Faced with a paroxysmal neurological event(s), the practitioner must first decide whether the event is a seizure, because this is the most significant clinical problem. Once an event has been determined to be a seizure, it must be further classified as to seizure type or seizure syndrome to determine appropriate work-up, prognosis, and treatment.

Seizures occur in about 8% of all people over a lifetime; however, the prevalence rate of epilepsy is between 0.5% and 1% of the population. Epilepsy begins before age 20 years in approximately 75% of patients (Holmes, 1987). Two different schemes are used in the classification of epileptiform events: classification by type of seizure and classification by epilepsy syndrome. The term seizure refers to the specific neurological event, such as an absence seizure or a tonic-clonic seizure, while the term epilepsy represents the chronic vulnerability or manifestation of seizure events. The term epilepsy syndrome refers to a full syndrome consisting of the type(s) of seizures seen in that syndrome, electroencephalogram (EEG) findings, typical age of patient, and typical prognosis. For example, absence seizure refers to the specific event of staring for several seconds; whereas absence epilepsy refers to the syndrome of a young, neurologically normal child whose EEG shows 3/second spike-wave discharges and whose seizures eventually remit in 90% of patients. The seizures and their corresponding epilepsy syndromes are divided into two broad categories: generalized and partial. By definition, primary generalized seizures are those that start simultaneously from both hemispheres. Partial seizures start from one location within a hemisphere (localization-related epilepsy). When a seizure focus spreads or generalizes to both hemispheres, the seizure and process is termed secondarily generalized seizures. The epilepsy syndromes are similarly divided into the generalized and partial epilepsies. The classification of seizures and the major childhood epilepsies is summarized in Table 46-1.

During the history, one must determine if the seizure has any features of a focal onset event: Did the seizure start or affect one part of the body more than the others? Was there an aura? The latter question is important because a well-defined aura certainly means that the seizure began focally. The aura of a seizure is actually just its focal onset. During an aura, the rest of the brain is “watching” that part of the brain have its seizure. In contrast, a generalized seizure does not have a well-defined aura. Consciousness requires one working cerebral hemisphere and an intact brainstem. A generalized seizure, however, affects the entire brain at its onset and thus leaves “no one there” to be aware of the spell. Determination of an aura, then, is extremely useful. Remember to ask both the observer and the child about the specific onset of the seizure. Young children may be unable to verbalize an aura and may just demonstrate unusual behavior or run to their parent to get help. Also, the aura or focal onset of a seizure may be so brief that it is not noticed before secondary generalization of the seizure occurs. Thus, a focal seizure does not necessarily have an identifiable aura.

As an initial step, nonepileptiform conditions such as those in Display 46-1 need to be considered and evaluated as appropriate for conditions such as cardiac arrhythmias, prolonged QT interval, etc. Evaluation of seizures per se usually includes obtaining a complete blood count (CBC), SMA20, EEG (preferentially containing sleep), and magnetic resonance imaging (MRI) scan. A noncontrast computed tomography (CT) scan is frequently used as an initial screen in the emergency department but is not by itself generally a sufficient neuroimaging technique when evaluating seizures. It should be followed by a contrast CT scan or, quite preferentially, a MRI scan. Lumbar puncture should be performed if meningitis or encephalitis is a consideration. Toxicology screen may also be appropriate.

The diagnosis of an epileptiform event is established by carefully considering the history and correlating the EEG findings.

The family needs to know that it is unlikely—although certainly not impossible—to be hurt or die from a seizure. The decision to treat with anticonvulsants is often made jointly by the family, the primary practitioner, and the neurologist. Factors in the decision include the type of seizures (including focality and duration), type of epilepsy syndrome, age of the child, family concerns, and EEG and MRI results.

The decision for each child must be individualized, taking into account the risks of seizures versus the risks of medication.

Status epilepticus is defined as either continuous seizure activity lasting at least 15 to 20 minutes or intermittent seizure activity over at least a 15- to 20-minute period, during which time the patient does not regain consciousness. Status epilepticus is a neurological emergency, although long-term neurological damage is unusual. A study by Shinnar (Maytal, Shinnar, Moshe, et al., 1989) showed that most of the neurological damage seen after status epilepticus can be traced to the underlying etiology, and that 98% of children presenting in status epilepticus due to either idiopathic epilepsy or fever had a normal neurological outcome. There are several recent reviews on the treatment of status epilepticus in children (Pellock, 1998; Sabo-Graham, et al., 1998; Tasker, 1998). The most practical points are discussed in the following section.