A 3-year-old previously healthy boy is brought to the pediatric neurology clinic with a 4-week history of sudden-onset seizures. Parents describe brief jerking movements of both arms immediately followed by sudden collapse and falls. EEG shows a normal background with bursts of generalized discharges at 2–5 Hz. The pattern marked **A** in the diagram is consistent with which diagnosis and is associated with which seizure semiology?
A. Doose syndrome (myoclonic-atonic epilepsy) with characteristic myoclonic-atonic seizures causing drop attacks
B. West syndrome with hypsarrhythmia and infantile spasms
C. Childhood absence epilepsy with 3 Hz spike-and-wave and brief staring spells
D. Lennox-Gastaut syndrome with slow spike-wave activity and prominent tonic seizures
Explanation
Why Doose syndrome (myoclonic-atonic epilepsy) with characteristic myoclonic-atonic seizures causing drop attacks is right
The EEG pattern marked A — generalized 2–5 Hz spike-and-wave and polyspike-and-wave discharges with a normal background in a previously healthy 3-year-old with myoclonic jerks followed by sudden loss of tone and falls — is the hallmark of Doose syndrome (myoclonic-atonic epilepsy). The ILAE Classification (2017) and Nelson Pediatrics define the myoclonic-atonic seizure as a brief symmetric myoclonic jerk immediately followed by a sudden loss of postural tone (atonic component), producing characteristic drop attacks. This seizure type, combined with the 2–5 Hz generalized spike-and-wave pattern, is pathognomonic for Doose syndrome, which accounts for 1–2% of childhood epilepsies and typically presents between 7 months and 6 years (peak 2–4 years) in previously healthy children.
Why each distractor is wrong
Lennox-Gastaut syndrome with slow spike-wave activity and prominent tonic seizures: LGS presents with slow spike-wave at <2.5 Hz (often 1.5 Hz), paroxysmal fast activity, and tonic seizures. The 2–5 Hz pattern and myoclonic-atonic seizures are NOT features of LGS; tonic seizures in Doose syndrome suggest evolution toward LGS and worse prognosis.
Childhood absence epilepsy with 3 Hz spike-and-wave and brief staring spells: CAE presents with 3 Hz spike-and-wave and brief absence seizures (staring, unresponsiveness), not myoclonic-atonic seizures with drop attacks. The age of onset (typically 4–8 years) and seizure semiology differ from Doose syndrome.
West syndrome with hypsarrhythmia and infantile spasms: West syndrome (marked D in the diagram) presents with hypsarrhythmia, infantile spasms (flexor or extensor), and developmental regression, typically in infants <12 months. The 2–5 Hz pattern and myoclonic-atonic seizures are not features of West syndrome.
