Normal Pressure Hydrocephalus
Dr Vernon Coleman
The diagnosis of normal pressure hydrocephalus is missed more than 80% of the time. Between 5% and 10% of patients diagnosed as suffering from Alzheimer’s disease or dementia are in fact suffering from the curable disease idiopathic normal pressure hydrocephalus – which can be fairly easily treated with a simple operation.
The three symptoms of idiopathic normal pressure hydrocephalus are:
A tendency to fall a good deal. If an elderly patient falls a lot then a diagnosis of idiopathic normal pressure hydrocephalus must be considered.
Dementia.
Urinary incontinence.
Why do doctors continue to ignore normal pressure hydrocephalus and to suppress the evidence of its significance?
There are two reasons.
First, idiopathic normal pressure hydrocephalus can be treated and cured with a simple surgical operation. Drug companies make millions out of selling drugs for the treatment of Alzheimer’s disease and if patients with idiopathic normal pressure hydrocephalus were properly diagnosed, the demand for their drugs would plummet. And profits would fall. Sadly, many charities now work hand in glove with drug companies and so they follow the company line.
Second, doctors in the UK are now paid a generous fee whenever they make a diagnosis of Alzheimer’s disease. But they do not get paid when they make a diagnosis of normal pressure hydrocephalus. Doctors have a financial interest in over-diagnosing Alzheimer’s disease.
The result is that countless millions of patients with idiopathic normal pressure hydrocephalus have been diagnosed as suffering from Alzheimer’s disease. They have been given drugs and abandoned. They have been left to die when they could have been treated and cured.
The truth is that the medical establishment is so influenced by the drug industry that it pays little attention to normal pressure hydrocephalus which is, as a result, under-researched, under-diagnosed and under-treated. There is almost certainly no disease affecting large numbers of people which is less understood. Within the medical profession it is known (when it is known at all) as the ‘wet, wacky and wobbly disease’ – more a childhood term of abuse than a phrase redolent with respect.
Organisations which specialise in caring for the elderly are often appallingly ignorant about the disease, as are health websites. I asked the questions on the internet, ‘why are old people unstable?’ and ‘why do old people fall?’ and none of the first several dozen responses mentioned ‘normal pressure hydrocephalus’. In the UK, the NHS Choices website devotes less than 70 words to the disease and describes the condition as ‘uncommon’ which is manifest nonsense since it affects a vast number of patients and is (with vitamin B12 deficiency) the commonest treatable cause of major disability and mental incapacity among the elderly.
Researchers are not interested in investigating the disease because a cure is already available and, since there is no need for a ‘wonder drug’ there are not going to be any big, fat grants from drug companies. And doctors are not interested in diagnosing or treating the disease because it invariably involves older patients, and doctors are encouraged by governments (and much of society) not to take much interest in elderly patients.
If you made a list of the 100 commonest, potentially fatal but most easily cured medical conditions which are most often mistakenly diagnosed as something else, then normal pressure hydrocephalus would be top of the list.
The only things we know for certain are that idiopathic normal pressure hydrocephalus is much commoner than is generally thought, produces devastating results, is usually mistaken for something else and it is treatable. Patients who have been stuck in bed or in wheelchairs can, after treatment, get up and walk. They can resume their lives; talking and enjoying work and hobbies.
So, what is normal pressure hydrocephalus?
Under normal circumstances the space between the brain and the skull is filled with cerebrospinal fluid; a substance which is produced within the spaces of the brain, circulates in and around the brain and is gradually reabsorbed. In normal circumstances, the fluid is produced in the same quantities as it is being reabsorbed. The cerebrospinal fluid, which also surrounds the spinal cord, is there primarily to protect the brain in case of injury.
In the condition known as normal pressure hydrocephalus, the fluid is not reabsorbed as fast as it is produced.
When there is too much fluid in and around the brain, the stuff accumulates in the ventricles – the spaces within the brain – and the brain is put under pressure, being pushed outwards. The result of this unusual pressure is that the brain is compressed and damaged in a variety of ways. The symptoms and signs of damage will depend upon the area of the brain affected. If the problem is not treated then the damage to the brain will be irreversible.
Logically, one might expect that with too much fluid in a confined space there would be an increase in fluid pressure. By definition this does not happen with normal pressure hydrocephalus. The intracranial pressure is normal and instead of putting up the pressure, the increased amount of fluid dilates the ventricular system. If a scan is done, the ventricles usually look dilated. However, even when patients have a magnetic resonance imaging (MRI) of the brain or computerised tomography (CT), the wrong diagnosis can still be made because doctors who are not aware of normal pressure hydrocephalus will probably assume not that the ventricles have become larger but that the brain has become smaller as a result of cerebral atrophy.
There are two types of normal pressure hydrocephalus – secondary and idiopathic. Secondary normal pressure hydrocephalus can be caused by a variety of external problems including a head injury, a tumour, an infection or a bleed. But idiopathic normal pressure hydrocephalus occurs with no underlying cause – it just happens.
Idiopathic normal pressure hydrocephalus, which was first described in 1965 by Hakim and Adams, does not appear to be any commoner in men than in women or in women than in men, and there is not as yet any evidence showing whether it is particularly likely to affect any particular racial or ethnic groups. Although it can affect people of any age it does, however, seem to be most commonly seen among patients in their sixties or older and it is this which results in patients being so often misdiagnosed as suffering from Alzheimer’s disease.
The symptoms of idiopathic normal pressure hydrocephalus make it surprisingly easy to diagnose.
The initial, main symptom is often a curious, wide-legged, unsteady walk. The patient’s feet seem to stick to the floor, and have to be dragged up in order to make the next step. Patients adopt a wide-legged gait in an attempt to make themselves more stable but they are, nevertheless, often unstable and may fall. Indeed, falling is a common problem with patients suffering from idiopathic normal pressure hydrocephalus, and in any elderly person who falls more than once or twice, the possible diagnosis of idiopathic normal pressure hydrocephalus should be placed quite high up on the list of possible causes.
Sadly, it is still the case that many leading health websites do not even mention normal pressure hydrocephalus as a possible cause of falls though since it is fairly common and treatable, the disorder should be listed towards the top of any such list, together with balance problems and drug side effects.
Since time is of the essence in diagnosing idiopathic normal pressure hydrocephalus, this disorder should always be considered very early on when a patient has fallen more than once or twice. Simply dismissing falls as ‘an inevitable part of ageing’, as some doctors are prone to do, is grossly irresponsible and unprofessional. Falling is not associated with any of the other common dementias, such as Alzheimer’s disease.
The gait disturbance tends to get steadily worse as the amount of fluid increases and the ventricles within the brain expand. When the ventricles expand, they put pressure on the part of the nervous system which descends into the spinal cord.
In the early stages of normal pressure hydrocephalus, the gait disturbance will probably be mild and result in the patient being unsteady and having impaired balance, particularly when trying to walk up and down stairs or steps or even kerbs. The patient will probably also complain that their legs feel weak, though there will probably be no explanation for this.
As the disease progresses, so the patient’s gait steadily gets worse. The patient will not lift their feet properly when walking and will walk very slowly. It is because of the gait disturbance that normal pressure hydrocephalus is often misdiagnosed as Parkinson’s disease. The tendency to fall is so common in normal pressure hydrocephalus that it is, I think, reasonable to say that if a patient falls a good deal and suffers from some form of dementia then a diagnosis of idiopathic normal pressure hydrocephalus must be considered first of all.
In the final stages of the disease, patients may be unable to walk, then unable to stand and finally even unable turn over when lying in bed.
The second symptom is dementia, a chronic disorder of the mental processes which is caused by some brain disease or injury and which is characterised by mental disorder, personality changes and impaired reasoning. And this is why normal pressure hydrocephalus is so often misdiagnosed as Alzheimer’s disease, or some other cause of dementia. The dementia in idiopathic normal pressure hydrocephalus usually involves the frontal lobe (because of the situation of the swelling ventricles within the brain) and patients will usually appear slow witted, forgetful and apathetic. There may be an absence of mood (patients are neither happy when they might be expected to be happy nor sad when sadness might be appropriate) and patients often have difficulty in speaking. The first sign of the dementia associated with this disease is often a curious difficulty in planning, organising or putting things in order. The patient may also have difficulty in paying attention and in thinking in an abstract way.
Patients may lose interest in daily activities, they forget names and things to be done, they have difficulty in dealing with routine tasks and their short-term memory may be poor. (One sufferer complained that he could no longer read a book because when he got to page 10 he could not remember what had happened on page 1.)
Although this symptom is usually placed second chronologically, it may be noticeable much earlier in some patients. I suspect that the reason the mental problems are not recognised or recorded, may often be because relatives and friends don’t know what to look for, don’t register subtle changes as being indicative of any underlying pathology and may dismiss changes as being simply consequences of ‘old age’.
It is important to remember that dementia is not a disease but a consequence of some underlying disease. And it is vital to remember that although the dementia associated with normal pressure hydrocephalus may appear similar, in superficial terms, to the dementia associated with Alzheimer’s disease, the two underlying disorders are quite different entities. There is, sadly, no cure for Alzheimer’s disease at the moment but there is a remarkably effective and relatively simple cure available for normal pressure hydrocephalus. To describe normal pressure hydrocephalus as a variation of Alzheimer’s disease (as I have seen done) is as nonsensical as describing heart disease as a type of cancer.
The final symptom to occur is often urinary incontinence.
Patients tend to have an increased sense of urgency (they suddenly need to urinate) but in the later stages, as the frontal lobe damage increases, they become indifferent to the consequences and genuine urinary incontinence may result. In some cases the urinary incontinence may occur quite early on in the disease. Some patients also develop faecal incontinence.
Whatever symptoms may occur they tend to progress with time, sometimes slowly and sometimes quite quickly. Careful questioning of the patient suggests that symptoms may have been present for months or even years before a doctor was consulted. By then the patient may have, to a certain extent, become accustomed to their disability and the chances are high that they themselves will have learned to regard the difficulty in walking, the slowness of thought or the incontinence as an inevitable consequence of ageing. In many cases it is only when there is a critical loss of function, or a disability which dramatically affects the patient’s independence, which leads to the patient seeking medical advice. At that point, the chances are high that the only solution on offer will be a default diagnosis of Alzheimer’s disease, a bed in a nursing home or hospice or a suggestion that a relative should take over and provide accommodation and care.
The symptoms associated with normal pressure hydrocephalus do vary a good deal. The one constant factor seems to be the delay in making the diagnosis. Time and time again patients and relatives will report that it took years for an accurate diagnosis to be made and that even then it was only after the patient had seen a good many doctors. The evidence now suggests that in 80% of patients the correct diagnosis is never made.
So, how common is idiopathic normal pressure hydrocephalus?
Idiopathic normal pressure hydrocephalus has been so little investigated that it is difficult to be certain how common it really is but there are three ways to tackle this vital question. All these methods make it very clear that idiopathic normal pressure hydrocephalus is far more common than most doctors believe. (A large proportion of doctors, including a surprising number of neurologists and psychiatrists are quite unfamiliar with the disorder.)
First, a study in Japan showed that normal pressure hydrocephalus affects a far higher number of individuals than is historically considered possible. Since there are no genetic or racial variations in the incidence of the disease, the figures can be applied globally.
The Japanese researchers investigated 567 individuals aged 65 and older and found seven patients with idiopathic normal pressure hydrocephalus. The researchers conclude ‘the prevalence of possible idiopathic normal pressure hydrocephalus to be 1.4%’ among individuals aged 65 and older.
When researchers in Sweden investigated the prevalence of probable idiopathic normal pressure hydrocephalus in a population of 65 years and older, they found the incidence to be 4%, with a higher proportion of men than women being diagnosed with the disease.
In the UK, there are approximately 10 million people aged 65 or older. If we use the Japanese figures for the UK’s population then it would seem that there are currently around 140,000 people in the UK with normal pressure hydrocephalus. In the US, where there are considerably more than 40 million people aged 65 or older, the Japanese figures would suggest that there are around 560,000 people suffering from normal pressure hydrocephalus. If we use the Swedish figures then it suggests that there are currently 400,000 people in the UK with idiopathic normal pressure hydrocephalus. And in the US the figure is a staggering 1,600,000.
The research has shown that only a very tiny percentage of these individuals have been accurately diagnosed as suffering from idiopathic normal pressure hydrocephalus. The vast majority of these individuals who have been diagnosed at all will have been diagnosed as suffering from Alzheimer’s disease or some other form of dementia or from Parkinson’s disease. Many individuals, of course, will not have been given a diagnosis at all but will have been simply labelled ‘old’ and dismissed as not worthy of attention.
The Hydrocephalus Association in the United States estimates that there are 700,000 adults in America who have idiopathic normal pressure hydrocephalus but that only a fifth of these patients have been diagnosed. The remainder have been misdiagnosed as suffering from Alzheimer’s, some other dementia or Parkinson’s disease. Available scientific evidence suggests that the majority of the rest could be treated and restored to good health.
If the Hydrocephalus Association in America is correct, there are 560,000 patients in the US who have idiopathic normal pressure hydrocephalus but who do not know it, have not been diagnosed or treated and who are being left to die, untreated and without hope. The figures for the UK and other countries are undoubtedly similar. The evidence suggests that there are 175,000 patients in the UK who have treatable idiopathic normal pressure hydrocephalus but who have been misdiagnosed as suffering from an untreatable dementia and (since doctors receive a fee for diagnosing it) probably labelled as suffering from Alzheimer’s disease.
Around the world there are probably several million patients who have normal pressure hydrocephalus and who could, have been cured if they had been correctly diagnosed.
The key thing to remember is that normal pressure hydrocephalus can be cured with a single, relatively simple surgical procedure. And the bottom line is that patients with dementia, who are confined to a hospital or nursing home or to bed in their own homes, can become independent again if they are treated.
Very few specialist studies have been done to measure the incidence of idiopathic normal pressure hydrocephalus among patients in ‘assisted living facilities’ or ‘extended care facilities’ but the results which exist show that between 9% and 14% of the patients studied had idiopathic normal pressure hydrocephalus.
The tragedy, as I have already explained, is that patients with idiopathic normal pressure hydrocephalus are often mistakenly diagnosed as suffering from other disorders such as Alzheimer’s disease, other dementias or Parkinson’s disease.
‘Many people go undiagnosed and untreated because the symptoms of normal pressure hydrocephalus can mimic Alzheimer’s disease, Parkinson’s disease and other neurological or spinal disorders that can occur in adults as they age’, says Michael Williams, a neurologist and director of the Adult Hydrocephalus Center at the Sandra and Malcolm Berman Brain and Spine Institute at Sinai Hospital of Baltimore in Maryland.
The size of this scandal is difficult to comprehend and as the number of people in their 60s and beyond increases, so the number of people with treatable normal pressure hydrocephalus will increase proportionally.
As I mentioned earlier, normal pressure hydrocephalus was first identified in 1965. No one has any idea how many people have been misdiagnosed since then. Because of ignorance among doctors and nurses, idiopathic normal pressure hydrocephalus is rarely diagnosed and so it is invariably categorised as a ‘rare disease’.
But idiopathic normal pressure hydrocephalus is not a rare disease. It is clear that when the disease is looked for, it is common.
Once you know what to look out for, idiopathic normal pressure hydrocephalus is not particularly difficult to diagnose. It should not be ‘missed’ as often as it is.
The principle symptoms of idiopathic normal pressure hydrocephalus are: a wide-legged, unsteady gait, a tendency to fall a good deal (commonly falling backwards, incontinence (usually urinary but double incontinence sometimes occurs) and dementia. Other symptoms and signs may include headaches. Patients usually appear slow thinking and have impaired memory. They may lose their inhibitions and behave inappropriately in company – saying or doing things that are completely out of character. Patients have difficulty in starting and carrying out tasks, find it hard to focus and lose motivation. They tend to sleep a good deal.
Because other types of dementia may produce similar symptoms, or symptoms which can be confused with these, or because the dementia may be by far the most dominant symptom that it overwhelms the others, it is dangerous to try to make a diagnosis of idiopathic normal pressure hydrocephalus from the symptoms alone.
Once diagnosed, idiopathic normal pressure hydrocephalus is remarkably simple to treat. And the treatment, a relatively small operation, usually provides a permanent cure. There is no need for long-term drug therapy.
The aim of treatment is to get rid of the excess cerebrospinal fluid which has accumulated and which is doing the damage. In order to remove the excess fluid, a small piece of plastic tubing (known as a shunt) is placed in the ventricles of the brain and run under the skin to the abdomen where the fluid drains away and is gradually absorbed.
Whatever type of shunt is used, a good response is usually obtained within a few hours of the procedure being performed, with the patient being able to walk more easily and being less incontinent. There is also often a significant improvement in mental function.
The earlier the diagnosis is made, and the earlier treatment is initiated, the greater the chances that the patient’s mental capacities will improve. Some early studies suggested that only patients in the early stages of the disease benefitted but more recent studies have shown that putting in a shunt will result in a noticeable or marked improvement in between 70% and 86% of patients who have quite severe symptoms. The prognosis when idiopathic normal pressure hydrocephalus has been diagnosed and treated is excellent. Once the shunt operation is performed, patients with idiopathic normal pressure hydrocephalus will often make quite remarkable recoveries.
It is worth remembering that patients who have the condition and are not treated will continue to deteriorate and will eventually die.
There are, sadly, some (including many in political positions of authority) who do not believe in providing health care for those who have passed a certain age. However, from a purely financial point of view this is nonsense.
If you have a relative or friends whom you think might be suffering from this disorder then you should spare no effort in pushing doctors to consider the diagnosis and to conduct the necessary tests.
Idiopathic normal pressure hydrocephalus was identified in 1965 but even today there is still very little about the disease in medical journals, and medical textbooks devote very little space to the disease.
The failure to diagnose normal pressure hydrocephalus has undoubtedly resulted in millions of patients living out the final years of their lives requiring full-time nursing care. How many countless million years of productive life have been wasted? And how many relatives and friends have suffered unnecessarily as they have watched their loved ones die slowly and with a steadily increasing loss of cerebral function?
The pure financial cost of this failure by the medical profession is impossible to estimate accurately. It is estimated that the cost of dementias to the UK is £26.3 billion a year. The country could save between £1.3 billion and £2.6 billion a year by diagnosing and treating patients with idiopathic normal pressure hydrocephalus.
It is no exaggeration to say that many millions of patients who require 24 hour nursing care could be returned to useful, independent, productive and rewarding lives if those patients with idiopathic normal pressure hydrocephalus were correctly diagnosed and not merely dismissed as suffering from an incurable dementia.
If you suspect that a relative or friend might have idiopathic normal pressure hydrocephalus then you must take action.
Remember: whenever a diagnosis of Alzheimer’s disease or any other type of dementia is made then it is wise to seek a second or third opinion. Similarly, when a diagnosis of Parkinson’s disease is made another opinion should be sought. Idiopathic normal pressure hydrocephalus is often missed but it can be treated with spectacular, life-saving results.
NOTE
The essay above is a shortened version of a chapter taken from Vernon Coleman’s book `The Dementia Myth’- which contains details of curable causes of dementia. To purchase a copy please visit the bookshop on www.vernoncoleman.com or CLICK HERE
Copyright Vernon Coleman May 2025
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