Prevalence of pediatric periodic leg movements of sleep after initiation of PAP therapy

Positive-airway-pressure (PAP) is a treatment for obstructive-sleep-apnea (OSA). In adults, initiation of PAP-therapy may unmask periodic-limb movements-of-sleep (PLMS). We present a series of children in whom PLMS was aggravated or induced following initiation of PAP therapy. Methods: Retrospective analysis was performed on children who had PAP-studies performed over a 3-year period. Children with OSA without significant PLMS on baseline studies and who then showed a periodic-limb-movement-index (PLMI) (>5/hr) during titration with PAP-therapy were identified. Charts were reviewed for demographics, OSA severity based on apnea hypopnea index (AHI), PLMI, PLM-arousal-index (PLMAI) and pressures titrated. Results: Two hundred fourteen PAP-titration studies (151 on continuous positive airway pressure [CPAP] and 63 on bilevel positive airway pressure [BiPAP]) were done. Eleven (10 on CPAP, 1 on BiPAP) met study criteria. Eight patients were boys. The median age was 12 years (range 6 months-18 years). On baseline studies, median AHI was 5/hr (range 1.5-32/hr), median PLMI was 1/hr (range 0-4/hr) and median PLMAI 0.3/Hr (range 0-2/hr). On titration studies, pressures ranged from 4 to 14 cm of water, median AHI was 0.5/hr (range 0-1), median PLMI was 12/hr (range 5-55/hr) and median PLMAI 9/hr (range 0-25). PLMS were seen predominantly during N1, N2 sleep and on PAP of >7 cm of water. One patient had resolution of PLMS at 1-year follow-up. Conclusion: PLMS were seen in 5.1% of children after initiation of PAP. OSA may mask PLMS, which appears as breathing improves. Alternatively, PAP may unmask or induce PLMS. PLMS may potentially be a cause of treatment failure in children on recent-onset PAP therapy.