Heidi L. Barnes Heller

Evaluation of therapeutic phenobarbital concentrations and application of a classification system for seizures in cats: 30 cases (2004-2013).

OBJECTIVE To determine the percentage of cats with a phenobarbital (PB) concentration between 15 and 45 μg/mL that had a ≥ 50% reduction in the number of seizures and to investigate applicability of the 2011 International League Against Epilepsy (ILAE) classification system in cats. DESIGN Retrospective case series. ANIMALS 30 cats with suspected or confirmed epilepsy. PROCEDURES Medical records for 2004 to 2013 at 3 veterinary hospitals were searched. Information collected included signalment, duration of observation before treatment, frequency of seizures before PB administration, seizure phenotype, dose of PB, serum PB concentration, number of seizures after PB administration, duration of follow-up monitoring, and survival time. A modified 2011 ILAE classification system was applied to all cats. RESULTS Seizure control was achieved in 28 of 30 (93%) cats with a serum PB concentration of 15 to 45 μg/mL. This comprised 10 of 11 cats with structural epilepsy, 14 of 15 cats with unknown epilepsy, and 4 of 4 cats with presumptive unknown epilepsy. Thirteen cats had no additional seizures after initiation of PB treatment. CONCLUSIONS AND CLINICAL RELEVANCE Seizure control was achieved in most cats with a serum PB concentration between 15 and 45 μg/mL, regardless of the cause of the seizures. A modified 2011 ILAE classification was applied to cats with seizures and enabled classification of cats without specific genetic testing and without identified structural or inflammatory disease. This classification system should be incorporated into veterinary neurology nomenclature to standardize communication between veterinarians and improve comparisons among species.

Therapeutic serum phenobarbital concentrations obtained using chronic transdermal administration of phenobarbital in healthy cats.

Seizures are a common cause of neurologic disease, and phenobarbital (PB) is the most commonly used antiepileptic drug. Chronic oral dosing can be challenging for cat owners, leading to poor compliance. The purpose of this study was to determine if the transdermal administration of PB could achieve serum PB concentrations of between 15 and 45 μg/ml in healthy cats. Nineteen healthy cats were enrolled in three groups. Transdermal PB in pluronic lecithin organogel (PLO) was applied to the pinnae for 14 days at a dosage of 3 mg/kg q12h in group 1 (n = 6 cats) and 9 mg/kg q12h in group 2 (n = 7 cats). Transdermal PB in Lipoderm Activemax was similarly applied at 9 mg/kg q12h for 14 days in group 3 (n = 6 cats). Steady-state serum PB concentrations were measured at trough, and at 2, 4 and 6 h after the morning dose on day 15. In group 1, median concentrations ranged from 6.0–7.5 μg/ml throughout the day (observed range 0–11 μg/ml). Group 2 median concentrations were 26.0 μg/ml (observed range 18.0–37.0 μg/ml). For group 3, median concentrations ranged from 15.0–17.0 μg/ml throughout the day (range 5–29 μg/ml). Side effects were mild. One cat was withdrawn from group 2 owing to ataxia and sedation. These results show therapeutic serum PB concentrations can be achieved in cats following chronic transdermal administration of PB in PLO at a dosage of 9 mg/kg q12h. More individual variation was noted using Lipoderm Activemax. Transdermal administration may be an alternative for cats that are difficult to medicate orally.

Prevalence, clinical presentation, prognosis, and outcome of 17 dogs with spinal shock and acute thoracolumbar spinal cord disease.

OBJECTIVE To describe the prevalence, signalment, clinical features, etiology, and outcome in dogs with acute thoracolumbar disease and suspected spinal shock. DESIGN Retrospective clinical case study (2005-2010). SETTING Private specialty practice. ANIMALS Medical records of 263 dogs with thoracolumbar spinal magnetic resonance imaging were reviewed. If decreased or absent withdrawal reflexes were present in 1 or both pelvic limbs, in the absence of a spinal lesion in the lumbosacral intumescence, dogs were diagnosed with spinal shock. Dogs with suspected or confirmed spinal neoplasia, myelomalacia, or meningomyelitis were excluded. Seventeen of 263 dogs (6%) met inclusion criteria. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Thoracic lesions were significantly more likely to result in spinal shock when compared to lumbar lesions (P = 0.03). Fibrocartilaginous embolism was the most commonly diagnosed etiology (7 of 17 dogs), and was more common in the thoracic spine compared to in the lumbar spine (P = 0.10). Six of 17 dogs (35%) were diagnosed with intervertebral disk herniation; 4 of 17 dogs (24%) with suspected acute noncompressive nucleus pulposus extrusion. Two dogs were lost to follow-up. Fourteen of 15 (93%) dogs had improved or normal reflexes by 60 days post injury. CONCLUSIONS Although the prevalence of spinal shock was low, it should be considered in any dog presenting with an acute history of thoracolumbar spinal injury with reduced or absent reflexes in the pelvic limbs. The presence of spinal shock should not dissuade a veterinarian from pursuing appropriate diagnostic testing and therapy for the underlying etiology.Objective To describe the prevalence, signalment, clinical features, etiology, and outcome in dogs with acute thoracolumbar disease and suspected spinal shock. Design Retrospective clinical case study (2005–2010). Setting Private specialty practice. Animals Medical records of 263 dogs with thoracolumbar spinal magnetic resonance imaging were reviewed. If decreased or absent withdrawal reflexes were present in 1 or both pelvic limbs, in the absence of a spinal lesion in the lumbosacral intumescence, dogs were diagnosed with spinal shock. Dogs with suspected or confirmed spinal neoplasia, myelomalacia, or meningomyelitis were excluded. Seventeen of 263 dogs (6%) met inclusion criteria. Interventions None. Measurements and Main Results Thoracic lesions were significantly more likely to result in spinal shock when compared to lumbar lesions (P = 0.03). Fibrocartilaginous embolism was the most commonly diagnosed etiology (7 of 17 dogs), and was more common in the thoracic spine compared to in the lumbar spine (P = 0.10). Six of 17 dogs (35%) were diagnosed with intervertebral disk herniation; 4 of 17 dogs (24%) with suspected acute noncompressive nucleus pulposus extrusion. Two dogs were lost to follow-up. Fourteen of 15 (93%) dogs had improved or normal reflexes by 60 days post injury. Conclusions Although the prevalence of spinal shock was low, it should be considered in any dog presenting with an acute history of thoracolumbar spinal injury with reduced or absent reflexes in the pelvic limbs. The presence of spinal shock should not dissuade a veterinarian from pursuing appropriate diagnostic testing and therapy for the underlying etiology.

Efficacy of glucocorticoid monotherapy for treatment of canine meningoencephalomyelitis of unknown etiology: a prospective study in 16 dogs

Abstract Canine non‐infectious, inflammatory meningoencephalomyelitis is termed meningoencephalomyelitis of unknown etiology (MUE) and may affect dogs of any age, breed or gender. Treatment with immunosuppressive medication has been widely reported, however no prospective clinical trials with a standard glucocorticoid monotherapy are available. The objectives were to compare the cerebrospinal fluid (CSF) analysis at diagnosis and after treatment with a standard glucocorticoid (GC) dose and to determine the survival time in dogs with MUE. We hypothesized that abnormal CSF findings would normalize in dogs with MUE, and survival time would be longer than previously reported for glucocortocoid therapy alone. Inclusion criteria were: (1) normal minimum database, (2) no GC use within 5 days, (3) magnetic resonance imaging performed, (4) negative infectious disease titres, and (5) abnormal CSF analysis. All dogs received GC therapy at 1 mg/kg per os q 12 h. Responders had normal CSF analysis at 1 month. Sixteen dogs met the inclusion criteria. Median total nucleated cell count (TNCC) and protein concentration at time of diagnosis were 39 cells/μL (0–1400 cells/μL), and 49 mg/dL (25–293 mg/dL), respectively. Median TNCC and protein concentration at 1 month were 1 cell/μL (0–120 cells/μL), and 24 mg/dL (13–175 mg/dL), respectively. Seven of 16 dogs (44%) were responders. There was no significant difference in survival between the CSF responders and CSF non‐responders (P = 0.85). Overall median survival was 602 days (45–654 days). This study supports using GC therapy in dogs with MUE.

Serum levetiracetam concentrations and adverse events after multiple dose extended release levetiracetam administration to healthy cats

Background Multiple dose administration of antiepileptic drugs to cats presents a challenge for owners. Extended release levetiracetam (XRL) has once daily recommended dosing interval, but multiple dose administration of XRL has not been evaluated in cats. Objective Evaluate serum levetiracetam concentrations and adverse clinical effects after 11 days of once daily XRL administration to healthy cats. Animals Nine healthy privately owned cats, body weight ≥ 5 kg Methods Extended release levetiracetam (500 mg/cat) was administered PO q24h for 10 days. On day 11, blood was collected at trough, 4, 6, and 8 hours after tablet administration. Owners maintained records of adverse effects throughout study. Levetiracetam was quantitated in serum using immunoassay validated in cats. Results Median dose 94.3 mg/kg q24h. Median (range) trough, 4, 6, and 8 hour serum levetiracetam concentrations were 7.0 (2.3‐14.1), 82.6 (7.8‐125.3), 92.3 (13.3‐97.3), and 72 (22.8‐96.4) μg/mL, respectively. Peak was not observed in 4 cats because of missed samples (n = 2) and failure to reach maximal concentration (C max) by 8 hours (n = 2). Median time of maximal concentration (T max) for the remaining 5 cats 5.2 (range 4‐6) hours. Adverse effects were minimal and included ataxia (n = 1), sedation (n = 1), and vomiting or regurgitation (n = 1). All signs resolved without dose adjustment or additional treatment. Conclusions and Clinical Importance Mean trough serum levetiracetam concentrations were ≥5 μg/mL and adverse effects were minimal throughout dosing period, indicating that the drug was well tolerated. Once daily XRL (500 mg/cat) administration may provide an easier alternative to 3 times daily dosing of intermediate‐release levetiracetam for epileptic cats.

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.

The Utility of Ultrasound and Radiography in Veterinary Neurology

With readily available advanced neuroimaging such as MRI or CT scans, simple radiography and ultrasound can be overlooked and underutilized diagnostic tools. Each of the following conditions may be diagnosed using plain radiographs in dogs and cats. Importantly, note that the diagnosis of intervertebral disc herniation (IVDH) is not on this list. Calcification of the intervertebral disc in situ, narrowed disc spaces, and spondylosis deformans may be indications of degenerative discs but are not diagnostic for a herniated disc. Calcification of the intervertebral disc in situ is not commonly seen at the time of diagnosis of a herniated disc.

RETROSPECTIVE STUDY EVALUATING ASSOCIATIONS BETWEEN MIDLINE BRAIN SHIFT ON MAGNETIC RESONANCE IMAGING AND SURVIVAL IN DOGS DIAGNOSED WITH MENINGOENCEPHALITIS OF UNKNOWN ETIOLOGY

Difficulty has been encountered when trying to identify ante mortem prognostic indicators for dogs with meningoencephalitis of unknown etiology (MUE). Identifying MRI imaging parameters associated with prognosis may impact treatment decision-making for clinician and owner. Our hypotheses for this retrospective cohort study are that dogs diagnosed with MUE that had midline shift on brain MRI would have a poorer survival compared to dogs without midline shift; and that younger age, lower weight, and low cerebrospinal fluid (CSF) cell count would be correlated with improved survival. Medical records were reviewed from two institutions. Inclusion criteria included: clinical signs referable to intracranial disease, brain MRI at presentation, abnormal CSF analysis, and negative infectious disease testing. Magnetic resonance imaging scans were evaluated for midline shift using the T2-weighted transverse image at the interthalamic adhesion and at the site of maximal deviation. Fifty-two dogs met the inclusion criteria. Median midline deviation was 0.12 cm. Median survival for dogs with no shift was 906 days and with shift was 84 days. Survival was not significantly different between groups (P = 0.11). This remained true when correcting for age (P = 0.22) and CSF TNCC (total nucleated cell count) (P = 0.12). Age at the time of diagnosis (P = 0.02) and CSF TNCC (P = 0.03) were significantly associated with survival. Cerebrospinal fluid protein value (P = 0.84) and weight (P = 0.82) were not significantly associated with survival. In this study of 52 dogs with MUE, MRI evidence of midline brain shift between 0.04 and 0.3 cm at the level of the interthalamic adhesion was not associated with shorter survival.