Disclosure
When evaluating a child who has experienced a first seizure, the clinician needs to address the following:
Seizures may occur in as many as 1% of children. Many children who experience a first seizure may never experience a second seizure. However, a seizure may be the initial presentation of a more serious medical condition. Epilepsy is a condition in which a child has 2 or more seizures without a proximal cause for the seizures.
Identification of the seizure etiology helps identify potential treatment alternatives and the prognosis for that child. Some common childhood seizures are observed in the following situations:
Many childhood seizures are categorized according to specific syndromes, including the following:
History Because the first seizure often is not witnessed by medical personnel, the medical history becomes the most important part of the evaluation. Ask the person who has witnessed the seizure to describe the event from its start to finish, as this is helpful in the evaluation of the seizure. In the history, a description (eg, the patient was staring with his eyes up and to the right) is more useful than a label (eg, the patient had a petit mal seizure). Elicit a history of chronic medical conditions (eg, diabetes), medications (eg, clozapine), changes in diet (eg, excessive water intake leading to hyponatremia), and recent or remote history of head trauma or CNS infections. A family history of epilepsy or febrile seizures, particularly among first-degree relatives, is also important in understanding the etiology. A history of developmental delay is also important in assessing risk of future events. Physical
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Initial laboratory evaluation of a first seizure can include serum studies for glucose, electrolytes, calcium, and magnesium. The American Academy of Neurology recommends that clinicians use their clinical judgment. Perform a CT scan if the patient has had a recent head trauma, has significantly altered mental status, has a significant headache, has papilledema, or has a bulging fontanelle. Consider a lumbar puncture (LP) in patients who have fever and a stiff neck or who have fever and are unconscious. If an indication for CT was present, obtain this prior to LP, as there may be a risk of inducing cerebral herniation with space-occupying lesions or obstructive hydrocephalus. If suspicion of CNS infection is high, appropriate empiric antibiotics should begin promptly. Steroids are currently thought to improve outcome in some forms of CNS infection and should be given before the antibiotics as a rapid infusion. LP is best obtained prior to antibiotic administration, but it can be obtained during or after, if technical factors would introduce a substantial treatment delay. Give particular attention to the laboratory evaluation of the neonate. Frequently, glucose and calcium abnormalities can be observed in the first week of life. When a metabolic abnormality is suspected in the neonate, also evaluate serum ammonia, serum for amino acids, and urine for organic acids. Ammonia levels greater than 200 mmol/L in neonates or 100 mmol/L in older patients are very suggestive of metabolic disease and emergent workup and treatment is indicated.
Consider EEG and MRI in a patient with a first seizure. These measures may not always be necessary. Perform an EEG to address specific concerns. For example, certain seizure types are associated with specific EEG patterns; therefore, an EEG may be helpful in classifying seizure type. An EEG does not determine whether the patient had a seizure or if the patient has epilepsy. For example, 10% of healthy individuals have an abnormal EEG, whereas 50% of patients with epilepsy have a normal first EEG. An EEG becomes very useful if the patient does not seem to awaken after an appropriate amount of time after the first seizure. In this setting, the EEG can determine if the patient is still having subtle seizure activity. A recent recommendation from the American Academy of Neurology suggested that all children with a first seizure should have an EEG examination performed. However, not all neurologists agree with this recommendation because even an abnormal EEG may not affect therapeutic recommendations. Even when an EEG is performed, it need not always be performed on an emergent basis. In many instances, delaying the EEG by 1 week or more improves its informational yield as postictal changes, which can mask epileptiform activity, can be seen for up to 1 week following seizures in children. Similarly, not all patients with a first seizure need an MRI. However, if the child has recurrent seizures, focal or new neurological deficits, and/or papilledema, an MRI scan will be useful. Patients who have clearly defined epileptic syndromes, such as petit mal epilepsy or benign rolandic epilepsy, do not need an MRI.
Anticonvulsants are used to decrease the probability of a second seizure. Unfortunately, most (if not all) anticonvulsants are not antiepileptics, that is, these medications do not cure epilepsy. In acutely ill children (eg, seizures associated with encephalitis), the chance of a recurrent seizure is high; therefore, medications that can be administered quickly through IV access, such as fosphenytoin or benzodiazepines, are useful. In some situations, such as febrile seizures, the probability of a second event is low; therefore, treatment should be withheld for a single short seizure. In other conditions, such as petit mal epilepsy or JME, the likelihood of a recurrent event is high; therefore, appropriate anticonvulsants (eg, valproate) should be administered early to the patient. In most childhood epilepsies, the goal is to keep the child seizure free for a period of time (1-2 years) or until an appropriate age when the child would no longer be expected to be at risk of having seizures.
Giving a definitive prognosis after a single seizure is difficult, but some general rules do apply. Children who have a single, short, generalized seizure along with normal neurological development and normal findings on neurological examination have a 40% chance of having a second seizure. In this same situation, a normal EEG portends a recurrence risk of only 25%, whereas an abnormal EEG portends a higher risk of recurrence (50-70%). Children with developmental problems, structural CNS lesions, or focal neurological deficits have a higher risk of recurrence. Identifying the seizure as part of a syndrome has additional predictive value. In febrile seizures, only 30% of patients will have a second seizure. Similarly, patients with benign rolandic epilepsy are not likely to have a recurrence, whereas patients with JME are highly likely to have a recurrence.
Inform the patient's family about the following:
If a child has a second seizure, place the child in a semiprone position to allow gravity to pull secretions and the tongue out of the airway. Attempt to keep the neck straight to keep the airway most open. Place no objects in the child's mouth. Most seizures last for less than 2 minutes; however, if a seizure lasts longer (more than 5 min), take the child to an emergency department for administration of medications to stop the seizures. If the seizure is the second unprovoked seizure (eg, no fever, illness, drug exposure, sleep deprivation, or proximate head trauma), contact the patient's primary physician or a neurologist because anticonvulsant therapy is frequently indicated. Children with the possibility of a having a second seizure should not engage in activities that are potentially harmful. They should not be allowed to take unsupervised baths (because of the risk of drowning) or to climb higher than 5 feet. Supervised swimming, bike riding (helmeted), and playing video games are considered by most neurologists to be safe activities. Older patients should sacrifice driving, according to the laws of their state. For instance, in the State of Wisconsin, patients need to be seizure free for 3 months before they can resume driving. After a single seizure, an appointment should be made with the child's primary care physician or a neurologist. This is useful in order to address any further questions the family has, review the need for further diagnostic testing, and discuss any further therapy. Direct families of patients to reliable sources of information. The Epilepsy Foundation of America provides comprehensive information. For excellent patient education resources, visit eMedicine's Brain and Nervous System Center. Also, see eMedicine's patient education article Epilepsy.
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