An 11-year-old boy is brought to the emergency department by ambulance after he briefly lost consciousness. The patient's mother found him on the kitchen floor shaking and jerking. She believes that he was out of her sight for only a few minutes. When asked about any other abnormal behaviors, she says that her son often stares into space and does not respond to questions during these episodes. The patient has no known medical conditions or history of recent illnesses. He is afebrile with normal vital signs. The patient seems sleepy but is oriented to time and place and has no abnormalities on physical examination. Several hours later, he is alert and says that he wants to go home. Which of the following agents is the best long-term treatment for this patient?
Seizure types | Medication | |
Generalized onset (both hemispheres) | ||
Tonic-clonic |
| Broad spectrum*: levetiracetam, valproic acid |
Myoclonic |
| |
Atonic |
| |
Absence |
| Ethosuximide |
Focal onset (single hemisphere) | ||
Aware |
| Narrow spectrum: phenytoin,** carbamazepine, gabapentin |
Impaired awareness |
| |
*Can be used for both generalized & focal seizures. **Can be used for management of status epilepticus. LOC = loss of consciousness. | ||
This patient with frequent staring spells (ie, absence seizures) and an unprovoked tonic-clonic seizure most likely has undiagnosed juvenile absence epilepsy. Absence seizures are characterized by momentary lapses in consciousness (~10 seconds) associated with a classic 3-Hz spike-wave pattern on electroencephalogram. Younger children with absence seizures typically do not develop other seizure types; however, later onset (eg, age 10-12) of absence epilepsy is associated with an increased incidence of generalized onset tonic-clonic or myoclonic seizures.
Although a first-time unprovoked seizure may not require treatment, this patient has had multiple seizures, including both absence and tonic-clonic seizures. Ethosuximide is the preferred first-line agent for the treatment of isolated absence seizures; however, it does not suppress tonic-clonic seizures (Choice B). Treatment with a broad-spectrum antiepileptic such as valproic acid is required in these patients because it is effective for both absence and tonic-clonic seizures.
(Choices A, C, and D) Carbamazepine, phenytoin, and gabapentin are narrow-spectrum antiepileptics that can be used to treat focal onset seizures (including focal onset seizures that progress to bilateral tonic-clonic seizures). However, they are not effective for treating generalized onset seizures (eg, absence, myoclonic) which can actually be worsened by treatment with carbamazepine or phenytoin.
Educational objective:
Older children with absence seizures may also develop generalized onset tonic-clonic or myoclonic seizures. Although ethosuximide is effective against isolated absence seizures, it is not effective for tonic-clonic seizures. Valproic acid is a broad-spectrum antiepileptic that treats both types of seizures.