Update on Pediatric Epilepsy
The understanding of seizures and epilepsy has grown tremendously in the past decade, and many more treatment options have become available. Yet, pediatric epilepsy still remains a great challenge for clinicians to manage. This article describes how seizures and epilepsy are understood and classified today and how to approach the management of patients with seizures and updates the pediatrician on the newest approaches to epilepsy treatment.
Classification of seizures and epilepsy
The International League Against Epilepsy (ILAE) defines a seizure as “a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain” [1]. Diagnosis of seizures and epilepsy largely depends on being able to identify a seizure clinically. However, most seizures are not witnessed by medical professionals, and the diagnosis depends on a caregiver’s description.
Most seizures are characterized by unresponsiveness and eye opening. In fact, eye closure during a seizure is a sensitive indicator of pseudoseizure [2]. In addition, most patients who are having a seizure are unresponsive to painful stimuli. Parents of children with staring spells often say that the child does not respond to his or her name being called. This can be the case even with daydreaming. Parents are often asked to shake the child on the shoulder to see if they can abort the staring. If they cannot, it is more likely to be a seizure.
The ILAE has been working on a revision to the organization of seizures and epilepsy for many years. Their recent report has simplified the classification of seizures (Box 1) [3].
Box 1 Classification of seizures
Data from Revised terminology and concepts for organization of seizures and epilepsies: report of the ILAE commission on classification and terminology, 2005-2009. Epilepsia 2010;51(4):676–85.
It is to be noted that the term “focal” is used instead of “partial.” Focal seizures are no longer broken down into “complex partial” and “simple partial”. This terminology was thought to be confusing and misused. It is also to be noted that the use of simple and complex in terms of febrile seizures is completely unrelated to simple and complex partial seizures. Nevertheless, the commission recognizes that it is important to describe any alteration of consciousness as part of a seizure [3].
Absence seizures have been subcategorized further. A typical absence seizure involves an abrupt staring spell often accompanied by eyelid blinking and an abrupt return to responsiveness. There is no prodrome, no loss of tone, and no postictal phase. Often the children will be talking, then stop talking to stare into space for a few seconds, and then resume talking where they last left off. Atypical absence seizures are less abrupt; they last longer and can have postictal confusion. Myoclonic absence is an absence seizure with myoclonic jerks of the head, shoulders, and arms. Prominent eyelid myoclonus followed by absence seizure is also recognized as an absence subtype.
Myoclonic seizures are characterized by brief contractions of the whole body, or isolated parts of the body. A myoclonic jerk followed by the sudden loss of tone of the whole body is known as a myoclonic atonic seizure. Myoclonic atonic and myoclonic tonic seizures while a patient is standing can result in falls and injury.
Clonic seizure consists of rhythmic jerking of the body that can be asymmetric, even in a generalized clonic seizure. Tonic seizures involve sustained muscle contraction, and patients can appear to be in a decerebrate posture. A tonic-clonic seizure usually consists of a tonic phase in which the patient loses consciousness, falls to the ground, and is stiff for less than 30 seconds and then, a clonic phase in which the patient jerks all limbs for longer than 30 seconds, sometimes minutes. Tonic-clonic seizures have a postictal phase in which patients are lethargic and confused for up to an hour, or longer if sedative medications are given.
Focal seizures can consist of myoclonic jerks or can have tonic or clonic components. What distinguishes focal seizures is that they are thought to arise from one hemisphere. Sometimes this origin can be difficult to tell clinically. Also, focal seizures can just have sensory changes, or cognitive changes such as confusion, hallucinations, and staring. Both focal seizures and absence seizures can be described as staring spells, and it can be difficult to distinguish between them.
Infantile spasms are categorized as an “epileptic spasm.” It is unclear whether this type of seizure is focal or generalized, therefore, it has been categorized as “unknown.”
Classification of epilepsy
The epilepsies have a separate classification from seizures. For example, a patient has to have an absence seizure to have absence epilepsy, but patients with childhood absence epilepsy can have other types of seizures as well. Epilepsy describes a propensity for seizures because of an “enduring alteration in the brain” [1]. This alteration can be because of a known underlying structural cause, such as a remote encephalitis, or it can be because of a known epilepsy syndrome. The 1989 international classification of epilepsies categorized epilepsy syndromes as “idiopathic,” “symptomatic,” and “crytogenic” [4]. These terms have been abandoned because of their inaccuracy and inconsistency with new genetic and neuroscience knowledge. The commission now recognizes epilepsies called “electroclinical syndromes” (Box 2). These are a cluster of clinical symptoms and electroencephalographic (EEG) characteristics that appear at certain ages. In addition, there are “distinctive constellations,” which are also recognizable clusters of clinical symptoms but do not have the strong developmental component of the electroclinical syndromes.
Box 2 Electroclinical syndromes and other epilepsies (abbreviated)
Data from Revised terminology and concepts for organization of seizures and epilepsies: report of the ILAE commission on classification and terminology, 2005–2009. Epilepsia 2010;51(4):676–85.
It is beyond the scope of this article to describe every electroclinical syndrome, but the author describes a few of the syndromes in the other sections of this article.
Approach to seizures and epilepsy
Evaluation of a child with a seizure should always begin with an assessment of the cardiopulmonary status, including airway, breathing, and circulation. It is common during generalized tonic-clonic seizures for the patient to have increased secretions from the mouth, therefore it is recommended that unconscious seizure patients be placed lying on their side to allow secretions to escape and to prevent aspiration. Although it is not uncommon for parents of a child with seizures to request oxygen tanks to have at home, clinically significant hypoxia during a seizure is rare. Suctioning of the mouth can be helpful, especially in the hospital setting. The blood glucose level is frequently measured by paramedics in the field.
Besides an increase in respiratory secretions, other autonomic changes are frequently noted during a seizure. Most patients with complex partial seizure or generalized tonic-clonic seizures have tachycardia and hypertension. Changes in respiratory rate in either direction are frequent as well. In most seizure patients who have not been given antiepileptic medication, the cardiopulmonary changes are not severe enough to require resuscitation and mechanical ventilatory support. Other autonomic changes during a seizure can include flushing, pallor, sweating, bilateral pupillary dilation, abdominal pain, vomiting, and urinary incontinence [5].
Once it is established that the patient has stable cardiopulmonary status, the patient’s mental status should be assessed. Commonly, the patient is in a postictal state. If the patient had a generalized tonic-clonic seizure, the postictal state is characterized by the ceasing of limb movement, stupor or coma, and normalizing of the heart rate, blood pressure, and respiration. The length of the postictal period is related to the length of the seizure. Generalized tonic-clonic seizures lasting less than a few minutes are usually followed by a postictal stupor or coma of 5 to 30 minutes. The patient can remain depressed for longer, especially if given benzodiazepines to treat the seizure.
In rare cases, a patient who seems to be in the postictal state may be having nonconvulsive seizure activity. This situation is more likely if the original convulsive seizure was prolonged, meeting the definition for status epilepticus. The patient should be observed for normalization of vital signs and for gradual return of responsiveness. An EEG should be considered for patients who remain comatose. Status epilepticus is discussed in a separate section later.
After the patient is stabilized, a complete history and physical examination can be obtained. Questions and examination should be directed in an attempt to determine the cause of the seizure. Table 1 lists the common causes of seizures and the studies that can be done to help confirm the diagnosis.
Table 1 Common causes of seizures
| Cause of Seizure | Suggested Studies |
|---|---|
| Metabolic abnormalities: hypoglycemia or hyperglycemia, hyponatremia or hypernatremia, hypocalcemia or hypercalcemia, hypomagnesemia, uremia, liver failure, hyperammonemia | Basic chemistries, calcium and magnesium levels, liver function tests, ammonia levels |
| Infection: meningoencephalitis, sepsis, neurocysticercosis | Lumbar puncture, send cerebrospinal fluid for appropriate infectious titers/PCR, sepsis evaluation, head CT, MRI with gadolinium |
| Neoplasm, vascular malformation | Head CT, MRI with gadolinium |
| Trauma | Head CT |
| Inherited neurodegenerative disorder | Appropriate genetic testing |
| Toxic causes, drug withdrawal | Urine toxicology screen, ethanol levels, other specific drug tests |
| Perinatal stroke/asphyxia | Head CT, MRI |
| Congenital brain malformation | Head CT, MRI |
| Febrile seizure | Lumbar puncture in selected cases |
| Epilepsy | EEG, antiepileptic drug levels (to check for compliance) |
Abbreviations: CT, computed tomography; MRI, magnetic resonance imaging; PCR, polymerase chain reaction.
With an accurate history and physical examination, few to none of the studies in Table 1 will need to be performed acutely. Conversely, children with known epilepsy should still have investigations into the secondary causes of seizure, such as infection and trauma, if clinically warranted. The main piece of clinical information to obtain is to determine whether the child has returned to his or her baseline neurologic status. These children are only likely to need further studies on an outpatient basis. Children who remain lethargic after an appropriate postictal period need continued monitoring, possible admission, and further studies, such as lumbar puncture for viral encephalitis or subarachnoid hemorrhage or computed tomography of the head for subdural hematoma or hydrocephalus.
All children with a first-time afebrile seizure without an obvious secondary cause such as trauma should have an EEG [6]. EEG can be done as an outpatient if the patient is at the baseline neurologic status when presenting after the seizure. Antiepileptic drug therapy is generally not recommended after a first seizure, but this decision should be individualized [7]. There is no evidence that treating after the second seizure, as opposed to the first seizure, changes the long-term course or prognosis of the patient’s epilepsy.
Antiepileptic drugs
Medications are first line in the treatment of epilepsy. Once it is determined that a child has recurrent seizures, that is, epilepsy, initiating a daily medication in an attempt to prevent seizures is recommended. The choice of medication depends on many factors, including seizure type and syndrome, side effect profiles, forms of administration, drug interactions, underlying medical conditions, and cost.
There are many antiepileptic medications available in the United States. Tables 2 and 3
