Usually clinical, initially with progressive dilation of
the ventricles that may take days to weeks to reach the classic signs of
hydrocephalus (head enlargement in infants, sun-setting eyes, irritability,
lethargy, nausea, vomiting, weakness, cognitive difficulties, incontinence,
headache). The older child may show signs of subtle psychomotor
deterioration. Diagnosis of hydrocephalus is confirmed by ultrasonography
through the anterior fontanelle (in infants) and by computerized tomography
or magnetic resonance imaging when the fontanelle is closed. Nuclear
medicine cisternogram reveals absent (or delayed) passage of tracer over
convexities. Most patients undergo ventriculoperitoneal shunt derivation
without prior assessment of CSF pressure, so the term chronic hydrocephalus has been proposed as
an alternative title.