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Partial (focal) seizure

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Central nervous system
Central nervous system

Alternative Names    Return to top

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

Definition    Return to top

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

See also:

Causes    Return to top

All seizures are caused by abnormal electrical disturbances in the brain. Partial (focal) seizures occur when this electrical activity remains in a limited area of the brain. The seizures may sometimes turn into generalized seizures, which affect the whole brain. This is called secondary generalization.

Partial seizures can be further characterized as:

The abnormal electrical activity is due to an area of abnormal brain tissue. The abnormal tissue may have been present since birth or earlier (congenital), or may develop after a head injury, infection, stroke, or certain other conditions. In many patients, no obvious cause can be determined.

A partial 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.

Risk factors include any injury to the brain. This includes trauma, stroke, brain tumors, infections (such as meningitis), or prior brain surgery. A family history of these types of seizures may also increase your risk.

Symptoms    Return to top

Patients with focal seizures can have any of the symptoms below, depending on where in the brain the seizure starts. 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.

Other symptoms:

Exams and Tests    Return to top

It is extremely difficult to diagnose a single focal seizure. However, the diagnosis is easier to make in patients who have repeated, similar episodes --especially if there are risk factors such as a history of head injury. A doctor will diagnose this type of seizure based on the symptoms and after ruling out other medical conditions that can cause similar symptoms.

An EEG may show changes and possible the location of the cause of the seizure. This test can be normal in between seizures. A normal EEG does not rule out a seizure disorder.

Blood tests may be done to determine the cause of the seizures. This may include:

Tests for the cause may include procedures such as:

Treatment    Return to top

A person who has seizure for the first time should be taken to an emergency room. They may have a serious, underlying medical condition that needs to be treated.

FIRST AID

First-aid measures should be performed as appropriate.

If a person has repeated or prolonged seizures without regaining consciousness or returning to normal behavior, the body may develop a severe lack of oxygen. This an emergency situation - seek immediate medical help.

TREATMENT BY A MEDICAL TEAM

The health care team may need to take measures to protect the airway. This may include using tubes to keep the airway open. Breathing will be supported as needed.

If a cause is identified, treating the cause may stop seizures. Treatment may include medication, surgery to repair of tumors or brain lesions, or other therapies.

An isolated seizure due to an obvious trigger (such as fever or a drug) is treated by eliminating or avoiding that factor. An isolated seizure without an obvious trigger may not require treatment.

Antiseizure medicines may prevent or reduce the number of future seizures. Medicines may be used alone or in combination with another drug.

Patients who continue to have seizures despite several medications may benefit from a vagal nerve stimulator (implantable device similar to a heart pacemaker that stimulates a nerve in the neck) or from brain surgery to remove tissue responsible for causing the seizures.

Informational jewelry or cards (such as Medic-Alert bracelets) alerting others about the seizures may help a patient receive prompt medical treatment if one occurs. 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. Every state has rules about driving and seizures, but they are different from state to state.

Support Groups    Return to top

Epilepsy Foundation of America -- www.epilepsyfoundation.org

Outlook (Prognosis)    Return to top

How well a person does depends on the underlying cause of the focal seizures. Patients who have recurrent seizures that are not due to a temporary condition (for example, a drug side effect or infection) have a chronic condition called epilepsy.

Seizures that occur alone 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 lead to a long-term 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 lasts for a long time or if many seizures occur in close proximity.

Serious injury can occur if the seizure occurs while the person is driving or operating dangerous machinery. 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.

Possible Complications    Return to top

Women who are pregnant or planning to become pregnant may need to take additional medications or vitamins, such as folic acid supplements, to reduce the risk of birth defects associated with certain antiseizures drugs. Such women may need to be followed in a high-risk pregnancy clinic.

Certain antiseizure drugs may cause or worsen osteoporosis. People taking these medicines for a long period of time should discuss their risk of osteoporosis with their doctor.

When to Contact a Medical Professional    Return to top

Call your local emergency number (such as 911) if this the first time a person has had a seizure or a seizure is occurring in someone who is not wearing a medical ID bracelet and does not carry instructions explaining what to do in the event of a seizure.

If the person has had a seizure before, call for an ambulance if:

Call the health care provider if a person with seizures has new symptoms, inluding:

Prevention    Return to top

Generally, there is no known prevention for seizures. However, the following can reduce the chances of a seizure:

Reduce the chance of head injuries by wearing head protection and avoiding risky behavior.

References    Return to top

Foldvary-Schaefer N, Wyllie E. Epilepsy. In: Goetz, CG. Textbook of Clinical Neurology. 3rd ed. Philadelphia, PA: Saunders Elsevier; 2007: chap 52.

Krumholz A, Wiebe S, Gronseth G, et al. Practice parameter: evaluating an apparent unprovoked first seizure in adults (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology. 2007;69(21):1991-2007.

Pollack CV Jr. Seizures. In: Marx, JA, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 6th ed. Philadelphia, PA: Mosby Elsevier; 2006: chap 100.

Spenser SS. Seizures and Epilepsy. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, PA: Saunders Elsevier; 2007: chap 426.

Tomson T, Hiilesmaa V. Epilepsy in pregnancy. BMJ. 2007 Oct 13;335(7623):769-73.

Update Date: 6/19/2008

Updated by: Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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