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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.

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RESUMEN

Introducción: La malformación de Chiari tipo I consiste en el descenso de las amígdalas cerebelosas a través del foramen magno. Con frecuencia es asintomática, pero puede presentar clínica por afectación de cerebelo, troncoencéfalo, porción superior de la médula cervical y pares craneales bajos. Objetivo: Se presenta nuestra experiencia de 16 años con 16 casos de malformación de Chiari tipo I; sólo en 2 existen síntomas atribuibles a la anomalía de Chiari tipo I, y en una de ellas la primera manifestación clínica consistió en un trastorno respiratorio durante el sueño. Caso clínico: Niña de 15 años con tos crónica diaria, agravada con el ejercicio, de 5 años de duración. La madre observaba desde hacía 1 año que al dormir la niña roncaba y realizaba repetidamente pausas de apnea. Tenía cefaleas ocasionales e hipersomnolencia diurna. Las exploraciones física y neurológica fueron normales, salvo ausencia de reflejo nauseoso bilateral. El estudio polisomnográfico nocturno evidenció un patrón seudoperiódico con alternancia de pausas de apnea con ciclos de respiraciones profundas, con graves repercusiones gasométricas y sobre la frecuencia cardíaca. La resonancia magnética mostró anomalía de Chiari tipo I. La ventilación mecánica no invasiva supuso una mejoría clínica y gasométrica en la paciente. Discusión: La descompresión quirúrgica es discutida. Está indicada de forma precoz, antes de que aparezca daño neurológico irreversible. Se asocia con una reducción significativa en el número de apneas centrales y microdespertamientos. Se recomienda en casos sintomáticos o en casos con progresión radiológica de la anomalía de Chiari o de la siringomielia asociada (AU)

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 the 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 (AU)

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