Reversible central sleep events in type I Chiari malformation

Abstract

A 13-year-old girl with a 2-year history of snoring and witnessed sleep apnea, with occasional headache and poor academic performance, was referred for a sleep study. Physical examination was normal, with tonsil size of II/IV and no neurologic findings. She underwent a polysomnography (PSG) for suspected obstructive sleep apnea (OSA), but no obstructive events were found. The test revealed a slightly higher conventional central apnea index, where events are associated with arousal or oxygen desaturation (2.2/h) and other central breathing events without oxygen desaturations or arousals (Figs 1 and 2). Oxygen desaturation index was 1.2/h with a minimum oxygen saturation of 95%. Capillary blood gas analysis showed a pCO2 of 32 mmHg. Cerebral magnetic resonance imaging (MRI) revealed Chiari malformation type I (CM-I) associated with cervical and dorsal syringomyelia (Figs 3–5). A watchful waiting approach was taken. One year later, the PSG is completely normal (Fig. 6). Central apnea index is 0.2/h without any other events, and end-tidal pCO2 and capillary blood gas analyses are also normal.