infantile epileptic spasms syndrome
An age-specific epileptic encephalopathy featuring brief axial muscle contractions, developmental regression, and hypsarrhythmia on EEG.
Full Definition
Infantile epileptic spasms syndrome (IESS), formerly known as West syndrome, is a devastating epileptic encephalopathy typically onset between 2-12 months of age. The condition is characterized by the clinical triad of epileptic spasms (brief, symmetric contractions of axial muscles often occurring in clusters), developmental arrest or regression, and hypsarrhythmia on EEG. Spasms may be flexor (jackknife), extensor, or mixed, and typically occur in series upon awakening. Early recognition and treatment with ACTH or vigabatrin is crucial for optimal outcomes, as delays in treatment are associated with worse developmental prognosis.
Usage
Usage note: Preferred modern term over 'West syndrome'. Note 'epileptic' not 'epileptogenic' spasms.
In Context
- "The 6-month-old was diagnosed with infantile epileptic spasms syndrome and started on ACTH therapy." — Treatment plan
- "Early treatment of infantile epileptic spasms syndrome is associated with better neurodevelopmental outcomes." — Clinical guideline