Introduction
Normal pressure hydrocephalus is a reversible cause of dementia seen in elderly patients. It is thought to be secondary to reduced CSF absorption at the arachnoid villi. These changes may be secondary to head injury, subarachnoid haemorrhage or meningitis.
Epidemiology
- Incidence: 6.00 cases per 100,000 person-years
- Peak incidence: 60-70 years
- Sex ratio: 1:1
| Condition | Relative incidence |
|---|---|
| Normal pressure hydrocephalus | 1 |
| Multiple system atrophy | 0.10 |
| <1 | 1-5 | 6+ | 16+ | 30+ | 40+ | 50+ | 60+ | 70+ | 80+ |
Clinical features
A classical triad of features is seen
It is thought around 60% of patients will have all 3 features at the time of diagnosis. Symptoms typically develop over a few months.
- urinary incontinence
- dementia and bradyphrenia
- gait abnormality (may be similar to Parkinson's disease)
It is thought around 60% of patients will have all 3 features at the time of diagnosis. Symptoms typically develop over a few months.
Investigations
Imaging
- hydrocephalus with an enlarged fourth ventricle
- in addition to the ventriculomegaly there is typically an absence of substantial sulcal atrophy
Management
Management
- ventriculoperitoneal shunting
- around 10% of patients who have shunts experience significant complications such as seizures, infection and intracerebral haemorrhages