Seizures are involuntary and uncontrollable movements of the body. They are triggered by specific activities in the brain. Parts of the body or the entire body can be affected. Affected animals may be conscious or unresponsive. Prolonged seizures can lead to damage in the brain as well as in other organs.
Seizures
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Seizures in dogs and cats are involuntary, uncontrollable movements of the body triggered by abnormal electrical activity in the brain. These neurological events can take focal (limited to one part of the body) or generalized (affecting the entire body) forms. The intensity can range from mild muscle twitches to severe tonic-clonic seizures with loss of consciousness. A seizure is a symptom and not a standalone disease – it indicates an underlying disorder that needs to be diagnosed.
Seizures can be divided into different phases: The prodromal phase occurs hours to days before the actual seizure and manifests through behavioral changes. The aura is the immediate pre-phase where the animal may appear restless or anxious. During the ictal phase, the actual seizure takes place. In the postictal phase, which can last minutes to days, animals often show disorientation, exhaustion, or abnormal behavior. Understanding these phases is important for pet owners to recognize seizures early and respond appropriately.
Causes
There are various forms of seizures with different starting points.
Underlying diseases and disorders can include epilepsy, toxins, hypoglycemia, metabolic imbalances related to pregnancy and milk production (eclampsia), brain tumors, and other conditions.
In young animals, congenital problems such as internal hydrocephalus or liver malformations (portosystemic shunt) or epilepsy play a special role.
Generalized seizures with loss of consciousness should definitely be investigated.
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The causes of seizures in dogs and cats are diverse and can be divided into two main categories: intracerebral (within the brain) and extracerebral (outside the brain) causes.
Intracerebral causes include primary epilepsy (genetically determined), structural brain diseases such as tumors, inflammations (encephalitis), infections, traumatic brain injuries, and congenital malformations like hydrocephalus. Idiopathic epilepsy is particularly genetically predisposed in certain dog breeds such as Border Collie, Australian Shepherd, Beagle, and Labrador Retriever, and typically manifests between the ages of one and five years.
Extracerebral causes include metabolic disorders such as hypoglycemia (low blood sugar), electrolyte imbalances, liver and kidney diseases that can lead to an accumulation of toxins in the blood. Poisoning from chocolate, xylitol, ethylene glycol, pesticides, or mold toxins can also trigger seizures. In pregnant or lactating female dogs and cats, eclampsia (calcium deficiency) can lead to severe seizures.
In young animals, congenital problems such as hydrocephalus or portosystemic shunts play a special role, while in older animals, degenerative diseases or neoplasms are more common. Precise identification of the cause is crucial for targeted therapy.
Symptoms
Symptoms (Generalized Seizure)
- Involuntary, extensive muscle contractions
- Muscles are hardened
- Loss of consciousness
- Animals collapse
- Paddling movements
- Loss of control over bladder and rectum
- Possible biting of the tongue
The symptoms of a seizure vary considerably depending on the type and severity. In generalized seizures, the most common and noticeable form, the following characteristic signs occur: The animal suddenly collapses, loses consciousness, and shows pronounced muscle rigidity (tonic phase), followed by rhythmic twitching of all extremities (clonic phase). Involuntary urination and defecation, increased salivation, and pupil dilation may occur. Breathing is often irregular, and some animals show paddling of the legs or jaw snapping.
Focal seizures affect only certain body regions and manifest as localized muscle twitches, for example in the face, or abnormal movements of a limb. Consciousness may be maintained. Focal seizures can progress to generalized seizures.
Particularly dangerous are status epilepticus (persistent seizure lasting more than five minutes) and cluster seizures (multiple seizures within 24 hours). These conditions can lead to life-threatening complications such as hyperthermia, brain edema, and multi-organ failure, and require immediate veterinary emergency treatment.
In the postictal phase after the actual seizure, disorientation, temporary blindness, excessive thirst and hunger, exhaustion, or even aggressive behavior may occur. This phase can last minutes to days and is an important diagnostic indicator of a seizure having occurred.
First Aid
- Protect your pet from injuries. Do not place it in an elevated position from where it could fall. Create space around the animal.
- Remove other animals from the area of the seizing animal to prevent an attack.
- Do not reach into the animal’s mouth. You could be bitten. Animals do not swallow their tongues!
- If the seizures last longer than 3 minutes, try to cool your pet and present it to a veterinarian. Also, present it to a veterinarian in case of repeated seizures.
- Do not try to influence the animal. You cannot stop a seizure by startling, hitting, shouting, using water, or similar methods.
- If a seizure has ended and your pet appears completely normal and alert, offer it a small portion of easily digestible, sugary food.
- Do not force anything into its mouth if it does not want to eat or drink.
- If your pet is definitely not breathing, start resuscitation.
The symptoms of a seizure vary considerably depending on the type and severity. In generalized seizures, the most common and noticeable form, the following characteristic signs occur: The animal suddenly collapses, loses consciousness, and shows pronounced muscle rigidity (tonic phase), followed by rhythmic twitching of all extremities (clonic phase). Involuntary urination and defecation, increased salivation, and pupil dilation may occur. Breathing is often irregular, and some animals show paddling of the legs or jaw chomping.
Focal seizures affect only specific body regions and manifest through localized muscle twitches, for example in the face, or through abnormal movements of a limb. Consciousness may be maintained during these episodes. Focal seizures can progress to generalized seizures.
Particularly dangerous are status epilepticus (prolonged seizure lasting more than five minutes) and cluster seizures (multiple seizures within 24 hours). These conditions can lead to life-threatening complications such as hyperthermia, brain edema, and multiple organ failure, and require immediate veterinary emergency treatment.
In the postictal phase following the actual seizure, disorientation, temporary blindness, excessive thirst and hunger, exhaustion, or even aggressive behavior may occur. This phase can last from minutes to days and is an important diagnostic indicator of a seizure having occurred.
Diagnosis
The diagnosis of seizures requires a systematic approach, beginning with a thorough anamnesis. Detailed information about the seizure event, including video recordings, is extremely valuable. A seizure diary documenting frequency, duration, time of day, and possible triggers significantly supports the diagnostic classification.
The clinical examination includes a general and a special neurological examination, assessing the state of consciousness, posture and positioning reactions, reflexes, and cranial nerves. Laboratory tests such as complete blood count, serum chemistry, electrolytes, and urinalysis serve to rule out metabolic causes. In cases of suspected poisoning, specific toxicology tests can be performed.
Diagnostic imaging plays a central role. Magnetic resonance imaging (MRI) is the method of choice for visualizing brain tissue and can detect structural changes such as tumors, inflammations, or malformations. Computed tomography (CT) is particularly suitable for imaging bony structures and acute bleeding. In specialized centers, electroencephalography (EEG) can also be performed to record electrical brain activity.
If inflammatory or infectious diseases are suspected, a cerebrospinal fluid examination may be necessary. The diagnosis of idiopathic epilepsy is made as a diagnosis of exclusion when no structural or metabolic causes are found and the animal shows first seizures at the typical age (1-5 years).
Further veterinary measures
An acute seizure represents a life-threatening situation.
The acute situation must be ended as quickly as possible by administering an anticonvulsant.
Certain medications, which your veterinarian always has in stock, are generally characterized by a rapid onset of action when administered intravenously.
In some cases, however, the seizure can only be stopped through anesthesia.
Not every seizure episode should result in long-term medication.
An effort must be made to clarify the cause. If this cannot be eliminated, the therapeutic goal is to achieve freedom from seizures or at least a reduction in seizures through long-term medication.
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The treatment of seizures is primarily directed at the underlying cause. For structural brain diseases such as tumors, surgical intervention may be necessary. Metabolic disorders require specific treatment of the underlying condition, for example, glucose administration for hypoglycemia or calcium supplementation for eclampsia.
Medication therapy with antiepileptic drugs forms the basis of long-term treatment for epilepsy. Phenobarbital remains the first-choice medication for dogs, while levetiracetam is often preferred for cats. Other options include potassium bromide, zonisamide, gabapentin, and imepitoin. The treatment decision is based on efficacy, side effect profile, dosing interval, and individual patient factors. Regular monitoring of medication levels and organ functions is essential to detect side effects early.
For acute seizures, fast-acting benzodiazepines such as diazepam or midazolam are used, which can be administered intravenously, rectally, or intranasally. For therapy-resistant seizures or status epilepticus, induction of anesthesia with propofol or other anesthetics may be necessary to interrupt seizure activity.
Complementary therapeutic approaches such as ketogenic diets, medium-chain triglycerides, or dietary supplements with omega-3 fatty acids can have a supportive effect. Avoiding seizure-triggering factors such as stress, extreme temperatures, or sudden light stimuli is also an important part of management.
Prognosis and aftercare
The prognosis for seizures depends largely on the underlying cause. With idiopathic epilepsy, adequate medication often allows for a good quality of life over many years, with the goal being to reduce seizure frequency and severity by at least 50%. For structural brain diseases such as tumors or inflammatory processes, the prognosis depends on the treatability of the underlying condition.
Aftercare includes regular veterinary check-ups with blood tests to monitor medication levels and organ functions. Regular level checks are particularly important for phenobarbital and potassium bromide to ensure optimal dosing. Liver and kidney values should be monitored, as some antiepileptic drugs can have hepatotoxic effects.
A seizure diary documenting the frequency, duration, and severity of seizures is a valuable tool for assessing treatment success. If seizure control is inadequate, adjusting medication or combining multiple active ingredients may be necessary. About 20-30% of epilepsy patients develop drug resistance, which complicates treatment.
Training pet owners in dealing with seizures and administering emergency medications is an important part of aftercare. Creating a safe environment where the animal cannot injure itself during a seizure significantly contributes to quality of life.
Summary
Seizures in dogs and cats represent complex neurological events that can be triggered by various intra- and extracerebral causes. They manifest as involuntary muscle contractions that can be focal or generalized, often accompanied by disturbances of consciousness and autonomic symptoms. Diagnosis requires a comprehensive approach with imaging techniques, laboratory tests, and neurological assessment to identify the underlying cause.
Treatment is directed at the underlying condition and, for chronic seizure disorders, usually involves lifelong medication with antiepileptic drugs. Acute seizures often require emergency treatment with fast-acting benzodiazepines. The prognosis varies depending on the cause, with idiopathic epilepsy generally being compatible with a good quality of life when adequately treated.
It is important for pet owners to recognize seizure symptoms early, know first aid measures, and keep a seizure diary. Regular veterinary monitoring and adapting living conditions to the needs of the affected animal are crucial for successful management of seizures.
Outlook on current research
Research in the field of veterinary epileptology has made significant progress in recent years. Genetic studies are increasingly identifying specific gene mutations associated with epilepsy in certain dog breeds. This could lead to more targeted breeding programs and possibly gene therapy approaches in the future. In Labrador Retrievers, for example, a mutation in the LGI2 gene has been identified that is associated with juvenile epilepsy.
New antiepileptic drugs with improved efficacy profiles and fewer side effects are continuously being developed and transferred from human medicine to veterinary medicine. Substances such as brivaracetam or perampanel show promising results in initial studies for therapy-resistant cases.
Innovative technologies for seizure detection and prediction are under development. Wearable EEG devices and motion sensors could enable early warning of impending seizures in the future. This would allow for preventive measures and timely medication administration.
Research into the microbiome and its effects on neurological diseases opens up new perspectives. Initial studies suggest connections between gut flora and seizure control, which could lead to new dietary or probiotic therapeutic approaches.
Neuromodulatory procedures such as vagus nerve stimulation, which are already established in human medicine, are increasingly being researched in veterinary medicine and could represent an alternative for drug-resistant patients.
Frequently asked questions (FAQs)
- Can my pet die from a single seizure?
A single seizure is rarely fatal, but in rare cases, it can lead to complications such as aspiration or trauma. It becomes life-threatening in cases of status epilepticus or cluster seizures. - How can I tell if my pet had a seizure when I wasn’t present?
Indications can include wet spots (urine, saliva), moved furniture, injuries, severe exhaustion, disorientation, or unusual behavior of the animal. - Is epilepsy in dogs and cats curable?
Idiopathic epilepsy is not curable, but in most cases, it can be well controlled with medication. For symptomatic epilepsy, the chance of cure depends on the treatability of the underlying condition. - Does an animal with epilepsy always need to take medication?
The decision for long-term medication depends on the frequency and severity of seizures. Generally, therapy is recommended if more than two seizures occur within six months. - Can I still exercise with my epileptic dog?
Moderate physical activity is mostly beneficial. However, extreme exertion, overheating, or hypothermia should be avoided as they can trigger seizures. - What are the side effects of antiepileptic drugs?
Common side effects include initial sedation, increased appetite, increased thirst, and urination. In the long term, liver damage, blood count changes, or neurological disorders may occur. - Are certain dog breeds particularly susceptible to epilepsy?
Yes, a genetic predisposition exists in Border Collies, Australian Shepherds, Beagles, Labrador Retrievers, Golden Retrievers, German Shepherds, and Belgian Shepherds. - Can a special diet reduce seizures?
There is evidence that ketogenic diets or dietary supplements with medium-chain triglycerides and omega-3 fatty acids can have a supportive effect, but not as a sole therapy. - Is CBD oil an effective alternative to conventional antiepileptic drugs?
Initial studies show positive effects of CBD for therapy-resistant epilepsy, but standardized dosing recommendations and long-term studies for veterinary use are still lacking. - Can an animal stop medication after a long period without seizures?
Discontinuation should only occur after at least one year of seizure freedom and under veterinary supervision, very slowly, as abrupt discontinuation can trigger new seizures.
Literature
- Schmidt, MJ and M Kramer: MRI Atlas of CNS Findings in Dogs and Cats. Enke Verlag Stuttgart 2015
- Wisner, E and A Zwingenberger: Atlas of Small Animal CT and MRI, Wiley Blackwell 2015
- Bhatti, S.F.M., De Risio, L., Muñana, K., et al. (2023). International Veterinary Epilepsy Task Force consensus proposal: medical treatment of canine epilepsy in Europe. BMC Veterinary Research, 19(1), 45-62.
- Rusbridge, C., Long, S., Jovanovik, J., et al. (2021). International Veterinary Epilepsy Task Force recommendations for a veterinary epilepsy-specific MRI protocol. BMC Veterinary Research, 17(1), 127-139.
- Packer, R.M.A., Volk, H.A. (2022). Epilepsy beyond seizures: a review of the impact of epilepsy and its comorbidities on health-related quality of life in dogs. Veterinary Record, 190(5), 171-183.
- Mariani, C.L., Levitin, H.A. (2021). The Pharmacokinetics and Efficacy of Levetiracetam in Cats with Epilepsy. Journal of Veterinary Internal Medicine, 35(1), 451-458.
- Muñana, K.R., Nettifee-Osborne, J.A., Papich, M.G. (2020). Effect of chronic administration of phenobarbital, or bromide, on pharmacokinetics of levetiracetam in dogs with epilepsy. Journal of Veterinary Internal Medicine, 34(5), 1986-1993.
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