EPILEPSY

Epilepsy – forms, diagnosis, therapy

Epilepsy is a disease of the brain whose cells discharge uncontrollably during a seizure. In both humans and animals, its successful management is of great importance for the patient’s environment and has a strong emotional component.

What happens in the brain during a seizure

An uncontrolled, high-frequency, sometimes rhythmic discharge of nerve cells develops in a so-called “epileptic focus”. As a result, neighboring nerve cells are included in these rhythmic discharges and thus spread over large parts of the brain. A patient’s seizures always spread along the same pathways and neuronal networks and, in the long term, always occur more easily. The brain’s ability to learn and remember can possibly support this phenomenon.

Forms of epilepsy in animals

Epilepsy is already described in sources from around 4000 years ago. The name comes from the Greek and means “seizure”, in Old German it was called falling sickness. In principle, all living creatures with a brain can be affected. It is known that even birds can have epileptic seizures.

We distinguish between different types of seizures of varying intensity in our pets. What they all have in common is a clouding of consciousness, usually also salivation, and the seizures are often accompanied by urination, defecation, rowing movements and emotional outbursts. Anxiety or clinginess can accompany seizures if the patient does not completely lose consciousness during the seizure. We also sometimes observe increased anxiety and attachment during the seizure-free period in epileptics.

Serial seizures consist of more than one seizure in 24 hours. A status epilepticus is a seizure lasting more than 5 minutes.

Possible causes of epilepsy

More than half of our epileptic patients have a genetic predisposition, so we speak of a hereditary form of epilepsy. However, all cerebral diseases or even diseases that only affect the brain’s metabolism have the potential to trigger epileptic seizures.

Poisoning can trigger so-called reactive epilepsy. Examples include insecticides and slug pellets. Malfunctions of internal organs such as the liver and kidneys can also trigger this reactive form of epilepsy.

Infections and structural changes in the brain can trigger so-called symptomatic epilepsy. This shows how important diagnostics are with regard to successful treatment.

Diagnostics

In addition to a thorough general examination, the clinical neurological examination is of great importance. Blood, urine and cerebrospinal fluid tests as well as MRI scans of the brain also provide valuable information. Patients with hereditary epilepsy will have normal findings in all examination procedures (diagnosis of exclusion). An EEG (brain wave measurement) is the only detection method that can show characteristic abnormalities in these patients.

Therapy

Reactive and structural epilepsy should, if possible, be treated according to its cause. In many cases, temporary, sometimes lifelong, antiepileptic treatment is necessary, as we know it from patients with hereditary epilepsy.

The aim of therapy is to achieve freedom from seizures and minimize the undesirable side effects of antiepileptic drugs.

The best treatment results are achieved in dogs that have had as few seizures as possible before starting treatment. The time factor is therefore crucial, which also speaks in favor of comprehensive diagnosis at an early stage.

In veterinary medicine, we have three approved active substances for long-term therapy: imepitoin, phenobarbital and potassium bromide. The latter is approved for combination treatment.

Phenobarbital and potassium bromide require serum controls for adjustment and are more likely to be associated with side effects such as unsteady gait, fatigue, hunger and thirst. The newer active ingredient, imepitoin, is much better tolerated.

If seizure control is inadequate, antiepileptic drugs can also be combined well. In difficult cases, other substances from human medicine can be used (e.g. gabapentin, levetiracetam, zonisamide).

Despite comprehensive diagnostics and intensive care, only around a third of patients can be made seizure-free. One third experience an improvement in seizures and one third of patients turn out to be resistant to treatment.

Studies on the therapeutic benefits of a change in diet suggest that medium-chain triglycerides, in particular capric acid, may have a positive effect on seizure control. Occasionally, the use of acupuncture has given rise to hopeful reports. Surgical options are generally beyond our financial means, although the use of a pacemaker to stimulate the vagus nerve has shown demonstrable effects in studies.