According to the Epilepsy Foundation, 120,000 persons younger than age 18 have a first seizure every year in the United States. Between 75,000 and 100,000 of them are younger than age 5 and their first seizure is a febrile one. What’s more, every year about 45,000 U.S. children younger than age 15 develop epilepsy—a diagnosis that applies when a person has had at least two unprovoked seizures. An epilepsy diagnosis indicates susceptibility to recurrent seizures.
This article defines seizures and related terms, describes types of seizures and their possible causes, and identifies appropriate interventions (including drug therapy) for children who experience them.
Differentiating seizures, status epilepticus, and epilepsy
A seizure is a transient episode of abnormal electrical brain activity, with an excessive discharge rate in a group of cerebral neurons that leads to involuntary changes in behavior, level of consciousness (LOC), sensation, and/or motor activity. A seizure may be prolonged or so brief it’s barely noticeable. Physiologic changes occurring during a seizure include altered cerebral blood flow, autonomic changes (such as tachycardia and blood pressure changes), increased glucose and oxygen consumption, and increased production of lactic acid and carbon dioxide.
During the period just after a seizure (postictal period), memory and intellectual functioning may be impaired, but this effect is transient. Unless prolonged, seizures rarely cause lasting effects on the brain. When prolonged, though, a seizure may lead to permanent neurologic damage from lactic acidosis, hypoglycemia, and other consequences of autonomic changes and altered cerebral blood flow. The risk of brain damage rises with status epilepticus—defined as a seizure lasting 30 minutes or more or a series of seizures in rapid succession without the person regaining consciousness between seizures.
Seizure disorder, or epilepsy, is diagnosed when a person has had two or more seizures not provoked by some other condition, such as hypoglycemia, hyponatremia, fever, alcohol use, or drug abuse. Diagnosis of a specific epilepsy syndrome is based on such factors as the patient’s age at onset, family history, seizure type and frequency, electroencephalographic (EEG) pattern, and neuroimaging results.
What causes seizures?
Seizures can stem from a wide range of conditions. A febrile seizure—the most common type in young children—is linked to fever in a child from age 6 months to 5 years. Other possible causes of seizures include:
- infections, such as meningitis, encephalitis, or brain abscess
- metabolic disorders, including hypoglycemia, hypocalcemia, hypoxia, and inborn errors of metabolism
- neurologic, developmental, traumatic, or vascular abnormalities; for instance, birth injuries with resultant stroke or intracranial hemorrhage, hypoxic-ischemic encephalopathy, focal cortical dysplasia, head trauma, and such conditions as tuberous sclerosis or Sturge-Weber syndrome (a rare congenital disorder marked by a port-wine stain birthmark)
- drug, alcohol, and other toxicologic exposures.
In about 70% of patients with seizures, no cause is found. These seizures are termed idiopathic.
While numerous factors can cause a single seizure, in epilepsy the brain is susceptible to recurring seizures from an underlying condition affecting the brain’s electrical energy. Epilepsy can result from damage to the brain’s electrical system stemming from the factors described above, or it may be linked to genetic conditions or a combination of genetic and environmental factors.
Types of seizures
Seizures are broadly classified as partial or generalized. In a partial seizure, onset occurs in a discrete focal area of the brain; the seizure may spread to both hemispheres and become generalized. In contrast, a generalized seizure originates from both hemispheres.
Partial seizures can be categorized further as simple or complex.
- Simple partial seizures include those that cause motor signs, somatosensory or special sensory symptoms (such as visual, auditory, or olfactory symptoms), autonomic symptoms, or psychic symptoms. LOC remains unimpaired.
- With a complex partial seizure, LOC changes. This may begin as a simple partial seizure followed by impaired LOC, or LOC may be impaired at the onset.
Types of generalized seizures include the following:
- An absence (petit mal) seizure is marked by sudden transient loss of awareness that typically lasts 10 seconds or less. The facial expression is blank.
- A myoclonic seizure is characterized by jerking of trunk and arm muscles in conjunction with an abrupt head drop. No loss of consciousness occurs.
- In a clonic seizure, extremity muscles jerk rhythmically as they alternately contract and relax.
- A tonic seizure involves sustained spasmodic muscle contractions with rigidity.
- A generalized tonic-clonic (grand mal) seizure begins with a tonic phase of sustained muscle rigidity, commonly accompanied by pallor, eye deviation, and incontinence. A clonic phase follows, marked by rhythmic jerking of extremities. Mental status is impaired during both the seizure and immediate postictal period.
- An atonic seizure has an abrupt onset and causes loss of consciousness and muscle tone.
Although a generalized seizure tends to be accompanied by impaired LOC, sometimes it’s too brief to discern impaired consciousness. The most common type of pediatric seizure is a generalized tonic-clonic seizure.
Evaluating a child for seizures
A child who has had a febrile seizure must be evaluated to identify the cause and rule out life-threatening infections. Anticonvulsant medications aren’t recommended after a first-time febrile seizure.
A child who has had two or more unprovoked seizures requires a full work-up, including an evaluation by a pediatric neurologist, EEG, and magnetic resonance imaging (MRI). An MRI is the best radiologic test for finding subtle abnormalities, such as focal cortical dysplasia and hippocampal sclerosis. However, computed tomography may be done urgently to rule out a brain tumor or an intracranial hemorrhage.
Intervening for status epilepticus or seizures lasting more than 5 minutes
For a child with status epilepticus, immediate priorities are airway management and seizure termination. Secure the patient’s airway, breathing, and circulation. As needed, give oxygen, support ventilation, and establish I.V. access. To stop the seizure, be prepared to administer such drugs as lorazepam, diazepam, midazolam, phenytoin, or phenobarbital. (For first-aid guidelines for parents, see the box below.)
Teaching parents about first aid for seizures
Seizures commonly occur outside a healthcare setting, so be sure to teach parents of children with a history of seizures what to do the next time a seizure occurs. Inform them that many seizures cause only a brief period of unresponsiveness and don’t require first aid. Otherwise, provide these instructions.
For a generalized tonic-clonic seizure, teach parents to stay calm and follow these guidelines:
Explain to parents that various symptoms may occur right after the seizure, including memory loss, confusion, depression, fear, and feelings of frustration or embarrassment. Tell them they may notice the child has bitten the tongue, has bruises or other injuries, or has lost bladder or bowel continence. Other symptoms may include difficulty talking, exhaustion, headache, nausea, vomiting, thirst, or weakness. Inform them that a condition called Todd’s paralysis—weakness on one side of the body—may last from 30 minutes to several hours.
Whether to initiate antiseizure drug therapy after a single seizure is an individualized decision, as the risk of a second seizure in an otherwise normal child is low. An abnormal EEG or signs and symptoms of neurologic impairment are indications for treatment. The ultimate goal of drug therapy is to prevent or control seizures with minimal adverse effects. Choice of medication is influenced by the child’s age, seizure type, potential adverse effects, and whether a specific epilepsy syndrome is identified. (Click the PDF icon above for a guide to commonly used antiseizure medications in children.)
If medications fail to control seizures or cause unacceptable adverse effects, other treatments are considered. Options include vagus nerve stimulation (VNS) and a ketogenic diet. Usually, the child continues to take antiseizure medications at a reduced dosage after starting other treatments.
VNS therapy is recommended only for adults or children older than 12. A small battery is implanted subcutaneously, and electrodes are threaded under the skin and attached to the vagus nerve. The electrodes send small electrical pulses along the vagus nerve to the brain to prevent seizures. During a seizure, a magnet may be swiped over the VNS to shorten the seizure or reduce its severity.
When two or more medications fail to control seizures, a ketogenic diet may be tried. In this diet, roughly 80% of calories come from fat; the diet mimics starvation by forcing the child to burn fat calories for energy. Although it’s unclear how the diet controls seizures, it has been found to improve seizure control in about one-third of children and eliminate seizures in another third.
For severe intractable epilepsy, surgical intervention may be recommended, such as resection of focal cortical dysplasia, hemispherectomy, or corpus callosotomy.
A seizure in a child is frightening for the child, parents, and bystanders—and can be challenging for healthcare providers. But with appropriate evaluation and treatment, most pediatric seizures can be adequately controlled or even eliminated.
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