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Otolaryngologic Manifestations of Arnold-Chiari Malformation. Syboney Zapata, M.D., F.A.A.P. Pediatric Otolaryngology Austin Ear, Nose, & Throat Clinic. Objectives. Recognize symptoms of ACM pertinent to ENT Discuss differential diagnosis Review diagnostic studies.
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Otolaryngologic Manifestations of Arnold-Chiari Malformation Syboney Zapata, M.D., F.A.A.P. Pediatric Otolaryngology Austin Ear, Nose, & Throat Clinic
Objectives • Recognize symptoms of ACM pertinent to ENT • Discuss differential diagnosis • Review diagnostic studies
Arnold-Chiari Malformation • Herniation of cerebellar tonsils through foramen magnum • Neuronal impairment of brainstem, upper spinal cord, & cranial nerves
Symptoms of ACM Pertinent to the Otolaryngologist Auditory/vestibular dysfunction Vocal cord paralysis Sleep apnea
Vestibular Symptoms in Cerebellar Disorders • Cerebellum largely involved in COORDINATION • Cerebellar dysfunction presents as unsteadiness, clumsiness, and difficulty with stabilizing eye movements
Mechanism of Auditory/Vestibular Symptoms • Direct pressure on vestibular areas • Increased fluid pressure throughout the brain • Increased pressure of inner ear via cochlear aqueduct
Mechanism of Auditory/Vestibular Symptoms • Further stretching of elongated nerves • Bending of 8th nerve over bony edge of porus acousticus • Compression of brainstem nuclei
Auditory/Vestibular Symptoms in ACM • Sensorineural hearing loss • Vertigo & Dizziness • Nystagmus (Downbeating) and Poor Pursuits
Diagnostic Evaluation of Auditory/Vestibular Symptoms in ACM • Electronystagmography (ENG) • Rotational chair testing • Vestibular Evoked Myogenic Potential Testing (VEMP) • Electrocochleography testing (ECOG) • Fistula testing • Moving platform posturography
Diagnostic Evaluation of Auditory/Vestibular Symptoms in ACM • Electronystagmography (ENG) • Rotational chair testing • Vestibular Evoked Myogenic Potential Testing (VEMP) • Electrocochleography testing (ECOG) • Fistula testing • Moving platform posturography
Electronystagmography • Determines whether or not dizziness is due to inner ear disease • Excellent for diagnosis of unilateral ear disorders • 4 main parts: - Calibration test - Tracking test - Positional test - Caloric test Intended to diagnose CNS disorders
Rotational Chair Testing • Determines whether or not dizziness is due to inner ear or brain disorder • Obtained in addition to ENG • 3 main parts: - Chair test - Optokinetic test - Fixation test
Vocal Cord Paralysis Flexible laryngoscopy demonstrates bilateral vocal cords in the paramedian position and no mobility with vocalization
Vocal Cord Paralysis • Congenital TVC paralysis • ACM accounts for most central neurologic causes of bilateral TVC paralysis • Tracheostomy often necessary
Sleep Apnea • Central Apnea: Cessation of both airflow and respiratory effort • Obstructive Apnea: Cessation of airflow in the presence of continued respiratory effort • Mixed Apnea
When to Order a Sleep Studyin the Pediatric Population • Symptoms in morbidly obese patient • Apnea in absence of snoring • Apnea without adenotonsillar hypertrophy • Underlying neurologic disorders • Craniofacial abnormalities
Central Sleep Apnea • Dysfunction of medullary centers of respiratory control • Cranial nerve dysfunction involving laryngeal nerves or bulbar muscles, which mediate airway patency
Central Sleep Apnea • Anticipate immediate improvement after decompression surgery • Reports of recovery taking up to 6-12 months
Conclusions • Physical exam in combination with diagnostic studies may indicate central cause of imbalance and hearing loss • ACM should be considered in bilateral TVC paralysis • High index of suspicion of ACM in central/mixed sleep apnea
Ada M, et al. Congenital vocal cord paralysis. J Craniofac Surg. 2010 Jan;21(1):273-4 • Dauvilliers Y, et al. Chiari malformation and sleep related breathing disorders. J Neurol Neurosurg Psychiatry 2007;78:1344-1348 • Hain TC. www.dizziness-and-balance.com • Hershberger ML and Chidekel A. Arnold-Chiari Malformation Type I and Sleep-Disordered Breathing: Review of Literature. J Pediatr Health Care. 2003;17(4) • Kuma A, et al. The Chiari I malformation and the neurologist. Otol Neurotol. 2002 Sep;23(5):727-35 • Murray C, et al. Arnold Chiari type I malformation presenting with sleep disordered breathing in well children. Arch Dis Child. 2006 April;91(4):342-343 • Rowley JA. Obstructive Sleep Apnea-Hypopnea Syndrome: Multimedia. www.emedicine.com. Updated May 14, 2010