Absence Seizure

Diagnosis of Absence Seizures

The diagnostic evaluation for absence seizures involves a comprehensive clinical history, neurological examination, and targeted testing to confirm seizure activity and exclude other neurological conditions.

• Clinical History and Physical Examination:
  A detailed account of seizure characteristics—including onset, duration, frequency, and associated symptoms—is obtained from caregivers. A neurological examination is performed to identify any additional abnormalities or comorbid conditions.

• Electroencephalography (EEG):
  EEG is a noninvasive, painless procedure that records the brain’s electrical activity through electrodes placed on the scalp with conductive paste or an elastic cap.

  • Hyperventilation Protocol: Controlled rapid breathing may be used during the test, as it can precipitate absence seizures in many children.

  • EEG Pattern: During an absence seizure, the EEG typically shows characteristic 3-Hz spike-and-wave discharges, differentiating it from normal background activity.

• Brain Imaging:
  Magnetic resonance imaging (MRI) of the brain may be performed to exclude structural causes such as tumors, strokes, or other lesions. Since MRI requires the child to remain still for an extended period, sedation may be considered in younger children.

Treatment

The primary treatment for absence seizures is pharmacotherapy with antiseizure medications aimed at achieving complete seizure control with minimal side effects. The approach typically starts with the lowest effective dose and is adjusted as needed. If a child remains seizure-free for two or more years, medication tapering may be considered under medical supervision.

Commonly Used Medications

• Ethosuximide (Zarontin):

  • First-line therapy: Ethosuximide is often the preferred initial treatment for typical absence seizures.

  • Efficacy: Most children respond well, with a significant reduction in seizure frequency.

  • Potential Adverse Effects: Nausea, vomiting, somnolence, sleep disturbances, and behavioral hyperactivity.

• Valproic Acid:

  • Indications: Useful for patients with both absence seizures and generalized tonic-clonic seizures (grand mal seizures).

  • Adverse Effects: Nausea, decreased attention, increased appetite, weight gain, and rarely, pancreatitis or hepatotoxicity.

  • Reproductive Considerations: Valproic acid is associated with teratogenicity and should be avoided during pregnancy or preconception periods. Females of childbearing potential require thorough counseling regarding risks.

• Lamotrigine (Lamictal):

  • Efficacy: Considered less effective than ethosuximide or valproic acid for absence seizures but generally better tolerated.

  • Adverse Effects: May include rash, nausea, or mild gastrointestinal discomfort.

Ongoing Management

• Regular Monitoring:
  Periodic follow-up with EEG and clinical assessments ensures optimal dosing and early detection of breakthrough seizures.

• Tapering Therapy:
  If seizure control is maintained for an extended period, gradual medication reduction may be attempted under medical supervision.

• Individualized Care:
  Medication choice depends on the child’s age, seizure type, side effect profile, and comorbidities. In females approaching reproductive age, special considerations are required when selecting long-term antiseizure therapy.