Once-a-day oral treatment with phenobarbital in cats with presumptive idiopathic epilepsy.

OBJECTIVES: Phenobarbital (PB) q12h is the most common treatment recommendation for cats with recurrent epileptic seizures. Medicating cats may be challenging and result in decreased quality of life for both cat and owner. The aim of this retrospective study was to evaluate treatment with oral PB q24h in cats with presumptive idiopathic epilepsy. METHODS: Nine cats with presumptive idiopathic epilepsy, receiving oral PB q24h, were included in a retrospective descriptive study. RESULTS: Seizure remission was achieved in 88% (8/9) of the cats and good seizure control in 12% (1/9) of the cats, treated with a mean dose of oral PB of 2.6 mg/kg q24h (range 1.4-3.8 mg/kg). No cats required an increase of their PB frequency at any time during a mean follow-up period of 3.5 years (range 1.1-8.0 years). No cats displayed side effects or issues with compliance at the last recorded follow-up. CONCLUSIONS AND RELEVANCE: Once-a-day administration of PB for feline epilepsy was safe and resulted in satisfactory seizure control for the nine cats included in this study. The results of this study justify exploring this topic further in larger prospective studies.

Epilepsy in British Shorthair cats in Sweden.

OBJECTIVES: The primary objective of this study was to investigate the prevalence of epileptic seizures and of presumed idiopathic epilepsy (PIE, describing epilepsy of unknown origin) in a cohort of British Shorthair (BSH) cats in Sweden. The secondary objective was to describe epileptic seizure characteristics and outcome for cats with PIE. METHODS: Owners of BSH cats born between 2006 and 2016 and registered with SVERAK (the Swedish Cat Clubs' National Association) were invited to reply to a questionnaire about their cat's general health. Owners who indicated that their cat had experienced epileptic seizures were invited to participate in an in-depth telephone interview about the epileptic seizures. The clinical characteristics of epileptic seizures in BSH cats were determined from the results of the interview. RESULTS: In this population comprising 1645 BSH cats (representing 28% of registered BSHs), the prevalence of epileptic seizures was 0.9% and for PIE it was 0.7%. BSH cats with PIE presented with infrequent but consistent epileptic seizures. Twenty-seven percent of BSH cats with epileptic seizures had cluster seizures but none presented with status epilepticus. None of the BSH cats was treated with antiepileptic drugs, and none of the owners reported epileptic seizure remission in their cat. CONCLUSIONS AND RELEVANCE: The prevalence of PIE in this population of BSH cats was 0.7%. The prevalence of epileptic seizures was 0.9%. In general, PIE in the BSH cat displayed a relatively benign phenotype where progression of epileptic seizures was uncommon.

Evaluation of the effect of phenobarbital administration on the biochemistry profile, with a focus on serum liver values, in epileptic cats.

OBJECTIVES: Phenobarbital (PB) is the most common antiseizure drug (ASD) used for the management of feline epilepsy. In dogs, PB is known to cause serum liver enzyme induction and hepatotoxicity, especially after administration long term or in high concentrations. In cats, insufficient evidence is available to draw similar conclusions. The aim of this study was to evaluate the effect of PB administration on the serum biochemistry profile of epileptic cats. As an additional objective, other adverse effects arising, related to PB treatment, were recorded. METHODS: Medical records of four veterinary centres were retrospectively reviewed for epileptic cats receiving PB treatment. Cats were included if they had a diagnosis of idiopathic epilepsy or structural epilepsy; a normal baseline serum biochemistry profile; at least one follow-up serum biochemistry profile; no concurrent disease or had not received medication that could possibly influence liver function or lead to serum liver enzyme induction. Alkaline phosphatase, alanine aminotransferase (ALT), aspartate transaminase and gamma-glutamyl transferase activities, and total bilirubin, bile acids, glucose, albumin, total protein, urea and creatinine concentrations before and during PB administration were recorded. PB serum concentration was also recorded, when available. RESULTS: Thirty-three cats (24 males, nine females) with a median age of 3 years (range 2 months to 12 years) met the inclusion criteria. Idiopathic or structural epilepsy was diagnosed in 25 (76%) and eight (24%) cats, respectively. The follow-up period ranged from 9 to 62 months. This study found an increase in ALT in three cats, possibly related to a PB serum concentration >30 µg/ml. No statistically significant increase in serum liver enzymes or other evaluated biochemistry parameters was found by comparing pre- and post-treatment parameters. CONCLUSIONS AND RELEVANCE: PB administration did not result in hepatic enzyme induction or other biochemical abnormalities in cats. This strengthens the safety profile of PB as an ASD in cats.

Evaluation of antibodies in cerebrospinal fluid for the diagnosis of tick-borne encephalitis in dogs.

Tick-borne encephalitis (TBE) is caused by the neurotropic tick-borne encephalitis virus (TBEV). In dogs, this virus may affect the central nervous system (CNS), causing meningoencephalitis, meningomyelitis, radiculitis or any combination of these. Diagnosis of TBE relies on a combination of clinical signs of CNS disease and laboratory findings, including CSF pleocytosis and serum TBEV antibody titers. Exposure to TBEV does not necessarily cause clinical disease, and seroprevalence has been reported as high as 40% in endemic areas. This causes concerns of over-diagnosing TBE in dogs with CNS disease. By examining TBEV antibodies in dogs with and without neurological disease in a TBEV endemic area, this study aimed to evaluate the diagnostic value of TBEV antibodies in the cerebrospinal fluid (CSF) in dogs. Eighty-nine dogs were included in the study, 56 with neurological disease and 33 neurologically normal control dogs. A positive TBEV CSF and serum IgG antibody titer (> 126 U/mL) was found in 3/89 dogs (3.4%). A positive serum TBEV antibody titer was found in 11 of the 89 dogs (12.4%). None of the control dogs showed a positive CSF antibody titer, whilst two showed positive serum concentrations. A positive CSF IgG antibody titer supports a clinical diagnosis of TBE in patients with acute onset of CNS disease and may help reduce the risk of over-diagnosis.

Diagnosis, treatment and postsurgical complications in a dog with epileptic seizures and a naso-ethmoidal meningoencephalocele.

BACKGROUND: Naso-ethmoidal meningoencephalocele is usually a congenital anomaly consisting of a protrusion of cerebral tissue and meninges into the ethmoidal labyrinth. The condition is a rare cause of structural epilepsy in dogs. We report the clinical presentation, surgical intervention, postoperative complications and outcome in a dog with drug resistant epilepsy secondary to a meningoencephalocele. CASE PRESENTATION: A 3.3-year-old male neutered Tamaskan Dog was referred for assessment of epileptic seizures secondary to a previously diagnosed left-sided naso-ethmoidal meningoencephalocele. The dog was drug resistant to medical management with phenobarbital, potassium bromide and levetiracetam. Surgical intervention was performed by a transfrontal craniotomy with resection of the meningoencephalocele and closure of the dural defect. Twenty-four hours after surgery the dog demonstrated progressive cervical hyperaesthesia caused by tension pneumocephalus and pneumorrhachis. Replacement of the fascial graft resulted in immediate resolution of the dog's neurological signs. Within 5 months after surgery the dog progressively developed sneezing and haemorrhagic nasal discharge, caused by sinonasal aspergillosis. Systemic medical management with oral itraconazole (7 mg/kg orally q12h) was well-tolerated and resulted in resolution of the clinical signs. The itraconazole was tapered with no relapsing upper airway signs. The dog's frequency of epileptic seizures was not affected by surgical resection of the meningoencephalocele. No treatment adjustments of the anti-epileptic medication have been necessary during the follow-up period of 15 months. CONCLUSIONS: Surgical resection of the meningoencephalocele did not affect the seizure frequency of the dog. Further research on prognostic factors associated with surgical treatment of meningoencephaloceles in dogs is necessary. Careful monitoring for postsurgical complications allows prompt initiation of appropriate treatment.

Transient hyperammonaemia following epileptic seizures in cats.

OBJECTIVES: The aim of this study was to determine whether transient postictal hyperammonaemia exists in cats. METHODS: The medical records of all feline patients that presented at a Swedish veterinary hospital between 2008 and 2018 were retrospectively reviewed to find those that had a recent or ongoing epileptic seizure. To qualify for inclusion, the medical record had to include information on at least one ammonia value taken in close proximity to, or during, an active seizure, the cat must have exceeded the normal upper limit of blood ammonia concentration on initial testing (reference interval 0-95 µmol/l), and there needed to be a follow-up ammonia value available within a maximum of 3 days. RESULTS: Five cats were included in the study, and they had blood ammonia concentrations on initial testing ranging from 146 to 195 µmol/l. They were all retested within a period of 2 h to 3 days of the original reading. All five cats had a spontaneous decrease in ammonia levels without any specific treatment for hyperammonaemia. CONCLUSIONS AND RELEVANCE: Pursuant to the findings of this retrospective study, transient hyperammonaemia may be noted after epileptic seizure in cats. Consequently, a differential diagnostic list in feline patients with hyperammonaemia could, depending on the context, include non-hepatic-related pathologies, such as epileptic seizures.

Feline hippocampal and piriform lobe necrosis as a consequence of severe cluster seizures in two cats in Finland.

Feline hippocampal and piriform lobe necrosis (FHN) has been reported from several countries worldwide and is considered an important aetiology for feline epileptic seizures. The aetiology of FHN remains unclear, however it is suspected that FHN might occur secondary to intense epileptic activity as described in humans and dogs although this has not yet been documented in cats. The purpose of our report is to describe the first cases of FHN in Finland diagnosed by magnetic resonance imaging (MRI) and histopathology. The two cases we describe had a well documented history of pre-existing seizures with normal brain MRI at the onset of cluster seizures but MRI done when the cats exhibited clinical deterioration secondary to severe seizure activity, revealed lesions in the hippocampus and piriform lobes typical of FHN. Our report confirms that feline hippocampus and piriform lobe necrosis does occur in the Finnish cat population and should therefore be considered as a differential diagnosis in cats with seizures. In addition, the presentation, clinical findings, results of MRI and/or histopathology shows that cats may develop FHN secondary to severe seizure activity.

The influence of sex hormones on seizures in dogs and humans.

Epilepsy is the most common chronic neurological disorder in both humans and dogs. The effect of sex hormones on seizures is well documented in human medicine. Catamenial epilepsy is defined as an increase in frequency and severity of seizures during certain periods of the menstrual cycle. Oestradiol increases seizure activity and progesterone is believed to exhibit a protective effect. The role of androgens is controversial and there is a lack of research focusing on androgens and epilepsy. Indeed, little is known about the influence of sex hormones on epilepsy in dogs. Sterilisation is believed to improve seizure control, but no systematic research has been conducted in this field. This review provides an overview of the current literature on the influence of sex hormones on seizures in humans. The literature on idiopathic epilepsy in dogs was assessed to identify potential risk factors related to sex and sterilisation status. In general, there appears to be an over-representation of male dogs with idiopathic epilepsy but no explanation for this difference in prevalence between sexes has been reported. In addition, no reliable conclusions can be drawn on the effect of sterilisation due to the lack of focused research and robust scientific evidence.

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

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

Computed tomography and cross-sectional anatomy of the brain in clinically normal dogs.

OBJECTIVE: To provide a detailed anatomic description of brain structures in clinically normal dogs by means of computed tomography (CT). ANIMALS: 4 clinically normal adult German Shepherd Dogs weighing 30 to 35 kg. PROCEDURE: Each dog was anesthetized and positioned in ventral recumbency for CT examination of the brain; transverse scans were completed at 2-mm intervals from the cribriform plate of the ethmoid bone to the cranial part of the atlas by use of a third-generation CT scanner. Contrast material was injected IV, and a second series of scans was completed. Images (with or without contrast) from all dogs were reviewed by use of a soft tissue setting (window width, 150 Hounsfield units; window level, 50 Hounsfield units). One of the dogs was euthanatized, and a 3.5% formaldehyde solution was perfused via the common carotid arteries. After fixation, the brain was embedded in gelatin and sectioned into 5-mm-thick transverse sections by use of a stainless-steel knife. Anatomic sections were photographed and compared with the corresponding CT views. RESULTS: Most features of the brain that were identified on anatomic sections could be identified on the corresponding CT scans despite the low contrast between structures, particularly if adjacent bony and soft tissue structures were used as landmarks. Additional anatomic structures surrounding the brain were also identifiable on the CT images. CONCLUSIONS AND CLINICAL RELEVANCE: Images obtained in this study could be used as a guide for evaluation of CT images of the brain in dogs with brain diseases.