More commonly seen in the elderly. It is thought to begin as a classic ‘high pressure’ hydrocephalus in which the ICP gradually falls to cause NPH, however, the mechanism is not 100% certain.
Patients do not commonly present with symptoms of hydrocephalus (e.g. vomiting, headache) but instead present classically with Adam’s Triad:
- Dementia
- Urinary Incontinence
- Ataxia/gait apraxia
which comes on slowly over a few months. There are large ventricles seen on CT but CSF pressure is often normal. A VP shunt is often useful at resolving the hydrocephalus but many patients’ symptoms do not improve. Therefore, the risks/benefits of performing a shunt procedure should be considered carefully in these patients.