Hydrocephalus
Hydrocephalus: Excerpt from Handbook of Diseases
An excessive accumulation of cerebrospinal fluid (CSF) within the ventricular spaces of the brain, hydrocephalus occurs most commonly in neonates. It can also occur in adults as a result of injury or disease. In infants, hydrocephalus enlarges the head, and in both infants and adults, the resulting compression can damage brain tissue.
With early detection and surgical intervention, the prognosis improves but remains guarded. Even after surgery, such complications as developmental delay, impaired motor function, and vision loss can persist. Without surgery, the prognosis is poor: Mortality may result from increased intracranial pressure (ICP) in people of all ages; infants may also die prematurely of infection and malnutrition.
Causes
Hydrocephalus may result from an obstruction in CSF flow (noncommunicating hydrocephalus) or from faulty absorption of CSF (communicating hydrocephalus).
Noncommunicating hydrocephalus
In noncommunicating hydrocephalus, the obstruction occurs most commonly between the third and fourth ventricles, at the aqueduct of Sylvius, but it can also occur at the outlets of the fourth ventricle (foramina of Luschka and Magendie) or, rarely, at the foramen of Monro.
This obstruction may result from faulty fetal development, infection (syphilis, granulomatous diseases, meningitis), a tumor, a cerebral aneurysm, or a blood clot (after intracranial hemorrhage).
Communicating hydrocephalus
In communicating hydrocephalus, faulty absorption of CSF may result from surgery to repair a myelomeningocele, adhesions between meninges at the base of the brain, or meningeal hemorrhage. Rarely, a tumor in the choroid plexus causes overproduction of CSF, producing hydrocephalus.
Signs and symptoms
In infants, the unmistakable sign of hydrocephalus is enlargement of the head clearly disproportionate to the infant’s growth. Other characteristic changes include distended scalp veins; thin, shiny, fragile-looking scalp skin; and underdeveloped neck muscles. (See Characteristics of hydrocephalus.)
In severe hydrocephalus, the roof of the orbit’s depressed, the eyes are displaced downward, and the sclerae are prominent. A high-pitched, shrill cry as well as abnormal muscle tone in the legs, irritability, anorexia, and projectile vomiting commonly occur.
In adults and older children, indicators of hydrocephalus include a decreased level of consciousness (LOC), headache, nausea, vomiting, and other symptoms of increased intracranial pressure. Ataxia, incontinence, and impaired intellect may also be present.
In infants, the fontaneles may not feel full due to the infant’s inability to increase the head circumference when the brain is under pressure. Because the sutures aren’t fused, the skull widens to accommodate the pressure.
Diagnosis
In infants, abnormally large head size for the patient’s age strongly suggests hydrocephalus. Skull X-rays show thinning of the skull with separation of sutures and widening of the fontaneles.
Other diagnostic tests, including angiography, computed tomography scans, and magnetic resonance imaging, can differentiate between hydrocephalus and intracranial lesions and can also demonstrate the Arnold-Chiari deformity (a type of neural tube defect), which may occur in an infant with hydrocephalus.
Treatment
Surgical correction is the only treatment for hydrocephalus. Usually, such surgery consists of insertion of a ventriculoperitoneal shunt, which transports excess fluid from the lateral ventricle into the peritoneal cavity.
A less common procedure is insertion of a ventriculoatrial shunt, which drains fluid from the brain’s lateral ventricle into the right atrium of the heart, where the fluid makes its way into the venous circulation. Endoscopic third ventriculostomy (ETV) involves creating a passage between the third ventricle and the basal cisterns. This procedure is used for noncommunicating hydrocephalus in patients over age 2.
Complications of surgery include shunt infection, septicemia (after ventriculoatrial shunt), adhesions and paralytic ileus, migration, peritonitis, and intestinal perforation (with peritoneal shunt).
Special considerations
On initial assessment:
❑ Obtain a complete history from the patient or the family. Note the patient’s general behavior, especially irritability, apathy, and decreased LOC.
❑ Perform a neurologic assessment. Examine the eyes: pupils should be equal and reactive to light. In adults and older children, evaluate movements and motor strength in the extremities. (Watch especially for ataxia.)
age alert Irritability, restlessness, and change in cognitive function are all indicators of increased ICP in both adults and children. A change in eating, sleeping, and pitch of cry are strong indicators of increased ICP in infants.
Before surgery to insert a shunt:
❑ Encourage maternal-neonatal bonding when possible. When caring for the neonatal yourself, hold him on your lap for feeding, stroke and cuddle him, and speak soothingly.
❑ Check the fontaneles for tension or fullness, and measure and record head circumference.
Clinical tip To appropriately assess fontaneles, lay the infant down and then raise him to a sitting position. Truly tense fontaneles will be present in the sitting position. Remember that if the infant is crying, fontanele pressure will increase. This wouldn’t be indicative of hydrocephalus.
On the patient’s chart, draw a picture showing where to measure the head so that other staff members measure it in the same place, or mark the forehead with ink.
❑ To prevent postfeeding aspiration and hypostatic pneumonia, place the infant on his side and reposition him every 2 hours, or prop him up in an infant seat.
❑ To prevent skin breakdown, make sure the infant’s earlobe is flat, and place a sheepskin or rubber foam under his head.
❑ When turning the infant, move his head, neck, and shoulders with his body to reduce strain on his neck.
❑ Feed the infant slowly. To lessen the strain from the weight of the infant’s head on your arm while holding him during feeding, place his head, neck, and shoulders on a pillow.
After surgery:
❑ Place the infant on the side opposite the operative site, with his head level with his body.
❑ Check temperature, pulse rate, blood pressure, and LOC. Also check the fontaneles daily for fullness. Watch for irritability, which may be an early sign of increased ICP and shunt malfunction.
❑ Watch for signs of infection, especially meningitis: fever, stiff neck, irritability, or tense fontanelles. Also watch for redness, swelling, and other signs of local infection over the shunt tract. Check the dressing often for drainage.
❑ Listen for bowel sounds after ventriculoperitoneal shunt.
❑ Check the infant’s growth and development periodically, and help the parents set goals consistent with the infant’s ability and potential.
❑ Help the parents focus on their child’s strengths, not his weaknesses. Discuss special education programs, and emphasize the infant’s need for sensory stimulation appropriate for his age.
❑ Teach the parents to watch for signs of shunt malfunction, infection, and paralytic ileus. Tell them that shunt insertion requires periodic surgery to lengthen the shunt as the child grows older, to correct malfunctioning, or to treat infection.
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Book Source Details
- Book Title: Handbook of Diseases
- Author(s): Springhouse
- Year of Publication: 2003
- Copyright Details: Handbook of Diseases, Copyright © 2003 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Handbook of Diseases
Authors: Springhouse
Publisher: Lippincott Williams & Wilkins
Copyright: 2003
ISBN: 1-58255-266-5
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