ABSTRACT
This review considers the unique pathophysiologies and problems confronting adults who have been treated for hydrocephalus since infancy. Most of these patients will have to change the setting in which they receive care. Therefore, general neurosurgeons who will become the new caretakers for these adult patients must understand the challenges involved. Hydrocephalus in adults has a limited number of origins, and a limited number of points of obstruction can cause the condition. In contrast, congenital conditions that cause hydrocephalus can lead to multiple points of obstruction, making management of these infants difficult. Infants also have distensible heads, which can lead to unique causes of hydrocephalus. Intracranial venous hypertension causes pseudotumor cerebri in adults but it is a rather common cause of hydrocephalus in infants with distensible heads. The most common cause of infantile hydrocephalus is spina bifida associated with a Chiari II malformation. There are four different points of obstruction in these patients, each manifesting with a unique syndrome at the time of shunt failure. The concept of shunt dependency is being redefined as the popularity of endoscopic third ventriculostomy increases. Although the use of the technique in the context of spina bifida remains controversial, the procedure may allow more than 70% of children shunted in infancy whose ventricles expand at the time of shunt failure to live without a shunt. Unlike adults, 20% of infants who are still shunt dependent as adults will have very high intracranial pressure at the time of shunt failure even though the ventricles do not expand. A significant percentage of these patients will benefit from a valve-regulated lumboperitoneal shunt. Any adult who experiences ventricular dilatation at the time of shunt failure should be considered a candidate for endoscopic third ventriculostomy.
KEYWORDS
Arrested hydrocephalus - pseudotumor cerebri - slit ventricle syndrome - spina bifida
