AANN Core Curriculum, 7th Edition, Ch. 11 Hydrocephalus: Digital Version-Chapter 11

Chapter 11

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Hydrocephalus is enlargement of the brain’s ventricles caused by an imbalance in cerebrospinal fluid (CSF) production, flow, or absorption. Causes include congenital abnormalities, neural tube defects, intrauterine infection, aqueductal stenosis, hemorrhage, infection, tumors, trauma, and age-related impairment of absorption. Ventricular enlargement from brain-tissue loss alone is termed hydrocephalus ex vacuo, not true hydrocephalus.<br /><br />CSF flows from the lateral ventricles through the ventricular system and down the spinal canal, then circulates around the brain and is absorbed through arachnoid villi into the superior sagittal sinus. In communicating hydrocephalus, flow pathways remain open but absorption is impaired. In obstructive hydrocephalus, a blockage—often at the aqueduct of Sylvius—prevents CSF flow. Normal pressure hydrocephalus (NPH), a communicating form usually affecting older adults, is associated with gait disturbance, cognitive decline, and urinary urgency or incontinence. Despite its name, pressure may be high, normal, or low, and symptoms may improve with shunting.<br /><br />Symptoms vary by age. Infants may have an enlarging head, tense fontanel, irritability, feeding difficulty, and developmental delay. Older children and adults may develop headache, vomiting, vision changes, lethargy, seizures, or cognitive and behavioral changes. NPH commonly presents with a slow, wide-based gait, impaired cognition, and urinary symptoms.<br /><br />Diagnostic studies include CT, MRI, rapid-sequence MRI, and ultrasound in infants with open fontanels. CSF-flow MRI, lumbar puncture, or temporary CSF drainage may help assess NPH; selected cases may use other specialized studies.<br /><br />Treatment commonly involves a ventriculoperitoneal shunt; alternatives include ventriculoatrial or ventriculopleural shunts and endoscopic third ventriculostomy, particularly for obstruction. Temporary drainage may be used in premature infants.<br /><br />Shunt complications include obstruction, fracture, infection, underdrainage, and overdrainage. Nurses monitor neurological status, signs of raised intracranial pressure, wounds, and infection, and teach patients and caregivers to recognize shunt problems, seek prompt care, and follow MRI-related valve instructions.

Keywords

hydrocephalus

cerebrospinal fluid

ventricular enlargement

obstructive hydrocephalus

communicating hydrocephalus

normal pressure hydrocephalus

ventriculoperitoneal shunt

intracranial pressure

aqueductal stenosis

shunt complications