Pediatric emergency medicine trisk 2496 2496
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Hydrocephalus in a newborn (accumulation of intracranial CSF) develops from
an imbalance between production and reabsorption of CSF. The majority of cases
result either from obstruction to the CSF circulation, called obstructive or
noncommunicating hydrocephalus, or from failure to absorb CSF by the
arachnoid villi and cisterns, called communicating hydrocephalus . Both of these
conditions can be caused by a congenital lesion (e.g., aqueductal stenosis [ Fig.
96.20 ], Dandy–Walker malformation, or Arnold–Chiari II malformation), or by
acquired disease (e.g., posthemorrhagic, postmeningitic [bacterial, viral, fungal,
or parasitic]), tumor-related compression (least common), or ventriculoperitoneal
shunt malfunction. Overproduction by a choroid plexus papilloma or villous
hypertrophy is rare. The neonatal course may identify prematurity with
intraventricular hemorrhage and posthemorrhagic hydrocephalus, with or without
ventriculoperitoneal shunt placement. Occasionally, postnatal enlargement of the
head occurs after the baby is at home and may present with rapidly increasing
head circumference, full fontanelle, and splayed sutures. Presence of open
squamosal suture (between temporal and parietal bones) is a useful sign. Signs of
increased intracranial pressure are more common after 2 years of age due to
presence of open sutures in neonates. Papilledema is rare in neonates. In
unchecked cases, the head enlargement will cause bossing of the forehead, sunset
appearance of the eyes (downward deviation of eyes with prominence of the
sclera) due to compression of the gaze center in the tectum ( Fig. 96.21 ),
esotropia due to paresis of the abducens nerve (VI), thinning of the skull bones
leading to a “cracked pot” sound on percussion (Macewen sign). Head US is the
most rapid diagnostic tool for evaluation. MRI gives detailed examination, can
show meningeal enhancement in case of meningitis, and can delineate
complications (intracranial abscess, venous thrombosis, and empyema). CT scan
can be used to provide additional detail, evaluate patients for shunt malfunction
and intracranial calcifications in cases with congenital infection. Neurosurgical
consultation will be required. Treatment of hydrocephalus should be directed
toward ventricular decompression, or resection of the mass, or both. Prognosis is
determined by the underlying etiology and timing of treatment. Shunt
complications includes occlusion of proximal or distal ends, fracture,
displacement, migration, and infection.
