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Epilepsy Information

Causes

This is a tricky question with no clear-cut answer. Often doctors can't pinpoint exactly what causes epilepsy in a particular individual. But scientists do know that these are some of the things that can make a person more likely to develop epilepsy:

• birth trauma (inadequate oxygen supply to the brain, blood incompatibility, or hemorrhage)
• perinatal infection
• anoxia
• meningitis, encephalitis, or any other type of infection that affects the brain
• brain tumors or strokes
• inherited disorders or degenerative disease, such as phenylketonuria or tuberous sclerosis
• head injury or trauma
• metabolic disorders, such as hypoglycemia and hypoparathyroidism
• cerebrovascular accident (hemorrhage, thrombosis, or embolism).

Signs and symptoms

Partial seizures

Arising from a localized area of the brain, partial seizures cause focal symptoms. These seizures are classified by their effect on consciousness and whether they spread throughout the motor strip, causing a generalized seizure.

A simple partial seizure begins locally and generally does not cause an alteration in consciousness. It is not uncommon for this type to present with sensory symptoms (lights flashing, smells, hearing hallucinations), autonomic symptoms (sweating, flushing, pupil dilation), and psychic symptoms (dream states, anger, fear). The seizure lasts for a few seconds and occurs without preceding or provoking events.

A complex partial seizure involves impairment in consciousness. Amnesia for the events that occur during and immediately after the seizure is a differentiating characteristic. During the seizure, the patient may follow simple commands. This type of partial seizure generally lasts for 1 to 3 minutes

Generalized seizures

As the term suggests, generalized seizures cause a generalized electrical abnormality within the brain. They can be convulsive or nonconvulsive and include several types.

• Absence seizures occur most often in children, although they may affect adults. They usually begin with a brief change in level of consciousness, indicated by blinking or rolling of the eyes, a blank stare, and slight mouth movements. The patient retains his posture and continues preseizure activity without difficulty. Typically, each seizure lasts from 1 to 10 seconds. If not properly treated, seizures can recur as often as 100 times a day. An absence seizure is a nonconvulsive seizure, but it may progress to a generalized tonic-clonic seizure.
• Myoclonic seizures (bilateral massive epileptic myoclonus) are characterized by brief, involuntary muscular jerks of the body or extremities, which may occur in a rhythmic manner. Consciousness is not usually affected.
• Generalized tonic-clonic seizures typically begin with a loud cry, precipitated by air rushing from the lungs through the vocal cords. The patient then loses consciousness and falls to the ground. The body stiffens (tonic phase) and then alternates between episodes of muscle spasm and relaxation (clonic phase). Tongue biting, incontinence, labored breathing, apnea, and subsequent cyanosis may also occur. The seizure stops in 2 to 5 minutes, when abnormal electrical conduction of the neurons is completed. The patient then regains consciousness but is confused and may have difficulty talking. If he can talk, he may complain of drowsiness, fatigue, headache, muscle soreness, and arm or leg weakness. He may fall into a deep sleep after the seizure.
• Atonic seizures are characterized by a general loss of postural tone and a temporary loss of consciousness. They occur in young children and are sometimes called "drop attacks" because they cause the child to fall.

Status epilepticus

Status epilepticus is a continuous seizure state that can occur in all seizure types. The most life-threatening example is generalized tonic-clonic status epilepticus, a continuous generalized tonic-clonic seizure without intervening return of consciousness.

Status epilepticus is accompanied by respiratory distress. It can result from abrupt withdrawal of anticonvulsant medications, hypoxic encephalopathy, acute head trauma, metabolic encephalopathy, or septicemia secondary to encephalitis or meningitis.

Unclassified seizures

This category is reserved for seizures that don't fit the characteristics of partial or generalized seizures or status epilepticus. Included as unclassified are events that lack the data to make a more definitive diagnosis.

Diagnosis

Clinically, the diagnosis of epilepsy is based on the occurrence of one or more seizures and proof or the assumption that the condition that caused them is still present.

Diagnostic information is obtained from the patient's history and description of seizure activity, family history, physical and neurologic examinations, and computed tomographic scanning or magnetic resonance imaging. These scans offer density readings of the brain and may indicate abnormalities in internal structures.

Confirming evidence

Paroxysmal abnormalities on the EEG confirm the diagnosis by providing evidence of the continuing tendency to have seizures. A negative EEG doesn't rule out epilepsy because the paroxysmal abnormalities occur intermittently. Other tests include serum glucose and calcium studies, skull X-rays, lumbar puncture, brain scan, and cerebral angiography.

Treatment

Generally, treatment of epilepsy consists of drug or medication therapy specific to the type of seizure. The most commonly prescribed drugs include phenytoin, carbamazepine, phenobarbital, and primidone administered individually for generalized tonic-clonic seizures and complex partial seizures.

For some people, surgery is successful if drugs fails. Avoiding known triggers and attention to lifestyle can sometimes improve seizure control.

Many people experience a single seizure, while approximately 50 per cent go on to have further seizures. It is not possible to know for certain who will have more than one seizure. The circumstances of the seizure, the family history or the test results might suggest that the risk of another seizure is higher in some people. Treatment aims to prevent seizures and maximise quality of life.

Prevention

If the seizures are related to another medical condition, identification and treatment of that medical condition is the key to prevention. If anticonvulsant medication is prescribed, taking the medication on the recommended schedule and not missing medication is important.

• Some people with epilepsy are quite sensitive to alcohol. If this pattern develops, avoid alcohol. Others may have seizures only after ceasing heavy alcohol intake. The key to prevention is avoidance of alcohol.
• Sleep deprivation and stress certainly may increase the frequency of seizures in some people with epilepsy.