Self-Limited & Absence Epilepsies

Self-Limited & Absence Epilepsies of Childhood

What You'll Learn

Febrile seizures: Most common childhood seizure type (2–5%); simple FS carry epilepsy risk of 1–2% (same as general population); no routine EEG/imaging per AAP; FEBSTAT links prolonged febrile SE → MTS → TLE
SeLECTS: Most common childhood focal epilepsy (15–25%); centrotemporal spikes with horizontal dipole; hemifacial sensorimotor seizures from sleep; remission by age 16 in virtually all
CAE vs JAE: CAE = dozens of absences/day, 3 Hz spike-wave, HV provokes >90%, 60–70% remit; JAE = less frequent absences, 80% GTC, typically lifelong treatment
CSWS/ESES: EEG pattern (SWI ≥50%) drives encephalopathy, NOT seizure frequency; overnight EEG is mandatory; treat with high-dose benzodiazepine pulse → corticosteroids
Drugs to AVOID in absence: CBZ, OXC, PHT, VGB — worsen absence seizures and may precipitate absence status
GRIN2A: Genetic link across the SeLECTS → LKS → CSWS spectrum (10–20% of CSWS/LKS)

HighYield Pearls

SeLECTS / BECTS: hemifacial twitching + drooling + speech arrest with preserved awareness, mostly nocturnal/on awakening → centrotemporal spikes; remits by 16; treat only if frequent (LEV, OXC, VPA); AVOID polytherapy
Panayiotopoulos (early-onset benign occipital, 3–6 yr): ictal autonomic features — vomiting, pallor, syncope — from sleep; seizures often >30 min (autonomic status); EEG multifocal shifting spikes; benign, AED often not needed
Gastaut (late-onset childhood occipital, 6–14 yr): elementary visual hallucinations + ictal blindness + postictal migraine-like headache; daytime; occipital spikes block on eye opening; only ~1/3 remit; treat if frequent
CAE: 4–10 yr, multiple brief absences with 3-Hz generalized spike-wave activated by hyperventilation; ethosuximide first-line (CAE trial: ETX > VPA > LTG for absence remission, ETX best attention profile)
Jeavons (eyelid myoclonia with absences): eye-closure–induced eyelid myoclonia + photoparoxysmal response + absences; LIFELONG — AVOID lamotrigine (may worsen); VPA/LEV/clonazepam preferred
AVOID Na-channel blockers (CBZ, OXC, PHT, GBP, PGB, TGB, VGB) in absence/myoclonic seizures — they worsen seizures and may precipitate absence/myoclonic status
Ethosuximide = absence only (no GTC coverage); switch to VPA/LTG if GTC develops
CSWS / ESES: continuous spike-wave in slow-wave sleep (≥85% NREM) + cognitive/language regression → high-dose benzodiazepine pulse, steroids/IVIG, clobazam; EEG burden drives the encephalopathy, not seizure count
Genetics to know: GRIN2A (atypical SeLECTS / LKS / CSWS spectrum), CHD2 & GABRA1 (CAE/JME spectrum), SLC2A1 / GLUT1 deficiency (early-onset absence + myoclonic-atonic phenotype — ketogenic diet)

🔍 Quick ReferenceEEG · Clinical · Treatment / prognosis

EEG signs

Centrotemporal spikes with horizontal dipole, activated by sleep → SeLECTS / BECTS
3-Hz generalized spike-and-wave activated by hyperventilation → Childhood absence epilepsy (CAE)
Multifocal high-amplitude spikes, shifting localization, occipital predominance → Panayiotopoulos syndrome
Occipital spikes that attenuate / block on eye opening (fixation-off sensitivity) → Gastaut late-onset occipital epilepsy
Photoparoxysmal response with eye-closure–induced generalized polyspike-wave → Jeavons (eyelid myoclonia with absences)
Continuous spike-wave ≥85% of NREM sleep (SWI) → CSWS / ESES

Clinical phenotype

Nocturnal hemifacial twitching + drooling + speech arrest, awareness preserved, school-age child → SeLECTS / BECTS
Ictal vomiting, pallor, syncope, prolonged seizure >30 min from sleep in a preschooler → Panayiotopoulos syndrome
Elementary visual hallucinations (colored circles) + ictal blindness + postictal migraine → Gastaut occipital epilepsy
Dozens of brief blank stares per day, provoked by hyperventilation in a 6–8 yr old → CAE
Rhythmic eyelid fluttering + upward eye deviation triggered by eye closure / bright light → Jeavons syndrome
Cognitive / language regression with nocturnal seizures and abnormal sleep EEG → CSWS — Landau-Kleffner variant

Treatment / prognosis

Ethosuximide first-line, best attention outcome (CAE trial) → Childhood absence epilepsy
Often no AED needed; if treated, LEV / OXC / VPA monotherapy; AVOID polytherapy → SeLECTS / BECTS
Lifelong epilepsy with high relapse; AVOID lamotrigine; VPA ± LEV / clonazepam → Jeavons syndrome
AVOID CBZ / OXC / PHT / GBP / PGB / TGB / VGB — worsen seizures, may trigger absence status → Absence & myoclonic epilepsies
High-dose benzodiazepine pulse → corticosteroids / IVIG, clobazam; treat the EEG, not just seizures → CSWS / ESES
Benign, self-limited, remits by adolescence even without therapy → SeLECTS & Panayiotopoulos

Febrile Seizures

Simple vs Complex Febrile Seizures

Feature	Simple FS	Complex FS
Duration	<15 minutes	≥15 minutes (febrile SE if ≥30 min)
Focal features	No — generalized (GTC)	Yes — clonic activity lateralized, eye deviation
Recurrence within 24 h	Single episode only	>1 seizure in the same febrile illness
Frequency	~70–75% of all FS	~25–30% of all FS
Risk of epilepsy	1–2% (same as general population)	4–6% (up to 10% with multiple complex features)
Todd paralysis	No	May occur after prolonged focal seizures

Recurrence Risk Factors

Age <18 months at first febrile seizure (strongest predictor)
Lower temperature at the time of seizure
Shorter duration of fever before seizure onset
Family history of febrile seizures (first-degree relative)
Complex features on the initial seizure
Overall recurrence rate: ~1/3 of children with a first FS

Investigation — AAP Guidelines

Simple FS: No routine EEG, no neuroimaging, no labs
LP: Consider if age 6–12 months with incomplete immunization or if meningeal signs present
Complex FS: Consider EEG if focal/prolonged/recurrent; MRI if abnormal neuro exam or developmental delay
Antipyretics do NOT prevent FS recurrence; continuous daily ASM prophylaxis NOT recommended

FEBSTAT Study

Prolonged febrile seizures (≥30 min) → acute hippocampal injury (T2 signal on MRI)
Subset develops mesial temporal sclerosis (MTS) → temporal lobe epilepsy (TLE)
Supports the “two-hit” hypothesis: prolonged febrile SE + predisposed brain → MTS → drug-resistant TLE

SeLECTS (Self-Limited Epilepsy with Centrotemporal Spikes)

Key Features

Formerly: BECTS / benign rolandic epilepsy
Most common childhood focal epilepsy — 15–25% of all childhood epilepsies
Onset: 4–10 years (peak 7–10); slight male predominance
Remission in virtually all by age 16; EEG typically normalizes by mid-to-late adolescence, often after clinical remission

Seizure Semiology

Hemifacial sensorimotor seizures: unilateral clonic jerking of face/mouth, tingling of tongue/lips/cheek
Drooling (sialorrhea) and speech arrest (oropharyngolaryngeal involvement) with preserved consciousness
Often from drowsiness, sleep onset, or just before awakening (sleep-wake transitions); ~75% are exclusively nocturnal; may secondarily generalize during sleep
Brief: 30 sec to 2 min; infrequent (most have <10 lifetime seizures)

EEG

Centrotemporal spikes: high-amplitude, biphasic/triphasic sharp waves at C3/C4 or C5/C6
Horizontal dipole: negative over temporal, positive over frontal (board favorite)
Sleep-activated: spike frequency markedly increases in NREM sleep
Bilateral independent in ~30%; normal background (essential to distinguish from encephalopathies)

Treatment

Many children require no treatment (infrequent, nocturnal, self-limited)
If treatment needed: LEV, CBZ, OXC (sulthiame in Europe)
Discontinue after 1–2 years seizure-free or by age 14–16
Avoid overtreatment — overtreatment carries more risk than the epilepsy itself

Atypical Evolution of SeLECTS

A small subset may develop more frequent seizures, cognitive decline, and EEG features of CSWS/ESES
Red flags: language regression, behavioral deterioration, declining school performance
If suspected → obtain overnight EEG to assess for spike-wave activation in sleep
Presence of GRIN2A variants associated with higher risk of atypical evolution

🔒

Continue reading — sign in

The full note has more clinical pearls, tables, and board-focused tips. Free account, no fee.