NPH

Question 1

What are 3 characteristics of the cognitive impairment seen in NPH?

Answer 1

• decreased attention/concentration
• impaired executive function
• apathy
• psychomotor slowing
  (intact memory)

Question 2

How much CSF should be removed in a tap test? When do you assess for improvement?

Answer 2

Minimum 30ml, goal is 40-50ml

3h, 24h, 48h

Question 3

What are objective measures of improvement after a tap test?

Answer 3

• 10-m walk: # of steps and time
  —- Optional: pull test, 10-step tandem, 360 degree turn
• Cognitive testing
• Voiding diary

Question 4

List 5 complications of ventricular-peritoneal shunting for NPH?

Answer 4

Shunt overdrainage can cause: Subdural hematoma, Headache
Intracranial infection
Seizure
Abdominal injury: infection, ascites, perforation
Mechanical shunt failure/blockage
Arrhythmias (incorrect placement) (V-A shunt)

Question 5

What percentage of NPH is secondary (not idiopathic)?

Answer 5

50%

Question 6

7 causes of secondary NPH?

Answer 6

Impaired CSF absorption by…
● subarachnoid hemorrhage in 46.5%
● traumatic brain injury in 29%
● brain tumor and surgical resection in 6.2%
● meningoencephalitis in 5%
● cerebrovascular disease in 4.5%
● intracerebral hemorrhage in 4%
● brain surgery, radiosurgery, aqueductal stenosis, and Paget disease of bone were all less common, accounting for a combined 5%

Question 7

What is the prognosis of NPH shunted vs unshunted?

Answer 7

Shunted: 60% will improve, but only 30% will have sustained improvement (at 1 year)

Unshunted: 50% will deteriorate within 3 months of diagnosis; Other 50% will eventually deteriorate, although not as quickly

Question 8

8 features of gait of NPH

Answer 8

1. decreased step height
2. decreased step length
3. decreased cadence (speed of walking)
4. increased trunk sway during walking
5. widened standing base
6. retropulsion (spontaneous or provoked)
7. En bloc turning (turning requiring three or more steps for 180 degrees)
8. impaired tandem
9. difficulty in sit-stand

Question 9

What 4 features would suggest there will be a good response to shunting in NPH?

Answer 9

• early gait disorder
• gait disorder most prominent symptom
• shorter duration of symptoms (< 6 months)
• identified etiology of NPH (head trauma, ICH, meningitis)
• DESH (Japanese Guidelines)

Question 10

Neuroimaging features of NPH?

Answer 10

Evans index
DESH
Transependymal flow on FLAIR (periventricular CSF leak)