Answer to questions raised in PEDIATRIC NEUROLOGY SEQ

Answer to questions raised in PEDIATRIC NEUROLOGY SEQ

DIAGNOSIS:

Benign childhood epilepsy with centrotemporal spikes.

Benign childhood epilepsy with centrotemporal spikes (BECTS) or benign rolandic epilepsy is the most common form of idiopathic epilepsy in childhood.

The peak ages of onset are between 5 and 10 years. However, onset may occur in children as young as 3 years or as old as 13 years. Affected children are typically developmentally and intellectually normal. There is a strong genetic predisposition to epilepsy in BECTS. A gene on chromosome 15q14 has been implicated in some families.

The seizures in BECTS are brief and infrequent. Approximately 10% of children will experience only one seizure. In the majority of children (70%), seizures will occur only two to six times. Twenty percent of patients will experience more frequent seizures. In approximately 70% of children, seizures occur only at night. The seizures in BECTS have a characteristic semiology, involving hemifacial clonic movements, speech arrest, dysarthria, and excessive drooling. Preceding paresthesias around the mouth, gums, cheek, or lips may occur. During the seizure, there may be involvement of the ipsilateral arm or leg, as well as secondary generalization.

The seizures usually last 1 to 2 minutes.

The EEG background in BECTS is normal in the awake and sleep states. Epileptiform paroxysms are described as focal, diphasic spike-and-slow-wave activity of medium to high voltage located over the rolandic or centrotemporal regions. Epileptiform discharges may occur either unilaterally or independently and bilaterally. A horizontal dipole with maximum spike negativity over the central and temporal regions with positivity in the frontal regions is also a classic EEG finding.

Characteristically in this disorder, spike-and-wave activity increases in frequency and amplitude during drowsiness and nonrapid eye movement (REM) sleep. Centrotemporal spikes may occur only during sleep in approximately 30% of children.

Spontaneous resolution of seizures by adulthood (18 years of age) occurs in almost all patients with BECTS and, thus, it is given the designation of a “benign” epilepsy. Some academic and behavioral problems have been reported in children with BECTS, but the overall prognosis for intellectual and neurologic outcome is excellent.

The patient is a healthy 9-year-old girl who presents after a simple partial seizure involving right facial jerking, drooling, and speech arrest. Her neurologic exam is normal.

Right facial twitching as well as speech arrest localize to the left centrotemporal, rolandic region.

The patient in this case presents with the classic features of a focal seizure in the setting of BECTS, but the diagnosis of BECTS can be made only when both the clinical history and the EEG findings are consistent with this syndrome. Other localization-related epilepsies caused by underlying structural lesions (trauma, cerebrovascular disease, tumor, neuronal migration abnormalities, mesial temporal sclerosis) should also be considered.

For a patient who presents to the emergency room with a new-onset focal seizure, a head CT scan, as well as basic laboratory work (basic chemistries, CBC, toxicology screen), may be warranted. A referral (inpatient or outpatient) for an awake and sleep EEG is indicated to evaluate for focal epileptiform activity. The diagnosis of BECTS may be assigned only when the clinical history as well as the EEG are consistent.

The role of neuroimaging in a patient with BECTS is controversial. If the clinical

history is consistent and classic bilateral, independent centrotemporal spikeand-

wave activity is found on the EEG, a brain MRI is not always performed.

However, if there are atypical clinical features or the EEG shows unilateral or atypical epileptiform activity, a brain MRI is typically recommended to rule out structural abnormalities.

Treatment with anticonvulsants is often unnecessary in BECTS as seizures are typically infrequent and occur primarily in sleep. However, when seizures are more frequent or occur during wakefulness, they may be disruptive to a child’s quality of life. A variety of anticonvulsants have been used in the treatment of BECTS and most are efficacious. However, carbamazepine, oxcarbazepine, and gabapentin have tolerable side effects and are most commonly used in clinical practice.