Epilepsy caused by other illnesses

Cause

Frequency

Seizure types

Treatment

Treatment is often quite simple and effective. The most frequently used drugs are gabapentin, lamotrigine, levetiracetam, oxcarbazepine, valproate, and clonazepam. Phenobarbital can be used if complex partial seizures are not involved, but it often gives tiredness, apathy and depression and should therefore be avoided.

A 69-year-old man was brought into the intensive care unit. It was suspected that he had had a stroke. Eight months earlier had had a stroke in the brain and had suffered paralysis of the right arm and leg, and a slight speech impairment. He recovered almost completely in the course of 1½ months.

This time he had been admitted because his wife had heard peculiar noises coming from the bedroom, where he was preparing for bed. She found him lying unconscious on the bed, having urinated in his pants. By the time he arrived at the intensive care unit, he had regained consciousness. His was aphasic and paralyzed in the right arm and leg. A CT-scan showed the scar from his first stroke, but there was no new stroke. Later on the same day his speech was nearly normal again, and the paralysis had disappeared. An EEG led to the suspicion of epileptic discharges.

We had by now decided that the patient had had a convulsion. Speech impairment and paralysis were typical symptoms of partial seizures, which in his case had become secondary generalized.

Treatment was started with carbamazepine and he has now been free of seizures for many years.

Frequency

Head trauma as a cause of epilepsy can be seen in about 10-15% of all persons with epilepsy. The risk of developing epilepsy after a blow on the head depends on many different factors. Age is a relevant factor, in that children more often develop seizures than adults. The force of the blow also plays a large role. Slight concussion rarely leads to epilepsy. A heavy blow on the head can lead to a long period of unconsciousness and in some cases, bleeding on the surface of the brain or the crushing of brain tissue. This often leads to the development of epilepsy.

Particular types of fracture of the scull, where bone splinters are forced into the brain, causing damage to the membranes and tissue, leads to epilepsy developing in up to 80% of cases.

Cause

Different mechanisms can lead to the development of a seizure, either immediately after the trauma or later on. At the time of the trauma the brain may lack oxygen due to the pinching of the blood vessels leading to it. This seriously irritates the nerve cells. This lack of oxygen, anoxia, can also be the result of an injury to the chest, which may cause breathing problems, or even cause breathing to stop.

When the brain is hurled against the inside of the scull, blood can ooze out into the spinal fluid or directly into the brain tissue. This greatly irritates the nerve cells. The brain, just like any other part of the body, repairs damaged areas with scar tissue. This tissue is a foreign body to the brain cells, which are irritated by it. Abnormal electrical discharges can result, which can cause seizures.

Epilepsy can begin immediately after the trauma, or first 6 months or many years later.

Seizure types

Many seizure types can occur, but most often they will be simple partial seizures caused by scar tissue in a limited area of the brain. If the temporal lobes are damaged, complex partial seizures can occur.

Generalized convulsive seizures are also frequently seen, presumably caused by a more general brain damage. It is also possible that the damage is more centrally localized, with the inhibitory network of nerves having been put out of action. In a few cases status epilepticus may be seen.

Treatment

A 14 year old girl was referred to the epilepsy clinic with simple partial seizures, with convulsions in her left arm and leg. The seizures had begun 6 months after she had been involved in a serious traffic accident. The car in which she was a passenger crashed head-on into a truck, and she suffered a fractured scull and brain lesions. For fourteen days she lay unconscious on the neurosurgical ward with paralysis of the left arm and leg, before she slowly began to recover, with the help of physiotherapy. When the seizures started she was still having difficulty concentrating, and limped a little with her left leg.

She was put on oxcarbazepine and became free of epileptic seizures.

Seizure types

Simple partial seizures are most often seen, also complex partial seizures with or without secondary generalized convulsions.

Brain tumors usually originate in the brain's grey matter or membranes, but they can also be so-called metastases, which originate from tumors in other parts of the body. They originate most commonly in the lungs, breasts or kidneys.

Frequency

The person usually has simple partial seizures. In many cases the person suffers from epileptic seizures for many years, without any other symptoms having appeared which might suggest that the seizures were caused by a tumor.

It is unusual to find a family history of epilepsy. In the beginning there are only rare seizures, but they gradually increase in strength and frequency. In time it becomes more and more difficult to control them with drugs. If a patient suddenly has status epilepticus with no apparent cause, a brain tumor may be suspected. After seizures, paralysis of an arm or leg on one side may be seen, or possibly speech difficulties lasting for hours. With time, psychic symptoms develop, leading to dementia.

All brain tumors, if left untreated, will sooner or later give rise to progressing neurological symptoms and signs.

Some tumors grow very slowly, 15-20 years passing from the time the epilepsy begins, until the tumor really gives problems. The course will depend on whether the tumor is benign or malignant, and if it can be operated on so that all tumor tissue can be removed.

The best drugs for treatment of the seizures are levetiracetam, vigabatrin, oxcarbazepine, carbamazepine, valproate, clobazam, clonazepam, phenytoin or rarely, phenobarbital, in that order.

In the case of the first drugs on the list, they should first be tried alone, then, if necessary, in combination. At the same time a decision must be made as to whether the tumor should be removed.

In the case of a drug resistant epilepsy the patient may be a candidate for surgery with removal of tumor and the epileptic focus.

In the case of an easily treated epilepsy caused by a benign tumor originating from the brain's tissues, it may be an advantage to delay surgery for as long as possible, as the operation can result in lasting neurological deficits appearing.

Even after the tumor has been removed, the anti-epileptic treatment should be continued unaltered, if the epileptic focus has not been removed. The seizures are not caused by the tumor itself, but by the scar its growth has caused. This scar will remain unless an attempt is also made to remove it during the operation. If there have been no seizures for 5 years, an attempt should be made to phase out the medication.

A 71-year-old woman was referred to the clinic with seizures which lasted for about 2 minutes, during which she imagined she could hear her bridge club friends talking behind her left shoulder. She did not like talking about these attacks, because she on the one hand felt that she must be going mad, while on the other hand the experience was so realistic that she did not quite know if it really had occurred or not.

By CT scanning her brain, we found a tumor that was too big to be operated on. Anti-epileptic treatment succeeded for a time in preventing attacks, but as the tumor grew they returned. As time passed her "friends" closed in on her and said "bad things" about her, although she could not say just what it was they "said". During the last part of her life she had to be treated for mental illness as well as epilepsy, as she developed a paranoid psychosis.

Definition

Many different infections can, in the acute phase, cause epilepsy. Bacterial meningitis can develop into encephalitis and eventually a brain abscess. Tuberculosis is seen in countries with widespread poverty and inadequate nutrition. A healed brain tuberculosis often causes epilepsy through the build-up of tumor-like tissue, which later calcifies.

In tropical and sub-tropical countries parasites can cause fluid-filled cysts to be formed in the brain (cysticercosis). These cysts can be large and can cause scars by exerting pressure on the surrounding brain tissue.

Malaria is also often a cause of epilepsy in these countries. Finally there are many viruses, such as the measles, herpes and the polio viruses, which can cause encephalitis and epilepsy.

Only about 4% of patients with bacterial meningitis will develop epilepsy. In the case of viral meningitis, the frequency depends on the age at which the person is affected. Newborn babies will nearly all develop epileptic seizures while the frequency among small children is less. If seizures do not occur during the period of acute inflammation, they seldom appear later.

When the illness begins the patient will as well as seizures, have fever, a stiff neck, and perhaps feel muzzy. He will have a headache, nausea, vomiting and be irritable. It is important that the patient be admitted to hospital, so that a lumbar puncture can be done to determine the nature of the infection. Further symptoms will depend on the scar size, whether there are fluid-filled cysts or calcifications and where in the brain these are located. In the past the mortality rate was high in cases of acute infection. Today most bacterial and some viral infections can be treated with antibiotics.

Patients often suffer after effects in the form of brain damage, mental changes and paralyses.

Treatment

The epileptic seizures are best treated with levetiracetam, oxcarbazepine, topiramate carbamazepine, vigabatrin, clobazam, clonazepam, valproate or phenytoin. Phenobarbital can be used in the case of simple partial seizures with generalized convulsions.

The infection should be treated with antibiotics at the same time.

Frequency

The cause of mental retardation can be congenital brain damage, limited or diffuse. This can be due to a malformation in which nerve cells have come to lie in the wrong place, or it can be a case of poor development of the convolutions of the brain. It can also be caused by hereditary brain disease, metabolic abnormalities, a chromosome fault, for example Down's syndrome, or brain damage suffered at birth.

Birth damage often results in the child being spastic. However, spastics often have normal intelligence. All the types of brain damage mentioned can lead to abnormal electrical discharges resulting in epileptic seizures.

Treatment

These people often have large brain lesions and therefore very severe epilepsy, which can be difficult to treat. It could be tempting to use many drugs at the same time in an attempt to control the seizures.

It should be noted that the mentally retarded can be particularly sensitive to many of the side effects these drugs have. Because of their underlying condition, it may be difficult to notice these side effects. The treatment of these patients is therefore a task which calls for a special effort, both in the choice of treatment and in it's control.

Vagus stimulation will most often be the best treatment in combination with some of the major drugs.

People who drink so much that they become dependent on alcohol run a large risk of developing epilepsy. The mechanism involved is a phenomenon called "kindling", which means to set alight or inflame.

If one gives rats alcohol, then stops giving it to them, so that they have withdrawal symptoms, and then gives them alcohol again, and repeats this many times, their seizure threshold will decrease gradually so that some will start having seizures even without the alcohol being withdrawn.

Some animals will develop seizures if surprised, or on hearing a sudden noise. This is called a "kindled" epilepsy. The theory is that the same may happen with people who have a high alcohol consumption. It has not been conclusively proved, but it is a fact that alcoholics suffer from epilepsy much more frequently than the general population. A contributing cause could be head trauma, as alcoholics often fall and hit their heads.

This type of epilepsy must not be confused with the abstinence convulsions or withdrawal symptoms which only occur after alcohol intake has been stopped or curbed after a period of heavy drinking. Withdrawal symptoms are often seen in persons who suddenly stop drinking, perhaps because they have thought better of it, or because they have run out of money for alcohol.

In abstinence convulsions there will often be other symptoms, such as palpitations of the heart, a red blotchy skin, sweating, anxiety and restlessness. These symptoms are known to many, in a milder form, as a hangover.

Treatment