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Condition/Disorder Synonyms

  • Arnold-Chiari malformation

  • Chiari II malformation

  • Arnold-Chiari II

ICD-9-CM Code

  • 348.4 Compression of brain

  • 742.2 Congenital reduction for deformities of brain

ICD-10-CM Code

  • G93.5 Compression of brain

  • Q04.8 Other specified congenital malformations of brain

  • Q07.0 Arnold-Chiari syndrome

  • Q07.00 Arnold-Chiari syndrome without spina bifida or hydrocephalus

  • Q07.01 Arnold Chiari syndrome with spina bifida

  • Q07.02 Arnold-Chiari syndrome with hydrocephalus

  • Q07.03 Arnold-Chiari syndrome with spina bifida and hydrocephalus

Preferred Practice Pattern1

  • 5C: Impaired Motor Function and Sensory Integrity Associated with Nonprogressive Disorders of the Central Nervous System – Congenital Origin or Acquired in Infancy or Childhood

Key Features


  • Defect in cephalad portion of spinal column

  • Herniation of portions of the brainstem and spinal cord through the foramen magnum, including the cerebellum, medulla, and cervical spinal cord

Essentials of Diagnosis

  • Characteristic signs and symptoms with diagnosis confirmed by MRI

General Considerations

  • Most often occurs in presence of spina bifida


  • 90% of patients with Chiari malformation also have hydrocephalus

  • Three times more common in females than males2

Clinical Findings

Signs and Symptoms

  • Respiratory difficulties

  • Vision difficulties

    • Nystagmus

    • Diplopia

    • Blurred vision

    • Esotropia

  • Bradycardia

  • Cranial nerve palsies

  • Ataxia

  • Vertigo

  • Hydrocephalus

  • Headache

  • Neck pain

  • Decreased balance

  • Spasticity, numbness or tingling in hands

  • Poor fine-motor skills

  • Slurred speech

  • Developmental delay

Functional Implications

  • Delayed motor development

  • Difficulty swallowing

  • Poor balance

Possible Contributing Causes

  • Abnormality during fetal development

  • Teratogens

  • Possible genetic link

  • Infection

  • Insufficient maternal vitamins or minerals during gestation

Differential Diagnosis

  • Brain tumor

  • Syringomyelia

Means of Confirmation or Diagnosis


  • MRI

Findings and Interpretation


Medical Procedures


  • Geneticist

  • Neurologist

  • Orthopedic surgeon

  • Occupational therapist

  • Speech therapist

  • Admittance for surgical procedures, such as

    • Tracheostomy

    • Gastrostomy

    • Posterior fossa decompression

    • Cervical laminectomy


  • Delayed motor milestones

    • Rolling

    • Sitting

  • Decreased balance in sitting

  • Additional impairments typically associated with spina bifida

Tests and Measures

  • Pediatric Evaluation of Disability Inventory (PEDI)

  • Manual muscle test


  • Therapy

  • Child should avoid activities associated with risk for cervical injury

  • Developmental activities to facilitate gross motor development

    • Prone on elbows

    • Rolling

    • Sitting

  • Balance training

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