Normal Pressure Hydrocephalus (NPH)

Normal Pressure Hydrocephalus (NPH) is a rare condition that can be difficult for the non-specialist to spot. Its symptoms are common in other diseases, so it takes an experienced neurologist with extensive knowledge to make a definitive diagnosis. Without this, NPH can be missed and the opportunity for treatment lost or NPH can be incorrectly diagnosed and the wrong therapy administered. NPH primarily affects adults over the age of 60.

At MUSC Health, possible NPH patients are evaluated by a neurologist who will work with neurosurgeons, physical therapists, neuropsychologists and other providers to ensure correct diagnosis and treatment. 

What is Normal Pressure Hydrocephalus?

NPH is an abnormal buildup of cerebrospinal fluid (CSF) in the brain's ventricles (cavities). This causes the ventricles to enlarge, creating compression that leads to neurological symptoms. It is believed to be due to increased production or decreased reabsorption of CSF, but the true cause of idiopathic NPH is unknown. It is called "normal pressure" hydrocephalus because, despite the excess fluid, the pressure measured during a spinal tap is typically normal. 


The symptoms of NPH include problems with walking, progressive mental impairment, and impaired bladder control. Difficulty with walking is the most important feature of the condition. When these symptoms are accompanied by enlarged ventricles (revealed by CT scan of the head or brain MRI), concerns for NPH should be raised. It’s important to know that these symptoms are also seen in other neurological disorders, such as Alzheimer’s disease and Parkinson’s disease, which are more common. Because of that, these patients should always be referred to a neurologist for evaluation.

Risk Factors

In idiopathic NPH (cause unknown), age is the only currently well-defined risk factor. In secondary NPH, risk factors include having a brain tumor or brain infection, having had a brain injury or having undergone brain surgery. 


At MUSC Health, after evaluations by a neurologist and neuropsychologists, if NPH is truly suspected and it is felt that the patient has a chance of improvement with a shunt, the patient will be admitted to the hospital for further testing. If the patient's goals are only to improve memory and incontinence, he or she might not be a candidate, as these symptoms frequently do not respond to shunting fluids. Difficulty with gait is more commonly the symptom that may improve with shunting. 

Ongoing research seeks to better understand this difference in response to treatment and to assess how medical professionals can better predict who will improve and who will not.