Epilepsy is one of the canine diseases that can have various causes. An epileptic seizure poses a high risk of injury for the dog and, in severe cases, can lead to permanent brain damage. Extensive diagnostics are essential to identify the trigger for the dog’s epilepsy.
Definition
The term epilepsy describes a seizure disorder originating in the brain that cannot be explained by a currently existing illness or injury (as would be the case, for example, after a head injury). It involves spontaneous seizures.
These seizures are attributed to a sudden, simultaneous discharge of a large number of nerve cells in the brain. This leads to a massive overstimulation of the nervous system, resulting in uncontrolled movements and, occasionally, loss of consciousness.
Causes of Epilepsy in Dogs
The potential triggers for seizures are diverse. Consequently, epilepsy can be classified by the types of causes. There is a general distinction between primary and secondary epilepsy.
Primary Epilepsy
This form of the disease is also called idiopathic epilepsy or genetic epilepsy. It is considered a hereditary disease in dogs and is more prevalent in certain breeds, such as Rhodesian Ridgebacks.
Through imaging diagnostics, this form of epilepsy cannot be traced, as there are no abnormalities visible in the brain. Seizures may occur in young dogs, and between two seizures, the animals are completely symptom-free.
Secondary Epilepsy
Secondary or structural epilepsy occurs as a result of an illness or injury. Possible causes include meningitis or encephalitis, head trauma, brain hemorrhage, or brain tumors.
The pathological changes in brain tissue are clearly visible through imaging diagnostics. Depending on the specific cause, affected animals may exhibit neurological symptoms between two seizures.
Metabolic Epilepsy
Strictly speaking, metabolic or organic epilepsy is a form of secondary epilepsy since it occurs due to another disease. However, the original trigger is not in the brain but in metabolism. Dogs of all age groups can be affected. Possible causes include:
- Liver dysfunction: Elevated ammonia levels in the blood have a toxic effect on the brain.
- Kidney dysfunction: Impaired excretion of creatinine and urea, two body waste products, affects the brain due to their increased concentration in the blood.
- Hypoglycemia (low blood sugar): Prolonged fasting in puppies or excessive insulin administration to a diabetic patient leads to insufficient energy supply to the brain.
- Hyponatremia: Reduced blood sodium levels can result from conditions like prolonged vomiting, severe diarrhea, burns, heart, or kidney diseases.
Did you know?
Oxygen deprivation to the brain can lead to fainting spells, which, however, are unrelated to epilepsy.
Symptoms Depending on the Type of Seizure
An epileptic seizure in a dog can be generalized (affecting the entire body) or focal (localized). In the case of a generalized seizure, both cerebral hemispheres initiate a fireworks display of signals. A focal seizure occurs when only specific areas of the brain are affected.
Generalized Seizure
The typical epileptic seizure involves convulsive movements of the entire body.
In most cases, there are specific precursors marking what is known as Stage 1. These include:
- Personality changes, such as restlessness, withdrawal, noticeable clinginess
- Excessive licking, drooling
- Increased urination
Stage 1 transitions abruptly to Stage 2 after several minutes to several hours:
- Loss of consciousness, collapsing
- Stiffening of skeletal muscles
- Convulsions and twitches throughout the body
- Pedaling movements with the legs
- Drooling
- Vocalizations like whimpering
The actual seizure usually lasts a maximum of two minutes.
It is followed by Stage 3, which can last a few minutes to up to three days. Typical during this phase are:
- Confusion
- Disorientation
- Fatigue
- Balance problems
- Vision disturbances
- Increased hunger, thirst
During this phase, dogs are more prone to ingesting foreign objects, necessitating close monitoring by the owner.
Caution:
If unconsciousness lasts more than 10 minutes, there is a risk to life! The so-called status epilepticus is a critical emergency and requires immediate intensive therapy by a veterinarian.
Focal Seizure
A focal (partial) seizure can be relatively inconspicuous and go unnoticed by the owner: Involuntary movements are limited to specific areas of the body, and the dog remains conscious. Possible signs of such a focal seizure include:
- Muscle twitches, for example, in the ears, lips, skin, or a paw
- Licking, unusual tongue movements
- Chewing, snapping at the air
- Compulsive head movements
- Facial grimacing
- Unfounded barking
Even if the dog has (so far) never had a convulsive seizure, epilepsy should always be considered with such symptoms.
Diagnosis of Canine Epilepsy
If the owner’s history suggests an epileptic seizure or if the veterinarian has observed it (on-site or in a video recording), the specific cause must be determined.
For this purpose, an extensive blood test is initially suitable, checking the concentration of various electrolytes, enzymes, metabolic, and waste products in the blood. If changes are detected, the next step involves examining the relevant organs, for example, through an ultrasound or urine analysis.
If the seizures cannot be explained based on the blood results, the next step is usually a magnetic resonance imaging (MRI) to identify possible structural changes in the brain.
Treatment of Epilepsy in Dogs
Canine epilepsy must be treated when it occurs more frequently than every three months or when the seizures have a particular severity. The latter is the case with status epilepticus and serial seizures.
Genetic epilepsy is fundamentally treatable with medication, but achieving the optimal adjustment of antiepileptic drugs may take several weeks to months.
In the case of an organic disease or metabolic disorder, the underlying cause must be eliminated. In this context, it may also be necessary to adjust the dog’s diet. Some causes, such as a tumor or a so-called liver shunt, require surgical intervention.
