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.
The typical symptoms are:
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.
Patients experience their walking as unpredictable, stiff, and slow. The feet may be perceived as glued to the floor or that the legs feel heavy like logs. It can be difficult to climb stairs or walk on uneven surfaces such as in the forest. Patients often have poor balance and tend to repeatedly fall and injure themselves. The walk 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 walk can be locked in, which is noticeable, for example, when the person turns around and the turn requires many steps. Walking difficulties is the most easily identified symptom and therefore many patients describe walking difficulties as debut symptoms.
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.
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.
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.
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/
