Idiopathic epilepsy in dogs, neurological disorders, canine seizures caused by trauma, a toxin, a brain tumor, an infection, or an issue with your. Abstract. Canine idiopathic epilepsy has an estimated prevalence of per cent in primary veterinary practice (Kearsley-Fleet and others ) and as such is. Age at the onset of seizures is an important piece of information in the patient history. Idiopathic epilepsy is usually seen in dogs between the.
Epilepsy Dogs Idiopathic in
For example, Lafora's disease which affects some Miniature Wire Haired Dachshunds, Basset Hounds and Beagles is caused by a gene defect that leads to a 'storage disease' where a toxic substance accumulates in cells , changing the structure of the brain and leading to seizures.
A reactive seizure usually occurs in response to a temporary problem in brain function, which may be as a result of metabolic changes or poisoning - which is reversible when the cause or disturbance is rectified.
It is important that you stay calm. Most seizures are brief, and dogs are usually totally unaware of them. Affected dogs are not likely to suffer during the seizure, even if they appear violent.
Make sure you and your pet remain safe by moving any furniture out of the way so that your pet cannot hurt themselves. Under no circumstances should you put anything in your pet's mouth, including your hands. Your vet may prescribe 'emergency medication' to reduce the length of an epileptic episode. Most seizures only last minutes, but it is a good idea to time the seizures so you are sure of its length. It is very helpful to carefully observe the seizure.
In particular, what were the first signs? Was one side of the body affected first? What sort of movements did your pet exhibit, e.
Records of these observations along with your seizure diary will be very useful information for your vet. How often a dog with epilepsy experiences seizures can vary greatly between dogs and over an individual dog's lifetime. Recording how often your dog has seizures is important to track how well their treatment is working, and so your vet can alter their treatment if necessary.
Some dogs experience seizures very close together in time e. These types of seizure pose a particularly high risk to your dog's health, can be life-threatening and an emergency:. A cluster seizure occurs when a dog has two or more seizures within a hour period. Cluster seizures occur in around one third to three quarters of dogs with idiopathic epilepsy.
If your dog has cluster seizures, emergency medication may be prescribed by your vet for home use. These medications are administered if a cluster seizure occurs, to try and stop the seizure and to prevent more from occurring. You should never attempt to put anything in your dog's mouth, including your hands during a seizure.
Immediate treatment is necessary because status epilepticus can cause permanent neurological damage or even death. If status epilepticus occurs in your dog, immediately contact your vet for emergency treatment. Emergency treatment includes your vet administering high doses of medications that try to stop the seizure and minimise damage to your dog's brain and body.
Although seizures are distressing to witness, you should always try to stay calm when a seizure starts and time how long it lasts, so you know whether a seizure is lasting a particularly long time, and are prepared to contact your vet if status epilepticus occurs.
Some dogs may appear to have 'triggers' that lead to a seizure, while others do not. Identifiable triggers may differ from dog to dog. In people with epilepsy, common triggers include tiredness and lack of sleep, stress, and not taking medication. Stress is a trigger commonly reported by owners, and may be caused by a variety of situations including changes in the environment, changes in routine, car rides, thunderstorms, and visits to the vets to name a few.
Other owners report certain foods or medications seem to trigger seizures in their dog. Keeping a seizure diary may help identify triggers in your dog. In most cases, epilepsy in dogs cannot be cured. Maintaining a seizure-free status without causing unacceptable side effects is the ultimate goal of antiepileptic drug AED therapy.
The goal of medical treatment is therefore to improve your dog's quality of life by minimising how frequently the attacks occur and how severe they are. Additionally, the medications chosen for this should not cause serious side effects. If your vet recommends commencing AED therapy, ensure you discuss this thoroughly so that you understand the importance of this treatment and why it is necessary.
Your vet will be able to support you with this treatment, and regular health checks should be arranged so you can both monitor for adverse effects of the idiopathic epilepsy or the medication. Once started, AED treatment is continued indefinitely, in most cases for the rest of your dog's life, with periodic health checks and blood tests to ensure correct drug dosage, treatment efficacy and minimal treatment-related side effects.
Your vet will be able to advise you as to which antiepileptic drug AED is most suited to treating your dog's epilepsy. Factors that may influence your vets decision may include the type of seizure your dog experiences, how often they seizure, and if they have any problems with their kidneys or liver.
The first medications your vet can legally prescribe to treat your dog's epilepsy in the EU are either Imepitoin or Phenobarbital. If the desired reduction in seizures is not seen with the 'first line' medications, they may choose to 'add-on' Potassium Bromide as a second medication. There are several AEDs used to treat epilepsy in humans that are being used to treat epilepsy in dogs; however, these medications can only be used if the approved treatments have failed.
Always keep your dog on a constant diet as changes to what your dog eats can change blood levels of certain drugs. Furthermore, new diets are currently being developed, which might help to improve seizure control even further. Antiepileptic drug treatment is generally considered to be successful if the frequency of their seizures is reduced by at least half, though seizure freedom should be aimed for.
To determine whether the medication is working, an accurate seizure diary is required. From this you can track patterns in your dog's seizure frequency and severity to see if improvements are occurring.
Tier III confidence level for the diagnosis of IE is based on the factors listed in tier I and II and identification of electroencephalographic abnormalities characteristic for seizure disorders. This consensus article represents the basis for a more standardised diagnostic approach to the seizure patient. These recommendations will evolve over time with advances in neuroimaging, electroencephalography, and molecular genetics of canine epilepsy. The online version of this article doi: Epilepsy is defined as a disease of the brain characterized by an enduring predisposition to generate epileptic seizures.
The term idiopathic epilepsy IE has been used in a variety of settings in the veterinary literature and by veterinarians in clinical practice. Analogous with a recently debated proposal for a revised classification by the International League against Epilepsy ILAE [ 3 ], it has also been proposed that the term idiopathic should be replaced in the veterinary literature [ 4 ].
The term genetic epilepsy was therefore introduced to refer to epilepsy occurring as a direct result of a known or strongly suspected genetic defect or defects and in which epileptic seizures are the primary clinical sign of the disorder.
In general, genetic epilepsies usually have no identifiable structural brain lesions or other neurologic deficits, and have an age-dependent onset. The term unknown epilepsy has been proposed to refer to epilepsy where the underlying cause is unknown [ 3 , 4 ]. In our consensus proposal on classification and terminology see consensus on epilepsy definition, classification and terminology in companion animals we have explained why we recommend retaining the term IE, and have defined IE as a disease in its own right, per se.
However in the clinical setting IE remains most commonly a diagnosis of exclusion following diagnostic investigations for causes of reactive seizures and structural epilepsy. To date different criteria have been used in the veterinary literature to diagnose IE. The majority of veterinary studies have used a history of recurrent epileptic seizures, an unremarkable inter-ictal clinical and neurological examination and an unremarkable complete blood cell count and serum biochemistry profile as the minimum criteria for its diagnosis.
However, the exact parameters included in the biochemistry profile vary among studies and institutions. An unremarkable magnetic resonance imaging MRI study of the brain and cerebrospinal fluid CSF analysis have been used inconsistently as diagnostic criteria and there has been wide variability in MRI protocols. To improve consistency in the diagnosis of IE amongst institutions and clinical studies we have produced the following consensus proposal.
The diagnostic approach to the patient presenting with a history of suspected epileptic seizures incorporates two fundamental steps:. First of all the clinician needs to determine whether the dog is indeed having epileptic seizures. A detailed and accurate history is the foundation for investigation of the seizure patient [ 9 ]. The owner of the epileptic dog should complete a standardised epilepsy questionnaire Additional file 1 and obtain video-footage whenever possible.
This information can help the clinician to clarify the nature of the event e. Numerous disorders can result in episodic paroxysmal events that may mimic epileptic seizures. A detailed review of paroxysmal movement disorders as well as other events which may mimic epileptic seizures is beyond the scope of this consensus article and can be found elsewhere [ 10 , 11 ].
A complete clinical and neurological examination may help identify abnormalities suggestive of underlying disease processes, including cardiovascular system abnormalities in dogs with syncope and clinical signs of neuromuscular disease, vestibular dysfunction or forebrain disease.
Paroxysmal movement disorders or paroxysmal dyskinesias refer to abnormal, sudden, involuntary contraction of a group of skeletal muscles which recur episodically [ 10 ]. These paroxysms can be challenging to differentiate from epileptic seizures, particularly from focal motor epileptic seizures.
Animals affected by movement disorders are often normal between episodes. The absence of other clinical signs during the episodes, including autonomic signs, changes in consciousness and electroencephalographic abnormalities, have been suggested to support the diagnosis of paroxysmal movement disorders [ 10 ].
However, focal epileptic seizures can occur with no concurrent alteration in consciousness or autonomic signs and electroencephalography EEG is often challenging to perform in the clinical setting. The signalment and age at onset of the paroxysmal event can assist in establishing the nature of these events. Certain movement disorders are breed-specific, generally occur in young dogs and their phenotype may be well characterised [ 10 ]. To date the associated genetic defect e. Genetic investigations in other breeds are ongoing.
Identification of causative genetic mutations of breed specific movement disorders will significantly improve our ability to diagnose these conditions. Interestingly, specific mutations in human patients with dyskinesias may also be associated with epileptic seizures or a high occurrence of seizure disorders in their relatives [ 15 ].
A genetic predisposition to IE has been suggested in numerous canine breeds [ 16 ] and a familial history of recurrent epileptic seizures or IE should raise the suspicion of IE, although diagnostic procedures need to be performed to exclude other aetiologies. The presence of impaired consciousness e. During the ictus particularly during the generalized epileptic seizure phase the animal cannot be distracted and the owner cannot alter the course of the event by manipulating the dog.
Conversely, dogs with paroxysmal movement disorders tend to continue to attempt to perform the activity they were previously doing e. For example, in the majority of Dobermanns with idiopathic head tremor, the owners reported that they could consistently interrupt each head tremor episode. In some cases, stroking the dogs, talking to them, or asking them to get up was sufficient to interrupt the episode. In other cases, stronger stimuli favourite toys or snacks, encouraging them, taking them for a walk were needed to interrupt the head tremor episode [ 17 ].
Similarly in a study in English bulldogs with idiopathic head tremors, several owners reported that distraction or treats were generally sufficient to alter or stop the episodes [ 18 ]. A recent study highlighted the challenge in differentiating epileptic and non-epileptic paroxysmal events.
This study investigated the level of agreement between veterinarians both neurology specialists and non-specialists in the description and classification of videos depicting canine and feline paroxysmal events, where the observers were blinded to the history, results of diagnostic investigations and treatment response [ 19 ].
The level of agreement on whether a paroxysmal event was an epileptic seizure or other paroxysm was fair. Overall agreement on epileptic seizure type was moderate. Generalised epileptic seizures had the highest level of agreement and focal epileptic seizures had the lowest. Agreement was fair for level of consciousness and the presence of autonomic signs, but poor for neurobehavioral signs.
Agreement for motor signs ranged from poor to moderate. There were significant differences in epileptic seizure semiology and classification between specialists and non-specialists. Absolute confirmation of the epileptic nature of an event can only be obtained by observing simultaneously the characteristic EEG changes and physical manifestation of the seizures, however this is rarely practical in veterinary medicine and currently there is no reliable, standard protocol for acquiring EEG recordings in dogs.
Variability in the physical factors mentioned above has contributed to discrepancies in the results of numerous veterinary studies evaluating EEG. Efforts are currently in progress to further develop EEG recording in veterinary clinical practice. Although it is unlikely that EEG will become a routine diagnostic procedure for all epileptic dogs in the near future, EEG may become more widely used by veterinary neurology specialists for the investigation of selected cases e.
As an example, a veterinary video-EEG study diagnosed a juvenile Chihuahua with subtle myoclonic absence events with perioral myoclonia and head twitching [ 21 ]. The author identified bilateral generalised synchronous 4Hz spike-and-wave complexes on ictal EEG time locked with the "absence-like" event, along with rhythmically correlated head and nose twitching.
In this case video-EEG was essential to confirm the epileptic nature of the episodes. Currently the paucity of veterinary literature does not allow a clear consensus recommendation for EEG recording in veterinary patients to be proposed. After having established that the episodic paroxysmal events do indeed represent epileptic seizures, the next step is to determine the underlying cause as this will have major implications on treatment selection and prognosis. Both intra and extra cranial disorders can cause seizure activity.
Reactive seizures can result from systemic metabolic disorders e. The history and clinical presentation may help the clinician to suspect a particular aetiology, although diagnosing certain intoxications can be quite challenging. Another study showed that dogs with reactive seizures caused by exogenous toxicity have a significantly higher risk of developing status epilepticus, particularly as first manifestation of a seizure disorder, than dogs with other seizure aetiologies [ 23 ]. Dogs with poisoning had a 2.
The clinical presentation in dogs with metabolic and toxic disorders is variable and depends on the underlying aetiology.
Dependent on the specific toxin, muscle tremors and fasciculations are frequently the initial clinical signs. Metabolic disorders can present with an acute, subacute, or chronic onset and may be progressive or relapsing and remitting. For example, chronic lead intoxication may result in recurrent seizures.
Systemic clinical abnormalities can often be detected on general physical examination. Generally neurological examination reveals deficits consistent with diffuse, bilateral and often symmetrical forebrain involvement. Neurological examination is often abnormal and may reveal asymmetric neurological deficits in dogs with lateralised brain pathology.
Dogs with inter-ictal neurological abnormalities were Epileptic seizure type e. A detailed description of diagnosis of exogenous toxic, metabolic and structural forebrain disorders is beyond the scope of this consensus article and can be found elsewhere [ 30 — 32 ]. The diagnosis of IE is one of exclusion and is made based on the age at epileptic seizure onset, unremarkable inter-ictal physical and neurological examinations, and exclusion of metabolic, toxic and structural cerebral disorders by means of diagnostic investigations.
A history of IE in genetically related dogs further supports the diagnosis. MDB blood tests include: Urinalysis includes specific gravity, protein, glucose, pH, and sediment cytology. A family history of IE further supports the diagnosis. Neurobehavioural comorbidities can occur in dogs with IE [ 33 ], similarly to human patients [ 34 ], and their presence should therefore not imply a diagnosis of structural epilepsy. Additional discretionary laboratory parameters depending on the index of disease suspicion include: In addition, imaging of the thorax and abdomen should be performed when metastatic neoplastic disease is a possibility.
Ocular fundic examination and non-invasive blood pressure measurement should also be performed when hypertension is suspected. Further details on diagnostic investigations to identify underlying aetiologies of seizures can be found elsewhere [ 30 ]. Unremarkable fasting and post-prandial bile acids, MRI of the brain see consensus statement on epilepsy-specific brain MRI protocol and CSF analysis in addition to factors listed in tier I. If the results of routine CSF analysis are abnormal then additional testing on CSF and serum for regional infectious disorders should be performed.
CSF abnormalities generally mild may occur as a result of epileptic seizure activity [ 35 ] see below: Time to resolution of epileptic seizure-associated CSF abnormalities is unknown. Identification of ictal or inter-ictal EEG abnormalities characteristic for seizure disorders according to criteria validated in human medicine, in addition to factors listed in tier I and II.
However, further research is needed to characterise the optimal protocol for EEG use in clinical veterinary practice. The MRI signal changes are located unilaterally or bilaterally, predominantly in the piriform and temporal lobes, and sometimes also in the olfactory bulb and frontal lobe.
The signal changes are characterised by varying degrees of hyperintensity on T2 weighted, FLAIR and diffusion-weighted imaging, hypointensity on T1 weighted images, and occasionally heterogenous contrast enhancement following gadolinium administration [ 36 , 37 ]. Histologic examination of the affected temporal cortex, hippocampus and piriform lobe revealed oedema, neovascularization, reactive astrocytosis, and acute neuronal necrosis [ 36 ].
Repeated MRI of the brain after a period of seizure control, along with clinical and CSF analysis findings, may help to differentiate epileptic seizure-induced changes from inflammatory or neoplastic epileptogenic structural lesions [ 36 ].
Mild postictal CSF pleocytosis and sometimes also increased protein concentration have been reported as a transient CSF abnormality in people, generally following repetitive generalized tonic-clonic seizures [ 38 ]. A study in idiopathic epileptic dogs identified an association between CSF white blood cell WBC count and time interval between the last seizure and the collection of the CSF.
The pathophysiology of seizure-induced CSF pleocytosis remains unclear. It is possible that a transient disturbance of the blood—brain barrier function which has been demonstrated after seizures in experimental animals and release of chemotactic substances into the CSF during the seizures result in these CSF abnormalities [ 40 ].
Repeated CSF sampling after a seizure free interval reveals no abnormalities [ 38 ]. Results of CSF analysis normal versus abnormal were significantly associated with the results of the MRI study normal versus abnormal , in dogs with both normal and abnormal neurological examination [ 42 ]. Another study reported clinically significant MRI abnormalities, including olfactory or frontal lobe neoplasia, in 2.
Another recent study demonstrated that age at seizure onset and neurological examination findings were both significantly associated with type of brain disease functional versus structural [ 24 ].
Dogs that were older at seizure onset were significantly more likely to have an asymmetrical structural cerebral lesion mean age at seizure onset 7. The odds of identifying an asymmetrical structural cerebral lesion rather than IE increased 1. Dogs with neurological abnormalities inter-ictally were Dogs with single seizures rather than cluster seizures were more likely to have IE than an asymmetrical structural cerebral lesion [ 24 ].
In another study, of 51 dogs presenting with status epilepticus as the first manifestation of seizure disorder,
Symptoms and Safety Procedures for Pets with Idiopathic Epilepsy
There are many causes of seizures. Idiopathic epilepsy, the most common cause of seizures in the dog, is an inherited disorder, but its exact cause is unknown. The term idiopathic means a disease of unknown cause. We now better understand that idiopathic epilepsy in dogs most likely has an underlying genetic cause. Your vet may suspect that your dog has epilepsy if they have at least two Idiopathic epilepsy usually affects young to middle age dogs (6 months to 6 years .