[Central sleep apnea syndrome as the first sign of type I Chiari malformation].

INTRODUCTION: Type I Chiari malformation consists on the caudal displacement of cerebellar tonsils through the foramen magnum. It is often asymptomatic, although it may display symptoms as a result of cerebellum, brainstem, high cervical spinal cord or the lower cranial nerve, involvement.

OBJECTIVE: We report our experience over the last 16 years. We have identified 16 patients with type I Chiari malformation. Only 2 cases showed common type I Chiari symptoms and just one had respiratory disorder as the first clinical sign.

CLINICAL CASE: A 15 year old girl presented with a 5 years' history of chronic daily cough aggravated by exercise. Snoring and sleep apnea had been noted by her mother for 1 year. The girl eventually suffered from migraine and diurnal hypersomnolence. The physical and neurological examination was normal with the only exception being the absence of bilateral nauseous reflex. A nocturnal polysomnography study demonstrated a pseudoperiodic pattern with apnea pauses associated to cycles of deep breathing, resulting in severe gasometric repercussion and bradycardia. Magnetic resonance imaging of the brain showed Chiari I malformation. Non-invasive mechanical ventilation treatment significantly improved the clinical symptoms and gasometric analysis.

DISCUSSION: Surgical posterior fossa decompression is discussed. Early decompression before appearance of irreversible neurological damage is recommended. It is associated with a significant reduction in the number of central apneas and sleep arousals. Surgical intervention is recommended in symptomatic patients and in cases of radiographic Chiari malformation or syrinx progression.