Normal Pressure Hydrocephalus Evaluation

The diagnosis of normal pressure hydrocephalus is often difficult to make. The UCLA Adult Hydrocephalus Program has physicians with specific expertise in this diagnosis. Each patient is evaluated initially in our outpatient center, and those patients considered to possibly have the diagnosis of normal pressure hydrocephalus undergo an extensive inhospital evaluation which typically includes the following tests:

Diagnostic Services

• Testing during a four-day hospital stay identifies Normal Pressure Hydrocephalus patients with the highest likelihood of improving with a shunt procedure. Conversely, the tests also indicate which patient is least likely to benefit from a shunt procedure, and therefore avoid the risks of a surgical procedure.
• While in the hospital, patients are under the care of specially trained neurologists with expertise in placing and managing intracranial pressure (ICP) monitors and lumbar cerebrospinal fluid (CSF) catheters.

Day 1

• Admission protocol: All patients stop taking aspirin, Plavix, Coumadin and all non-steroidal medications (such as Motrin) at least 10 days prior to surgery.
• Insertion of ICP monitor: A thin wire with a tiny sensor at its end is inserted just below the surface of the brain to continuously measure pressure.
• This procedure requires local anesthesia only (Novocain numbing medication) and typically has minimal discomfort.
• While the patient is asleep, pressure levels are monitored overnight and then analyzed.

Day 2

• Placement of lumbar catheter: Using the same technique of a spinal tap, a small, flexible catheter is inserted into the lower back to drain CSF.
• The procedure also is performed using local anesthesia.
• The catheter is attached to a collection system.
• The patient must avoid breaking the catheter.
• Measurement of CSF outflow resistance: After the lumbar catheter is in place, a small amount of fluid will be injected through the catheter to determine the amount of resistance for CSF to be absorbed. Resistance is calculated using the data obtained from the ICP monitor during the injection. Elevated values of CSF outflow resistance have been found to be predictive for improvement after a shunt procedure.
• Initiation of CSF drainage: The nursing staff will drain 10cc CSF at the beginning of each hour and then stop the flow until the next hour. This will continue for three days. This process simulates what occurs with a shunt, and therefore can be thought of as a temporary shunt. If improvement occurs with temporary drainage, then a similar improvement is likely following the surgical placement of a permanent shunt.
• During the drainage procedure, it is important to inform the nurse or the doctor of headache or nausea, since this may be an indication that the drainage rate needs to be reduced.

Days 3 and 4

• CSF drainage: CSF drainage will continue as described above. In addition, a neurologist or physical therapist will assess whether the patient's gait and other problems improve.
• Discharge from the hospital: All monitors and drains will be removed and the patient discharged on the fourth day. The patient and family receive a questionnaire to fill out at home.
• Risks: The procedure holds risks, but chances of serious complication are very low. Complications of the ICP monitor and lumbar drain include infection (including meningitis), bleeding, stroke, weakness and death.

Post Procedure

• Recovery: Typically, the greatest amount of improvement is seen in the days immediately following discharge from the hospital.
• Close observation by family members to see if the patient's walking, bladder control and memory function have improved compared with function prior to fluid drainage is an important clinical tool.
• The patient or caregiver will be asked to fill out a daily evaluation sheet for 10 days following discharge. This can be done online using the web or on a paper form sent home with the patient.
• Duration of improvement also helps assess response.
• Follow-up: Two weeks after hospitalization the patient sees a neurologist in clinic to review results of the lumbar drain test.
• If lumbar drainage eases symptoms of hydrocephalus even temporarily, the patient likely will be a candidate for surgical placement of a shunt.
• Other options may be available for patients who do not qualify for surgical placement of a shunt.