Definitive Guide to Understanding and Treating Seizures in Dogs
Seizure disorder – also known as epilepsy – is among the most common neurological diseases in dogs. Seizures are the clinical manifestation of rapid and excessive electrical discharge of neurons in the brain (Lane et.al., 1990). Dog seizures, therefore, is characterized by the presence of unprovoked and recurrent seizures that results from the brain’s abnormal functioning. The problem of recurrent seizures in dogs is a particularly challenging case in veterinary medical practice. A common belief in veterinary medicine is that the vast majority of dogs with epilepsy have experienced generalized seizures most frequently in the form of convulsions. An accurate diagnosis of the type and causes of dog seizures is the guaranteed way to determine the needed treatment to manage and control seizures in dogs. In this article, the important notions about seizures in dogs will be explored and be discussed comprehensively. The entire content of this article will revolve around the following sections:- Categories of Dog Seizure
- Four Phases of Dog Seizures
- Types of Dog Seizures
- Treatment for Dog Seizures
Categories of Dog Seizures
Epileptic seizures or ES are commonly divided into 3 groups based on the underlying disease condition: (a) idiopathic ES, (b) symptomatic ES, and (c) reactive ES (Zimmerman et.al., 2009).
1.) Idiopathic ES (Primary)
The term idiopathic ES or primary epilepsy is used when there can be no identified underlying cause in dog seizure but with possible familial disposition. It is characterized by periodic and unpredictable seizures mediated by the rhythmic firing of large groups of neurons.2.) Symptomatic ES (Secondary)
Symptomatic or secondary epilepsy is a term used to mean when epileptic seizures are the result of the structural disease of the dog’s brain. It starts at any point of a dog’s life, characterized by partial seizures with or without secondary generalization, and is caused by a known disorder in the dog’s central nervous system.3.) Reactive ES
The term reactive ES is used to refer to a healthy brain’s reaction to a temporary systemic disorder. Endogenous metabolic diseases or exogenous poisoning is the underlying cause of a reactive ES. A reactive seizure is reversible when the cause or disturbance in the brain’s activity is remedied.Four Phases of Dog Seizures
In the study of Bollinger-Schmitz et.al (2000), seizures are comprised of four main phases:
- Prodromal phase: This phase covers the time preceding the seizure by hours or days. It is the period just before the appearance of seizure symptoms.
- Preictal phase: This phase precedes the seizure activity by minutes or hours. It is the period where a dog may appear nervous, restless, whining, shaking, or salivating.
- Ictus phase: This phase covers the actual seizure stage in which a dog may be mildly shaking, staring aimlessly, licking its lips, or may completely lose its consciousness and body functions.
- Postictal phase: This is minutes to hours following the ictus phase. Immediately after seizure, a dog may experience confusion, disorientation, restlessness, salivation, or temporary blindness.
Types of Dog Seizures
Lavely (2014) in his study on the “Pediatric Seizure Disorders in Cats and Dogs” stated that dog seizures are classified as generalized seizures and partial seizures.
1.) Generalized Seizures
In a generalized seizure, both of the dog’s cerebral hemispheres are involved. Seizures of this type result in loss of consciousness and the entire body of the dog is affected. Signs include convulsions, paddling, or increased tone. Salivation is also common and some dogs may vomit, urinate, or defecate at the time of seizure. The common periods with generalized seizures are the so-called preictal period (or before the seizure) and postictal period (or after the seizure). Signs in pre-ictal and postictal periods may include panting, anxiety, attention seeking, and pacing.2.) Partial Seizures
In a partial seizure, the dog’s cerebral involvement is focal. This type of seizure affects only a portion of the dog’s body. During simple partial seizure, the consciousness of the dog is unimpaired but is eventually altered during a complex partial seizure. In a complex partial seizure, the dog impulsively runs around and appears to be panicked and aggressive, is hissing and growling. Psychomotor seizure is a type of partial seizure consisting of a period of altered behavior accompanied by a complex motor activity. In this type of seizure, dogs present recurring episodes of strange behaviors like hysteria, aggression, tail-chasing, and fly biting (Ghaffari et.al., 2010).Treatment for Dog Seizures
Choosing the right treatment for a dog that is suffering from epileptic seizure requires balancing effectiveness and tolerability. Not all treatments work equally well in all dogs since their medical history and profile, potential for adverse effects, severity of seizure disorder, and the owner’s concerns vary significantly. The goal of medical treatment is to improve the life quality of your dog by minimizing how frequently the attacks occur and how severe they are. Although some medications can be very effective, these may cause side effects that can eventually lead to other diseases. Thus, it is extremely important that the medications to be used are properly tested and prescribed by a veterinarian. In this section, different types of treatments for dog seizures will be discussed to give dog owners wide selections on which treatment type is most appropriate for their pet dog. Your vet will be able to recommend to you which of these treatments is most suited in treating your dog’s seizure.Anticonvulsant Drugs
Anticonvulsant drugs intend to decrease the frequency and severity of seizures in dogs, thereby improving their life quality with as few adverse effects as possible. In the study of Lavely (2014) anticonvulsant choices as treatment for dog seizures include the following drugs:
Phenobarbital
Phenobarbital is the most effective anticonvulsant and has been used as the primary treatment for dog seizures. This drug increases the seizure threshold and decreases the spread to surrounding neurons. It also enhances the inhibitory postsynaptic effects of gamma-aminobutyric acid (GABA), inhibits glutamate activity, and decreases calcium flux across neuronal membranes. Adverse effects of phenobarbital to dogs include:
- Sedation
- Ataxia
- Polyphagia
- Polyuria/Polydypsia
- Increased liver enzymes
- Gastrointestinal effects
- Polyphagia
- Polyuria/Polydypsia
- Ataxia
- Sedation
- Nursing dogs, since levetiracetam drugs is excreted into maternal milk.
- Pregnant dogs, since high dosage of levetiracetam increases embryofetal mortality.
- Ventricular septal defects
- Cardiomegaly
- Valvular and arterial anomalies
- Leukopenia
- Mild thrombocytopenia
- Hepatic effects
- Blood dyscrasias (reversible with stopping felbamate therapy)
Dietary Therapy
Most dogs diagnosed with epileptic seizure show improvement when treated with anticonvulsant drugs. However, there still remains a significant number of dogs that do not show such improvement even with medications. These drug medications have not sufficiently controlled seizures in dogs and in fact, have created severe side effects. This is the case of refractory seizures.
Refractory seizures or drug-resistant seizures refer to seizures that are not controlled with seizure medications. This happens when dog seizures continue despite appropriate administration of two anti-epileptic drugs, either alone or in combination (Engel, 2014). Refractory seizure is particularly challenging to treat since despite dosing and drug choice, dog seizures may still remain uncontrolled.
Ketogenic Diet
The importance of dietary treatments in dogs with seizures is another important consideration to make. The ketogenic diet – a low carbohydrate, high-fat, and moderate protein – has been cited to treat refractory seizures in dogs.
In a study made by Law et.al. (2015), it found out that seizures in dogs were reduced significantly when their meal was subjected to a ketogenic diet for 3 months. While in dogs fed with a standard diet for the same span of time, no significant improvement was seen.
The recorded benefits of ketogenic diet in dogs are the following:
- It has reduced an attention deficit or hyperactivity disorder in dogs with epilepsy, including chasing and stranger-directed fear.
- It has decreased seizure frequency, seizure severity.
- It has minimized the potential adverse effects of anti-epileptic drugs.
