Congenital hydrocephalus means hydrocephalus that is present at birth (or develops before birth). For parents, this diagnosis — sometimes made during pregnancy, sometimes shortly after birth — can be frightening. Understanding its causes and treatment can help you feel more prepared to care for your baby.
What it means "Congenital" refers to a condition present from birth. In congenital hydrocephalus, the problem with CSF balance is present as the baby's brain develops, often because the fluid pathways didn't form normally or were disrupted. It's one of the more common congenital conditions affecting the nervous system.
Common causes Congenital hydrocephalus has several possible causes, including:
- Aqueductal stenosis — a narrowing or blockage of the cerebral aqueduct (a frequent cause).
- Spina bifida (myelomeningocele) — an opening in the spine that is very often associated with hydrocephalus, typically through a related condition called the Chiari II malformation.
- Dandy-Walker malformation — a malformation involving the fourth ventricle and cerebellum.
- Infections during pregnancy — certain maternal infections can disrupt CSF pathways.
- Bleeding within the developing brain.
- Genetic factors — some forms run in families or are linked to specific genetic changes.
In some babies, no single cause is identified.
How it's found Congenital hydrocephalus may be detected:
- Before birth, on a routine prenatal ultrasound that shows enlarged ventricles, sometimes followed by a fetal MRI.
- After birth, through signs such as a rapidly enlarging head, a bulging soft spot (fontanelle), downward-deviated eyes ("sunsetting"), irritability, or feeding problems — prompting imaging like a cranial ultrasound, CT, or MRI.
How it's treated Treatment is surgical, using the same main options as other forms of hydrocephalus — a shunt (most commonly a ventriculoperitoneal, or VP, shunt) or, in selected babies, an ETV with or without choroid plexus cauterization (ETV/CPC). The goal is to relieve the fluid buildup and protect the developing brain. Babies treated for hydrocephalus are followed closely as they grow.
What about outlook? The outlook for a baby with congenital hydrocephalus depends heavily on the underlying cause, the degree of any associated brain changes, and how well treatment controls the fluid — not on hydrocephalus alone. Many children with treated congenital hydrocephalus develop well, attend school, and lead full lives, while some face developmental or learning challenges that benefit from early support and therapies. Your child's medical team can give you the most accurate picture for your situation as they grow and develop.
A diagnosis of congenital hydrocephalus is the beginning of a journey, not a verdict. With modern treatment, close follow-up, and developmental support when needed, many children do well. Specialized pediatric neurosurgery and developmental teams will be your partners along the way.