Normal pressure hydrocephalus
Normal pressure hydrocephalus (NPH) is caused by buildup of excessive cerebrospinal fluid (CSF) in the ventricles (spaces in the brain) without significant pressure. CSF accumulation causes enlargement of the ventricles and pressure on the brain. NPH consists of one or more of the three classic symptoms: walking (gait) difficulties, dementia and impaired bladder control. NPH is one of the only dementias in which symptoms can be controlled or possibly reversed with treatment.
- Primary NPH is idiopathic, meaning the cause is unknown.
- Secondary NPH can occur as a result of other conditions including:
- Brain bleed (subarachnoid hemorrhage, subdural hematoma)
- Brain surgery
- Head injury
- Infections such as meningitis
- Tumor or cyst
- Incontinence or urinary urgency — inability or difficulty with controlling the bladder, feeling a sudden urge to urinate, accidentally urinating on oneself
- Mild dementia — short-term memory loss, forgetfulness, difficulty performing tasks, loss of interest or loss of motivation • Difficulty walking — imbalance, wide based gait, shuffling gait, or “magnetic gait” that can feel as if your feet are stuck to the floor
In most cases, the cause of NPH is not well understood, so there are currently no preventative measures known to reduce risk. Prompt evaluation and treatment of NPH may result in better control or resolution of symptoms.
The risk factors for NPH are not set in stone, but these factors may play a role:
- Diabetes mellitus
- High blood pressure
- Vascular disease (history of stroke or mini-stroke)
- Medical history and symptom review. The provider will review your symptoms and inquire about your ability to perform daily tasks.
- Physical examination. The doctor will perform a neurologic exam including assessing gait, strength, reflexes, and may perform cognitive assessment or neuropsychological evaluation.
- Diagnostic tests. MRI or CT scans of the brain may show enlargement of the ventricles. Lumbar puncture (spinal tap) reveals normal to minimally increased pressure. Larger volumes of CSF can be removed to see if the patient may benefit from surgery for NPH.
- Surgery may be performed to stop the progression or even reverse symptoms of NPH.
- Shunt system is a procedure in which a device is placed in the ventricle of the brain and connects to a tube that is then placed in another part of the body, sometimes the peritoneal cavity where CSF can be redirected and reabsorbed to help maintain normal CSF levels in the brain.
- Endoscopic third ventriculostomy, currently in clinical trials, is being evaluated in patients with narrowing (blockage) of the cerebral aqueduct (structure connecting the third and fourth ventricles) to bypass the blockage and allow CSF drainage.
- Physical therapy or occupational therapy may be ordered to help improve mobility and function in daily activities.
- Regular follow-ups after surgery are necessary to assess for complications or problems with the shunt. • New or worsening symptoms should be discussed with your physician.