Normal pressure hydrocephalus

From IDWiki
Revision as of 14:49, 7 March 2026 by Aidan (talk | contribs)

Background

  • May be idiopathic (mostly the focus here) or secondary (to prior infection, ICH, TBI, or radiation)
  • Idiopathic is more common in older patients and is somewhat a disease of aging

Clinical Manifestations

  • "Wobbly, wet, and wacky"
  • Earliest symptoms is gait instability/apraxia ("magnetic gait") progressing over months to years
    • May be shuffling, magnetic, or wide-based
    • Increased mediolateral variability during quiet standing
    • Postural instability worsens with eye closure
  • Next is dementia
    • Cognitive symptoms include psychomotor slowing, forgetfulness, decreased attention/concentration, impaired executive function
    • Apathy is a notable feature
  • Usually last symptom is urinary incontinence, in about 50% of patients at diagnosis
    • First as urgency with an inability to reach the bathroom in time, then later progressing to incontinence with apathy
  • There should be no headaches, nausea/vomiting, visual changes, or papilledema

Differential Diagnosis

Investigations

  • Should have normal CBC, lytes, creatinine, vit B12, TSH, calcium
  • CT head showing hydrocephalus
  • Lumbar puncture confirming normal pressure
    • CSF glucose and protein are typically normal

Grading

Grade Gait Cognition Urinary Incontinence
0 Normal Within normal range Absent
1 Unsteadiness without objective abnormality No clear dementia, but apathy present Frequency and/or urgency without incontinence
2 Needs a cane Needs support in social functioning, but remains independent at home Occasional episodes at night
3 Needs a walker, or 2 canes Requires partial assistance at home Intermittent episodes during the daytime
4 Unable to ambulate Fully dependent Frequent urinary incontinence

Management

  • High-volume lumbar puncture (30 to 50 mL)
    • Observe for improvement, particularly in gait
    • If there is improvement in symptoms, consider implanting a ventriculoperitoneal shunt