Normal pressure hydrocephalus

Background

• ↑CSF with gait, urinary and mentation symptoms
• Periventricular CSF (not global) so sacral (bladder and leg) motor fibres affected

Clinical

Triad

• Abnormal gait
• Urinary incontinence
• Dementia (reversible!)

History

• Predominantly (not exclusively) elderly
• Altered gait is often the first symptom.
  • Classically "magnetic" gait (feet stuck to the floor)
  • ±pyramidal tract signs (e.g. ↑tone/spasticity), particularly of legs
• Urinary symptoms = detrusor over-activity (periventricular pathology)
• Dementia - characteristic loss short term recall

Signs

• Altered cognition
• Pyramidal - Gait, hypertonia (legs) ±↑plantars
  • leading to festinant gait of Parkinson's
• Normal ICP (but ↑vol) = No papilloedema & normal opening pressure (LP)
• No sensory signs

Differential Dx

• Parkinson’s (rest tremor is unusual in NPH)
• Alzheimers and other dementias

Investigations

• CT brain (very sensitive so a normal CT rules NPH out)
• MRI is more specific (positive rules NPH in)
• Diagnostic LP with CSF volume (>50ml) drainage (NPH will respond)
• Vascular/inflam. dementia work-up (in-patient teams)
• Levodopa trial if ?Parkinson’s (NPH will not respond)

Management

• Admit Care of the Elderly for dementia / CSF shunt work-up

Links