What is normal pressure hydrocephalus?

If you or someone you know has developed difficulty walking, incontinence or short term memory loss, the problem may be a disorder called normal pressure hydrocephalus. Normal pressure hydrocephalus is thought to be caused by an accumulation of excess cerebrospinal fluid in the brain. Normal pressure hydrocephalus usually occurs in older adults, and it often remains undiagnosed for years or is misdiagnosed as Alzheimer’s disease, Parkinson’s disease or “old age”. Normal pressure hydrocephalus can also develop in patients with a history of brain tumor, cerebral hemorrhage, brain infection or head trauma. Importantly, the symptoms of normal pressure hydrocephalus can be relieved by a simple surgical procedure. Our multidisciplinary team is specially trained to diagnose and treat normal pressure hydrocephalus.

Watch this video showing walking difficulty with Normal Pressure Hydrocephalus.

How is normal pressure hydrocephalus diagnosed?

Neurological Examination

A careful examination is performed by neurologists or neurosurgeons that are skilled in the diagnosis and treatment of normal pressure hydrocephalus and other disorders that can cause similar symptoms (such as Alzheimer’s disease or Parkinson’s disease). Some patients can have normal pressure hydrocephalus as well as one of these other disorders at the same time. Thus, a careful examination that considers all of these disorders is critical.

Brain Imaging

Most (but not all) patients with normal pressure hydrocephalus have evidence of excess cerebrospinal fluid in the brain. Our neuroradiologists at The Adult Hydrocephalus Program are knowledgeable in diagnosing all types of hydrocephalus, including normal pressure hydrocephalus and other causes of dementia that can present with similar symptoms. Brain MRI or CT scans are obtained on all patients as part of the evaluation for adult hydrocephalus.

Physical Therapy Evaluation

Patients undergo a thorough evaluation by our team of physical therapists, all of whom are specially trained in the assessment of gait disorders. Initial timed assessments of gait and balance are performed prior to CSF drainage, and are then repeated daily while the cerebrospinal fluid is being drained. This provides a clear and objective determination of improvement in symptoms.

Lumbar Cerebrospinal Fluid Drainage

Although normal pressure hydrocephalus can be diagnosed with a large volume spinal tap, some patients require a more prolonged period of spinal drainage before improvement occurs. For this reason, patients are admitted for two to three days of lumbar drainage after undergoing an extensive gait and cognitive evaluation.

What are treatment options for normal pressure hydrocephalus?

The primary treatment for normal pressure hydrocephalus is placement of a ventricular shunt. The ventricular shunt consists of a small catheter that is passed into the fluid space of the brain where the cerebrospinal fluid is located. The catheter is connected to a valve that can be adjusted non-invasively to regulate the rate at which the cerebrospinal fluid is drained. The ventricular catheter and valve, in turn, are connected to a catheter that drains the cerebrospinal fluid into the abdomen where it is reabsorbed. The shunt is completely internal.

In select cases, hydrocephalus can be treated using a procedure called endoscopic third ventriculostomy. This procedure involves puncturing a membrane within the ventricular system to create an alternative pathway for CSF flow.

What are the different types of adult hydrocephalus?

Obstructive Hydrocephalus

Obstructive hydrocephalus occurs when the normal flow of cerebrospinal fluid within the brain is physically blocked. This leads to an accumulation of cerebrospinal fluid and increased pressure in the head that can cause headaches, problems with vision, nausea and vomiting, loss of bladder control, imbalance, memory loss or other symptoms. Although it is usually diagnosed in childhood, obstructive hydrocephalus can occur in adults. The Adult Hydrocephalus Program specializes in treating obstructive hydrocephalus, including endoscopic third ventriculostomy, ventricular shunts or surgical removal of the obstruction when appropriate.

Congenital Hydrocephalus

Congenital hydrocephalus develops around the time of birth, but it can persist into adulthood. In some cases, however, congenital hydrocephalus may not be diagnosed until adulthood. The Adult Hydrocephalus Program at Brigham and Women’s Hospital is equipped to diagnose and treat all forms of congenital hydrocephalus. In addition, several physicians in the Program are pediatric neurosurgeons who routinely treat children with hydrocephalus at our affiliated institution, Boston Children’s Hospital. Together with neurosurgeons at Brigham and Women’s Hospital who specialize in treating adult hydrocephalus, they form a multidisciplinary team that covers the full range of disorders affecting the flow of cerebrospinal fluid throughout the lifespan.

Communicating Hydrocephalus

Communicating hydrocephalus can develop after head trauma, brain hemorrhage, radiation or chemotherapy, infection, or in the context of tumors. In some cases, the etiology of communicating hydrocephalus is not known. The Adult Hydrocephalus Program at Brigham and Women’s Hospital is equipped to diagnose and treat all forms of communicating hydrocephalus, regardless of the cause.

Pseudotumor Cerebri (Idiopathic Intracranial Hypertension)

Pseudotumor cerebri (also known as Idiopathic Intracranial Hypertension) is characterized by headaches or visual loss due to abnormally elevated pressure in the head. Pseudotumor cerebri usually occurs in young or middle-aged women, although men can be affected as well. The headaches can interfere with one's ability to perform daily activities. If left untreated, this disorder can lead to visual loss or even blindness. Treatments for pseudotumor cerebri include ventricular shunt placement or weight loss where appropriate. At the Adult Hydrocephalus Program, lumbar punctures and careful eye examinations by our neuro-ophthalmologists are used to diagnose pseudotumor cerebri so that it can be treated, thereby preserving vision and relieving the severe headaches associated with this disorder.

Chiari I Malformation

Patients who complain of chronic headaches localized to the back of the head, or headaches that are made worse by coughing, sneezing or physical exertion may have a disorder called Chiari I Malformation. The symptoms of Chiari I Malformation develop when a portion of the brain (the cerebellum) presses on surrounding brain areas and blocks the normal flow of cerebrospinal fluid. Other symptoms of Chiari I Malformation include gait imbalance, swallowing difficulty, problems with hearing, or numbness, tingling, pain or weakness involving the arms or legs. In some cases, this can cause a fluid collection to develop in the spinal cord (a syrinx), and this can disrupt normal spinal cord function. Chiari I Malformation is most commonly diagnosed by magnetic resonance imaging and a clinical history that is consistent with the disorder.

The symptoms of Chiari I Malformation can be cured by surgery. During the surgical procedure, our highly-skilled neurosurgeons carefully remove bone near the base of the skull to decompress the brain and spinal fluid passageways while leaving the brain itself undisturbed, thereby restoring the flow of cerebrospinal fluid.

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