What is the recommended documentation and treatment for absence seizures?

Documentation and Treatment of Absence Seizures

For absence seizures, the recommended documentation should include electroencephalography (EEG) with 3-4 Hz spike/polyspike and slow wave discharges, while first-line treatment includes ethosuximide, valproic acid, or lamotrigine, with ethosuximide being preferred for pure absence seizures.

Documentation Recommendations

EEG Documentation

• EEG is essential for diagnosing absence seizures, which are characterized by generalized 3-4 Hz spike/polyspike and slow wave discharges 1
• For accurate diagnosis, video-EEG monitoring is the gold standard, as it allows correlation between clinical manifestations and EEG patterns 2
• Continuous or repeated EEG monitoring is reasonable for patients who do not follow commands after seizure events 3

Clinical Documentation

• Document specific characteristics of the absence seizure:
  • Duration (typically seconds) 1
  • Level of impairment of consciousness (severe, moderate, mild, or inconspicuous) 1
  • Associated motor manifestations (clonic, tonic, atonic components) 1
  • Automatisms and autonomic disturbances if present 1
  • Precipitating factors (hyperventilation, photic stimulation, emotional factors) 1

Seizure Diary

• Digital app-based seizure diaries show higher precision (85.7%) compared to paper diaries (66.9%) for patient self-reporting 4
• Patients typically sense only about 10% of their absence seizures, making objective documentation crucial 5

Treatment Recommendations

First-Line Medications

• Ethosuximide is the preferred first-line agent for pure absence seizures with approximately 70% efficacy 1

  • Mechanism: Suppresses the paroxysmal three cycle per second spike and wave activity by depressing motor cortex activity and elevating CNS threshold to convulsive stimuli 6
  • Limitation: Not suitable as monotherapy if other generalized seizure types coexist 1

• Valproic acid controls absence seizures in approximately 75% of patients 1

  • Also effective for generalized tonic-clonic seizures (70%) and myoclonic jerks (75%) 1
  • Starting dose: 10-15 mg/kg/day, increased by 5-10 mg/kg/week to achieve optimal clinical response 7
  • Target therapeutic plasma concentration: 50-100 mcg/mL 7
  • Caution: May be undesirable for women of childbearing potential due to teratogenicity 1

• Lamotrigine may control absences in 50-60% of patients 1

  • Also effective for generalized tonic-clonic seizures 1
  • Caution: May worsen myoclonic jerks; skin rashes are common 1

Combination Therapy

• For resistant cases, a combination of ethosuximide, valproic acid, or lamotrigine may be necessary 1
• Low doses of lamotrigine added to valproic acid may have a dramatic beneficial effect in refractory cases 1
• Adjunctive medications to consider:
  • Clonazepam (particularly for absences with myoclonic components) 1
  • Acetazolamide as an adjunctive drug 1

Special Considerations

Atypical Absence Seizures

• Atypical absences are usually more difficult to treat and often require polytherapy 2
• These typically occur in patients with severe epilepsies and learning difficulties 2
• Prognosis depends on underlying etiology or associated epilepsy syndrome 2

Monitoring Treatment Response

• Absence seizures during sleep may indicate drug resistance and poor prognosis 8
• Automated absence detection systems can reduce EEG review time from 1-2 hours to 5-10 minutes 5

When to Consider EEG Testing

• Consider emergent EEG in patients suspected of being in nonconvulsive status epilepticus 3
• EEG should be performed when patients have persistent altered consciousness after a seizure 3

Common Pitfalls to Avoid

• Failing to recognize that absence seizures may be underreported by patients (patients typically sense only about 10% of their absences) 5
• Using medications that may worsen epilepsy, cognition, or behavior in patients with atypical absences 2
• Discontinuing antiepileptic drugs abruptly, which can precipitate status epilepticus 7
• Overlooking absence seizures during sleep, which may indicate drug resistance 8