Use of sedation-awakening electroencephalography in dogs with epilepsy.

BACKGROUND: Electroencephalography (EEG) recording protocols have been standardized for humans. Although the utilization of techniques in veterinary medicine is increasing, a standard protocol has not yet been established. HYPOTHESIS: Assessment of a sedation-awakening EEG protocol in dogs. ANIMALS: Electroencephalography examination was performed in a research colony of 6 nonepileptic dogs (control [C]) and 12 dogs with epilepsy admitted to the clinic because of the epileptic seizures. METHODS: It was a prospective study with retrospective control. Dogs with epilepsy were divided into 2 equal groups, wherein EEG acquisition was performed using a "sedation" protocol (IE-S, n = 6) and a "sedation-awakening" protocol (IE-SA, n = 6). All animals were sedated using medetomidine. In IE-SA group, sedation was reversed 5 minutes after commencing the EEG recording by injecting atipamezole IM. Type of background activity (BGA) and presence of EEG-defined epileptiform discharges (EDs) were evaluated blindly. Statistical significance was set at P > 0.05. RESULTS: Epileptiform discharges were found in 1 of 6 of the dogs in group C, 4 of 6 of the dogs in IE-S group, and 5 of 6 of the dogs in IE-SA group. A significantly greater number of EDs (spikes, P = .0109; polyspikes, P = .0109; sharp waves, P = .01) were detected in Phase 2 in animals subjected to the "sedation-awakening" protocol, whereas there was no statistically significant greater number of discharges in sedated animals. CONCLUSIONS AND CLINICAL IMPORTANCE: A "sedation-awakening" EEG protocol could be of value for ambulatory use if repeated EEG recordings and monitoring of epilepsy in dogs is needed.

Reliability and interobserver variability of a grading system of ventricular distension in dogs.

Introduction: Internal hydrocephalus is the most common malformation of the central nervous system in dogs. Although the grades of ventricular distension have importance for long-term prognosis, there is no standard classification scheme describing the grade of the ventricular distension in dogs. Materials and methods: Magnetic resonance imaging (MRI) scans from 147 dogs of various breed, sex, skull conformation, and weight were reviewed retrospectively and blinded between three observers. Based on objectively assessable morphologic characteristics, the lateral cerebral ventricles were graded as normal, minimally, mildly, moderately, severely enlarged or end stage (grade 0 to grade 5), respectively. Evans' index or the ventricle brain index was also measured in all animals. Interobserver agreement between a very experienced, experienced, and unexperienced person was evaluated by the Spearman coefficient and kappa tests. Additionally, correlation to the ventricle brain index was determined using the Spearman coefficient and F-tests. Results: The Spearman correlation coefficient reached a very strong correlation (r = 0.97) between the experienced and very experienced observer and a strong correlation (r = 0.91) between the very experienced and unexperienced observer. The kappa value revealed excellent interobserver agreement between the very experienced and experienced observers (weighted kappa 0.91) and moderate between the very experienced and unexperienced observers (weighted kappa 0.75). The ventricular-brain index correlated (r = 0.94, Spearman coefficient test) with the grading system, indicating that a more elevated ratio was related to a more advanced degree of ventricular enlargement. The interobserver agreement with regard to the grade between the neurologist in training and a board-certified neurologist was excellent and between the board-certified neurologist and general practitioner achieved lower values. Conclusion: The presented MRI-based grading of ventricular enlargement is a reliable and functional method for an objective grading of the ventricular system in dogs. Some experience in MRI and brain anatomy is needed for interpretation and grading.

Risk factors, treatment, and outcome in dogs and cats with subdural hematoma and hemispheric collapse after ventriculoperitoneal shunting of congenital internal hydrocephalus.

BACKGROUND: Overshunting and hemispheric collapse are well-known complications after ventriculoperitoneal shunt (VPS) implantation. Risk factors that predispose to overshunting, treatment options, and prognosis after therapeutic intervention have not been described. HYPOTHESIS/OBJECTIVES: To identify preoperative risk factors for overshunting, the effect of surgical decompression, and their outcomes. ANIMALS: Seventy-five dogs and 7 cats. METHODS: Retrospective case cohort study. Age, breed, sex, body weight, number of dilated ventricles, ventricle brain ratio, intraventricular pressure, and implanted pressure valve systems were evaluated as possible risk factors. RESULTS: Overshunting had a prevalence of 18% (Cl 95% 9.9-26.66). An increase of 0.05 in VBR increased the risk of overshunting by OR 2.23 (Cl 95% 1.4-3.5; P = .001). Biventricular hydrocephalus had the highest risk for overshunting compared to a tri- (OR 2.48 with Cl 95% 0.5-11.1) or tetraventricular hydrocephalus (OR 11.6 with Cl 95% 1.7-81.1; P = .05). There was no influence regarding the use of gravitational vs differential pressure valves (P > .78). Overshunting resulted in hemispheric collapse, subdural hemorrhage, and peracute deterioration of neurological status in 15 animals. Subdural hematoma was removed in 8 dogs and 2 cats with prompt postoperative improvement of clinical signs. CONCLUSIONS AND CLINICAL IMPORTANCE: Biventricular hydrocephalus and increased VBR indicate a higher risk for overshunting. The use of differential valves with gravitational units has no influence on occurrence of overshunting related complications and outcomes. Decompressive surgery provides a favorable treatment option for hemispheric collapse and has a good outcome.

Manual therapeutic plasma exchange for treatment of a dog with suspected acute canine polyradiculoneuritis.

BACKGROUND: Acute canine polyradiculoneuritis is one of the most common polyneuropathies occurring in dogs. The disease is very similar to the Guillain-Barré syndrome in humans. In veterinary medicine, there is no established treatment for this disease, while in human medicine, therapeutic plasma exchange and intravenous immunoglobulin administration are two main immunotherapy treatments of this syndrome. CASE PRESENTATION: A 12-year-old male Jack Russel Terrier was presented with a history of acute weakness of the pelvic limbs progressing to flaccid tetraplegia with respiratory compromise. Complete diagnostic workup was performed including blood work, diagnostic imaging (radiographs of the thorax as well as ultrasound of the abdomen) and echocardiography. Based on the clinical course, neurological localisation and the results of electrodiagnostic examination acute canine polyradiculoneuritis was suspected. During the hospitalization, the dog deteriorated and was admitted to the intensive care unit for respiratory support via tracheostomy tube. In addition to symptomatic treatment, immunotherapy via single treatment of manual therapeutic plasma exchange was administered. This procedure was safe, and the dog showed improvement of clinical signs 3 days after therapy was initiated, as well as improvement of neurological signs (from grade 4 tetraplegia to grade 3) within 5 days. However, the dog was euthanized 3 weeks later due to complications related to the tracheostomy. CONCLUSIONS: This is the first case report of a manual therapeutic plasma exchange in a dog with suspected acute canine polyradiculoneuritis suggesting that this method is safe and well tolerated in dogs with this disease. It may be a reasonable adjunctive treatment to supportive therapy in severe cases.

Prevalence of seizures in dogs and cats with idiopathic internal hydrocephalus and seizure prevalence after implantation of a ventriculo-peritoneal shunt.

BACKGROUND: Seizures are considered a clinical sign in dogs with internal hydrocephalus but are not found in recent studies. Seizure prevalence due to ventricular enlargement and the prevalence of postoperative seizures in animals is not known. OBJECTIVES: To determine seizure prevalence in dogs and cats with idiopathic internal hydrocephalus, to identify risk factors for seizure development, and to determine seizure prevalence in a 2-year period after ventriculo-peritoneal shunting (VPS). ANIMALS: Records and MRIs of 197 animals from 2001 to December 2019 were investigated. A total of 121 animals (98 dogs and 23 cats) were included in the study. METHODS: A retrospective multicenter case cohort study was conducted. Databases were searched for dogs and cats with internal hydrocephalus. MRI and CSF examinations were evaluated for signs of additional underlying disorders. Prevalence of seizures was estimated for animals showing only hydrocephalus internus. Risk factors were evaluated according to age, morphometric and morphological findings in the brain. All animals that underwent surgery were reexamined 2 years after surgery. RESULTS: One hundred twenty-one animals (98 dogs and 23 cats) with internal hydrocephalus met the inclusion criteria. Seizure prevalence in dogs and cats with internal hydrocephalus was low (1.7%; <5.8% CI 95%). Seizures were not observed in the 2-year period after surgery. CONCLUSION AND CLINICAL IMPORTANCE: Seizure prevalence in dogs and cats diagnosed with hydrocephalus internus is low. Seizures in association with VPS do not seem to be a complication of the procedure.

Multiple cartilaginous exostoses in a Swiss Mountain dog causing thoracolumbar compressive myelopathy.

BACKGROUND: Multiple cartilaginous exostoses are a rare, benign, proliferative condition of cartilage and bone. They can be asymptomatic, or they may cause pain, lameness, paresis and even paralysis, depending on their location and size. In cases of spinal cord or nerve root compression, surgery is the treatment of choice. Therefore, an advanced imaging diagnostic work-up is indicated. Due to the unclear pathophysiology and progression of this condition, it is difficult to predict its prognosis. CASE PRESENTATION: A 9-month-old female Swiss Mountain dog was presented with a history of gait abnormalities, kyphosis and hypersensitivity consistent with a thoracolumbar myelopathy. Multiple calcified masses, most prominent at the Th7-Th9 level and the L2-L3 level, were observed. Magnetic resonance imaging of the thoracolumbar vertebral column revealed severe dorsal spinal cord compressions near the dorsal arch of the Th7-Th9 and L2-L3 vertebrae. Two of these masses were removed surgically. The successful removal of both masses was confirmed by postoperative computed tomography. The histopathological examination of the resected tissue revealed multiple cartilaginous exostoses. The first neurological and magnetic resonance follow up examination carried out 6 months postoperatively showed improvement of the clinical status. At that time, no mass regrowth was observed. The last follow up neurological examination carried out 15 months postoperatively showed gait improvement and resolution of pain. CONCLUSION: This is the first case report of multiple cartilaginous exostoses with a complete pre- and postoperative evaluation and a 15 month follow-up.

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.