Can Dandy Walker malformation cause seizures?

Can Dandy-Walker Malformation Cause Seizures?

Yes, Dandy-Walker malformation can cause seizures, though this is not the most common presenting feature and occurs primarily when associated with other brain malformations or complications.

Seizure Risk in Dandy-Walker Malformation

The relationship between Dandy-Walker malformation (DWM) and seizures depends critically on the anatomical subtype and presence of associated brain abnormalities:

Primary Dandy-Walker Malformation (Isolated Form)

• When the vermis shows preserved lobulation (two fissures, three lobes, and a fastigium despite being small and rotated), seizures are uncommon and neurological outcomes are typically normal 1
• In this isolated form without associated brain malformations, 19 of 21 patients (90%) functioned normally, suggesting seizures are not a primary feature 1

Dandy-Walker with Associated Brain Malformations

• When the vermis is severely dysplastic (one fissure or no fissures), it is constantly associated with major brain anomalies, most often complete corpus callosum agenesis, and these patients experience seizures and mental retardation 1
• The seizures in these cases likely result from the associated cortical malformations rather than the DWM itself 1

Clinical Presentations with Seizures

Case reports document seizures occurring in DWM patients, but typically in complex scenarios:

• A 14-year-old male with DWM presented with seizures alongside psychiatric symptoms and tremor, requiring ventriculoperitoneal shunting and anticonvulsant therapy with valproate 2
• A newborn with DWM presented with right-sided seizures at 42 hours of life, though this case was complicated by concurrent cerebral sinovenous thrombosis, making causation unclear 3
• An 18-year-old male with DWS presented with epilepsy, intellectual disability, and psychosis, representing the neuropsychiatric complications that can accompany this malformation 4

Mechanism of Seizure Development

When seizures occur in DWM, the mechanism is typically indirect:

• Hydrocephalus from fourth ventricle obstruction can lead to increased intracranial pressure and secondary brain damage 2, 3
• Associated cortical malformations (which occur in 40-50% of drug-resistant epilepsies in children) are the more direct epileptogenic substrate 5
• Periventricular damage from chronic hydrocephalus may create epileptogenic foci 3

Clinical Implications

The presence of seizures in a patient with DWM should prompt:

• Detailed MRI evaluation with attention to vermian anatomy (looking for dysplastic features) and screening for associated brain malformations, particularly corpus callosum agenesis 1
• Assessment for hydrocephalus requiring shunt placement, as early surgical intervention may prevent secondary brain damage and improve outcomes 2
• Recognition that seizures indicate either associated cortical malformations or complications (hydrocephalus, thrombosis) rather than the DWM itself 3, 1

Prognosis

Seizure prognosis correlates with vermian anatomy and associated anomalies:

• Patients with preserved vermian lobulation and no associated brain malformations have excellent neurological outcomes with minimal seizure risk 1
• Patients with severely dysplastic vermis and associated brain malformations universally experience mental retardation and are at high risk for epilepsy 1
• The vermis anatomy on sagittal T2-weighted MRI sequences is statistically correlated with neurological and intellectual outcome 1