Makindo Medical Notes

⚡ Absence seizures last only 5–20 seconds and end abruptly, with the child resuming activity as if nothing happened. Though brief, their frequency can significantly disrupt learning and quality of life.

💡 Terminology & Classification

• The older term “petit mal epilepsy” is now obsolete and should be avoided.
• Current ILAE (2017) classification recognises three main groups of absence seizures:
• Typical absences – sudden, brief impaired awareness, with 3 Hz spike-and-wave EEG; seen in childhood absence epilepsy (CAE) and juvenile absence epilepsy (JAE).
• Atypical absences – slower onset/offset, often longer; EEG shows < 2.5 Hz spike-and-wave; usually in epileptic encephalopathies such as Lennox–Gastaut.
• Absences with special features – include eyelid myoclonia (Jeavons), myoclonus, or automatisms during the episode.
• When documenting, specify absence seizure type and, if possible, the syndrome context (e.g. CAE, JAE, Lennox–Gastaut).

📌 About

• Part of the generalized seizure spectrum.
• Onset usually between ages 4–8, more common in girls 👧 than boys 👦.
• Classified as typical, atypical, and special feature absences.

🧬 Aetiology

• Often presumed genetic in origin.
• Sometimes associated with family history or subtle cortical network dysfunction.

🩺 Clinical Features

• 📉 May present with a recent decline in school performance.
• 👁️ Brief lapses in consciousness with open, blinking eyes ("daydreaming").
• 👄 Twitching of mouth or subtle automatisms may occur.
• ⏱️ Duration: usually < 30 seconds.
• 🔁 Frequency: can be dozens to hundreds daily.
• 🌬️ May be provoked by hyperventilation.

🔎 Investigations

• 🧾 EEG: Generalized 3Hz spike-and-wave discharges during attacks; interictal EEG often normal.
• 🧲 MRI: Used if atypical features or diagnostic uncertainty.
• 🧪 Screen for metabolic disorders when indicated.

🧠 EEG Example

💊 Management

• In pure childhood absence epilepsy, seizures often remit by ~12 years. Fewer than 10% later develop tonic-clonic seizures.
• ⚠️ Safety advice: avoid swimming unsupervised, climbing heights, or cycling on busy roads.
• First-line: Ethosuximide – effective but associated with rare aplastic anaemia, skin reactions, and hepatic/renal impairment.
• Alternatives: Lamotrigine (can cause severe skin reactions) or Valproate (risk of hepatotoxicity, pancreatitis, teratogenicity).
• Treatment decisions should balance seizure control vs. side effects and future pregnancy considerations (esp. with valproate).

📚 References

• Absence seizures in children – NCBI Review
• ILAE 2017 Classification of Seizures