NPH, Normal Pressure Hydrocephalus, is a brain disease that is often misdiagnosed because it mimics other brain conditions. This can result in patients waiting years to receive a treatment that could give them significant improvement… or never receiving it at all.
It is estimated that 15,000 Canadians and 700,000 Americans have NPH but less than 20% are diagnosed correctly. Instead, they are diagnosed with Alzheimer’s or Parkinson’s Disease, or just old age.
“Hydrocephalus” means increased water or fluid in the brain. This condition can also occur in children, but they usually have increased pressure in the brain while adults with the condition have pressure that fluctuates from normal to elevated. It is treated by surgically inserting a shunt to drain fluid from the brain and spinal cord (called cerebrospinal fluid) into another part of the body.
Adults produce 500 ml (2 cups) of cerebrospinal fluid each day. This fluid supports and cushions the brain, removes waste and distributes important substances. When its circulation is blocked, fluid accumulates, causing the cavities within the brain (called ventricles) to enlarge, pressing on parts of the brain and causing malfunction. The type of malfunction would depend on which area was receiving pressure.
Symptoms
The adult version of the disease, Normal Pressure Hydrocephalus, was named before newer forms of brain monitoring showed that pressure could be high as well as normal, but the name stuck even though it isn’t quite accurate. NPH most commonly occurs in adults over age 60. Symptoms include:
Difficulty standing and walking, a shuffling gait
Impaired bladder control
Memory problems and lack of concentration
It is not necessary to have all 3 symptoms to be diagnosed with NPH. In many cases, physical symptoms appear first, followed by mental symptoms like forgetfulness.
Cause
Most cases of NPH are “idiopathic”, which means the cause is unknown. This is also referred to as “primary NPH”. There is also “secondary NPH” that is caused by another condition, such as head injury, brain surgery, subarachnoid hemorrhage (bleeding in the brain), tumors, cysts (closed, sac-like abnormal structures that contain fluid, air or a semisolid substance), meningitis or other brain infections.
Symptoms progress with time. The longer and more severe the symptoms, the less likely treatment will be successful, but some patients with symptoms for years can improve with treatment. One study found that 87% of those treated had experienced improvement.
How is it diagnosed?
Often the affected person or a family member brings the symptoms to the attention of the family doctor, leading to a diagnosis. Sometimes enlarged ventricles (fluid-filled spaces) in the brain are found when the brain is scanned for another reason. It is recommended to see a neurologist or neurosurgeon if NPH is suspected for an evaluation and interpretation of test results.
3 types of testing can be used:
An interview, physical exam (to rule out other causes) and a neurologic exam to assess brain function
Observation of walking and turning
Questions about bladder function
Pencil and paper tests to examine attention, reaction time, memory, reasoning, language and emotional state).
Brain imaging to look for enlarged ventricles in the brain
CT scan
MRI (can detect impaired fluid flow as well as enlarged ventricles)
Tests to predict whether surgery will help
Lumbar puncture/spinal tap (A thin needle is inserted into the fluid around the base of the spine in the lower back. Pressure can be tested and up to 50 ml of fluid is drained off to see if lowering fluid pressure will improve symptoms)
Because of the high rate of misdiagnosis, the Hydrocephalus Association is conducting a campaign to inform doctors and the public about NPH. Check out their website -- it’s a good place to start, if you are interested in more information.
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