Category: collapse-cat

Fainting occurs when there is an insufficient blood supply to the brain. When a person is standing up the head is higher than the heart and therefore blood has to be pumped uphill and so if there are any problems with the circulation it is made more obvious. In cats their head is almost in line with the heart – this is why fainting is less common in cats than people.

During a fainting episode your cat will fall to the ground, usually on its side. It may show involuntarily muscle twitching and lose control of its bladder or bowels – these features can also be seen during a seizure and this is why some owners mistake a fainting episode for a seizure. However, during a faint, the body as a whole may be limp and floppy and the tongue and gums may be much paler than normal for your cat – these features are not typically seen during a seizure.

There are a number of different causes of reduced blood supply to the brain. Generally, reduced blood supply to the brain is caused by episodes of low blood pressure. This can be caused by the heart beating at an abnormally rapid or slow heart rate, or even stopping completely for a few seconds. Low blood pressure can also result from very weak contractions of the heart or from narrowing or excessive leakage of the heart valves.

Many of the medical conditions that can cause fainting are more prevalent in older cats. In younger animals fainting is occasionally associated with congenital heart disease. However, it is important to stress that some animals can faint at any age in the absence of underlying heart disease. This often happens following excitement or a specific set of circumstances. In cats the most common cause of fainting is cardiomyopathy (heart muscle disease).

Some drugs can increase the likelihood of your pet fainting. If your pet is taking any medication be sure to mention it to your vet, even if you think they will already know about it.

Your vet will first want to be sure that your pet is fainting and not having a seizure. First your vet will want to know about the episodes – when they happen and what the cat is doing at the time. Although it can be very frightening the first time your pet faints you should try to stay calm and record as much information as you can to pass on to your vet.

Try to time how long your cat is unconscious (it always seems much longer than it really is) and what your cat was doing before and immediately after the episode. In between fainting episodes most animals are completely normal and so your vet may be unable to detect anything on clinical examination. If you are able to capture one of the episodes on video (for example, on your mobile phone) this can be useful for the vet.

There are enough different causes of fainting that your vet will not usually be able to tell what is wrong with your cat just by looking at them. Cardiac testing will normally be required and an ECG recording (electrical recording of the heart beat) is a vital component of this, often accompanied by ultrasound and sometimes x-rays of the heart. It is likely that blood tests will also be required.

Tests can sometimes go on for weeks or months, depending on how often your pet is fainting. In some cases your vet may arrange for your pet to be fitted with a heart monitor to wear at home. In some cases nothing abnormal will ever show up on the tests, offering reassurance that it is unlikely that a serious medical or cardiac problem was causing the fainting.

The treatment for fainting depends on the underlying cause. In some cases there is no treatment and cats may continue to have intermittent fainting episodes throughout their lives. It may be possible to determine when attacks are likely to occur (e.g. a cat may always have an attack when it gets very excited) and it might then be possible to avoid circumstances likely to trigger episodes.

In specific cases drug treatment may be available which will help minimise the problem and some conditions may require a surgical procedure (for example, implantation of a pacemaker) to stop the problem.

However, the good news is that many fainting episodes are not linked to serious underlying disease and in these cats the frequency of episodes can often be reduced by careful management. When they do occur the episodes last less than a minute with a rapid full recovery to normal behaviour almost immediately. The biggest concern is to rule out any serious underlying disease that may be a threat to your pet and for your vet to be able to recommend the best treatment in individual cases.

If you have any concerns about your cat contact your own vet for further advice.

Epileptic animals are born with the condition and cannot be cured. The aim of treatment is to ‘control’ their seizures. Whilst anti-epileptic drugs will make some animals seizure-free, for most treatment is judged to be successful if the frequency and severity of the seizures is reduced with few side-effects. You must understand that, if your cat is epileptic, they are likely to continue to have some seizures despite being on treatment. It is not possible to achieve seizure control in some cats despite adequate therapy.

Once treatment for epilepsy starts it is likely to be continued lifelong. Many cats only have a single seizure episode, and so it is not sensible to put all these animals on permanent treatment (when many would not have another seizure anyway). Some vets recommend starting treatment of seizures after a second seizure episode. Other vets are more cautious and like to balance the benefits of treatment with its potential adverse effects.

You should consider treatment for your pet if:

• They are having more than one seizure a month and/or you find the frequency distressing
• They have a very severe seizure or cluster of seizures, whatever the frequency
• Their seizures are increasing in frequency or severity
• Underlying brain disease has been identified as the cause of the seizures

Many drugs used in people with epilepsy are either toxic to pets or are removed from the body so quickly that good ‘control’ of seizures cannot be achieved. The first treatment in cats is usually either phenobarbitone, diazepam (ValiumR), gabapentin (NeurotinR) or levetiracetam (KeppraR).

Individual animals respond in different ways to anti-epileptic treatment. It is not the number of tablets given that is important but the level of drug in the body. The blood level of drug determines not only the good effects (also known as therapeutic effects) but also the toxic effects. Blood levels of phenobarbitone can be measured to ensure that they are within a certain range (therapeutic range) that controls seizures with minimal side-effects.

A blood test can help your vet decide whether your cat should receive more of less medication. Some animals have seizures controlled with blood levels of drug at the low end of the therapeutic range while others will need higher drug levels to experience beneficial effects.

Blood levels of phenobarbitone should be measured:

• 2 weeks after starting treatment or changing the dosage.
• If the seizures seems to be occurring more often.
• Every 3 to 6 months to check that blood concentration does not drift out of the intended range.
• When drug-related side effects are suspected.

Occasionally the side effects of drugs used in the management of epileptic seizures can be worse than the seizures themselves. Mild side effects are common when treatment is first started (or the dose is increased). Phenobarbitone can cause increased thirst and appetite, more frequent urination, mild sedation and mild wobbliness in the back legs.

More serious side effects are rarely seen with phenobarbitone but include liver toxicity and blood abnormalities (low red blood cells, low platelets and low white blood cell count). Liver toxicity is mainly seen in cats on diazepam. Complete blood profiles (liver function tests and haematology) are recommended on a six monthly basis to monitor to such potential side-effects.

There are many reasons why an animal may not respond to treatment:

• Incorrect diagnosis of epilepsy (if there is an underlying cause for the seizures).
• Insufficient dose of medication.
• Development of ‘resistance’ to the effect of the drug (also known refractory epilepsy).

If the quality of life of an epileptic animal is compromised by frequent and/or severe seizures despite appropriate choice and blood concentration of drug, they can be classified as having refractory epilepsy.

The first choice for treatment of refractory epilepsy in cats receiving phenobarbitone treatment is to add diazepam or one of the newer (and more expensive) human anti-epileptic drugs, eg gabapentin (NeurotinR) or levetiracetam (KeppraR).

It is very likely that your pet will have to stay on treatment for the rest of its life. It is important not to alter or stop your pet’s treatment without veterinary advice. Dosage reduction should only be considered if your pet has had no seizures for at least a year. Sudden changes in the blood levels of anti-epileptic drugs can trigger seizures. If drug doses are reduced this should be done very gradually over many months. However, if your pet is not experiencing significant side-effects, you should not be concerned that they need to remain on treatment.

A seizure (also known as a fit) is a short event with an abrupt start and end. The term seizure can relate to a problem in the nervous system (epileptic seizure, narcolepsy/cataplexy, acute balance loss) or a disease in another organ (e.g. heart disease causing syncope). The term paroxystic event is usually used to describe seizures of uncertain origin.

An epileptic seizure is not a disease in itself but the sign of abnormal brain function. Many types of epileptic seizure are described in humans, dogs and cats. The most common type is the generalised tonic-clonic epileptic seizure (also known as grand mal seizures). Partial epileptic seizures affect only part of the body and are much more difficult to differentiate from non-epileptic seizure (particularly movement disorders).

Epilepsy means repeated epileptic seizures due to abnormal activity in the brain. It is caused by an abnormality in the brain itself. If the seizures occur because of a problem elsewhere in the body, for example a low sugar level, this is not epilepsy.

Epileptic seizures can be caused by problems inside the brain (intra-cranial causes) or outside the brain (extra-cranial causes).

Extra-cranial causes

Extra-cranial causes of seizures include intoxication and metabolic diseases. In these cases, the brain is perfectly healthy but reacts to a toxin or a change in the blood make-up (usually caused by liver or kidney disease, salt imbalance, low sugar level, or an under-active thyroid gland). This type of seizure is also described as reactive epileptic seizures. Diagnosis of extra-cranial causes of epileptic seizures is based on blood tests or a known history of access to a toxin.

Intra-cranial causes

Intra-cranial causes are divided into primary and secondary epilepsy. In secondary epilepsy, the epileptic seizures are a sign of a disease in the brain.  This disease might be a brain tumour, an inflammation or infection of the brain (encephalitis), a brain malformation, a recent or previous stroke or head trauma. Epileptic seizures may be the only sign of illness or there may be other signs (circling, blindness, wobbliness, restlessness and/or sleepiness). To confirm a diagnosis of secondary epilepsy an underlying brain disease must be identified using MRI or CT-scans of the brain and tests on the fluid surrounding the brain (CSF analysis).

In primary epilepsy (also known as idiopathic epilepsy), there is no disease in the brain but the epileptic seizures are caused by a functional problem (an imbalance in the messengers in the brain).

Primary epilepsy is the most common cause of epileptic seizures in young adult cats, although not as common as in dogs. The number of seizures each cat has is extremely variable between individual cats (from many seizures a day to a seizure every few months). Animals with primary epilepsy are typically normal in between seizures.

The diagnosis of primary epilepsy can only be made by excluding all other causes and results of all investigations (blood test, MRI scan or CT-scan of the brain and CSF analysis) will come back normal.

Primary epilepsy is the most likely cause of seizures if your cat:

1. has its first seizure at a young adult age
2. is normal between the seizures

Identification of the exact cause of the epileptic seizures is essential in choosing an appropriate treatment to control them.