Normal Pressure Hydrocephalus Overview Normal pressure hydrocephalus is a condition that is not due to a block within the ventricular system. Still, there is an obstruction in the subarachnoid space, preventing cerebrospinal fluid (CSF) from flowing over the ventricles. This condition is more common in the elderly. Aetiology A history of subarachnoid hemorrhage (SAH), head injury, or meningitis may be associated with the development of normal pressure hydrocephalus. Clinical Features The clinical features of normal pressure hydrocephalus include progressive memory impairment and dementia, slowness, marked unsteadiness of gait, and urinary incontinence. Investigations The removal of 50 ml of CSF can lead to a temporary improvement in cognition. CT or MRI can show dilatation of the ventricular system and relatively normal sulci. Periventricular lucencies can also be found on MRI. Management The treatment for normal pressure hydrocephalus involves the insertion of a shunt to improve the c