Comparison of short- versus long-term ketogenic diet for intractable infantile spasms.

Purpose: To compare the prognoses between short-term (8 months) and conventional long-term (> 2 years) trials involving patients with refractory infantile spasms who successfully completed the ketogenic diet (KD).

Methods: Of 40 patients who achieved seizure-free outcomes and showed improvement in hypsarrhythmic patterns within 6 months of the KD, with a 3:1 fat to nonfat ratio as an add-on treatment, 16 patients were randomized into the short-term trial group and the diet was tapered throughout two additional months. Twenty-four patients were randomized into a long-term trial group, and 19 patients could successfully discontinue the diet after 2 years. Primary outcome measures included seizure relapse and frequency of 35 patients for > 12 months after successful completion of the KD.

Key Findings: Of 16 patients in the short-term trial group, two patients relapsed with clusters of spasms, and one patient had recurrence of occasional focal seizures. Of 19 patients in the long-term trial group, two patients progressed to Lennox-Gastaut syndrome and one patient experienced recurrence of occasional focal seizures with secondary generalization. An early response to the KD, evidenced by short latency before seizure freedom and disappearance of hypsarrythmia and cryptogenic etiology, may indicate a successful early discontinuation of the KD. Significant growth failure was complicated only in conventional long-term trial group.

Significance: Use of the KD for only 8 months in children who become spasm-free appears to be justified, with similar outcomes, recurrence rate, and less growth disturbance than a longer-term, traditional use.