Hydrocephalus in newborns represents one of the most challenging conditions faced in neonatal care. Early recognition and appropriate intervention are crucial for optimal outcomes. The key to managing newborn hydrocephalus lies in recognizing changes over time.

“It’s not what the brain looks like at any moment. It’s what it looks like today versus previously,” said Thomas M. Moriarty, M.D., pediatric neurosurgeon with Norton Children’s Neuroscience Institute, affiliated with the UofL School of Medicine. Dr. Moriarty presented “Hydrocephalus in the Newborn” at the 22nd annual Pediatric Neurology Update continuing medical education opportunity.

At a routine well-baby visit, a pediatrician will plot head circumference measurements on a growth chart. But regular checkups and documented measurements may not bring to light accelerating head growth. It’s not the absolute size that matters, but the pattern of change, according to Dr. Moriarity.

Clinical presentation can be subtle. Parents might notice something “just not quite right” about their baby’s appearance or behavior: A small face relative to an enlarged cranium can be striking when recognized. However, not all cases present so dramatically. Sometimes, it’s the gentle fullness of a fontanel, felt during a quiet moment when the baby isn’t crying or straining, that raises the first red flag for a hydrocephalus diagnosis.

Causes of neonatal hydrocephalus include:

• Intraventricular hemorrhage — the most common cause
• Spina bifida
• Congenital malformations
• Infections

In newborns, there typically hasn’t been time for acquired hydrocephalus to develop from a brain tumor or trauma.

Imaging for newborn hydrocephalus

The choice of imaging for newborn hydrocephalus depends on several factors:

• This is preferred for detailed assessment of newborn brain anatomy and delivers quick-sequence protocols that are especially suitable for newborns. Additionally, MRI is excellent for identifying underlying causes of hydrocephalus in newborns
• This can be faster, and because it shows bone structure, it is essential for brain surgery planning. Norton Children’s Hospital and Norton Children’s Radiology, affiliated with the UofL School of Medicine, have been leaders in minimizing newborn radiation exposure.
• This is a quick and easy method, but it’s not useful for surgical planning, according to Dr. Moriarty.

Hydrocephalus treatment in newborns

Treatment typically begins with temporary measures for preemies, particularly for intraventricular hemorrhage. The ventricular access device largely has replaced older approaches like serial lumbar punctures or fontanel taps. This small silicon reservoir, nestled beneath the scalp, allows controlled removal of excess cerebrospinal fluid while the brain’s natural drainage systems work to recover.

For many infants, permanent cerebrospinal fluid diversion becomes necessary. The modern ventriculoperitoneal shunt, despite its imperfections, has transformed outcomes. However, this shunt surgery initiates a lifelong journey of vigilance. Each child with a shunt demonstrates individual variation in their dependence on it — from those requiring it for 100% of their cerebrospinal fluid drainage to others who need it for only a small percentage.

An endoscopic third ventriculostomy — a surgically created hole in the third ventricle that allows excess fluid to drain without the need for a shunt — works best in older patients. It’s very rare to have a child in their first year who will benefit from an endoscopic third ventriculostomy.

Outcomes often defy initial predictions based on imaging alone. Some infants diagnosed with severe fetal hydrocephalus, showing dramatically enlarged ventricles on prenatal imaging, develop normally after appropriate intervention, eventually demonstrating normal cognitive development. Conversely, other infants with seemingly similar imaging findings can have very significant neurological compromise.

These contrasting cases demonstrate an important principle: While hydrocephalus is indeed serious and potentially life-threatening without treatment, the presence of enlarged ventricles alone doesn’t determine the outcome. Timing proves crucial — if the disruption occurs after neural migration is complete, outcomes can be surprisingly good, despite alarming imaging findings.