a day ago
Why Normal Pressure Hydrocephalus (NPH) like Billy Joel's is so hard to diagnose
The gradual onset of impaired mobility and cognitive decline in later life is almost invariably inauspicious – indicative of some progressive neurological disorder for which regrettably there is not much that can be done. There are however a few (very important) exceptions highlighted recently by the news that American singer/songwriter Billy 'Uptown Girl' Joel is currently receiving treatment for the obscurely named condition Normal Pressure Hydrocephalus (NPH).
This is a disorder of the Cerebrospinal fluid (CSF) secreted in generous quantities from the two cavernous ventricles within the brain from where it circulates over its surface and down the spinal column before being reabsorbed. Its diverse functions include, variously, nourishing the tissues with which it is in contact, keeping the brain buoyant within the bony skull, and acting as a 'shock absorber' protecting it from traumatic injuries to the head.
The precise mechanism of NPH is not known, but it is probably due to partial obstruction of the flow of the fluid around the brain so it accumulates within the ventricles, causing them to enlarge, thus compromising the function of the neuronal circuits in close proximity. Hence the impaired mobility – an abnormal shuffling gait as if the feet are 'glued to the ground' – and the cognitive impairments characteristic of mild dementia: forgetfulness, poor concentration, changes in personality and behaviour and so on.
Logically then a surgical procedure that drains the excess fluid from the ventricles should, by allowing those adversely affected neuronal circuits to recover, result in a marked improvement. As indeed it may. But that of course presupposes making the diagnosis in the first place, which is problematic on several counts.
NPH is frequently overlooked
The gradual insidious onset may too readily be misattributed to the normal process of ageing where some degree of impaired mobility and cognitive decline is unexceptional. Then by the time the symptoms are severe enough to warrant medical attention, there is a high probability they may be due to some progressive neurological disorder (such as Alzheimer's) so other possible explanations are not pursued. And while one might expect an MRI scan would show the ventricles to be enlarged, the findings can be ambiguous, especially in the early stages, and require further confirmatory specialist tests.
The upshot being that NPH as a remediable cause of cognitive decline is almost certainly commoner than might be supposed and frequently overlooked. This is well illustrated by the cautionary experience of a reader who was advised his mother's deteriorating mental state was due to a series of 'mini strokes' and it would be best to place her in a nursing home and 'get on with the rest of my life'.
This he was most reluctant to do. Soon after she fell and broke her arm, requiring a further stay in hospital 'where the doctors all tried to reconcile me to coming to terms with my mother's worsening dementia'.
Instead he sought a second opinion privately from a neurologist who picked up on the two important clues that her mental decline had coincided with her gait becoming unsteady (hence the broken arm) and also urinary incontinence (a further 'late' symptom of NPH) – attributed by her GP to cystitis, but which had not responded to treatment with antibiotics. Further investigations confirmed she did indeed have NPH. Following the procedure to drain the excess fluid from those expanded ventricles she has made 'virtually a complete recovery'.
