Partial (focal) seizure Health Article

Definition

A partial seizure is an episode of abnormal electrical activity in one specific part of the brain.

Alternative Names

Simple seizure; Jacksonian seizure; Seizure - partial (focal)

Causes, incidence, and risk factors

All seizures are caused by abnormal electrical disturbances in the brain. Partial (focal) seizures occur when this electrical activity remains confined to a limited area of the brain; they may sometimes progress to generalized seizures, which affect the whole brain.

Partial seizures can be further characterized as simple (not affecting awareness and memory) or complex (affecting awareness and memory of events before, during, and immediately after the seizure, and affecting behavior).

The abnormal electrical activity results from localized areas of abnormal brain tissue. These areas may have been present since birth or earlier (congenital), or they may develop following head trauma, infections, stroke, and certain other conditions. In many patients, no obvious cause can be determined. Partial seizures are more likely to be caused by a definable lesion in adults than in children.

A partial (focal) seizure may occur at any age, as a single episode or as a repeated, chronic seizure disorder (epilepsy). They are seen less frequently in children than in adults, but still account for about 45% of pediatric seizure disorders.

Risk factors include any injury to the brain. This includes trauma, stroke, brain tumors, infections (such as meningitis), or prior brain surgery.

Symptoms

Patients with focal seizures can have any of the symptoms below. Patients with simple focal seizures do not lose consciousness and will be aware and remember the events that occur at the time. Patients with complex partial seizures will have abnormal consciousness and may or may not remember any or all of the symptoms or events surrounding the seizure.

• Abnormal motor control
  • Muscle contraction /relaxation (clonic activity) -- common
  • Affecting one side of the body (leg, part of the face, or other isolated area)
  • Abnormal head movements
  • Forced turning of the head
• Automatisms -- purposeless, complex movement (such as picking at clothes)
  • Abnormal mouth behaviors
  • Lip smacking
  • Chewing/swallowing without cause
• Forced turning of the eyes
• Abnormal sensations
  • Numbness, tingling, crawling sensation, etc.
  • May occur in only one part of the body or may spread
  • May occur with or without motor symptoms
• Hallucinations (visual, hearing, touch, smells, etc.)
• Abdominal pain or discomfort
• Nausea
• Sweating
• Flushed face
• Dilated pupils
• Rapid heart rate/pulse

• Black out spells -- periods of time lost from memory
• Changes in vision
• Sensation of deja vu
• Changes in mood or emotion

Signs and tests

The diagnosis is based on the symptoms, taking into consideration the patient's other history. It is extremely difficult to diagnose a single focal seizure. However, the diagnosis is easier to make in patients who have recurrent, stereotyped episodes --especially if there are risk factors such as a history of head injury.

Some of the tests that may be performed include:

• EEG -- this can show characteristic changes confirming partial (focal) seizures, and may show the focus (the location of the cause). A normal EEG does not rule out seizures.
• EEG monitoring over several days may be necessary in order to record an event while it is occurring.
• Head CT or head MRI scan -- these may show the location and extent of the lesion causing the symptom.

Treatment

Whenever someone has a seizure for the first time, he or she should be taken to an emergency room, as there may be a serious underlying medical condition which needs to be treated. First-aid measures should be performed as appropriate, including protecting the person from injury during the seizure, preventing him or her from inhaling vomit or mucus into the lungs, keeping the airway clear, and assistance with breathing.

Treatment of the causes may stop the seizures. This may include medication, surgical repair of tumors or brain lesions, and other treatments.

An isolated seizure with an obvious avoidable trigger, such as fever or toxic reactions, is treated by removing or treating the precipitating factor.

An isolated seizure may not require treatment. Findings on MRI or EEG may determine how likely recurrent seizures are and may help determine the need for ongoing treatment, such as anticonvulsants (anti-seizure medications). The response to these drugs varies, and medication and dosage may have to be adjusted repeatedly.

Multiple, repeated seizures are usually treated with anti-seizure drugs such as phenytoin or carbamazepine for preventive, long-term use. Follow-up includes review of the need for drugs and monitoring for side effects. Drugs may need to be continued indefinitely.

Some patients with seizures that are difficult to treat may respond to a vagal nerve stimulator -- a device that stimulates a nerve in the chest and reduces the number of seizures. Other patients may respond to surgery that removes the abnormal brain cells responsible for causing seizures.

Patients who have seizures that could result in loss of motor control or consciousness should be advised not to drive, swim alone, or engage in other activities during which a seizure could endanger themselves or others.

The patient might need to wear informational jewelry or cards (such as Medic-Alert) to aid in obtaining prompt medical treatment if a seizure occurs.