- Communicating hydrocephalus is due to impaired CSF resorption / extraventricular blockage occuring beyond the fourth ventricle in subarachnoid pathways + arachnoid granulations or is due to increased CSF production
— Neonatal intraventricular hemorrhage
— Subarachnoid hemorrhage
— Meningitis
— Choroid plexus papilloma / choroid plexus carcinoma - Non-communicating hydrocephalus is due to mechanical obstruction to CSF flow in ventricles leading to dilation of ventricles proximal to mass
— Aqueductal stenosis
— Chiari II malformation
— Dandy Walker malformation
— Brain tumors
— Vein of Galen malformation
Approach to the differential diagnosis of hydrocephalus:
- Hydrocephalus is an increase in the volume of cerebrospinal fluid
- In < 2 year old, hydrocephalus is commonly due to aqueductal stenosis, Chiari II malformation, neonatal intraventricular hemorrhage, neonatal infection, congenital brain tumors, choroid plexus tumors, vein of Galen malformation
- In > 2 year old, hydrocephalus is commonly due to posterior fossa tumors
- Do not mistake severe congenital hydrocephalus due to aqueductal stenosis with hydranencephaly
- Patients with benign enlargement of the subarachnoid space do not have hydrocephalus
Pediatric Imaging 