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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
          Vestibular Findings in
          Cerebellar Disorders
CEREBELLAR SYNDROMES           PHYSICAL EXAM
MIDLINE (“Imbalance”)          •Romberg
                               •Tandem gait
                               •Truncal ataxia
                               •Titubation
                               •Abnormal eye movements

HEMISPHERIC (“Incoordination   •Dysdiadochokinesis
of Limbs”)                     •Finger-to-nose/Heel-to-shin
         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
   Electronystagmography
• Determines whether or not dizziness is
  due to inner ear disease
• Excellent for diagnosis of unilateral
  ear disorders
• 4 main parts:
  - Calibration test   Intended to diagnose
                       CNS disorders
  - Tracking test
  - Positional test
  - Caloric test
Rotational Chair Testing
    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 Study
   in 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
      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
Central Sleep Apnea
      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
Thank You
• 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

				
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posted:8/25/2012
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