[Symptomatic West's syndrome: specific etiological link to unexpected response to treatment]

It has been known that patients with symptomatic West Syndrome (WS) generally show poor responses to classic treatment, either steroids or antiepileptic drugs (AED). However new evidences arose in the last few years showing that particular association of WS with Down Syndrome (DS), type 1 Neurofibromatosis (NF1) and cerebral palsy (CP) with periventricular leukomalacia (PL) tend to behave as cryptogenic or idiopathic cases showing control of infantile spasms (IS) and disappearance of hypsarrhythmia after treatment. The special case of vigabatrin as treatment for IS in babies with Tuberous Sclerosis is also an example.

We studied 15 patients with WS and DS with a follow-up of 1.5 to 9 years, 5 patients with WS and NF1 followed-up form 2 to 6 years and 10 patients with WS associated with CP and PL followed-up during 2.5 to 12 years. Seizures frequency, EEG and responses to treatment were evaluated.

1. WS and DS: IS had onset at a mean age of 6.5 months. No other type of seizures was registered. EEG showed typical hypsarrhythmia in 12 cases and asymmetric hypsarrhythmia 3. IS disappeared and EEG were normalized after 15 days of treatment in 10 patients and after 6 months in other 4 patients. Three patients presented myoclonic seizures and one motor partial seizures during follow-up, all of them responding to AED. 2. WS and NF1: Onset of IS took place between 4 and 9 months of age. EEG were hypsarrhythmic in all 5 patients. Four of them were seizure free after usual steroids treatment and showed no relapse during follow-up. 3. WS and CP associated with PL: These were 9 males and 1 female with IS starting at a mean age of 6.5 months, without history prior seizures. All EEG showed hypsarrhythmia. IS stopped and EEG became normal during the first month of treatment in 9 patients. In the other one the IS arrested with the use of vigabatrin 10 months after onset.

Patients with these particular etiologies associated with WS do not behave as the usual symptomatic cases of WS in their response to classic treatment of IS. In fact the control of IS and normalization of EEG had been as good or better than in cases of cryptogenic WS. Care should them be taken not to generalized the usual concept about poor prognosis of WS in the so called symptomatic cases.