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Background There are few effective drugs for treatment of seizures in avian species. Objectives To investigate the pharmacokinetics and safety of zonisamide in chickens. Methods Phase 1: chickens (n = 4) received a single oral dose of zonisamide at 20 mg/kg. Blood samples were collected intermittently for 36 hr after dosing. Phase 2: chickens (n = 8) received zonisamide in a dose escalation protocol (20, 30, 60 and 80 mg/kg orally every 12 hr). The dose was increased weekly, and peak and trough blood samples were collected on Days 1, 3, and 7 each week. Two birds were randomly euthanized at the end of each week. Plasma zonisamide concentrations were analysed using a commercial immunoassay. Drug concentration vs. time data were subjected to non‐compartmental pharmacokinetic analysis. Results For Phase 1, peak plasma zonisamide (Cmax) was 15 ± 3 µg/ml at 2 ± 1 hr (Tmax). The disappearance half‐life was 6.5 ± 1 hr. Mean plasma concentrations remained within the (human) therapeutic range (10–40 µg/ml) for 6 hr. For Phase 2 of the study, plasma concentrations of zonisamide remained within or close to the recommended mammalian therapeutic range for birds in the 20 and 30 mg/kg dose. Area under the curve (AUC) and Cmax were dose dependent. Two birds developed immune‐mediated haemolytic anaemia. Conclusions Zonisamide appears to be a viable drug for use in chickens at a dose of 20 mg/kg orally every 12 hr., The pharmacokinetics and safety of zonisamide were investigated in chickens in single and repeated dose trials. Zonisamide appears to be a viable drug for use in chickens at a dose of 20mg/kg orally every 12 hr.

Background: Periodontal disease has been linked to the development of Alzheimer’s disease in people. It is theorized that the chronic inflammatory condition characteristic of oral dysbiosis in patients with periodontal disease leads to disruption of the blood-brain barrier, cytotoxin- and pathogen-induced brain damage, and accumulation of neurotoxic β-amyloid. In this inflammatory theory of Alzheimer’s disease, β-amyloid-a known antimicrobial protein-accumulates in response to oral pathogens. Canine cognitive dysfunction is considered a naturally occurring animal model of human Alzheimer’s disease. Like humans, periodontal disease is quite common in dogs; however, a link between periodontal disease and cognitive dysfunction has not been identified in this species. Aim: The purpose of this prospective investigation was to compare visual periodontal scores (from digital oral photographs) with numerical (0-54) cognitive assessment questionnaire forms in aging dogs with and without a clinical diagnosis of canine cognitive dysfunction. Methods: A visual analogue scale (0-4) was used to score the severity of periodontal disease in 21 aging dogs: 11 dogs with a clinical diagnosis of presumptive canine cognitive dysfunction and 10 dogs without a clinical history of cognitive decline. Individuals scoring the dental photographs were blinded to all case information, including cognitive assessment scores. Cognitive assessment scores were compared with periodontal disease scores for all dogs. Results: There was a significant (P

Background: Hippocampal atrophy is a key pathologic and magnetic resonance imaging (MRI) feature of human Alzheimer’s disease (AD). Hippocampal atrophy has not been documented via MRI in canine cognitive dysfunction (CCD), which is considered as the dog model of human AD.Aim: The purpose of this retrospective comparative volumetric MRI study was to compare total hippocampal volumes between successfully aging (control) dogs and dogs diagnosed with CCD.Methods: Mimics® software was used to derive total hippocampal volumes and total brain volumes from the MRI studies of 42 aging dogs (≥ 9 years): 16 dogs diagnosed with CCD and 26 successfully aging controls. Hippocampal volumes were normalized to total brain volume and these values were compared between groups using Mann–Whitney U tests.Results: Total hippocampal volume normalized to total brain volume was significantly less for CCD patients compared with control dogs (p = 0.04).Conclusion: The results of this study suggest that – similar to human AD – hippocampal atrophy is a pathological feature of CCD. This finding has potential importance for both investigating disease mechanisms related to dementia as well as future hippocampal-targeted therapies.

Canine cognitive dysfunction (CCD) is the canine analog of human Alzheimer disease (AD). The pathophysiology of CCD/AD is multifaceted. CCD is common in aged (>8 years) dogs, affecting between 14% and 35% of the pet dog population. Apparent confusion, anxiety, disturbance of the sleep/wake cycle, and decreased interaction with owners are all common clinical signs of CCD. Although there is no cure for CCD, several proven effective therapeutic approaches are available for improving cognitive ability and maintaining a good quality of life; instituting such therapies early in the disease course is likely to have the greatest positive clinical effect.

Status epilepticus (SE) and cluster seizures (CS) are common occurrences in veterinary neurology and frequent reasons of admission to veterinary hospitals. With prolonged seizure activity, gamma amino-butyric acid (GABA) receptors (GABAa receptors) become inactive, leading to a state of pharmacoresistance to benzodiazepines and other GABAergic medications, which is called refractory status epilepticus (RSE). Prolonged seizure activity is also associated with overexpression ofN-methyl-D-aspartic (NMDA) receptors. Rodent models have shown the efficacy of ketamine (KET) in treating RSE, and its use has been reported in one canine case of RSE. Boluses of KET 5 mg/kg IV have become the preferred treatment for RSE in our hospital. A retrospective study was performed to evaluate and report our experience with KET IV bolus to treat prolonged and/or repeated seizure activity in cases of canine CS, SE, and RSE. A total of 15 dogs were retrieved, for 20 hospitalizations and 28 KET IV injections over 3 years. KET IV boluses were used 12 times for RSE (9 generalized seizures, 3 focal seizures) and KET terminated the episode of RSE 12/12 times (100%); however, seizures recurred 4/12 times (33%) within ≤6 h of KET IV bolus. When used for CS apart from episodes of RSE, KET IV bolus was associated with termination of the CS episode only 4/14 times (29%). Only 4/28 (14%) KET IV boluses were associated with adverse effects imputable only to the use of KET. One dog experienced a short, self-limited seizure activity during administration of KET IV, which was most likely related to a pre-mature use of KET IV (i.e., before GABAergic resistance and NMDA receptor overexpression had taken place). This study indicates that KET 5 mg/kg IV bolus may be successful for the treatment of RSE in dogs.

Background Degenerative myelopathy (DM) in dogs is a progressive neurodegenerative condition that causes white matter spinal cord lesions. These lesions are undetectable on standard magnetic resonance imaging (MRI), limiting diagnosis and monitoring of the disease. Spinal cord lesions cause disruption to the structural integrity of the axons causing water diffusion to become more random and less anisotropic. These changes are detectable by the technique of diffusion tensor imaging (DTI) which is highly sensitive to diffusion alterations secondary to white matter lesion development. Objective Perform spinal DTI on cohorts of dogs with and without DM to identify if lesions caused by DM will cause a detectable alteration in spinal cord diffusivity that correlates with neurological status. Animals Thirteen dogs with DM and 13 aged-matched controls. Methods All animals underwent MRI with DTI of the entire spine. Diffusivity parameters fractional anisotropy (FA) and mean diffusivity (MD) were measured at each vertebral level and statistically compared between groups. Results Dogs with DM had significant decreases in FA within the regions of the spinal cord that had high expected lesion load. Decreases in FA were most significant in dogs with severe forms of the disease and correlated with neurological grade. Conclusions and clinical importance Findings suggest that FA has the potential to be a biomarker for spinal cord lesion development in DM and could play an important role in improving diagnosis and monitoring of this condition.

Hippocampal atrophy is a key pathologic and MRI feature of human Alzheimer’s disease (AD). Hippocampal atrophy has not been documented via MRI in canine cognitive dysfunction (CCD), which is considered the dog model of human AD. The purpose of this retrospective comparative volumetric MRI study was to compare total hippocampal volumes between successfully aging (control) dogs and dogs diagnosed with CCD. Mimics® software was used to derive total hippocampal volumes and total brain volumes from the MRI studies of 42 aging dogs (≥ 9 years): 16 dogs diagnosed with CCD and 26 successfully aging controls. Total hippocampal volume normalized to total brain volume was significantly less for CCD patients compared with control dogs (p=0.04). The results of this study suggest that-similar to human AD-hippocampal atrophy is a pathological feature of CCD. This finding has potential importance for both investigating disease mechanisms related to dementia as well as future hippocampal-targeted therapies.

Background Medical infrared thermal imaging (MITI) is a non-invasive imaging modality gaining popularity in the veterinary field. An infrared camera captures emission of heat and creates a color map in the form of a thermogram. Topical heat emission is influenced by localized disease processes as a result of autonomic nervous system imbalance. The purpose of this study was to determine the utility of using thermography to identify changes in thermographic patterns associated with syringomyelia (SM) presence or absence in Cavalier King Charles Spaniels (CKCS) with Chiari-like Malformation (CLM). Results In CKCS with CLM, MITI was most accurate at a texture distance of 6. Optimizing imaging feature sets produced a highest accuracy of 69.9% (95% CI: 59.5-79.0%), with 81.3% sensitivity and 57.8% specificity for identifying the presence of syringomyelia. Conclusion Thermographic image analysis is a successful non-invasive, diagnostic test that can be used to screen for syringomyelia presence in a CKCS with CLM.

The Chiari I malformation in humans and Chiari-like malformation in dogs (CLM) is a condition in which the cerebellum descends out of the foramen magnum affecting normal cerebral spinal fluid (CSF) flow. It is considered to be a developmental abnormality and is commonly confused with many other conditions. Chiari-like malformation in dogs affected approximately 85 % of Cavalier King Charles Spaniels evaluated, as reported in the most recent studies. The specific cause has not been determined; however, because of an abnormal shape or reduced skull size in the caudal occipital region, part of the cerebellum is forced through the foramen magnum, altering CSF flow patterns. Changes in CSF dynamics result in an abnormal accumulation of fluid within the substance of the spinal cord called a “syrinx.” The diagnosis of CLM in dogs and Chiari type I in humans can only be confirmed by MRI which is essential for determining the cause of syringomyelia. Current concepts in the diagnosis and treatment of Chiari-like malformation in dogs will be discussed.

Intracranial gliomas are a common malignancy in dogs, and are associated with a poor prognosis due to their aggressive nature and a lack of clinically effective treatments. The efficacies of various treatment modalities for canine brain tumours have been previously described, though little data exist on the use of cytotoxic chemotherapy. A comparative retrospective study, including 40 cases from 5 northeastern US veterinary hospitals, from 2008 to 2017, was conducted. Variables analysed in this study with relation to overall survival and prognostic significance included: age, sex, clinical signs, clinical sign duration, tumour location and treatment protocol used. Dogs with presumptive intracranial gliomas treated with lomustine chemotherapy lived longer (median, 138 days) than those treated exclusively with symptomatic care (median, 35 days; P = .0026 log-rank, 0.0138 Wilcoxon). Additionally, a duration of clinical signs ≥16 days prior to diagnosis (median, 109 days) was associated with a longer survival than a duration

The use of conventional multi-fractionated radiotherapy for the treatment of glial tumours is well documented in the literature. Recently, stereotactic radiotherapy (SRT) has become more widely available allowing for hypo-fractionated protocols; however, its usefulness in the treatment of canine intracranial gliomas is largely undetermined. We conducted a retrospective analysis, including 21 dogs diagnosed with presumptive intracranial gliomas treated with one or more courses of three fractions of 8 to 10 Gy CyberKnife SRT. The objective of this study was to evaluate the efficacy, safety and prognostic factors associated with the use of SRT for the treatment of canine intracranial gliomas. Overall MST for all dogs was 636 days (d). Dogs treated with one course of the described SRT protocol had a MST of 258 days while those treated with >1 course had a MST of 865 days (P = .0077 log rank, 0.0139 Wilcoxon). Dogs treated with one course of SRT who received adjuvant chemotherapy had a MST of >658 days and lived significantly longer than those who did not receive chemotherapy (MST, 230 days) (P = .0414 log rank, 0.0453 Wilcoxon). The most common adverse event included presumptive transient demyelination in 3/21 dogs, which was treated successfully with corticosteroids in all patients. This study provides evidence that SRT is effective in prolonging survival in dogs with intracranial gliomas, and may provide similar results to conventional fractionated protocols, while decreasing the number of hospital visits and anaesthetic episodes. Additionally, it appears that patients can be safely treated with multiple rounds of SRT resulting in improved survival times.

The objective of this study was to compare specific brain MRI anatomic measurements between three groups of geriatric ( > 8yrs) dogs: 1) neurologically impaired dogs with presumptive spontaneous brain microhemorrhages and no clinical evidence of canine cognitive dysfunction 2) dogs with canine cognitive dysfunction 3) dogs without clinical evidence of cognitive impairment or abnormalities on neurologic examination (control dogs). MR images from 46 geriatric dogs were reviewed and measurements were obtained of interthalamic adhesion height (thickness) and mid-sagittal interthalamic adhesion area for all dogs, in addition to total brain volume. Interthalamic adhesion measurements, either absolute or normalized to total brain volume were compared between groups. Signalment (age, breed, sex), body weight, presence and number of SBMs, as well as other abnormal MRI findings were recorded for all dogs. All interthalamic adhesion measurement parameters were significantly (p

Background Medical infrared thermal imaging (MITI) is a noninvasive imaging modality used in veterinary medicine as a screening tool for musculoskeletal and neurological disease processes. An infrared camera measures the surface body heat and produces a color map that represents the heat distribution. Local trauma or disease can impair the autonomic nervous system, which leads to changes in the local dermal microcirculation and subsequent alteration of surface body heat. Disruption of autonomic flow to the cutaneous vasculature at deeper levels can also result in asymmetric thermographic results. The purpose of this study was to evaluate surface temperature differences between limbs affected by bone neoplasia and their normal contralateral limbs. Results A statistically significant difference in average temperature was noted between regions of interest of the two groups (paired difference: 0.53 C° ± 0.14; P = 0.0005). In addition, pattern recognition analysis yielded a 75–100% success rate in lesion identification. Conclusions Significant alterations noted with average temperature and thermographic patterns indicate that MITI can document discernible changes associated with the presence of canine appendicular bone tumors. While MITI cannot be used as the sole diagnostic tool for bone cancer, it can be used as a screening modality and may be applicable in early detection of cancer.

The practice of acupuncture is becoming increasingly popular in veterinary medicine, especially as a method of providing pain relief. Originally based on principles derived from centuries of observation, conventional scientific mechanisms of action for acupuncture as a pain-relieving modality have recently been elucidated. Acupuncture points allow access to multiple regions of the body via the peripheral nervous system and its connection with the central nervous system. Local, segmental (spinal), and suprasegmental (brain) effects of acupuncture involve enhanced release of pain-relieving endogenous substances (e.g., opioids) and mitigated release of pain-inducing substances (e.g., inflammatory cytokines). In addition, there is evidence that acupuncture can induce positive neurochemical and cytoarchitectural change in the central nervous system via the phenomenon of neuroplasticity. Electroacupuncture is considered the most effective type of acupuncture delivery, allowing for more potent and long-lasting pain relief than is achieved via other methods (e.g., dry needling). The purpose of this review article is to summarize the relevant scientific literature from the last two decades relating to the physiological mechanisms of action of acupuncture as a pain-relieving modality.

Objective To report a transnasal, endoscopically guided ventral surgical approach for accessing the cranial and caudal segments of the sphenopalatine sinus for mass removal in a horse. Study Design Case report. Animal Adult horse with acute onset blindness referable to a soft tissue mass within the sphenopalatine sinus. Clinical Report A 7-year-old Warmblood gelding presented with a history of running into a fence and falling. No neurologic signs were identified at initial examination but acute blindness was noted 3 weeks later. On computed tomography (CT) the sphenopalatine sinus was filled with a large homogeneous mass with poor contrast enhancement that extended dorsally with thinning to the dorsal cortex of the sphenoid bone, just rostral to the entrance of the optic canals into the cranial cavity. Surgical access to the sphenopalatine sinus was achieved using a transnasal, endoscopically guided ventral pharyngotomy approach and the mass lesion was removed. A presumptive diagnosis of chondroma was made based on histopathology. The horse recovered well from surgery, and although it has not regained vision as of 6.5 years postoperatively, the disease has not progressed. Conclusion Transnasal, endoscopically-guided ventral surgical access to the sphenopalatine sinus is possible in horses and may improve access in horses with disease extending caudally beyond the palatine portion of the sinus. Use of smaller diameter or specialized instruments, such as various endoscopic bone cutting instruments, and CT image guidance may improve sinus access by this route.

Congenital malformations of the thoracic vertebral bodies are commonly encountered in veterinary practice. These anomalies are prevalent in juvenile and adult small-breed dogs. These anomalous vertebrae typically result in various degrees of kyphosis and scoliosis in the region of the abnormality. They are thought to occur following developmental errors during embryonic or fetal vertebral segmentation and ossification; most are incidental. This article focuses on those anomalies of the thoracic vertebral bodies that lead to clinical signs of neurologic dysfunction. Based on a limited number of reported cases, the prognosis for surgically managed dogs with thoracic vertebral body abnormalities is favorable.

Objective Thermal radiofrequency (TRF) of the saphenous nerve (a sensory nerve) combined with pulsed radiofrequency (PRF) of the sciatic nerve (a sensory and motor nerve) might relieve intractable stifle osteoarthritis (OA) pain in dogs. The objective was to determine if saphenous nerve TRF induces Wallerian degeneration and if sciatic nerve PRF induces degeneration or dysfunction. Study design Blinded, controlled, randomized, preclinical study. Animals A group of six intact, female Beagle dogs aged 14–16 months. Methods In each dog, one pelvic limb was assigned randomly to the control group and the other to the treatment group. Dogs were anesthetized and, using ultrasonography, radiofrequency electrodes were positioned adjacent to saphenous and sciatic nerves bilaterally; TRF and PRF were performed only in the treatment limb. Motor nerve conduction velocity (MNCV) was measured in both sciatic nerves 2 weeks later, and the dogs were euthanized. Hematoxylin and eosin-stained sections of saphenous and sciatic nerves were examined using light microscopy. Degeneration and inflammation were scored 0 (none) to 3 (severe). A one-tailed, paired Wilcoxon signed-rank test was used to test for differences in scores and MNCV between control and treatment nerves. Results Degeneration and inflammation scores were higher in treatment saphenous nerves in 5/6 dogs [83%; 95% confidence interval (CI), 36%, 99%]; however, after Bonferroni correction only degeneration score was higher (p = 0.0313). Degeneration, inflammation or decreased MNCV were not observed in sciatic nerves (each outcome: 0/6 nerves, 0%; 95% CI, 0%, 48%). No dogs experienced postprocedural pain or neurological deficits. Conclusions and clinical relevance The degeneration in TRF-treated saphenous nerves appears sufficient to impair transmission. Sciatic nerve PRF did not cause degeneration with attendant motor deficits, consistent with a proposed neuromodulatory mechanism. A clinical trial is needed to confirm the combined techniques produce analgesia without motor deficits in dogs with stifle OA.

Objective: To describe the pharmacokinetic parameters of oral pregabalin in normal cats after single oral dosing. Animals: Six healthy adult research cats. Procedures: Following sedation and indwelling catheter placement, one oral (4 mg/kg) dose of pregabalin was administered. Blood samples were collected at 0, 15 and 30 min and 1, 1.5, 2, 3, 4, 6, 8, 12, 24, and 36 h after administration. Plasma pregabalin concentrations were measured by high-performance liquid chromatography and subjected to pharmacokinetic analysis using commercial software. Results: Four of six cats developed moderate sedation after pregabalin administration. The peak pregabalin concentration was 8.3 ± 1.6 μg/ml which occurred at 2.9 ± 1.2 h. Elimination half-life was 10.4 ± 2.6 h and area under the curve was 133.9 ± 71.5 μg-h/ml. Time above the minimum therapeutic concentration for seizure control in dogs and people (2.8 μg/ml) was 17.6 ± 6.2 h. Using these data, predicted minimum, maximum and average steady state concentrations were calculated for 12 and 24 h dosing intervals. Conclusions and Clinical Relevance: Pregabalin (4 mg/kg) administered orally to cats results in plasma concentrations within the range considered to be efficacious for seizure control in dogs and humans between 1.5 and at least 12 h. Because of moderate sedative side effects in the majority of cats at this dose and high calculated maximum steady state concentrations, a lower dose, given more frequently (1–2 mg/kg q 12 h), should be evaluated in prospective clinical studies.

Objective To report clinical features and outcomes of cats undergoing excision of intracranial meningiomas. Study Design Retrospective, multicenter case series. Sample Population One hundred and twenty-one cats. Methods Signalment, clinical signs, duration of clinical signs, preoperative drug therapy, diagnostic imaging reports, surgery, histopathology, and outcome were collected from records of cats undergoing excision of intracranial meningiomas. Survival estimates were made using Kaplan–Meier analysis. Results There were 76/121 neutered males and 83/121 domestic short-hairs. Body weight ranged from 1.5–8.7 kg (median 5.0 kg). Age at diagnosis ranged from 3-18 years (median 12 years). Clinical signs included changes in behavior, ataxia, seizures, visual deficits, circling, and paresis. Duration of neurologic signs ranged from

Background Few medications are available for parental administration to animals with seizures. Rectal administration of medications is often used if the animal cannot be administered oral medications. Hypothesis/Objectives To determine the pharmacokinetic differences in zonisamide when administered rectally in either of 2 vehicles and PO to dogs. Animals Eight healthy research dogs. Methods Randomized cross-over design. Zonisamide, 10 mg/kg, was administered rectally in polyethylene glycol (PEG-R), rectally in water (H2O-R), and as an oral capsule. Plasma zonisamide concentrations were measured until 72 hours after administration. Zonisamide was quantitated by HPLC and plasma concentration versus time curve data was analyzed by using noncompartmental modeling. Results Mean maximum plasma zonisamide concentrations (μg/mL) were significantly higher after oral administration (11.56 ± 4.04) compared to H2O-R (5.00 ± 1.83) (P = .004). Disappearance half-life (hours) and mean time to maximum concentration (hours) were not significantly different between methods of administration. Mean relative bioavailability of PEG-R (85 ± 69%) was significantly higher than that of H2O-R (53 ± 37%) (P = .039). Dogs tolerated all dosing forms with no evidence of adverse effects. Conclusions and Clinical Importance The vehicle in which zonisamide is dissolved influences rectal bioavailability, with PEG preferred to H2O-R. Because of the prolonged time to maximum concentration, rectal administration of zonisamide should not be used to treat status epilepticus in dogs. A dose higher than what was used in this study might be necessary, if currently recommended minimum therapeutic concentrations (10 μg/mL) are to be achieved with a single-dose administration.

Objective To investigate the histopathologic characteristics of concurrent splenic and liver masses in dogs undergoing splenectomy and liver mass biopsy/resection. Medical records of 125 client-owned dogs found to have splenic mass or masses and a liver mass or masses during surgery were examined. Signalment (age, sex, breed), body weight, and results of histopathology were recorded for all dogs. Results Twenty-seven percent (34/125) of the dogs in this study had no evidence of malignancy in either the liver or the spleen. Sixty of 125 dogs (48.0%) had malignancy in the spleen and liver, and 56 (56/60, 93.3%) of those dogs had the same malignancy in both organs. Signalment was similar to that in other reports of splenic pathology. In this clinical population of dogs, 27% of dogs with concurrent gross splenic and liver masses discovered intraoperatively had benign lesions in both locations and therefore had a favorable prognosis. Electronic supplementary material The online version of this article (10.1186/s13104-018-3220-1) contains supplementary material, which is available to authorized users.

Objective To report clinical findings including severe hyperthermia and hypernatremia after transethmoidal Cavitron ultrasonic surgical aspirator (CUSA)-assisted diencephalic mass removal. Study Design Retrospective case series. Animals Dogs (n = 4) and 2 cats. Methods Medical records (1997–2003) of dogs and cats that had transethmoidal CUSA-assisted diencephalic mass removal were reviewed. Retrieved data were: history, signalment, blood work, neurologic examination findings, MRI results, histopathology, postoperative complications, pre- and postoperative medical therapy, and outcome. Results Tumor types included: meningioma (n = 3), choroid plexus papilloma (1), astrocytoma (1), and pituitary macroadenoma (1). Median onset of hyperthermia was 3.5 hours (range: 1–6 hours) after extubation; median high temperature at onset was 40.3°C, (range: 39.6–41.7°C). Median onset of hypernatremia (median, 172 mmol/L; range: 168–196 mmol/L) was 4.5 hours (range: 1–9 hours) after extubation. Median time of death after hyperthermia was 10.5 hours (range: 6–13 hours) and after extubation was 13.5 hours (range: 11–15 hours). Conclusions Transethmoidal CUSA-assisted diencephalic mass removal is associated with early postoperative hyperthermia, hypernatremia, and death, and cannot be recommended.

Treatment protocols, treatment planning methods and tumour types in studies evaluating radiotherapy for canine brain tumours have been varied. This case series retrospectively evaluated the outcome of definitive, three-dimensional conformal radiation therapy (3D-CRT) as either a sole modality or as an adjuvant to surgery in 31 dogs diagnosed with meningioma by histopathology (n = 10) or cross-sectional imaging of the head (n = 21, assessed independently by two board certified radiologists). Prescribed dose ranged from 45 to 54 Gy in 2.5 to 3 Gy fractions. Median overall survival was 577 days (interquartile range = 272-829 days; range = 30-1942 days) when all deaths were considered and 906 days (interquartile range = 336-912 days; range = 10 -1942 days) when only dogs dying due to meningioma were considered. No significant difference in survival time was detected for the defined clinical or imaging findings or between treatment with radiotherapy alone versus adjuvant radiotherapy, suggesting that 3D-CRT may be a viable alternative to surgery.

Craniocervical junction abnormality (CJA) is a term that encompasses a number of developmental anatomical aberrations at the region of the caudal occiput and first two cervical vertebrae. Chiari-like malformation appears to be the most common CJA encountered in dogs, and there has been a tremendous amount of clinical investigation into this disorder in recent years. Other abnormalities in this region include atlanto-occipital overlap, dorsal constriction at C1/C2 and atlantoaxial instability. This review article presents an overview of the current understanding of CJA in dogs, as well as medical and surgical treatment options available.

To report a transnasal, endoscopically guided ventral surgical approach for accessing the cranial and caudal segments of the sphenopalatine sinus for mass removal in a horse.Case report.Adult horse with acute onset blindness referable to a soft tissue mass within the sphenopalatine sinus.A 7-year-old Warmblood gelding presented with a history of running into a fence and falling. No neurologic signs were identified at initial examination but acute blindness was noted 3 weeks later. On computed tomography (CT) the sphenopalatine sinus was filled with a large homogeneous mass with poor contrast enhancement that extended dorsally with thinning to the dorsal cortex of the sphenoid bone, just rostral to the entrance of the optic canals into the cranial cavity. Surgical access to the sphenopalatine sinus was achieved using a transnasal, endoscopically guided ventral pharyngotomy approach and the mass lesion was removed. A presumptive diagnosis of chondroma was made based on histopathology. The horse recovered well from surgery, and although it has not regained vision as of 6.5 years postoperatively, the disease has not progressed.Transnasal, endoscopically-guided ventral surgical access to the sphenopalatine sinus is possible in horses and may improve access in horses with disease extending caudally beyond the palatine portion of the sinus. Use of smaller diameter or specialized instruments, such as various endoscopic bone cutting instruments, and CT image guidance may improve sinus access by this route.

Objective—To objectively describe morphometric features of the craniocervical junction region of Cavalier King Charles Spaniels (CKCSs) and non-CKCS dogs with suspected Chiari-like malformation (CLM) and identify associations between these features and the presence of other malformations in this region. Animals—216 CKCSs and 58 non-CKCS dogs. Procedures—Magnetic resonance and computed tomographic images of the head and craniocervical junction region of patients evaluated because of suspected CLM were assessed for cerebellar compression (CC), ventral spinal cord compression at the C1–C2 articulation (medullary kinking), and dorsal spinal cord compression at the C1–C2 articulation (dorsal compression). A compression index was calculated for each of these 3 locations in each dog. Multiple logistic regression analysis was performed to determine whether breed (CKCS vs non-CKCS) and compression index values were associated with the presence of other craniocervical junction abnormalities. Results—All 274 dogs had CC; medullary kinking was identified in 187 (68.2%) and dorsal compression was identified in 104 (38.0%). Atlantooccipital overlapping (AOO) was identified in 76 (27.7%) dogs. Breed of dog (CKCS vs non-CKCS) and value of CC index were the only significant predictors of AOO. The CKCSs had an almost 5-fold decrease in risk of AOO, compared with the non-CKCS dogs, and the risk of AOO nearly doubled for every 10% increase in CC index. Conclusions and Clinical Relevance—The anatomic abnormality responsible for CC was AOO in a substantial percentage of dogs suspected to have CLM. The CC index value may be used to help differentiate subtypes of craniocervical junction abnormalities in dogs.

Objective: To report the clinical signs, imaging findings and surgical treatment of a meningoencephalocele in a cat. Study Design: Case report. Animal: Domestic shorthaired cat, 4 months old. Methods: A parietal meningoencephalocele was identified and characterized by magnetic resonance and computed tomography (CT) imaging. The abnormal tissue was excised and submitted for histopathology, and the meningeal and skull defects were reconstructed. Results: The cat made a full recovery and the episodes of aggression, restlessness and apparent discomfort that occurred before surgery ceased after surgical treatment. The cat was clinically normal 1 year postoperatively. Conclusion: Surgical management of meningoencephalocele in cats may be a viable treatment option.

Objective—To evaluate clinical features and outcome of dogs with a confirmed spinal cord nephroblastoma and to describe the use of Wilms tumor-1 (WT-1) immunohistochemical staining to confirm a diagnosis of nephroblastoma in dogs. Design—Retrospective case series. Animals—11 dogs with a spinal cord nephroblastoma. Procedures—Medical records of dogs with a spinal cord nephroblastoma were reviewed. Information extracted included signalment, history, clinical signs, results of diagnostic testing, tumor location, treatment, and outcome. The diagnosis was confirmed through histologic review and WT-1 immunohistochemical staining of a tumor sample. In dogs with negative results for staining with WT-1, staining for cytokeratin, vimentin, and glial fibrillar acidic protein was performed. Results—11 dogs had a spinal cord tumor with a histologic appearance and immunohistochemical staining consistent with a nephroblastoma. Positive results for staining with WT-1 were detected in 9 of 11 dogs. Age at admission ranged from 5 to 48 months (median, 14 months). Nine dogs were female. All had progressive paraparesis, paraplegia, or ataxia. Duration of clinical signs ranged from 2 to 60 days (median, 14 days). Median survival time was 30 days from the time of diagnosis. Median survival time in dogs treated via surgical resection was 70.5 days. Conclusions and Clinical Relevance—The prognosis for dogs with a spinal cord nephroblastoma appeared to be poor, although combined surgical resection and radiation therapy may provide a good functional outcome. Results for staining with WT-1 can be used to support a diagnosis of nephroblastoma.

Objective—To compare clinical outcome in dogs with serologically diagnosed acquired myasthenia gravis (MG) treated with pyridostigmine bromide (PYR) with that of dogs treated with mycophenolate mofetil (MMF) and PYR (MMF + PYR). Design—Retrospective case series. Animals—27 dogs. Procedures—Medical records from August 1999 through February 2008 were reviewed to identify dogs with serologically diagnosed acquired MG treated with PYR or MMF + PYR. Data collected for each dog included signalment, whether the dog had megaesophagus or pneumonia (or both), thyroid hormone concentration, remission, time to remission, and survival time. Rates for detection of clinical signs and survival time were compared. Survival time was estimated via the Kaplan-Meier method. Influence of drug treatment protocol on likelihood of remission, time to remission, and survival time was examined. Effects of MMF treatment, megaesophagus, pneumonia, and low serum thyroid hormone concentration on time to remission and survival time were also analyzed. Results—12 dogs were treated with PYR, and 15 were treated with MMF + PYR. Mortality rates were 33% (PYR) and 40% (MMF + PYR). There was pharmacological remission in 5 and 6 dogs in the PYR and MMF + PYR groups, respectively. No significant differences were detected between treatment groups for remission rate, time to remission, or survival time. Megaesophagus, pneumonia, and low serum thyroid hormone concentration had no significant effect on time to remission or survival time for either treatment group. Conclusions and Clinical Relevance—The results did not support routine use of MMF for the treatment of dogs with acquired MG.

Craniocervical junction disorders are most frequently seen in toy and small-breed dogs. They can present a diagnostic challenge, as multiple anomalies can be present concurrently and share similar clinical manifestations. Some, such as Chiari-like malformations, may be present in asymptomatic dogs. A thorough evaluation of the entire craniocervical junction, frequently using more than 1 imaging modality, is necessary before making treatment decisions.

Objective—To assess tolerability and short-term efficacy of oral administration of pregabalin as an adjunct to phenobarbital, potassium bromide, or a combination of phenobarbital and potassium bromide for treatment of dogs with poorly controlled suspected idiopathic epilepsy. Design—Open-label, noncomparative clinical trial. Animals—11 client-owned dogs suspected of having idiopathic epilepsy that was inadequately controlled with phenobarbital, potassium bromide, or a combination of these 2 drugs. Procedures—Dogs were treated with pregabalin (3 to 4 mg/kg [1.4 to 1.8 mg/lb], PO, q 8 h) for 3 months. Number of generalized seizures in the 3 months before and after initiation of pregabalin treatment was recorded. Number of responders (≥ 50% reduction in seizure frequency) was recorded, and seizure frequency before and after initiation of pregabalin treatment was compared by use of a nonparametric Wilcoxon signed rank test. Results—Seizures were significantly reduced (mean, 57%; median, 50%) after pregabalin administration in the 9 dogs that completed the study; 7 were considered responders with mean and median seizure reductions of 64% and 58%, respectively. Adverse effects for pregabalin were reported in 10 dogs. Mean and median plasma pregabalin concentrations for all dogs were 6.4 and 7.3 μg/mL, respectively. Conclusions and Clinical Relevance—Pregabalin may hold promise as a safe and effective adjunct anticonvulsant drug for epileptic dogs poorly controlled with the standard drugs phenobarbital or potassium bromide. Adverse effects of pregabalin appeared to be mild. Additional studies with larger numbers of dogs and longer follow-up intervals are warranted.

Objective To describe the pharmacokinetics of pregabalin in normal dogs after a single oral dose. Study design Prospective experiment. Animals Six adult Labrador/Greyhound dogs (four females and two males) aged 2.6 (2.6–5.6) years old (median and range) weighing 33.4 (26.8–42.1) kg. Methods After jugular vein catheterization, the dogs received a single oral dose of pregabalin (∼4 mg kg−1). Blood samples were collected at: 0 (before drug administration), 15 and 30 minutes and at 1, 1.5, 2, 3, 4, 6, 8, 12, 24 and 36 hours after drug administration. Plasma pregabalin concentration was measured by HPLC. Noncompartmental analysis was used to estimate pharmacokinetic variables. Results No adverse effects were observed. The median (range) pharmacokinetic parameters were: Area under the curve from time 0 to 36 hours = 81.8 (56.5–92.1) μg hour mL−1; absorption half-life = 0.38 (0.25–1.11) hours; elimination half-life = 6.90 (6.21–7.40) hours; time over 2.8 μg mL−1 (the presumed minimal effective concentration) = 11.11 (6.97–14.47) hours; maximal plasma concentration (Cmax) = 7.15 (4.6–7.9) μg mL−1; time for Cmax to occur = 1.5 (1.0–4.0) hours. Assuming an 8-hour dosing interval, predicted minimal, average, and maximal steady state plasma concentrations were 6.5 (4.8–8.1), 8.8 (7.3–10.9), and 13.0 (8.8–15.2) μg mL−1. The corresponding values assuming a 12-hour interval were 3.8 (2.4–4.8), 6.8 (4.9–7.9), and 10.1 (6.6–11.6) μg mL−1. Conclusions and clinical relevance Pregabalin 4 mg kg−1 PO produces plasma concentrations within the extrapolated therapeutic range from humans for sufficient time to suggest that a twice daily dosing regime would be adequate. Further study of the drug's safety and efficacy for the treatment of neuropathic pain and seizures in dogs is warranted.

Objective: To determine plasma pharmacokinetics of levetiracetam after a single intravenous dose (60 mg/kg) in normal dogs using a high-performance liquid chromatography assay validated for canine plasma. Design: Pharmacokinetic study. Setting: A university-based canine research facility. Animals: Six healthy adult dogs. Interventions: Intravenous drug administration, multiple blood sample procurement. Measurements and main results: There were no obvious adverse effects associated with the intravenous (IV) bolus administration of levetiracetam in any of the dogs. Plasma levetiracetam concentrations remained above or within the reported therapeutic range for humans (5–45 μg/mL) for all dogs, for all time periods evaluated. Mean and median (in parentheses) values for pharmacokinetic parameters included the following: maximum plasma concentration, 254 μg/mL (254 μg/mL); half-life, 4.0 hours (4.0 hours); volume of distribution at steady state, 0.48 L/kg (0.48 L/kg); clearance, 1.4 mL/kg/min (1.5 mL/kg/min); and median residence time, 6.0 hours (6.0 hours). Conclusions: In normal dogs, a 60 mg/kg IV bolus dose of levetiracetam is well tolerated and achieves plasma drug concentrations within or above the therapeutic range reported for humans for at least 8 hours after administration. Based on the favorable pharmacokinetics and tolerability demonstrated for IV levetiracetam in this study, in addition to previously demonstrated efficacy of oral levetiracetam, IV levetiracetam may be a useful treatment option for emergency management of canine seizure activity.

Objective: Reports of cerebellar infarction in veterinary literature are rare. Documentation and descriptions of cerebellar infarction in human literature have been well described. Brain lesions suspected to be infarcts have been recognized with magnetic resonance imaging (MRI). Series summary: Four dogs presented to the Long Island Veterinary Specialists (LIVS) with the history of acute onset cerebellovestibular dysfunction. All animals were imaged using a 0.5 T super-conducting Magna GE MRI unit. Suspected cerebellar infarction was diagnosed in all dogs based on history, physical examination, and MRI findings. Further diagnostics were performed based on the individual case and owner compliance. Functional recovery was favorable in 3 dogs. One dog was euthanized shortly following the onset of neurological dysfunction. New or unique information provided: Cerebellar infarction appears to have characteristic MRI features. Affected tissue within the cerebellum is typically wedge-shaped with low signal intensity in T1-weighted images, high signal intensity in T2-weighted images, subtle rim enhancement without central contrast enhancement in T1 post-gadolinium, and selectively hyperintense in fluid-attenuated inversion recovery images. Anatomic regions serviced by rostral cerebellar arteries are affected. Vascular risk factors as compared with reports in human literature are also discussed.

Objectives— To describe a cranioplasty procedure used in conjunction with foramen magnum decompression (FMD) for the treatment of canine caudal occipital malformation syndrome (COMS), and to evaluate the clinical outcome. Study Design— Prospective clinical study. Animals— Dogs (n=21) with COMS diagnosed by magnetic resonance imaging (MRI). Methods— After FMD, titanium screws were placed around the perimeter of the foramen magnum defect and a skull plate fashioned from titanium mesh and polymethylmethacrylate was attached to the back of the skull, using the titanium screws as anchor posts. Follow-up was obtained by direct examination by the authors, telephone interviews with owners and referring veterinarians, and a questionnaire sent to owners of surviving dogs designed to assign objective measures of response to surgical intervention. Surgical success was defined as improvement in ≥1 aspects of clinical dysfunction (e.g. scratching, pain) postoperatively. Owner-assigned pre- and postoperative quality-of-life (QOL) scores (1–5) for surviving dogs were compared using a Wilcoxon's signed rank test for paired data (P≤.05). Results— No intraoperative complications occurred and postoperative complications were limited to transient worsening of a pre-existing head tilt and ataxia in 1 dog, and the need for oral pain medication for 1–4 weeks in 3 dogs. Seventeen dogs (81%) had clinical improvement after surgery. Although clinical signs resolved in 1 dog, it died after being hit by a car, 5 months after surgery. One dog had no change in clinical signs; this patient's clinical signs were not severe and the owners had opted for surgery primarily to prevent progression of disease. Two dogs were euthanatized; 1 because of no improvement of severe clinical signs, and 1 because of sustained recurrence of apparent head and neck pain 7 months later. One dog required a dorsal laminectomy at a second site (C1/C2 vertebral level), 2 months later. Four dogs has transient “flare-ups” of apparent head/neck pain 2–13 months later; all resolved with transient re-institution of oral analgesic therapy. Further surgery at the FMD was not needed. Based on the returned questionnaires, there was an overall significant improvement in QOL scores. Conclusions— FMD with cranioplasty was well tolerated, with no intraoperative complications, and minor postoperative complications. Most dogs improved clinically, and none required further surgery at the original FMD site. Clinical Relevance— FMD with cranioplasty may be an effective surgical method of treating dogs with COMS and is well tolerated. Based on prior reports of FMD for this disorder, it appears that cranioplasty may reduce the rate of surgical failure caused by formation of compressive scar tissue at the FMD site in the short term. Results of this preliminary study support further evaluation of the cranioplasty procedure in a larger group of dogs over a more extended follow-up period.

To report clinical features and outcomes of cats undergoing excision of intracranial meningiomas.Retrospective, multicenter case series.One hundred and twenty-one cats.Signalment, clinical signs, duration of clinical signs, preoperative drug therapy, diagnostic imaging reports, surgery, histopathology, and outcome were collected from records of cats undergoing excision of intracranial meningiomas. Survival estimates were made using Kaplan-Meier analysis.There were 76/121 neutered males and 83/121 domestic short-hairs. Body weight ranged from 1.5-8.7 kg (median 5.0 kg). Age at diagnosis ranged from 3-18 years (median 12 years). Clinical signs included changes in behavior, ataxia, seizures, visual deficits, circling, and paresis. Duration of neurologic signs ranged from1-23 months (median 1.25 months). At the time of writing, 13 cats were alive, 54 were dead or euthanatized, and 54 were lost to followup. Seven cats (13% of cats that died; 6% of all cats) died or were euthanatized in the immediate postoperative period (1 month post-surgery) and 9 cats (17% of all cats that died; 7% of all cats) died from causes related to the meningioma but outside the immediate perioperative period. The median survival time for all cats was 37 months (95% confidence interval 28-54 months).Cats undergoing excision of intracranial meningiomas had a low perioperative mortality and a long-term prognosis of more than 3 years.

OBJECTIVE To determine the usefulness of medical infrared thermal imaging (MITI) as a screening tool for hyperthyroidism in cats, evaluate the need for hair clipping over the ventral aspect of the neck to achieve optimal images, and determine whether there is a change in thermal patterns at 1 and 3 months after radioactive sodium iodide I 131 treatment. ANIMALS 17 cats with and 12 control cats without hyperthyroidism. PROCEDURES All cats underwent MITI first with the hair present and then after the hair was clipped. Each cat with hyperthyroidism was subsequently appropriately treated SC with radioiodide; reevaluations, including MITI before and after hair clipping and measurement of serum thyroxine concentration, were performed 1 and 3 months after treatment. RESULTS The MITI had 80.5% and 87.5% accuracy in differentiating hyperthyroid cats from clinically normal cats before and after the hair over the ventral aspect of the neck was clipped. Among cats with an initial serum thyroxine concentration > 4.0 μg/dL, the success rate for MITI-detected response to radioiodide treatment at the 1-month reevaluation was 92.86% in unshaved cats and 85.71% in shaved cats. The success rate for MITI-detected response to radioiodide treatment at the 3-month reevaluation was 100% in unshaved and shaved cats. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that MITI was successful in differentiating between hyperthyroid cats and clinically normal cats and identifying patients with thyroxine concentration within reference interval after radioactive sodium iodide I 131 treatment.