Dandy-Walker Malformation

Introduction

• An 1-year-old boy is brought to the emergency department by his parents due to increased irritability and an “enlarging head.” The parents deny any trauma but has noticed their infant appears weaker than his sister when she was his age. They did not receive adequate prenatal care due to the distance and cost to arrive to their closest obstetrician. On physical exam, the infant is inconsolable and has an increased head circumference for his age. Magnetic resonance imaging (MRI) of the head shows hypoplasia of the cerebellar vermis with cystic dilatation of the fourth ventricle leading to a non-communicating hydrocephalus.

Introduction

• Clinical definition
  • a neurological developmental anomaly of the
    • cerebellar vermis and
      • failure of proper closure of the fourth ventricle which results in
        • an abnormally large posterior fossa
• Epidemiology
  • incidence
    • 1 in 30,000 births
• Associated conditions
  • noncommunicating hydrocephalus
• spina bifida

Presentation

• Symptoms
  • intellectual or learning disability
  • seizures
  • issues with
    • movement
    • coordination
    • mood
• Physical exam
  • macrocephaly 
    • if hydrocephalus ensues
• may have spastic paraplegia

Imaging

• Prenatal ultrasound
  • indication used
    • when a CNS malformation is suspected
    • to diagnose Dandy-Walker malformation
      • other imaging modalities are used to diagnose Dandy-Waler malformation such as
        • fetal MRI and post-natal CT of the head
  • findings
    • dilatation of the fourth ventricle
    • presistent Blake’s pouch cyst
    • enlargement of the posterior fossa
• MRI
  • indication
    • imaging of choice for assessing for Dandy-Walker malformation
  • findings
    • hypoplasia of the cerebellar vermis
    • cystic dilatation of the fourth ventricle
• posterior fossa enlargement

Treatment

• Conservative
  • multidisciplinary team
    • indication
      • a multidisciplinary team approach is warrented in the management of Dandy-Waler malformation
        • this includes
          • special education
          • physical therapist
          • social services
          • neurologists
          • genetic counselors
• Operative
  • ventriculoperitoneal shunting
    • indication
      • used to treat hydrocephalus