Hydrocephalus: Causes, Risk Factors, and Age Groups

Hydrocephalus can occur at any age but has two peak incidence periods: infancy/early childhood and adulthood over 60.

Age Distribution

• Infants and young children: Congenital causes predominate
• Adults over 60: Normal pressure hydrocephalus (NPH) and acquired causes
• Young/middle-aged adults: Less common; usually acquired (trauma, tumor, hemorrhage)

Causes in Infants and Children

• Congenital: Neural tube defects (spina bifida), aqueductal stenosis, Dandy-Walker malformation, Chiari malformation
• Intraventricular hemorrhage (IVH) in premature infants
• Infections: Congenital (CMV, toxoplasmosis, rubella) or postnatal (meningitis)
• Brain tumors (posterior fossa tumors common in children)
• Traumatic brain injury

Causes in Adults

• Normal pressure hydrocephalus (NPH) — idiopathic or post-traumatic/post-infectious
• Traumatic brain injury (subarachnoid hemorrhage, contusions)
• Brain tumors (obstructing CSF pathways)
• Infections: Meningitis, encephalitis
• Stroke (hemorrhagic or ischemic affecting CSF pathways)
• Subarachnoid hemorrhage (aneurysm rupture)

Risk Factors

• Premature birth (<32 weeks)
• Family history of neural tube defects
• Maternal diabetes, obesity, or folate deficiency
• Certain genetic syndromes
• Previous brain surgery or radiation
• Coagulopathies increasing hemorrhage risk

Key Point

Early recognition of symptoms—rapid head growth in infants; headache, vomiting, gait disturbance, cognitive decline in adults—enables timely intervention and better outcomes.