Normal pressure hydrocephalus (iNPH)

Idiopathic normal pressure hydrocephalus (iNPH) is a treatable neurological disorder that causes walking and balance difficulties, cognitive impairment and continence problems. The symptoms are caused by a disturbance of cerebrospinal fluid production and uptake which leads to the collapse of the parts of the brain. The cause of the imbalance is unknown; therefore the name idiopathic. A similar condition, secondary NPH, can occur after brain damage such as bleeding, infection, stroke or severe head injury. The condition can be treated with a shunt operation that directs cerebrospinal fluid from the brain, usually to the abdominal cavity.

Symptoms

The typical symptoms are:

  • Difficulty walking and balancing
  • Cognitive impairment
  • urinary incontinence

The symptoms are insidious and can be very similar to normal ageing. This means it's difficult to detect iNPH.

Early symptoms may be discrete, motor and memory difficulties are hardly noticeable to anyone other than he who suffers. The symptoms are also similar to those seen in, for example, vascular dementia, Alzheimer's disease, Parkinson's disease and dementia, which can lead to misdiagnosis. It is not uncommon for people with iNPH to have to wait long before diagnosis can be made. Most often, all three symptoms occur (see above). Sometimes some symptoms may be missing, such as urinary incontinence. The severity of the disease varies greatly from discrete memory difficulties and mild balance problems, to inability to walk and pronounced fatigue.

Walking and balancing difficulties

Patients experience the aisle as uncertain, stiff and slow. The feet may be perceived as glued to the substrate or that the legs feel heavy like logs. It can be difficult to climb stairs or on uneven surfaces such as in the forest and land. Patients often have poor balance with repeated falls and injuries. The aisle is distinctly slow, wide-gauge (wide between the feet) with short rushing steps and decreased movements in the hip, knee and ankles. As with Parkinson's disease, the aisle can lock in, which can manifest itself as turning with sometimes many extra steps. Walking difficulties are the most easily identified symptom and therefore many patients describe walking difficulties as onset symptoms.

Cognitive impairment

Cognitive symptoms may vary. Sometimes only relatives pay attention to the difficulties. Memory difficulties, initiativelessness and fatigue are common early symptoms. An increased need for sleep is common with day sleep and sleep in front of the TV. Sometimes there is an increased irritability and a tendency to burst.. Patients may exhibit an emotionally discordant image with disinterest in activities and relatives. It is common for patients themselves to deny any such problems.

urinary incontinence

At the beginning of the disease, patients often experience frequent congestion. Later, urinary incontinence will start. This often has severe social consequences. The disease can in severe cases also cause stool incontinence.

Diagnosis

The diagnosis is based on the symptom picture in combination with the detection of broad ventricles on x-ray examination. The sometimes "difficult to interpret symptom"- picture allows iNPH to be confused with other neurological disorders. If the symptoms seem like iNPH, the primary care physician should supplement with a CT scan of the brain. If the ventricles are completely normal, iNPH can be excluded. If, however, the ventricles are dilated (and this does not have another cause), the suspicion of iNPH remains. Referral should then be sent to the nearest neurologist or neuro clinic. A new assessment and possibly new and more advanced evaluations may be needed.

Treatment

The only effective treatment of iNPH as of today is by leading the cerebrospinal fluid from the ventricle system to the blood, bypassing the obstacle that is the cause of the dilated ventricles. This is done by inserting a thin plastic tube, which is protected under the skin at the front of the body, operated in from the ventricles of the brain to the abdominal cavity (so-called ventrikulo-peritoneal shunt). Cognitive difficulties and other symptoms disappear if pressure is normalized and treatment happens early on. For more information about iNPH, see https://www.likvor.com/

Johan Sundelöf, Senior Physician, Specialist in Geriatrics and Palliative Medicine
Reviewed by: Johan Sundelöf, Senior Physician, Specialist in Geriatrics and Palliative Medicine
Updated: January 22, 2021
Published: 15 December, 2020

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