Idiopathic Epilepsy in Cats

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Idiopathic epilepsy is a specific term referring to a seizure disorder in cats that has no identifiable cause. It is also referred to as genetic or congenital epilepsy. The terms epilepsy, seizure, fit or convulsion all mean the same thing, the physical manifestation of a sudden, excessive electrical discharge of neurons in the brain that results in a series of involuntary contractions of the voluntary muscles, abnormal sensations, abnormal behaviors, or some combination of these events.

In your pet, the physical manifestation can vary between a far-away look or twitching in one part of the face to your pet falling on his side, barking, gnashing his teeth, urinating, defecating and paddling his limbs.

Seizures usually appear suddenly and end spontaneously, and can last from seconds to minutes. Idiopathic epilepsy can occur in all pedigree breeds as well as mixed-breed cats.

Because idiopathic epilepsy or a predisposition to epilepsy might be inherited, neither epileptic animals nor their first-degree relative should be used for breeding.

Components of a Seizure

There are three components of a seizure:

  • Aura. Certain signs of an impending seizure may be evident, such as restlessness, whining, shaking, salivation, affection, wandering or hiding. These signs may persist from seconds to days in duration and may or may not be apparent to you.

  • Ictus. During ictus, the seizure occurs. The attack may last seconds or minutes. Your cat may fall on his side and may look like he is kicking or paddling. He will salivate, lose control of his bladder, and be unaware of his surroundings.

  • Postictial stage. This stage occurs immediately after the seizure. Your cat will appear confused and disoriented and may wander or pace. This period may be short or it may last for days.

    What to Do If You Pet Has a Seizure

  • Do not panic. If your pet is having a seizure, he is unconscious and he is not suffering. Your pet may seem like he is not breathing, but he is.

  • Time the seizure. Actually look at a clock or watch and note the time; although it may seem like forever, it may only be 30 seconds.

  • Keep your pet from hurting himself by moving furniture away from the immediate area. Also protect him from water, stairs, and other sharp objects. If possible, place a pillow under his head to prevent head trauma.

  • Note what type of muscular activity or abnormal behavior does your pet exhibits during the seizures? Your veterinarian may want you to keep a record of the date and length of time of each seizure.

  • If the seizure lasts more than 5 minutes, call your veterinarian or veterinary emergency clinic immediately.

  • Pets do not swallow their tongues. Do not put your hand in your cat's mouth – you may get bit. Do not put spoons or any other object into your pet's mouth.

  • Keep children and other pets away from your seizing animal.

  • Remain by your pet's side; stroke and comfort your animal so when he comes out of the seizure you are there to calm him.

    After the seizure

  • Observe your pet's post-seizure behavior. Do not allow your pet access to the stairs until he is fully recovered. Offer water if he wishes to drink.

  • Be prepared for vocalization and stumbling after the seizure ends. You need to be strong and offer support and comfort to your pet. He will be confused and may feel as though he did something wrong. Speak softly and with a soothing voice.

  • If your pet has not fully recovered within 30 minutes, contact your veterinarian or local emergency facility.

    Signs That Require Emergency Veterinary Attention

  • Seizures that last longer than 10 minutes
  • Seizures that occur more than 2 times in a 24 hour time period
  • Seizures that begin before your pet has completely recovered from the previous seizure

    Diagnosis

    By definition, idiopathic epilepsy is a seizure disorder with no known cause, however it is important for your veterinarian to determine your pet's general health and make sure there is no underlying disease that may be causing the seizures. Your veterinarian will take a detailed history and perform a complete physical and neurological examination. Recommended blood tests may include a CBC, serum biochemistry panel, toxin screen, feline infectious disease panel, urinalysis and fecal examination.

    Treatment

    The goal of treatment is to reduce the severity and frequency of the seizures while avoiding unacceptable side-effects. It is rare to completely eliminate all seizures in cats with idiopathic epilepsy. Your veterinarian may chose to treat the disorder with anticonvulsant medications.

    Drug Therapy

  • Phenobarbital is usually the drug of first choice for idiopathic epilepsy. It is given two to three times a day by mouth. During the initial treatment period of 10 to 14 days, side effects are usually seen with this drug consisting of excessive drinking, urinating and eating. Some cats may act very lethargic as well. These side-effects are temporary and diminish two weeks after initiating treatment.

  • The other common anti-convulsant used in cats is oral diazepam or valium. It must be given three times a day. On a much more serious note, oral diazepam has been linked to a very rare but fatal idiosyncratic hepatic failure. Diazepam (Valium) is used for the treatment of status epilepticus. Your veterinarian usually gives it in emergency situation by the intravenous (IV) route.

  • Bromide is the active ingredient in potassium bromide and sodium bromide and is another anticonvulsant that can be used in addition to phenobarbital or as an initial drug. Many cats that do not initially respond to phenobarbital alone will have a dramatic decrease in seizure frequency and severity with the addition of bromide. Bromide is the drug of choice for animals with liver disease.

    Side-effects from the bromide include increased eating, drinking, urinating and incoordination. These side-effects are usually temporary but if they are problematic, a dose reduction in either one of the drugs may be recommended.

    Home Care

    At home, follow your veterinarian's recommendations regarding drug administration and monitoring, and maintain a complete seizure log with information regarding the seizures, any medication change, veterinary visits and illnesses.

    Haphazard drug administration or abrupt changes in medication may be worse than no treatment at all and may cause status epilepticus, a condition characterized by persistent seizure activity for a period of more than 30 minutes or repeated episodes of seizure activity without recovery in between.

    Blood tests will be required to monitor your cat's response to therapy and guard against toxic effects from the seizures as well as the anti-convulsant medications.

    The diagnosis of idiopathic epilepsy is not a death-warrant; epilepsy is a chronic disease that can be managed in the vast majority of cases. There is help for you and your cat. Work with a veterinarian with whom you feel a good rapport. Educate yourself on seizures and their treatment.

    • Oral phenobarbital is available in 15 mg tablets.

    • Injectable diazepam (Valium) can be given intravenously, per rectally or intranasally to stop seizures. It does not have the same risk of idiosyncratic fatal hepatic failure as oral diazepam does.

    • Phenobarbital can be given by mouth in the pill form. Injectable phenobarital can be given intravenously, intramuscularly or subcutanously.

    Idiopathic epilepsy is a specific term referring to a seizure disorder in cats that has no identifiable cause. Although idiopathic epilepsy is very common in dogs, seizures in cats have a 50:50 chance of having a specific cause found. If your cat has a seizure, it is worthwhile to do everything possible to find a cause for the seizures.

    Epilepsy is a condition characterized by recurrent seizures. Approximately 0.5 percent of cats are epileptic. Some cats can have one seizure without ever having a second. The seizures can be generalized or partial.

    Partial or focal seizures indicate activation of a limited number or group of neurons. Generalized seizures indicate a synchronous discharge of a large number of neurons in both sides of the brain. The majority of cats (50 to 60 percent) with idiopathic epilepsy have generalized seizures.

    Seizures usually appear suddenly and end spontaneously. Seizures can last from seconds to minutes. Generalized seizures that last more than 30 minutes or multiple seizures that occur so rapidly as to prevent complete recovery are considered emergency situations that require immediate intervention as permanent brain damage may occur after this 30 minutes.

    Some cats exhibit the following three stages of seizures. However, not all cats have the exact type of seizure stages.

  • The aura or prodromal stage is the time immediately before the actual seizure, which may last minutes or hours. During this time, your cat may show a slight change in behavior or attitude. In many cats, the seizures begin suddenly without any warning signs.

  • The ictus is the actual seizure episode in which your cat may become stiff, lose consciousness, fall over and begin paddling, vocalize, gnash the teeth, urinate, defecate, and salivate. This stage can last seconds to minutes and is generally the part of the seizure your veterinarian wants you to time. During this time, your cat is unconscious and is not suffering.

  • The post-ictal phase immediately follows the ictus and begins as your cat regains consciousness, as evidenced by looking around or focusing on something or someone. Some cats remain lying down in exhaustion or fall into a deep sleep. Some stand up after a few seconds or minutes. They may be disoriented, weak, poorly responsive, blind, deaf and/or anxious. Most cats return to normal within a few minutes although some cats may require days to recover completely.

    Several different diseases may cause seizures (convulsions). The term idiopathic epilepsy refers to a seizure disorder the cause of which remains unknown despite a thorough diagnostic evaluation. Treatment and prognosis (outcome) of seizures depend on their underlying cause. The following are the most important causes of seizures in cats:

  • Structural disorders
  • Viral or inflammatory disorders
  • Fungal disease (cryptococcosis)
  • Toxoplasmosis
  • Encephalitis
  • Rabies
  • Brain abscess
  • Head trauma
  • Brain tumor
  • Cerebral infarct (uncommon)
  • Vasculitis (inflammation of blood vessel)
  • Developmental disorders (hydrocephalus)
  • Metabolic disorders
  • Hypoglycemia (low blood sugar)
  • Migrating parasites
  • Hepatoencephalopathy (liver disease)
  • Advanced uremia (kidney failure)
  • Hypocalcemia (low blood calcium concentration)
  • Hypernatremia (high blood sodium concentration)
  • Hypoxia (low blood oxygen)
  • Thiamine deficiency (B-complex vitamin deficiency)
  • Poisoning
  • Antifreeze
  • Lead
  • Organophosphates
  • Carbamates
  • Many other poisons or toxins

  • Veterinary care should include diagnostic tests and subsequent treatment recommendations.

    Diagnosis In-depth

    Your veterinarian will take a detailed history regarding the seizure episodes including any information about the seizure, the breeding or litter history, toxin exposure and their previous health record.

    Your veterinarian will perform a complete physical and neurological examination that may include an examination of your pet's retinas.

    By definition, idiopathic epilepsy is a seizure disorder with no known cause, although it is important for your veterinarian to determine your pet's general health and make sure there is no underlying disease that may be causing the seizures. Recommended blood tests may include:

  • A complete blood count (CBC or hemogram) to check blood counts

  • Serum biochemistry tests to evaluate blood glucose, electrolyte and protein concentrations

  • Bile acid determinations to evaluate liver function

  • A feline infectious disease panel which includes tests for feline leukemia, feline immunodeficiency virus, feline infectious peritonitis, toxoplasmosis and cryptococcosis

  • Urinalysis to assess kidney function

  • Fecal examination to check for parasites

  • Based upon the presentation, age, breed, seizure episode and results of the above tests a diagnosis of idiopathic epilepsy may be made and treatment may be recommended.

    Treatment In-depth

  • The most overlooked aspect of treatment is keeping a seizure log in which you write down exactly when (time and day) your cat has a seizure, including the total length of the seizure and any predisposing activities that you remember. Note what your cat does during the seizure. If you suspect your cat had a seizure but you did not witness it, list it as a question mark in your seizure log.

  • Treatment is indicated for idiopathic epileptics depending on the severity and time between seizures. Generally, medical treatment is generally advised for animals who have one or more seizures every six weeks. Cats who have cluster seizures or go into status epilepticus (more than one seizure in a 24-hour period) may be treated even though the time between seizures is greater than six weeks.

  • If you and your veterinarian decide to treat your cat with an anticonvulsant, you must make a commitment to giving the medications exactly as prescribed with absolutely no changes in the dose or drug without veterinary consultation. Haphazard drug administration or abrupt changes in medication may be worse than no treatment at all and may cause status epilepticus.

  • The goal of treatment is to reduce the severity and frequency of the seizures while avoiding unacceptable side-effects. It is rare to eliminate completely all seizures in cats with idiopathic epilepsy.

  • Phenobarbital is usually the drug of first choice for idiopathic epilepsy. It is usually effective in more than 80 percent of the cases when administered at the correct dose and frequency. It is given two to three times a day. During the initial treatment period of 10 to 14 days, side effects are usually seen with this drug consisting of excessive drinking, urinating and eating. Some cats may act very lethargic as well. These side-effects are temporary and diminish two weeks after initiating treatment.

  • Phenobarbital comes in 15, 30, 60 and 100 mg tablets. Phenobarbital tablets are often referred to according to grains (gr.). For reference 1 grain equals 60 mg. There is also a syrup or elixir available.

  • Blood phenobarbital concentrations should be measured two weeks after any change in dose or if there is a change in seizures frequency or severity. Concentrations are determined by drawing blood. The level of drug needed to control seizures varies between individual cats but generally should be above 25 ug/dl before treatment is considered failed.

  • Cats can have liver problems with chronic, high-dose phenobarbital treatment. Regular annual or semi-annual blood tests may be recommended to evaluate your cat's liver function.

  • The other common anti-convulsant used in cats is oral diazepam or valium given three times a day. Oral diazepam has been linked to a very rare but fatal idiosyncratic hepatic failure. Most veterinarians will avoid this drug in cats if possible. If your cat is on this drug with no problems, it is not necessary to change the medication unless your cat has liver problems like anorexia, vomiting or abdominal pain.

  • Bromide is the active ingredient in potassium bromide and sodium bromide and is another anticonvulsant that can be used in addition to phenobarbital or as an initial drug. Many cats that do not initially respond to phenobarbital alone will have a dramatic decrease in seizure frequency and severity with the addition of bromide.

    Bromide is the drug of choice for animals with liver disease. Bromide is always given on a full stomach. Giving bromide on an empty stomach can cause vomiting. Bromide is not approved for use in cats, nor is it commercially available at this time. Bromide can be given as a capsule or dissolved in water or as syrup.

    Bromide has an extremely long half-life which means it can be given once a day. It also takes 6 to 8 weeks to reach therapeutic levels in the blood unless your veterinarian recommends giving a loading dose. Side-effects from the bromide include increased eating, drinking, urinating and incoordination. These side-effects are usually temporary but if they are problematic, a dose reduction in either one of the drugs may be recommended.

  • Diazepam (Valium) is used for the treatment of status epilepticus. Your veterinarian usually gives it in emergency situations by the intravenous (IV) route. Your veterinarian may recommend diazepam by rectal or nasal administration if your cat has severe seizures. This is not common situation and requires special training.

  • Alternative therapies range from acupuncture to herbs and vitamin therapies as well as dietary recommendations. Work with your veterinarian in selecting the right treatment for your cat's seizures.

  • Other drugs such as primadone, phenytoin, gabapentin, zonisamide, levitiracetam, carbamzaine and valproic acid are used in certain specific situation as tertiary drugs.

  • Maintain a complete seizure log with information regarding the seizures, any medication change, veterinary visits and illnesses. Always follow your veterinarian's recommendations regarding drug administration and monitoring.

  • Blood tests will be required to monitor your cat's response to therapy and guard against toxic effects from the seizures as well as the anti-convulsant medications.

  • The most common reason why treatment for idiopathic epilepsy fails is the lack of proper administration of drug. Do not change medication dose or frequency without speaking first to your veterinarian.

  • Gastrointestinal or other illnesses may affect drug administration and influence seizure frequency or severity.

  • Be aware that other drugs can affect anti-convulsant drug distribution. Always ask what the effect any drug may have on your cat's seizures.

  • During a seizure, do not attempt to open your cat's mouth or manipulate his tongue – you may get bitten inadvertently.

  • Protect your cat from injury by moving the animal away from hazardous objects like furniture with sharp corners or harmful locations like the top of the stairs.

  • Give your cat sufficient time to recover from the seizure. Speak calmly and try to comfort your cat during a seizure.

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