Dandy-Walker Malformation Lecture Notes

Overview

• Dandy-Walker Malformation: A congenital brain malformation primarily affecting the cerebellar development.
  • Cerebellum Functions: Regulates balance, coordination, movement, posture.

Key Features

• Cystic Dilation: Occurs in the fourth ventricle.
• Cerebellar Vermis: Hypoplasia or agenesis.
• Posterior Fossa: Enlargement noted.

Detection

• MRI Imaging: Key tool for diagnosing Dandy-Walker Malformation.
  • Control MRI shows a normal cerebellum.
  • Dandy-Walker MRI shows a smaller cerebellum, cystic dilation, and fluid accumulation.

Symptoms

• Macrocephaly: Enlargement of the head due to obstructed cerebrospinal fluid in the fourth ventricle.
• Motor Issues: Delayed milestones, hypotonia, motor coordination defects (ataxia).
• Other Symptoms: Craniofacial abnormalities such as cleft palate, prominent occiput, and upward slanting of eyes.

Histological Findings

• Foliation Reduction: Overall cerebellar foliation is reduced.
• Affected Regions: Flocculonodular lobe and inferior vermis undergo hypoplasia.

Diagnostic Signatures

• Tail Sign: Posterior cerebellum appears like a dog's tail, seen in 75% of patients.
  • Correlates with reduced growth of the posterior vermis and failure of rhombic lip region to internalize.
• Rhombic Lip: A germinal zone producing cerebellar cell types. Issues in rhombic lip are central to the malformation.

Genetic Associations

• Chromosomal Links: Trisomy 18, 13, 21, and 9 associated with Dandy-Walker Malformation.
• Gene Expression: Reduced proliferation and stemness related genes in rhombic lip.

Treatment and Management

• VP Shunt: Ventra peritoneal shunt surgery to drain excess fluid and balance intracranial pressure.
• Supportive Treatments: Includes physiotherapy, speech therapy, and medications.

Additional Notes

• Phenotypic Variability: Diverse symptoms and gene/pathway involvement.
• Research Highlights: Current research emphasizes the rhombic lip's role in disease origin.

Ensure to review MRI images and genetic studies for a better understanding of the Dandy-Walker Malformation. Engage in supportive therapies early to manage symptoms effectively.