Th17 cell-mediated immune response in a subpopulation of dogs with idiopathic epilepsy

Background Canine idiopathic epilepsy (IE) is a common neurological disease with severe impact on the owner´s and the dog’s quality of life. A subpopulation of dogs with IE does not respond to antiseizure drugs (non-responder). Th17 cells (T helper cells) and their proinflammatory Interleukin-17 (IL-17) are part of the immune system and previous studies showed their involvement in the pathogenesis of several autoimmune diseases. Non-responder might have an abnormal immune response against structures of the central nervous system. To discover a new aetiology of canine IE and thereby optimising the therapy of intractable IE, this prospective study aimed to investigate Th17 cells and IL-17 in dogs with IE. The underlying hypothesis was that in some dogs with IE a Th17 cell-mediated immune response could be detectable. Methods 57 dogs with IE and 10 healthy dogs (control group, C) were enrolled in the study. EDTA blood was taken to measure Th17 cells by flow cytometry. IL-17 was measured in 35 cerebrospinal fluid (CSF) and 33 serum samples using an enzyme-linked immunosorbent assay (ELISA). It was investigated whether there was a significant increase of stimulated Th17 cells in blood samples or of IL-17 in serum and CSF samples of dogs with IE in comparison to C. Correlations between the amount of Th17 cells/μL or IL-17 and different clinical parameters e.g. seizure frequency, seizure type, seizure severity or treatment response were evaluated. Additionally, Th17 cells/μL were randomly controlled of 17 dogs with IE and were examined for changes over time and in relation to treatment response. Results Ten dogs with IE had strongly elevated stimulated Th17 cells/μL within the blood (>100 Th17 cells/μL). A slight positive correlation between stimulated Th17 cells/μL and seizure severity (p = 0.046; rSpear = 0.27) was proven in these dogs. In addition, 4/10 dogs with elevated Th17 levels experienced cluster seizures and status epilepticus in comparison to 9% of the dogs with non-elevated Th17 levels (<100 Th17 cells/μL). Dogs with IE had significantly higher IL-17 values in CSF and serum samples compared to C (p<0.001; p<0.002; respectively). Conclusion In single dogs with IE, strongly increased amounts of Th17 cells were detectable and dogs with elevated Th17 cells seemed to have a greater risk for experiencing a combination of cluster seizures and status epilepticus. Therefore, an underlying Th17-cell mediated immune response was suspected and hence anti-inflammatory drugs could be indicated in these single cases with intractable epilepsy.

Prevalence, distribution, and clinical associations of suspected postictal changes on brain magnetic resonance imaging in epileptic dogs

OBJECTIVE To determine the prevalence of presumed postictal changes (PC) on brain MRI in epileptic dogs, describe their distribution, and recognize possible correlations with different epilepsy features. ANIMALS 540 client-owned dogs with epilepsy and a complete medical record that underwent brain MRI at 4 veterinary referral hospitals between 2016 and 2019. PROCEDURES Data were collected regarding signalment, seizure type, seizure severity, time between last seizure and MRI, and etiological classification of epilepsy. Postictal changes were considered when solitary or multiple intraparenchymal hyperintense lesions were observed on T2-weighted and fluid-attenuated inversion recovery images and were hypointense or isointense on T1-weighted sequences, which were not confined to a vascular territory and showed no to mild mass effect and no to mild contrast enhancement. RESULTS Sixty-seven dogs (12.4%) showed MRI features consistent with PC. The most common brain sites affected were the piriform lobe, hippocampus, temporal neocortex, and cingulate gyrus. Dogs having suffered cluster seizures or status epilepticus were associated with a higher probability of occurrence of PC, compared to dogs with self-limiting seizures (OR 2.39; 95% confidence interval, 1.33 to 4.30). Suspected PC were detected both in dogs with idiopathic epilepsy and in those with structural epilepsy. Dogs with unknown-origin epilepsy were more likely to have presumed PC than were dogs with structural (OR 0.15; 95% confidence interval, 0.06 to 0.33) or idiopathic epilepsy (OR 0.42; 95% confidence interval, 0.20 to 0.87). Time between last seizure and MRI was significantly shorter in dogs with PC. CLINICAL RELEVANCE MRI lesions consistent with PC were common in epileptic dogs, and the brain distribution of these lesions varied. Occurrence of cluster seizures or status epilepticus, diagnosis of unknown origin epilepsy, and lower time from last seizure to MRI are predictors of suspected PC.

Therapeutic Challenge in a Case of Recent Onset Refractory Cluster Seizures

A dilemma exists in context to the timing of surgery in a case presenting with explosive onset seizures secondary to a focal cortical dysplasia (FCD). This case report highlights the challenges faced in the management of a 4-year-old child with recent onset cluster seizures refractory to anti-epileptic drugs. A 4-year-old girl presented with an acute onset of cluster seizures (up to 32 in a day), semiologically characterized by tonic upper limb extension and laughter lasting for few seconds with no response to multiple anti-epileptic drugs. The clinical, electrographic, neuroimaging and interictal positron emission tomography data were concordant and consistent with a left middle frontal gyrus dysplasia which was successfully resected under electrocorticographic guidance. Patient is seizure free at 2 months of follow up. (Engel Class 1). Surgical resection is feasible and potentially more effective in the early phase of clinical presentation of FCD.

Case Report: Embedding “Digital Chronotherapy” Into Medical Devices—A Canine Validation for Controlling Status Epilepticus Through Multi-Scale Rhythmic Brain Stimulation

Circadian and other physiological rhythms play a key role in both normal homeostasis and disease processes. Such is the case of circadian and infradian seizure patterns observed in epilepsy. However, these rhythms are not fully exploited in the design of active implantable medical devices. In this paper we explore a new implantable stimulator that implements chronotherapy as a feedforward input to supplement both open-loop and closed-loop methods. This integrated algorithm allows for stimulation to be adjusted to the ultradian, circadian and infradian patterns observed in patients through slowly-varying temporal adjustments of stimulation and algorithm sub-components, while also enabling adaption of stimulation based on immediate physiological needs such as a breakthrough seizure or change of posture. Embedded physiological sensors in the stimulator can be used to refine the baseline stimulation circadian pattern as a “digital zeitgeber,” i.e., a source of stimulus that entrains or synchronizes the subject's natural rhythms. This algorithmic approach is tested on a canine with severe drug-resistant idiopathic generalized epilepsy exhibiting a characteristic diurnal pattern correlated with sleep-wake cycles. Prior to implantation, the canine's cluster seizures evolved to status epilepticus (SE) and required emergency pharmacological intervention. The cranially-mounted system was fully-implanted bilaterally into the centromedian nucleus of the thalamus. Using combinations of time-based modulation, thalamocortical rhythm-specific tuning of frequency parameters as well as fast-adaptive modes based on activity, the canine experienced no further SE events post-implant as of the time of writing (7 months). Importantly, no significant cluster seizures have been observed either, allowing the reduction of rescue medication. The use of digitally-enabled chronotherapy as a feedforward signal to augment adaptive neurostimulators could prove a useful algorithmic method in conditions where sensitivity to temporal patterns are characteristics of the disease state, providing a novel mechanism for tailoring a more patient-specific therapy approach.

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.

Cluster seizures and status epilepticus in new onset seizures among adult Egyptians

Background New onset seizure (NOS) is defined as the first seizure within a 24-h period ever experienced by the patient. Cluster seizures (CS) or status epilepticus (SE) can be the first manifestation of epilepsy or it may be a symptom of a brain tumor, a systemic disorder, an infection, or a syndrome. This study aims to determine the etiology of CS and SE in NOS among adult Egyptians. One hundred twenty adult Egyptian patients presented with NOS were enrolled in a hospital-based cross-sectional observational study within a time period of 6 months from March till September 2018. All patients were subjected to neurological examination including mini mental status examination, laboratory, neuroimaging, and electroencephalogram. Results Among 120 adult patients presented with NOS, males were prevalent (63%). Older adults (> 55 years) were prevalent (60%). Of the patients, 25% presented by CS, while 11% presented by SE. Post-stroke epilepsy (41%) was the predominant etiology of NOS. Cerebrovascular diseases (CVDs) were the prevalent etiology of SE in NOS (35%). NOS presented by CS were more prevalent among patients with brain tumors (29%) in comparison to CVDs (25%). Conclusion CS represented 25% of NOS in adult Egyptian patients. SE is prevalent among 11% of NOS. Despite CVDs being the most prevalent etiology of NOS in adult population (41%) including those presented with SE (35%), brain tumors are the most prevalent etiology of new onset CS (29%).

Probable Sudden Unexpected Death in Dogs With Epilepsy (pSUDED)

Sudden unexpected death in human epileptic patients (SUDEP) is defined as death related to recurrent unprovoked seizures, death occurring unexpectedly, and suddenly in a patient with reasonable state of health, without an obvious medical cause of death, trauma, asphyxia, or intractable status epilepticus, and in post mortem examination no obvious reason for death can be found. “Probable SUDEP” (pSUDEP) is defined as SUDEP not confirmed pathologically. The adapted abbreviation for dogs is used in the following: “pSUDED” (probable sudden unexpected death in dogs with epilepsy). The aim of the present monocentric retrospective study using an online questionnaire was to evaluate the occurrence of pSUDED. Data of canine patients presented with seizures between 01/1998 and 05/2018 were retrospectively analyzed and classified according to their etiology (n = 1,503). Owners were contacted by telephone to participate in answering a validated questionnaire. A total of 509 owners were reached, and 373 owners completed the questionnaire. In addition to signalement (e.g., breed), special attention was paid to the frequency and presentation of seizures and seizures in the context of death. Fifty-one percent (191/373) of the dogs were dead at the endpoint of the study. A large proportion of the dogs was euthanized (149/191) because of seizure severity or health problems unrelated to seizures. Idiopathic epilepsy (IE) was diagnosed in 19/34 dogs which died unexpectedly. Of these seven animals had to be excluded for further investigation of pSUDED because of status epilepticus or aspiration pneumonia as a result of the seizures. In 12 dogs with IE the last seizure event occurred between 6 h and ~3 months before death. pSUDED was suspected in these dogs and an occurrence rate of 4.5–10% was calculated. pSUDED appears in a similar occurrence rate as human SUDEP and should be considered as a possible complication in epileptic dogs. The results of this study suggest that dogs with IE but especially those with brachycephalic syndrome and cluster seizures have an increased risk to die of pSUDED. Owners of dogs with seizures should be educated about the risk of sudden death in dogs with epilepsy.

Granular Cell Tumor in the Brain of a Dog

Diagnostic Exercise from The Latin Comparative Pathology Group. Clinical History: 10 year-old, female spayed, Golden Retriever/Poodle mix. This patient had a mass removed laparoscopically from the right adrenal gland (cortical adenoma) and was started on a low dose of prednisone post-operatively. Eight days post-op, she began having cluster seizures and was started on levetiracetam therapy. The following day, the dog was moderately obtunded and stumbling. On neurological examination, mild generalized ataxia was noted along with decreased menace OS, and delayed proprioception in the left pelvic and left thoracic limbs. CBC and chemistry values were unremarkable except for a mild hepatic enzyme elevation. EEG showed seizure-like activity and abnormal brain waves resembling sleep state while awake. MRI revealed an eccentric right-sided mass extending over the frontal and parietal lobes with subtentorial herniation. Due to poor prognosis, euthanasia was elected. Necropsy and Microscopic Findings: Tenuously adhered to the right parietal lobe of the brain and the dura mater is a soft, round, white, plaque-like mass measuring 3.5 x 3.0 x 0.3 cm. The mass is friable and poorly-demarcated from surrounding brain parenchyma. A portion of the mass adheres to the supradjacent surface of the calvarium.

Intravenous Ketamine Bolus(es) for the Treatment of Status Epilepticus, Refractory Status Epilepticus, and Cluster Seizures: A Retrospective Study of 15 Dogs

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 of N-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.

Seizures in alcohol withdrawal syndrome

Alcohol withdrawal syndrome develops in individuals with alcohol dependence who discontinue or reduce alcohol intake after long-term or binge drinking. Withdrawal symptoms usually occur 6–8 hours after the last alcohol consumption and peak between 24–72 hours. Typical manifestations include tremor, nausea, vomiting, insomnia, agitation, and excess sweating. Complicated withdrawal syndrome may manifest with seizures (including cluster seizures), status epilepticus, acute psychosis and delirium, when hallucinations are accompanied by disorientation in time, place and situation. About 10–15% of patients develop complicated withdrawal syndrome. The seizures in alcohol withdrawal syndrome are triggered in the brain stem and have a mechanism other than that of classic epileptic seizures. Benzodiazepines, which are more effective than other classes of anticonvulsants (they primarily reduce the frequency of convulsions in the first two days after alcohol discontinuation and significantly reduce the risk of death), are the gold standard for the treatment of alcohol withdrawal syndrome. The Clinical Institute of Withdrawal Assessment for Alcohol Scale (CIWA-Ar) is a helpful tool for making decisions on treatment initiation or discontinuation. It should be noted that chronic use of benzodiazepines in the secondary prevention of alcohol withdrawal seizures is not recommended due to the addictive potential of these agents and a more severe course of alcohol withdrawal seizures with benzodiazepine co-dependence.