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
- 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.
Expectations (prognosis)
The outlook is largely determined by the underlying cause of the focal seizures. Patients who have recurrent seizures that are not due to a temporary condition (e.g., a drug side effect or infection) have a chronic condition called epilepsy.
Seizures that occur singly or in a closely associated group are commonly triggered by an acute condition such as brain injury and may occur as an isolated incident, or they may develop into a chronic seizure disorder. Seizures within the first 2 weeks of a brain injury do not necessarily mean that a chronic seizure disorder will develop. EEG and MRI findings may help determine whether the condition is likely to become chronic.
Death or permanent brain damage from seizures is rare, but either can occur if the seizure is prolonged or if many seizures occur in close proximity (status epilepticus).
Serious injury can occur if the seizure happens while the person is driving or operating dangerous equipment. These activities may be restricted for people with poorly controlled seizure disorders.
Infrequent seizures, however, need not severely restrict lifestyle. Work, school, and recreation do not necessarily need to be restricted, but precautions should be taken to reduce risks if a seizure should occur.
Complications
- Generalized seizures
- Epilepsy (recurrent seizures)
- Prolonged or closely occurring seizures (status epilepticus)
- Injury from falls, bumps, biting self
- Injury caused by a seizure during driving or operating machinery
- Aspiration pneumonia
- Permanent brain damage (stroke or other damage)
- Side effects of medications (with or without observable symptoms)
- Complications of surgery
- Women who choose to get pregnant should inform their doctor in advance for appropriate adjustments in medications (many of the anti-epileptic medications can cause birth defects)
Calling your health care provider
Call your local emergency number (911) if this the first time a person has had a seizure or a seizure is occurring in someone without a medical ID bracelet (instructions explaining what to do). In the case of someone who has had seizures before, call the ambulance for any of these emergency situations:
- This is a longer seizure than the person normally has, or an unusual number of seizures for the person
- Repeated seizures over a few minutes
- Repeated seizures where consciousness or normal behavior is not regained between them (status epilepticus)
Call your health care provider if any new symptoms occur (including possible side effects of medications):
- Drowsiness, restlessness, confusion, sedation
- Nausea/vomiting
- Rash
- Loss of hair
- Tremors or abnormal movements
- Problems with coordination
- Fevers, infections
Prevention
Treating the underlying disorders may reduce the risk of further seizures. In most cases, the seizures may not be preventable.
Avoid head injury by wearing helmets during risky activities, and avoid illegal drug use or excessive alcohol intake.
| • | Seizures |
| • | Generalized tonic-clonic se... |
| • | Epilepsy |
| • | Aspiration pneumonia |
| • | Stroke |
Reviewed By: Daniel Kantor, M.D., Director of the Comprehensive MS Center, Neuroscience Institute, University of Florida Health Science Center, Jacksonville, FL. Review provided by VeriMed Healthcare Network.
