Otolaryngologic Manifestations of Arnold-Chiari Malformation

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 of Limbs”)

•Dysdiadochokinesis•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- Tracking test- Positional test- Caloric test

Intended to diagnose CNS disorders

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 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

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