Normal Pressure Hydrocephalus (NPH) is a misleading name. The term "hydrocephalus"(literally "water on the brain") suggests an increase in the amount of cerebrospinal fluid within the brain which logically would increase the pressure within that closed compartment. However in this condition the pressure is not significantly increased. Imaging is more suggestive of a relative shrinking of the brain yet taking away fluid seem to improve symptoms in many cases.
It was first described as a single case report by a Colombian neurosurgeon, Salomón Hakim in 1957. The conditions was defined by a clinical syndrome consisting of three features- unsteady gait, contenence problems and dementia. In the years that followed documentation of the condition often reported cases where not all three were present leading some to doubt the condition really existed and there was freqient difficulty indistiguishing it from other conditions such as Parkinson's disease and other types of dementia.
Signs and Symptoms
This uncertainty persists to the modern day and fundamentally NPH remains a clinical diagnosis as investigations and imaging are of limited help. In our practice we rely on an opinion from an expert neurologist as well to ensure mimics such as Parkinson's disease are reasonably excluded.
Difficulty Walking
Worsening balance when walking is typically the earliest evidence of NPH.
The problem develops gradually and is typically seen in those over 60 years of age although rare cases at a younger age have been reported albeit still over the age of 40 years.
The characxteristic gait is sometimes described as "magnetic"- as though the feet were stuck to the ground and difficult to lift up. The stance becomes broad-based and turning 180 degress becomes difficult requiring three or more adjustments. It is usual to alternative explanations and spinal pathology should be excluded by a combination of physical exam and imaging.
Cognitive Impairment
There may be behavioural changes or difficulty in performing multistep procedures, working memory, formulation of abstractions/similarities as well insight into this problems.
Recall for recent events may become increasingly difficult.There may also be difficulty with fine motor movement including in the hands and a generalised slowing in tasks which is easy to confuse witht he bradykinesia seen in Parkinson's disease.
All of these changes can be documented using standardised questionnaires and again other conditions capable of mimicking these problems need to be excluded in so far as possible.
Incontinence
Incontineces of urine or faeces may occur and may be episodic or persistant. Of course there are other reasons such as pelvic floor weakness or prostate disease that may account for such problems later in life especially when the other features above are not very evident. For this reason evaluation by a urologist can be invaluable in making the diagnosis.
Investigation
Peripheral nerve tumours develop on nerves that have left the cranial or spinal bones and are travelling through the body to provide sensation, movement and the unconscious maintenance of blood flow to organs, temperature and autonomic functions.
Treatment
Occasionally neurologists and rheumatologists who are investigating the possibility of certain nerve and muscle diseases will require samples from specific nerves and/or muscles to assist them.
Nerve biopsy may be required when inflammation affects the tiny arteries delivering oxygen to peripheral nerves- vasculitis. As a result then nerve may lose function- peripheral neuropathy. This is usually indicative a systemic problem and treatment is typically with medication. Confirmation of the diagnosis prevents unnecessary exposure to potentially toxic medications. Related non-infectious inflammation in muscle is termed myositis.
Biopsy is usually under local anaesthesia and the sample requires prompt examination by a specialist neuropatholgist without chemical fixation.
There may be behavioural changes or difficulty in performing multistep procedures, working memory, formulation of abstractions/similarities as well insight into this problems. Recall for recent events may become increasingly difficult.
