Seizures (fits/epilepsy)

Seizures or fits are common in many species, including humans, dogs and cats. Seizures may or may not be associated with primary brain disease.  They can be individual events (not repeated) or occur frequently.  If seizures recur, the condition is called epilepsy. There can be many causes of seizures or the underlying cause can be unknown in which case it is termed idiopathic.

A fit or seizure results when there is abnormal neuronal activity in the cortex of the brain. A seizure is caused by a sudden burst of excess electrical activity in the brain, causing a temporary disruption in the normal messages passing between brain cells. This disruption results in the brain’s messages becoming halted or mixed up. A seizure is not a disease but a clinical sign, generally indicative of a forebrain disorder.

What are the symptoms associated with a seizure?

There are various forms a seizure can take including momentary lapses of awareness & "fly biting" however the most obvious type of seizure is a 'tonic-clonic' seizure.  These used to be referred to as 'Grand Mal' seizures. There are two stages to this type of seizure, initially the 'tonic' phase which begins with contraction of all skeletal muscles and loss of consciousness. The dog usually falls to his side with his legs stretched out with his head tilted back.

Sometimes he will vocalize or have facial twitching. Vocalizations are involuntary and do not indicate pain. Often the dog will drool excessively, urinate, defecate or eliminate his anal glands. The 'tonic' portion of the seizure is usually very brief and gives way to the 'clonic' phase of the seizure. Once the 'clonic' phase begins the dog will demonstrate rhythmic movements, typically this consists of clamping the jaws, body jerks and/or running movements of the legs.

There are usually four phases to a seizure:

• Phase 1 - the prodromal phase (an early sign that an attack is about to occur) - abnormal behaviour - can occur minutes or several hours before. Some dogs do not display this phase.
• Phase 2 - the aura - a very short-lasting period of unusual behaviour just before the seizure (may include whining, trembling, salivation, restlessness, hiding & apprehension)
• Phase 3 - the ictus or fit - uncontrollable limb movements, often the head is extended backwards, there is increased salivation, chomping of the jaws & vocalisation. Often the dog will lose control of their bowels & their bladder during this phase. This stage usually only last 2-3 minutes, but the fits can recur very rapidly inducing a state of continuous fitting (status epilepticus) or 'cluster' seizures
• Phase 4 - the postictus - the dog will attempt to stand, he will be dazed, disorientated and wobbly.  There will normally be unusual behaviour such as an inability to recognize familiar people, blindness/deafness and fearfulness.  This stage can last a few minutes or a few hours - during this stage the dog is conscious but not functional as such and this stage occurs due to brain exhaustion.

What to expect when a tonic-clonic seizure happens?

The dog may be engaging in their normal activities although it is more normal for them either to be asleep, to have just woken up from a sleep or to be relaxing/resting when a seizure starts.  Seizures very rarely occur during exercise or normal daily activities - many seizures occur in the evening or at night.

If a dog is awake prior to the fit they tend to pause whatever they are doing (the 'aura' phase), there will be a far away look in their eyes and owners may sense that their dog is behaving differently. As the seizure starts, they will shudder before toppling over onto their side.

The next stage is that they will become rigid with their head extended away from their body and their mouth open & their lips peeled back. They may make a noise (yelping or other vocalisation) and their body will usually twitch/jerk, they will salivate, their jaws will chomp, they may cough/gag, pee and poop. This is the 'tonic' part of the seizure.

The next stage is a second or two of relaxation before the fit continues with the 'clonic' stage i.e. the paddling of the legs (running) and further jerking of the body and jaw chomping, there will often be thrashing around (whilst still lying on their side). When the active stage of the seizure ends the dog will attempt to stand up, he will be wobbly, disorientated and may stagger. He may also appear blind, deaf and fearful; this is known as the post-ictal stage. After a period of minutes or possibly an hour or so the dog will return to his normal self - as if nothing had happened.

What should owners do?

Seizures can be frightening and upsetting to watch, owners need to remain calm and to ensure their dog is in a safe location so that he does not hurt himself during the seizure. However unless there is grave danger to his welfare it is best to allow the dog to fit without interfering with him or moving him, if it's possible a folded towel or similar can be placed around the dog/under his head etc., however due to the active nature of the seizure this may prove ineffective.

If possible, if the room is bright or noisy it's best to dim the lights/close the curtains and turn off any radios/TV's etc. so as to keep the room calm & restful.

It is best not to attempt to touch or comfort the dog during the active part of a seizure as they are very sensitive to stimulation and this could prolong the seizure. However, as they begin to recover comforting words may help. Gentle stoking is also comforting; however, as a precaution, owners should ensure their fingers are not adjacent to the dog’s mouth in case of accidental biting.

When the seizure ends, most dogs benefit from a peaceful time without noise/stress in their immediate environment & a darkened room/avoidance of bright lights can be beneficial. Many will need to sleep after a fit, however others may remain restless and some will be very hungry or thirsty and require feeding or a good drink.

Based on information from people with seizure disorders, it is believed that whilst a fit/seizure looks frightening to onlookers, the dog himself is unaware of the process & and is not traumatized by the whole event.  It is probable though that the disorientation associated with the 'post-ictal' stage is unsettling for the dog & your gentle handling of him and continued calming words and reassurances can help this stage to pass more quickly and gently.

Other forms of seizure activity

The most visually obvious type of seizure is the 'tonic-clonic' type. However there are other forms of seizures and these include "absence seizures" (Petit mal) which are characterized by a brief duration of unconsciousness where the dog may appear to stare blankly and "focal seizures" - the spasms are restricted to one area of the body, e.g. one limb, turning the body or head to one side only and/or facial twitches.

Important information

Any dog that has a first time seizure should be seen by a vet as soon as possible for a general health check and for advice. Owners of known epileptic dogs should consult their vet if they are at all concerned about their dog, if medication is not controlling the seizures or if there is an increase in either the number (frequency) or duration of seizures.

Seizures are normally of short duration, usually with a clear progression from start to end - owners should time the seizure as many appear to go on for much longer than they actually do. If owners are worried that the seizure is longer than 2 - 3 mins or the dog appears to go from one seizure to another within a short space of time medical advice should be sought without delay.

Seizures lasting more than 5 mins, 'cluster' seizures (multiple seizures in a short space of time) or status epilepticus (one continuous unremitting seizure lasting longer than 30 minutes or recurrent seizures without full recovery of consciousness between seizures) can be harmful (potentially life threatening) to the dog as his temperature will rise (due to the all the neurological activity/muscle activity) and this can cause damage to other organs such as the liver and kidneys as well as the brain..

Veterinary treatment (and/or veterinary prescribed medication) should be administered urgently in order to end the seizure (as appropriate). Rectal Diazepam (Valium) is extremely useful in breaking 'cluster' seizures and should be administered before the number of clusters increases as it is less effective once 2 or three seizures have already occurred, intravenous Phenobarbital will normally be given to end status epilepticus.

By giving Diazepam rectally, the drug enters the systemic circulation without passing through the liver as hepatic metabolism inhibits the absorption of the drug i.e. the liver is quite efficient at filtering out the drug rather than allowing most of it to enter the circulatory system.

First Aid Measures

If a seizure lasts longer than normal, or there are cluster seizures or status epilepticus the body temperature can rise very high rapidly. To help your dog put cool water on their feet, in their armpits, groin and tummy area or hold an ice pack (a plastic freezer bag filled with water and frozen should do the job) in the middle of their back & get them your vet ASAP.

Causes of seizures

• Structural lesions, encephalitis, traumatic injury, brain tumour, trauma during birth, head trauma etc.
• Low blood sugar concentrations (hypoglycaemia)
• Hypothyroidism
• Poisoning - various toxins
• End-stage kidney failure (toxins build-up due to body’s inability to excrete products of metabolism)
• Liver disease/failure (portosystemic shunt – ‘liver shunt’ or other liver disease)
• Interruption of blood-flow to the brain - stroke, tumour or other circulation problems
• Any disease which damage the nerve cells in the brain
• Head injury that causes scarring of the brain tissue
• High fever
• Vaccinations - they are thought to lower the bodies 'seizure threshold'
• Primary Epilepsy i.e. idiopathic (arising from an unknown cause)
• All dogs (& humans) have a "seizure threshold" beyond which certain issues may give rise to a seizure. Having a seizure lowers the "threshold" as can external factors/stress/metabolic disturbances/hormones etc.

Unless there is an identifiable cause of a seizure in a younger dog, the likely cause is Idiopathic. The age of onset of Idiopathic epilepsy is normally between 6 months & 3 years of age. Fits starting in older animals are most likely not idiopathic epilepsy, but one of the other causes.

Frequency of Seizures - External Influences

• Physical irritations such as pain, skin irritations, ear infections etc.  will increase the frequency of seizures. Additionally, worry or stress such as a visit to the vets or boarding kennel, visitors to the house, or any event in the life of the owner that makes the owner change habits or be upset may increase the frequency of seizures.
• Hormones such as oestrogen can lower the threshold to seizures of parts of the brain. Oestrogen is at high levels in female dogs in when in "season".
• Certain drugs may precipitate seizures. Antihistamines, tranquilizers and anti-emetics (travel sickness medication) should not usually be given to dogs who suffer from seizures.

Diagnosis

The diagnosis of idiopathic epilepsy is based upon clinical signs & ruling out other known causes of seizures via neurological testing, laboratory tests & computed tomography (CT) scans and MRI scans to examine the skull and brain.

Treatment

Opinion is divided about treatment regimes. Some vets do not advise treating animals unless they are having more than one seizure every 3 months (or 4 in a year) or if the dog is having several seizures in quick succession.

The traditional treatment for seizures is the anticonvulsant Phenobarbital (Epiphen), although Primidone may be used (the body converts it into Phenobarbital) and in some cases Potassium Bromide (Libromide) may be used alone or with Phenobarbital.

Any medications used should be administered according your vet's instructions & generally needs to given at precise intervals, failure to administer at the correct time or skipping a dose is likely to cause a seizure.

Common dosages are:

• Phenobarbital: 2 - 5 mg per kg bodyweight (dose divided & given 12 hrs apart)
• Libromide: 30 mg per kg bodyweight as a single dose (or divided & given 12 hrs apart)
• Clonazepam: 0.1 - 0.5 mg per kg bodyweight twice per day (AM & PM)

The therapeutic dose of phenobarbital & potassium bromide is monitored by blood serum testing, all dogs metabolize the drugs differently. Therefore the suggested dose (as above) is a guide, the true therapeutic dose is based on the results of peak levels of the drug circulating in the bloodstream via blood testing analysis.

Many dogs are kept on long-term treatment & in most cases this can be quite successful in controlling and/or reducing the frequency of seizures. Medication does not cure epilepsy; its aim is to control/minimise the frequency of seizure activity.

Phenobarbital is metabolized by the liver and is toxic at high levels. Regular blood testing is required to ensure the liver is functioning correctly, additionally a CBC (complete blood count) will be required to check the dog doesn't become anaemic.

Libromide is is removed from the body via the kidneys & is therefore suitable for use in dogs with liver disease, but must be used with care in dog’s with kidney disease. Generally, using both drugs allows a lower dose of Phenobarbital to be used which is beneficial as a lower dose decrease the risk of toxicity.

It should be noted that as Bromide is metabolized by the kidneys, anything that causes the kidneys to produce more urine will cause the level of Bromide to drop quicker than desired. A high salt diet means the drug will be eliminated more quickly, the opposite is also true, changing your dog’s diet may increase or decrease the amount of Bromide in their blood. Additionally dehydration (where the kidneys produce less urine) will cause Bromide levels to rise.

Clonazepam is a benzodiazepine. Clonazepam acts on receptors in the brain called GABA receptors. This causes the release of a neurotransmitter called GABA in the brain. GABA is involved in transmitting messages between the nerve cells and acts as a natural 'nerve-calming' agent. It helps keep the nerve activity in the brain in balance.  It can be a helpful drug in the management of seizures in some dogs, however like all drugs of this class, tolerance to its effects can develop, requiring a change to another drug.

The duration of treatment & drug dosage of the chosen drug or drugs should be kept to the minimum required to control the seizure episodes. If the dog does not have a fit for 8 - 12 months, many vets feel it is worth trying to wean him gradually off treatment by reducing the dose slowly over a period of months to see how he manages without medication.

Side Effects

Most dogs experience very few side effects of their medication. When side effects do occur, they are usually mild & are far outweighed by the risk of further seizures. Medications work to increase inhibition in the brain and therefore there is often a sedative side-effect. As a result, the dog may need to sleep a lot more than usual and seem quite lethargic. Coordination can also be an issue. Any side-effects are usually mild and for most they abate once the dog adjusts to the medication.

Occasionally, dogs have a paradoxical reaction to the medication. Rather than becoming sedated, the dog becomes restless, agitated & hyper. They seem unable to relax and may pace around the house unable to sleep or rest. The reason why some dogs respond in this manner is unknown; however adjusting the dose normally resolves the problem. Increased appetite is also a common side-effect associated with Phenobarbital.  Many dogs appear to want to eat for "England".  This can be their own food, your food, scavenging and sometimes inappropriate items that are not food but might be remotely edible!  Owners should ensure that weight gain is monitored and that they do not give in to their dogs desire to eat excessively.

Costs:

The cost of drug treatment varies as the dose per animal is based on bodyweight. Heavier dogs require higher doses therefore cost will be higher. For an average weight cocker spaniel cost is as follows:

For dogs maintained on Epiphen (phenobarbital) only a typical monthly cost would be approx. £9.00

For dogs taking Libromide (Potassium bromide) as an adjunct, a typical monthly cost would be approx. £18.00

For dogs taking Rivotril (Clonazepam) as an adjunct, a typical monthly cost would be approx. £22.00

Notes:

In almost all cases, seizures/epilepsy is not hereditary in English Cocker Spaniels. In a few cases, the tendency towards epilepsy might be inherited, but even with this tendency, certain conditions must exist in the brain before epileptic seizures will occur.

Epilepsy that runs in families suggests an underlying metabolic or genetic etiology, and this is the least common of epilepsy causes. Therefore, unless there are multiple epileptic dogs in the family of the affected dog the cause is unlikely to be genetic.

From research into human epilepsy, it is thought that only a small percentage of epilepsy is hereditary (caused by chromosomal abnormalities). In most instances, epilepsy is not inherited.

Although dogs are clearly not human, many human and dog diseases share similar causes, therefore until research is carried out into whether epilepsy in English cocker spaniels is hereditary the only information available is based on humans and at this stage, the hereditability of epilepsy is not confirmed.

Dogs being treated with Phenobarbital and Potassium or Sodium Bromide are potentially at higher risk of developing Pancreatitis.