 60.2% of cases. The median ages for cervical and thoracolumbar IVDH were 4.2 and 4 years, respectively. C3-C4 was the most commonly affected disk (57.8% of cervical IDVH) all locations combined. Spinal arachnoid diverticulum (SAD) was detected in 25 FBs, representing the second most common myelopathy (11.3%). A concurrent spinal abnormality was identified in 64.0% of SAD cases. Brain tumours represented 36.8% of encephalopathies, with glioma (confirmed or suspected) being the most common. Meningoencephalitis of unknown origin (MUO) represented 25.0% of brain disorders, females less than 5.5 years being more likely to be affected. Aside from central nervous system conditions, otitis interna associated with peripheral vestibular signs and bilateral congenital deafness (associated with white coat) were also common.

Conclusions

The findings of this study suggest that FB seems to be prone to several neurological diseases. IVDH is clearly predominant in FB and cervical location seems more represented than in other breeds. FBs affected by IVDH tend to be younger than previously described, either for both cervical and thoracolumbar locations. Thoracic SAD was the second most common myelopathy, with a concurrent spinal anomaly identified in two thirds of the cases. MUO was more likely to affect young to middle-aged females. These findings could be of interest for owners, breeders, practicing veterinarians and insurance companies.

Imepitoin is well tolerated in healthy and epileptic cats

Background

Epilepsy in the cat is a serious medical condition. To date there are no licensed treatments for feline epilepsy and no well-controlled clinical studies on the efficacy or safety of antiepileptic drugs in cats. The aim of this study was to collect tolerability data and first exploratory efficacy data of imepitoin in both healthy and epileptic cats.

Results

In two tolerability studies, 30 healthy cats received imepition twice daily in doses of 0, 30, 40 or 80 mg/kg bodyweight for 30 days. No serious adverse events were observed in any of the dose groups. In the imepitoin treated groups, emesis was observed in some animals temporarily and intermittently mainly in the second and third weeks of treatment.

In a small, single-arm, open label, uncontrolled clinical trial eight cats suffering from idiopathic epilepsy were treated with imepitoin twice daily at doses of 30 mg/kg bodyweight for 30 days. Four of these cats (50%) achieved seizure freedom for at least 8 weeks under treatment. Adverse events, mostly lethargy, decreased appetite and emesis, were often mild and transient.

Conclusion

In summary, imepitoin was well tolerated in healthy and epileptic cats and showed in a pilot trial indication for efficacy in treating feline epilepsy.

Intranasal Midazolam versus Rectal Diazepam for the Management of Canine Status Epilepticus: A Multicenter Randomized Parallel-Group Clinical Trial

Background

Intranasal administration of benzodiazepines has shown superiority over rectal administration for terminating emergency epileptic seizures in human trials. No such clinical trials have been performed in dogs.

Objective

To evaluate the clinical efficacy of intranasal midazolam (IN‐MDZ), via a mucosal atomization device, as a first‐line management option for canine status epilepticus and compare it to rectal administration of diazepam (R‐DZP) for controlling status epilepticus before intravenous access is available.

Animals

Client‐owned dogs with idiopathic or structural epilepsy manifesting status epilepticus within a hospital environment were used. Dogs were randomly allocated to treatment with IN‐MDZ (n = 20) or R‐DZP (n = 15).

Methods

Randomized parallel‐group clinical trial. Seizure cessation time and adverse effects were recorded. For each dog, treatment was considered successful if the seizure ceased within 5 minutes and did not recur within 10 minutes after administration. The 95% confidence interval was used to detect the true population of dogs that were successfully treated. The Fisher's 2‐tailed exact test was used to compare the 2 groups, and the results were considered statistically significant if P < .05.

Results

IN‐MDZ and R‐DZP terminated status epilepticus in 70% (14/20) and 20% (3/15) of cases, respectively (P = .0059). All dogs showed sedation and ataxia.

Conclusions and Clinical Importance

IN‐MDZ is a quick, safe and effective first‐line medication for controlling status epilepticus in dogs and appears superior to R‐DZP. IN‐MDZ might be a valuable treatment option when intravenous access is not available and for treatment of status epilepticus in dogs at home.

Physiological reactivity to spontaneously occurring seizure activity in dogs with epilepsy and their carers

There is a complex bidirectional relationship between stress and epilepsy. Stressful stimuli and subsequent cortisol release act as a trigger for seizure activity in some individuals with epilepsy, and seizure activity itself may act as a stressor to the affected individual. Epilepsy is the most common chronic neurological condition in domestic dogs and requires chronic management by their human carers, impacting upon the quality of life of both dog and carer. Seizures occur unpredictably and may be stressful for carers to witness and manage. In the present study we investigated the role of seizure activity as a stressor, measuring the effect of spontaneously occurring seizure activity in dogs with epilepsy upon their own cortisol levels and that of their carers. Furthermore, we tested whether individual differences in HPA reactivity were associated with owner personality characteristics and the quality of the dog-carer relationship. Saliva samples were obtained from sixteen dog-carer dyads in the home setting 20 and 40minute post-seizure, and at time-matched points on the following (non-seizure) day. Significant differences in cortisol levels were found in dogs at 40minute post-seizure (265.1% increase), and at 20minute post-seizure in their carers (40.5% increase). No associations were found between cortisol reactivity and the strength of the dog-carer bond. Carers with higher neuroticism scores exhibited higher cortisol levels at both post-seizure sampling points. As there was a gender bias in the carer sample (15/16 were female), and there are known sex differences in cortisol reactivity in response to psychological stress, the conclusions of this study may be limited to female carers. These findings are the first to objectively demonstrate the acutely stressful effects of seizures in dogs with epilepsy and their carers.

Investigating the potential of the anti-epileptic drug imepitoin as a treatment for co-morbid anxiety in dogs with idiopathic epilepsy

Background

Behavioural changes associated with idiopathic epilepsy (IE) have been identified in dogs, with fear and anxiety-related problems seen in both drug-naïve dogs and dogs treated with anti-epileptic drugs (AEDs). Treating anxiety-related behaviour in dogs with IE may be challenging, as seizures are a contraindication for many conventional anxiolytic drugs. In addition, many dogs with IE are already treated with AEDs to reduce their seizure frequency, which may have negative effects if used in polytherapy. Imepitoin is low-affinity partial agonist at the benzodiazepine (BDZ) site of the GABA_A receptor, and has been demonstrated to have both anticonvulsant and anxiolytic effects in laboratory rodents. Imepitoin has been developed for the treatment of IE in dogs, with demonstrated anticonvulsant effects and high tolerability and safety. To date, imepitoin’s potential to reduce anxiety in dogs with IE has not been investigated. An online survey was conducted to investigate the effect of imepitoin on fear and anxiety-related behaviours in dogs with IE. Eighty-five valid responses were received from owners of dogs with IE currently treated with imepitoin. Anxiety-related behaviour was quantified before and during imepitoin treatment using a validated questionnaire tool (C-BARQ).

Results

No differences were observed in the five fear/anxiety-related measures between the two time periods (before vs. during treatment) for dog directed fear, stranger directed fear, non-social fear, pain sensitivity and separation related behaviour. A median 45% reduction in seizure frequency/month was observed following imepitoin treatment; however, imepitoin did not appear effective in reducing seizure frequency in a minority of cases. Polyphagia was the most common chronic side effect, and more side effects were reported in polytherapy cases.

Conclusions

Imepitoin does not appear to improve anxiety-related behaviour in dogs with IE treated with this medication for its anti-epileptic effects. Investigating the effects of imepitoin upon the behaviour of dogs with recognised behavioural anxiety-related problems (e.g. specific fears and phobias, separation related behaviours), in both healthy dogs and dogs with epilepsy is required to further explore any potential anxiolytic effects of this medication.

The relationship between epileptiform discharges and background activity in the visual analysis of electroencephalographic examinations in dogs with seizures of different etiologies

Electroencephalographic (EEG) recordings in 125 outpatient dogs with various epileptiform encephalopathies were acquired under medetomidine sedation using subdermal wire electrodes. The features of canine EEG (background activity [BGA] and epileptiform discharges [EDs]) were assessed, described and compared. The dogs included neurologically healthy controls (N, n = 19), dogs with portosystemic shunt (PSS, n = 9), dogs with intracranial pathologies (IP, n = 27) and dogs with idiopathic epilepsy (IE, n = 70). A visual EEG analysis revealed significantly more pronounced high voltage, low-frequency BGA in the PSS and IP groups in comparison to the N and IE groups (PSS vs. N, PSS vs. IE P <0.0001; IP vs. N, IP vs. IE P = 0.043). At least one ED in the recording was found in 47.37% (n = 9/19) of the individuals in the N group, 88.9% (n = 8/9) of the dogs in the PSS group, 77.78% (n = 21/27) of the dogs in the IP group and 61.43% (n = 43/70) of the dogs in the IE group. The presence of bilateral symmetric triphasic (BST) waves was significantly higher in the PSS group than in the remaining groups. There was a strong prevalence of spike-waves in dogs with idiopathic epilepsy and of BST waves in dogs with portosystemic shunt. None of the dogs in group N had spike-waves or BST activity. EDs were observed more frequently in high and very high voltage, low frequency BGA than in low voltage, high frequency BGA.

Clinical evaluation of a combination therapy of imepitoin with phenobarbital in dogs with refractory idiopathic epilepsy

Background

Imepitoin was tested as a combination treatment with phenobarbital in an open-label mono-centre cohort study in dogs with drug-resistant epilepsy. Diagnosis of idiopathic epilepsy was based on clinical findings, magnetic resonance imaging and cerebrospinal fluid analysis. Three cohorts were treated. In cohort A, dogs not responding to phenobarbital with or without established add-on treatment of potassium bromide or levetiracetam were treated add-on with imepitoin, starting at 10 mg/kg BID, with titration allowed to 30 mg/kg BID. In cohort B, the only difference to cohort A was that the starting dose of imepitoin was reduced to 5 mg/kg BID. In cohort C, animals not responding to imepitoin at >20 mg/kg BID were treated with phenobarbital add-on starting at 0.5 mg/kg BID.

Results

The add-on treatment resulted in a reduction in monthly seizure frequency (MSF) in all three cohorts. A reduction of ≥50% was obtained in 36-42% of all animals, without significant difference between cohorts. The lower starting dose of 5 mg/kg BID imepitoin was better tolerated, and an up-titration to on average of 15 mg/kg BID was sufficient in cohort A and B. In cohort C, a mean add-on dose of 1.5 mg/kg BID phenobarbital was sufficient to achieve a clinically meaningful effect. Six dogs developed a clinically meaningful increase in MSF of ≥ 50%, mostly in cohort A. Neither imepitoin nor phenobarbital add-on treatment was capable of suppressing cluster seizure activity, making cluster seizure activity an important predictor for drug-resistance.

Conclusion

A combination treatment of imepitoin and phenobarbital is a useful treatment option for a subpopulation of dogs with drug-resistant epilepsy, a low starting dose with 5 mg/kg BID is recommended.

Phenobarbital administration every eight hours: improvement of seizure management in idiopathic epileptic dogs with decreased phenobarbital elimination half-life

Estimated prevalence of canine idiopathic epilepsy is 0.6 per cent in the first-opinion canine population in the UK. Phenobarbital monotherapy has been reported to reduce/eradicate seizure activity in 60-93 per cent of idiopathic epileptic dogs (IEDs). The objective of this study was to evaluate safety and efficacy of the administration of phenobarbital orally every eight hours in IEDs with phenobarbital elimination half-life less than 20 hours. Medical records of 10 IEDs in which steady state trough serum phenobarbital levels were within the reference range and phenobarbital elimination half-life had become less than 20 hours following prolonged administration every 12 hours were reviewed. Side effects and seizure frequency when phenobarbital was administered every 12 hours or 8 hours were compared. In all dogs the side effects of the antiepileptic medication treatment improved. When phenobarbital was administered every eight hours, 9/10 dogs experienced improvement in seizure frequency and 8/10 dogs maintained seizure freedom for a period three times longer than the longest interictal interval period previously recorded. Reduction in the severity and number of clusters of seizures was recorded in one of the remaining two dogs. The administration of phenobarbital orally every eight hours in IEDs with decreased phenobarbital elimination half-life appears safe and can improve seizure management. The results of this study were presented in abstract form (poster) for the 28th symposium of the European Society of Veterinary Neurology - European College of Veterinary Neurology (ESVN), September 18-19, 2015, Amsterdam, Netherlands.

Retrospective epidemiological study of canine epilepsy in Japan using the International Veterinary Epilepsy Task Force classification 2015 (2003-2013): etiological distribution, risk factors, survival time, and lifespan

Background

Epilepsy is the most common neurological disease in veterinary practice. However, contrary to human medicine, epilepsy classification in veterinary medicine had not been clearly defined until recently. A number of reports on canine epilepsy have been published, reflecting in part updated proposals from the human epilepsy organization, the International League Against Epilepsy. In 2015, the International Veterinary Epilepsy Task Force (IVETF) published a consensus report on the classification and definition of canine epilepsy. The purpose of this retrospective study was to investigate the etiological distribution, survival time of dogs with idiopathic epilepsy (IdE) and structural epilepsy (StE), and risk factors for survival time, according to the recently published IVETF classification. We investigated canine cases with epilepsy that were referred to our teaching hospital in Japan during the past 10 years, and which encompassed a different breed population from Western countries.

Results

A total of 358 dogs with epilepsy satisfied our etiological study criteria. Of these, 172 dogs (48 %) were classified as IdE and 76 dogs (21 %) as StE. Of these dogs, 100 dogs (consisting of 65 with IdE and 35 with StE) were included in our survival study. Median survival time from the initial epileptic seizure in dogs with IdE and StE was 10.4 and 4.5 years, respectively. Median lifespan of dogs with IdE and StE was 13.5 and 10.9 years, respectively. Multivariable analysis demonstrated that risk factors for survival time in IdE were high seizure frequency (≥0.3 seizures/month) and focal epileptic seizures.

Conclusions

Focal epileptic seizures were identified as a risk factor for survival time in IdE. Clinicians should carefully differentiate seizure type as it is difficult to identify focal epileptic seizures. With good seizure control, dogs with IdE can survive for nearly the same lifespan as the general dog population. Our results using the IVETF classification are similar to previous studies, although some features were noted in our Japanese canine population (which was composed of mainly small-breed dogs), including a longer lifespan in dogs with epilepsy and a larger percentage of meningoencephalomyelitis of unknown origin in dogs with StE.

Evaluation of quality of life of carers of Italian spinoni with idiopathic epilepsy

The carers of all UK Kennel Club registered Italian spinoni (IS) born between January 1, 2000 and December 31, 2011 were invited to participate in the study. The carers of 47 of 63 IS diagnosed with idiopathic epilepsy (IE) returned the questionnaire, which included numerous questions on various aspects of IE including the effect of IE on the dog's carer's quality of life. Median epileptic seizure number in the three months before study end or death was five epileptic seizures, 72 per cent of dogs had cluster seizures, 94 per cent of dogs were administered one or more antiepileptic medications and 36 per cent of dogs were euthanased due to poorly controlled IE. Seventy-one per cent and 65 per cent of the participants were moderately to extremely worried about the frequency and severity of their dog's epileptic seizures, respectively. Caring for an IS with IE caused conflict with the carer's work, education or daily activity often or very often in 50 per cent of the participants. Overall the limitations on the carer's life due to caring for an IS with IE were considered as very to extremely bothersome in 29 per cent of the participants, a little to moderately bothersome in 40 per cent of the participants and not at all bothersome in 31 per cent of the participants.

Comparing the effects of first-line antiepileptic drugs on the gait of dogs with idiopathic epilepsy

Idiopathic epilepsy (IE) is a common chronic neurological disease of the dog. Previous studies of anti-epileptic drug (AED) treatment have indicated that acceptable AED adverse effects are as important to owners as reductions in seizure frequency. AEDs in both dogs and human beings are frequently associated with the adverse-effect ataxia. The aim of this study was to compare ataxia levels in dogs with IE treated chronically with phenobarbitone or imepitoin, the two currently available first-line AED treatments. The gait of 6 imepitoin-treated dogs, 8 phenobarbitone-treated dogs and 10 age-matched healthy control dogs were compared. Fifty strides from a walking gait were analysed for each dog, quantifying ataxia via the variability in six established gait parameters. Three variables differed significantly between groups: lateral distance between (i) pelvic paw placements, (ii) thoracic paw placements and (iii) stance time, which were significantly more variable in the phenobarbitone-treated dogs than imepitoin-treated or control dogs. These results indicate that dogs treated with phenobarbitone experience ataxia compared with controls and imepitoin-treated dogs. Conversely, there was no difference between imepitoin-treated dogs and controls. These results along with further research are needed to quantify AEDs adverse effects, to help vets and owners make more informed drug-choices.

Congenital and inherited neurologic diseases in dogs and cats: Legislation and its effect on purchase in Italy

Many of the congenital neurologic diseases can result in incapacity or death of the animal. Some of them, such as idiopathic epilepsy and hydrocephalus, exhibit breed or familial predisposition and a genetic basis was proved or suggested. Some diseases can be presumptively diagnosed after a detailed signalment (breed predisposition), history (e.g. family history because many of these defects have familial tendencies), and through physical exam; other diagnostic methods (radiography, computed tomography, magnetic resonance, electrophysiologic tests, etc.) can provide supportive evidence for the congenital defect and help to confirm the diagnosis. Some cases can lead to civil law-suits when the lesions are congenital, but not easily recognizable, or when the lesions are hereditary but tend to became manifest only after some time (more than 12 months after the date of purchase, e.g., after the vice-free guarantee period has expired). Moreover, quite frequently an early diagnosis is not made because there are delays in consulting the veterinarian or the general practitioner veterinarian does not perceive subtle signs. This study was designed to focus on the medico-legal aspects concerning the buying and selling in Italy of dogs and cats affected by congenital and hereditary neurologic diseases that could constitute vice in these animals. While adequate provisions to regulate in detail the various aspects of pet sale have still to be drawn up by legislators, it may be helpful to involve breeders, by obliging them by contract to extend guarantees in the case of hereditary lesions, including neurologic diseases.