Thursday, May 12, 2011

Nursing Care of the Hydrocephalus Patient after Surgery

The most common operations that children with hydrocephalus undergo are shunt placement, shunt revision, and endoscopic third ventriculostomy. Because these children frequently have other diseases related to the hydrocephalus they often undergo other surgeries to treat a multitude of other problems.

Neurological Assessment
The assessment must occur in a developmentally appropriate manner. The nurse must also consider what is developmentally appropriate behavior for the infant or child, based upon his age. It is vital to also consider the individual child and his baseline. Many conditions related to hydrocephalus are also associated with significant delays, and because complications of hydrocephalus may worsen such delays, these children have a wide range of developmental abnormalities. A detailed history of developmental skill and baseline function is a vital part of being able to assess the infant/child.
Parents and families are an excellent resource to provide information about their particular child’s developmental level. The signs and symptoms of increasing intracranial pressure may initially be very subtle. Hence, the child’s caretaker is a valuable resource in such assessment and may notice subtle changes before nursing and medical staff.
Neurological assessment of the child after surgery to treat the hydrocephalus needs to be done frequently. The surgeon will usually specify the frequency, but assessment should occur every 1–4 h, depending on the condition of the child. An exam that is changing subtly over time may be an indication of a failed surgical treatment or postoperative complication. The first signs of increasing intracranial pressure are usually subtle and related to mildly increasing somnolence, lack of interest in activities (feeding) or play, and subtle behavioral changes. Level of consciousness is the most important single indicator of neurological status. Altered level of consciousness may progress to confusion, disorientation, somnolence, lethargy, obtundation, stupor, and coma.
A thorough neurological assessment starts with watching the child play and interact with those around him. Assessment also includes asking the child if he has a headache. The child should be examined for his ability to answer questions appropriately and follow directions. Asking a child to move his arms and legs will also allow the examiner to assess muscle strength, tone, and movement. Vital signs should also be assessed. Bradycardia can be a sign of increased intracranial pressure. Increased blood pressure is usually not a common finding in children until late in the process of increasing intracranial pressure.
It is important to carefully examine the eyes, noting that checking pupils without further exam is never an adequate exam. The pupils are checked for equality, roundness, and reactivity to light. Dilated and nonreactive pupils are a very late sign of increased intracranial pressure. A “sun-setting” appearance to the eyes or the loss of upward gaze is an abnormal finding. The extraocular movements should be intact.
The infant’s head should be examined. The occipital frontal circumference should be measured and documented on a daily basis to determine appropriate head growth. The fontanels should be palpated with the child upright and calm. The anterior fontanel should feel soft and pulsatile. A tense or bulging fontanel is suspicious for increased intracranial pressure. The suture lines of the skull should also be examined. Normal suture lines are palpable and apposed. If they are overriding, the infant may have overdrainage of the system. If the sutures are splayed there is likely increased intracranial pressure.

Wound and Dressing Care
The child will usually come from the operating room with a dressing over the incision. The dressing is normally removed, or changed, during the first few postoperative days. If a dressing is soiled or saturated with blood, most surgeons agree that it should be replaced. If the child is likely to pick at the incision, a dressing may be left on to prevent infection. Before a child goes home, most surgeons agree the dressing should be changed and the wound inspected for any erythema, drainage, swelling, or infection.

Medications
A substantial majority of neurosurgeons will order intravenous antibiotics for 24–48 h after the surgery to prevent shunt infection. Cefazolin or nafcillin are the most commonly used antibiotics, as Gram-positive organisms demonstrate a sensitivity to them. Vancomycin may also be used.
Pain management starts with good pain assessment. Age-appropriate pain assessment scales such as CRIES (crying, requires increased oxygen administration, increased vital signs, expression, sleeplessness), the Objective Pain Scale, and Oucher may be used. There is a wide variety of pain experienced by children after surgery for hydrocephalus. Pain may be related to the cranial incision(s), the abdominal incision, the amount of intra-abdominal manipulation, and the tunneling of the distal catheter through the subcutaneous tissue. Other factors influencing pain may include the age of the child, the child and/or family’s prior experience with pain, and the child and family’s anxiety. Pain is usually managed with medications, although other techniques may be helpful. The first drug of choice is usually acetaminophen. It should be adequately dosed at 15 mg/kg/dose and can be given orally or rectally. Nonsteriodal anti-inflammatory drugs (NSAIDS) may be used, but they can inhibit platelet aggregation and prolong bleeding time. For this reason, some neurosurgeons do not use NSAIDS during the immediate postoperative period.
If the child needs additional medication for pain, the surgeon’s beliefs about pain control in neurosurgical patients will be a factor. Some neurosurgeons will order opiates such as morphine sulfate, oxycodone, and codeine. Other surgeons do not want to alter the patient’s neurological exam with these drugs. The nurse should not administer these drugs if there is concern that the pain is due to increasing intracranial pressure or the neurological exam is changing. Other modalities to relieve pain may include age-appropriate relaxation techniques, play therapy, music therapy, massage, distraction, and acupuncture or acupressure.

Tuesday, May 3, 2011

Diagnosis of Hydrocephalus by Imaging Studies

The three major techniques used for diagnosis and evaluation of hydrocephalus are ultrasonography (US), CT, and MRI.

Ultrasonography
Prenatal US can be highly reliable and accurate in diagnosing hydrocephalus. Hydrocephalus can be detected in a fetus as early as the later part of the first trimester of pregnancy, although abnormal dilation of the fetus’s ventricles are more clearly detectable after 20–24 weeks gestation. Although prenatal US can detect abnormal CSF collection, it may not show the precise site or cause of the obstruction. Amniocentesis can often detect the presence of open neural tube defects, such as myelomeningocele, chromosome abnormalities, and in-utero infections, and may also help indicate the overall health of the fetus. In general, the first trimester development of significant hydrocephalus can be a poor prognostic sign for infant mortality and developmental progress. In some cases, mild ventricular dilation identified by US will resolve by the third trimester.
Cranial US is useful in infants and young children while the anterior fontanel is still open, usually under the age of 18 months. Through the fontanel, it can demonstrate lateral ventricular morphology and intraventricular clots. It is less accurate in its ability to look at the third and fourth ventricles and subarachnoid spaces. For this reason, the precise diagnosis and cause of hydrocephalus is rarely made by US alone. It is particularly useful, however, for follow-up screening of infants with untreated and treated hydrocephalus. The equipment is portable, involves no radiation, does not require sedation, and is considerably less expensive than CT/MRI.

Computed Tomography
Since the advent of CT scanning in 1976, it continues to be the most commonly used radiologic technique for the diagnosis and follow-up of hydrocephalus. CT images can accurately demonstrate the ventricular size and shape, the presence of blood and calcifications, cysts, and shunt hardware. In hydrocephalus, an enlarged ventricular system is usually seen, and is usually first seen in the lateral ventricles. CT images can also accurately reflect signs of increased intracranial pressure, such as compressed cerebral sulci, absent subarachnoid spaces over the convexity, and transependymal reabsorption of CSF in the white matter. When contrast enhancement is used, tumors, abscesses, and some vascular malformations can be visualized. It is currently the most rapid diagnostic screening tool, taking only a few minutes, and few children need to be sedated for the procedure. Despite the fact that it uses low-level radiation, little is known about the longterm effects of multiple scans. CT scanning has a lower resolution than MRI and is usually only performed in the axial plane.

Magnetic Resonance Imaging
Commercially available MRI was introduced in 1986 and is the examination of choice for revealing the underlying cause of hydrocephalus. It allows anatomical visualization in the axial, coronal, and sagittal planes, providing detailed information regarding the anatomy, and the position and extent of lesions. Subtle findings, such as white matter pathology, dysmorphic anatomy, and characteristics of lesions can be readily demonstrated. In addition, the aqueduct of Sylvius can be visualized, as well as membranes and loculated ventricular systems. With the addition of gadolinium (an intravenous contrast medium), some neoplasms and vascular lesions can be better visualized. CSF flow dynamics can be visualized through the use of phase-contrast cine MRI. This sequence takes only a few extra seconds and allows for real-time flow measurements
that are demonstrated on the sagittal plane of the MRI. Furthermore, constructive interference in the steady state (CISS) sequence MRI may be used. This sequence provides great detail of the ventricular system, basal cisterns, and may show membranes not otherwise seen on conventional MRI. Both phasecontrast cine MRI and CISS sequence MRI can be very helpful in determining the underlying cause of hydrocephalus. They can also provide valuable preoperative information related to the potential success of endoscopic third ventriculostomy, as well as postoperative information by being able to visualize the CSF flow pattern. MRI takes approximately 45 min or longer and, therefore, young children need to be sedated for the exam. Typically, children with normal development over the age of 5 or 6 years can often do the exam without sedation.