What Is Normal Pressure Hydrocephalus?
Normal pressure hydrocephalus (NPH) involves excessive accumulation of a clear fluid called the cerebrospinal fluid inside the brain. Hydro means water, and cephalo means brain. And one may develop problems with body balance, walking, memory, cognition, and bladder control. Many types of dementia disorders (cognition issues) affect the population, and one is caused by normal-pressure hydrocephalus. It is important to note that, unlike many other conditions where the fluid accumulation raises the pressure inside the head (intracranial pressure), the pressure remains the same in normal pressure hydrocephalus. Timely diagnosis and treatment give good results in recovery.
What Causes Normal Pressure Hydrocephalus in an Individual?
People above the age of sixty or seventy are the most affected by this condition. Sometimes, conditions like head injuries, brain inflammation, and a growing tumor inside the brain may also cause it. In normal-pressure hydrocephalus, only a normal amount of cerebrospinal fluid is produced, but the problem lies in the absorption of fluid back into the brain. Cerebrospinal fluid is continuously produced in the ventricles (a hollow chamber inside the brain). And it circulates and reaches the structures called arachnoid granulations, which absorb the fluid back into the brain.
But in this disease, there are problems with absorption; hence, the cerebrospinal fluid cannot be removed properly. It can be due to tissue changes in the arachnoid granulations (scarring or fibrosis). If the fluid is continuously produced and is not removed, ideally, the pressure inside the head is supposed to increase.
Interestingly, in an individual affected with normal pressure hydrocephalus, there is a slight increase in pressure. Still, it stays in the normal range because the ventricles will expand (dilate) to contain the excess fluid. The enlarged ventricles may pinch on the brain, and blood vessels obstruct the free flow of blood, affecting brain function over time.
What Are the Symptoms of Normal Pressure Hydrocephalus?
Normal-pressure hydrocephalus causes three typical symptoms in an individual, and together they are called Hakim’s triad. All these three symptoms are related to the nervous system.
The patients normally complain of:
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Gait Problems - They are probably the first noticeable sign of normal pressure hydrocephalus. Gait means an individual's way of walking. The balancing ability of the patient is bad; one may show a typical ‘magnetic gait,’ where it appears as if a big magnet pulls the patient’s feet onto the floor, and they tend to bend the body forward and take short steps. Taking the first step to start walking may be hard; one may feel that their feet are glued to the floor. Also, there is a tendency to lose balance and fall in changing directions while walking. Falls can be quite frequent for an affected individual.
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Dementia - This usually happens in the later stages of the disease. The early signs of dementia are attention issues and problems in executing things like planning, reasoning, problem-solving, etc. One may often become forgetful and lose interest in other people and activities. And finds it difficult to accomplish even simple day-to-day tasks like telling the time or counting money. Later signs of dementia include major memory loss.
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Urinary Incontinence and Urgency - Develop in the later stages of the disease. One may find it difficult to hold the urine, and there may be frequent accidental urination and dribbling of urine in unexpected situations. There is always an urgency to urinate that makes one go to the bathroom a little too often.
How Is Normal Pressure Hydrocephalus Diagnosed?
Diagnosing normal pressure hydrocephalus can be a bit challenging. Other neurological conditions like vascular dementia, Parkinson’s disease, or Alzheimer's can also have similar symptoms. Not necessarily every individual suffering from normal pressure hydrocephalus exhibits all the symptoms in the triad. And the brain's ventricles can be dilated for other reasons. Hence, the symptoms alone are not enough to diagnose this condition.
After reviewing the medical history and illnesses suffered in the recent past, the doctor will ask about the symptoms in detail. One needs to explain the nature of the symptoms, what are the current difficulties they face with walking, performing every task, etc. The duration of symptoms from the start and how they have progressed over the days are also important. The doctor may order:
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A neurology examination is to evaluate the functions of each brain area. It involves certain activities and tests to check the movements, strength, coordination, senses, response to various simulations, time-place-person awareness, and memory.
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Imaging studies such as computed tomography (CT) scans and magnetic resonance imaging (MRI) visualize the dilation of ventricles inside the brain, which is a sign of excess fluid.
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One may conduct a lumbar puncture or spinal tapping procedure, where the doctor may remove thirty to fifty milliliters of cerebrospinal fluid and see if that improves the symptoms in a couple of hours. If one can appreciate gait, continence, and cognition improvements, one can be sure that it is normal pressure hydrocephalus.
What Is the Treatment for Normal Pressure Hydrocephalus?
There is no exact treatment for an absolute cure of normal pressure hydrocephalus. Since the cerebrospinal fluid accumulates and compresses the brain to cause the symptoms, one should try to remove this fluid and see if that makes one better. Medicines may not be effective for this condition; surgery is considered the best option to date.
Surgery involves placing a ventriculoperitoneal shunt (VP shunt) in the brain. The doctor puts a tube (catheter) into the ventricle of the brain and connects it to the peritoneal cavity, meaning the individual’s abdomen. The shunt acts as an external drainage system. This way, the cerebrospinal flows into the abdomen, so the pressure cannot build up in the brain, and the patient does not feel the symptoms anymore. The shunt may be left in the body as a permanent pathway of cerebrospinal fluid drainage. This may need periodic follow-ups to ensure its proper working as well. One should be vigilant about shunt blockage, infections, or complications due to excessive fluid drainage by the shunt.
Conclusion:
The symptoms of normal pressure hydrocephalus are often confused with a handful of other neurological conditions. Hence, there is every chance one may overlook its diagnosis. Since, it is a treatable condition to a great extent, reaching the correct diagnosis may largely improve the affected one’s life. Draining the excess cerebrospinal fluid surgically improves the gait and balance problems. But one may still suffer cognitive issues and bladder control. Discussing the symptoms early on with a qualified medical professional can make a big difference in the recovery pattern.
