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Normal Pressure Hydrocephalus


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Normal Pressure Hydrocephalus

  1. 1. Normal Pressure Hydrocephalus Jerry Ryan MD University of Wisconsin - Madison
  2. 2. Objectives <ul><li>1. Evaluate patients suspected of having NPH and distinguish NPH from other causes of gait disturbance, incontinence and dementia </li></ul><ul><li>2. Identify patients who need referral for consideration of treatment of NPH. </li></ul><ul><li>3. Understand treatment of NPH and follow patients who have received neurosurgical interventions for NPH in the office. </li></ul><ul><li>4. Educate patients with NPH and their families about the disorder. </li></ul>
  3. 3. How big is the problem? <ul><li>Prevalence Normal Pressure Hydrocephalus (NPH) </li></ul><ul><ul><li>Estimates vary from 0- 5% as a cause for dementia </li></ul></ul><ul><ul><li>Some of variation due to inconsistent definition of NPH </li></ul></ul><ul><ul><li>Study of 166 patients shunted for presumed NPH calculated incidence of shunt responsive NPH to be one patient per 2.2 million persons per year </li></ul></ul>J Vanneste, P Augustijn, C Dirven, WF Tan and ZD Goedhart Neurology 1992;42:54–9
  4. 4. So why do I need to know about NPH? <ul><li>Potentially reversible cause of significant morbidity </li></ul><ul><li>Recent direct to consumer advertising </li></ul>
  5. 5. What should Family Physicians know about NPH? <ul><li>Diagnostic features </li></ul><ul><li>Diagnostic studies </li></ul><ul><li>Limitations of prognostic studies </li></ul><ul><li>Patients likely to benefit from treatment </li></ul><ul><li>Complications of treatment </li></ul><ul><li>Patient follow up </li></ul>
  6. 6. Etiology <ul><li>50% cases idiopathic </li></ul><ul><ul><li>Leading theory is impairment of CSF outflow </li></ul></ul><ul><ul><li>Intraventricular pressure studies reveal waves of increased pressure- B-waves </li></ul></ul><ul><ul><ul><li>Adult hydrocephalus syndrome </li></ul></ul></ul><ul><ul><ul><li>Adult symptomatic hydrocephalus </li></ul></ul></ul>
  7. 7. Etiology <ul><li>50% cases NPH secondary to other illnesses </li></ul><ul><ul><li>Subarachnoid hemorrhage </li></ul></ul><ul><ul><li>Meningitis </li></ul></ul><ul><ul><li>Cranial trauma </li></ul></ul><ul><li>Secondary NPH has higher response rate to shunting than idiopathic NPH </li></ul>
  8. 8. Pathophysiology <ul><li>Ventricle enlargement leads to periventricular ischemia regardless of etiology </li></ul><ul><li>Compression and stretching of arterioles and venules </li></ul><ul><li>Arterial hypertension and cerebral arteriosclerosis increased in NPH </li></ul>
  9. 9. CSF pathway <ul><li>CSF produced by choroid plexus at rate approximately 20 ml/hr </li></ul><ul><li>Flows from lateral ventricles through foramina of Monro into third ventricle </li></ul><ul><li>Enters fourth ventricle through aqueduct of Sylvius </li></ul><ul><li>Enters subarachnoid space </li></ul><ul><li>Resorbed by arachnoid villi at top of brain </li></ul>
  10. 10. CSF pathway
  11. 11. Diagnostic Triad <ul><li>Gait Disturbance </li></ul><ul><li>Urinary Incontinence </li></ul><ul><li>Dementia </li></ul>
  12. 12. Diagnostic Triad <ul><li>Gait disturbance </li></ul><ul><ul><li>No classic gait disturbance </li></ul></ul><ul><ul><li>Gait may be wide based, shuffling </li></ul></ul><ul><ul><li>More severely affected patients have “magnetic gait”- feet stuck to ground and difficult to initiate walking </li></ul></ul><ul><ul><li>Difficulties with walking motions resolve with minimal support of patient or lying patient down </li></ul></ul><ul><ul><li>May resemble Parkinson’s gait </li></ul></ul><ul><ul><li>Not associated with limb weakness </li></ul></ul><ul><ul><li>Hyperreflexia </li></ul></ul>
  13. 13. Diagnostic Triad <ul><li>Urinary Incontinence </li></ul><ul><ul><li>True incontinence found only in severely affected patients </li></ul></ul><ul><ul><li>Urinary urgency in most patients with NPH </li></ul></ul><ul><ul><li>Due to stretching of periventricular nerve fibers and loss of detrusor inhibition </li></ul></ul><ul><ul><li>Bladder sphincter muscle unaffected </li></ul></ul>
  14. 14. Diagnostic Triad <ul><li>Dementia </li></ul><ul><ul><li>Presence of dementia in NPH extremely variable </li></ul></ul><ul><ul><ul><li>Some shunt responsive patients have little or no dementia </li></ul></ul></ul><ul><ul><ul><li>Dementia usually least responsive of symptoms to intervention </li></ul></ul></ul><ul><ul><li>Mental status changes may resemble depression </li></ul></ul>
  15. 15. Differential Diagnoses- Alzheimer’s (AD) <ul><li>Both AD and NPH cause memory impairment </li></ul><ul><ul><li>AD- “cortical” abnormalities </li></ul></ul><ul><ul><ul><li>Aphasia, Apraxia, Agnosia </li></ul></ul></ul><ul><ul><ul><li>Impaired recognition and encoding deficits </li></ul></ul></ul><ul><ul><li>NPH- “subcortical” abnormalities </li></ul></ul><ul><ul><ul><li>Memory impairment but intact recognition </li></ul></ul></ul><ul><ul><ul><li>Slow information processing </li></ul></ul></ul><ul><ul><ul><li>Difficulty with complex tasks </li></ul></ul></ul>
  16. 16. Cognitive Impairments AD versus NPH Auditory memory Attention/concentration Executive function Behavior/personality changes Motor and psychomotor skills Visuospatial skills Language Reading Borderline Impaired Psychomotor slowing Fine motor speed Fine motor accuracy Memory Learning Orientation Attention/concentration Executive function Writing Impaired NPH AD
  17. 17. Differential Diagnoses- Alzheimer’s (AD) <ul><li>AD and NPH can usually be distinguished with formal neuropsychological testing </li></ul><ul><li>Primary care office testing may not be adequate to distinguish </li></ul><ul><li>Mental impairment early in course of AD but usually late in course of NPH and often minimal impairment </li></ul><ul><li>AD often associated with hippocampal atrophy on imaging studies </li></ul>
  18. 18. Differential Diagnoses- Parkinson’s Disease <ul><li>Both NPH and Parkinson’s Disease (PD) can have similar gait disturbances </li></ul><ul><ul><li>Hypokinesia </li></ul></ul><ul><ul><li>Freezing </li></ul></ul><ul><ul><li>Imbalance </li></ul></ul><ul><ul><li>Extrapyramidal symptoms </li></ul></ul><ul><li>Trial of levadopa can help distinguish between PD and NPH </li></ul>
  19. 19. Differential Diagnoses- Other <ul><li>Depression </li></ul><ul><li>Subcortical arteriosclerotic encephalopathy </li></ul><ul><li>Multi-infarct encephalopathy </li></ul><ul><li>Chronic alcoholism </li></ul><ul><li>B 12 , Folate deficiency </li></ul><ul><li>Electrolyte abnormalities </li></ul><ul><li>Cervical or lumbar stenosis </li></ul><ul><li>Peripheral neuropathy </li></ul>
  20. 20. Diagnostic studies <ul><li>Ventricle enlargement on CT or MRI </li></ul><ul><ul><li>Severity graded by ratio of maximal frontal horn width divided by transverse inner diameter of skull </li></ul></ul><ul><ul><li>0.32 minimal for NPH but 0.40 more typical </li></ul></ul><ul><li>Lack of hippocampus or cortical atrophy </li></ul><ul><li>Periventricular and cortical white matter lesions may be found in patients with NPH </li></ul><ul><li>Large number white matter lesions may be marker for poor response to shunting </li></ul>
  21. 21. Normal Ventricles
  22. 22. Enlarged Ventricles
  23. 23. Enlarged Ventricles
  24. 24. Enlarged Ventricles
  25. 25. Enlarged Ventricles
  26. 26. So now that I know it’s NPH what next? <ul><li>Response to shunting varies significantly between patients </li></ul><ul><ul><li>Study 166 shunted NPH patients </li></ul></ul><ul><ul><li>Overall response 36%, only 21% significant improvement </li></ul></ul><ul><ul><li>Only 15% of patients with idiopathic NPH showed marked improvement </li></ul></ul>J Vanneste, P Augustijn, C Dirven, WF Tan and ZD Goedhart Neurology 1992;42:54–9
  27. 27. Any Problems With Shunting? <ul><li>Complications of shunting </li></ul><ul><ul><li>Low immediate post-surgical risks </li></ul></ul><ul><ul><li>Severe to moderate shunt related morbidity of 28% </li></ul></ul><ul><ul><ul><li>Infection </li></ul></ul></ul><ul><ul><ul><li>Shunt malfunction </li></ul></ul></ul><ul><ul><ul><li>Intracranial bleed </li></ul></ul></ul><ul><ul><li>Death or severe morbidity 7% </li></ul></ul>J Vanneste, P Augustijn, C Dirven, WF Tan and ZD Goedhart Neurology 1992;42:54-9
  28. 28. Overdrainage
  29. 29. Are Benefits of Shunting Long Lasting? <ul><li>Most studies show fairly significant decline in benefits over time </li></ul><ul><ul><li>Initial improvement 60-75% of patients </li></ul></ul><ul><ul><li>Sustained improvement only 24-42% </li></ul></ul><ul><li>Results confounded due to high mortality from co-morbid conditions </li></ul><ul><ul><li>57% patients dead within 5 years in study by Raftopoulos </li></ul></ul>
  30. 30. How can I tell who will benefit? <ul><li>Good response to shunting </li></ul><ul><ul><li>Clinical presentation </li></ul></ul><ul><ul><ul><li>Gait disturbance preceded mental impairment </li></ul></ul></ul><ul><ul><ul><li>Short duration of mild mental impairment </li></ul></ul></ul><ul><ul><ul><li>Known cause of NPH- e.g. infection, bleed </li></ul></ul></ul>
  31. 31. How can I tell who will benefit? <ul><li>Good response to shunting </li></ul><ul><ul><li>Special studies </li></ul></ul><ul><ul><ul><li>Lack of white matter lesions on MRI </li></ul></ul></ul><ul><ul><ul><li>Marked resolution of symptoms with CSF drainage </li></ul></ul></ul><ul><ul><ul><ul><li>One time removal 30-50 cc CSF </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Multi-day drainage of 100-150 cc CSF </li></ul></ul></ul></ul><ul><ul><ul><li>B-waves greater than 50% of time with continuous intracranial pressure (ICP) monitoring </li></ul></ul></ul><ul><ul><ul><li>Resistance to CSF outflow greater than 18 mmHg </li></ul></ul></ul>
  32. 32. How can I tell who will benefit? <ul><li>Poor response to shunting </li></ul><ul><ul><li>Severe dementia </li></ul></ul><ul><ul><li>Dementia presenting symptom </li></ul></ul><ul><ul><li>MRI abnormalities </li></ul></ul><ul><ul><ul><li>Cerebral atrophy </li></ul></ul></ul><ul><ul><ul><li>Multiple white matter lesions </li></ul></ul></ul>
  33. 33. How can I tell who will benefit? <ul><li>Indeterminate significance </li></ul><ul><ul><li>Patient age </li></ul></ul><ul><ul><li>Duration of symptoms </li></ul></ul><ul><ul><li>Lack of response to removal CSF </li></ul></ul>
  34. 34. How accurate are predictors of response to shunting? Normal pressure hydrocephalus: an update, Stein, SC, Neurosurgery Quarterly (2001) 11 (1):26–35
  35. 35. How accurate are predictors of response to shunting? Normal pressure hydrocephalus: an update, Stein, SC, Neurosurgery Quarterly (2001) 11 (1):26–35
  36. 36. NPH Guidelines <ul><li>Worldwide group of experts assembled to develop guidelines for diagnosis and treatment of NPH </li></ul><ul><li>Meetings supported by shunt manufacturer </li></ul><ul><li>Limited number of RCT’s noted by group </li></ul><ul><li>Report published in Neurosurgery: Vol. 57 (3), Sept 2005 Supplement </li></ul>
  37. 37. Diagnosis- Probable Idiopathic NPH <ul><li>History </li></ul><ul><ul><li>Insidious onset </li></ul></ul><ul><ul><li>Age over 40 </li></ul></ul><ul><ul><li>Symptom duration 3-6 months </li></ul></ul><ul><ul><li>No antecedent event known to cause secondary NPH </li></ul></ul><ul><ul><li>Progressive over time </li></ul></ul><ul><ul><li>No other medical, psychiatric or neurological condition that could cause symptoms </li></ul></ul>
  38. 38. Diagnosis- Probable Idiopathic NPH <ul><li>Brain imaging </li></ul><ul><ul><li>Ventricular enlargement not attributable to cerebral atrophy or congenital disorder </li></ul></ul><ul><ul><li>No macroscopic obstruction present </li></ul></ul><ul><ul><li>At least one of the following </li></ul></ul><ul><ul><ul><li>Enlargement of lateral horns not attributable to hippocampus atrophy </li></ul></ul></ul><ul><ul><ul><li>Callosal angle greater or equal to 40 degrees </li></ul></ul></ul><ul><ul><ul><li>Evidence of altered brain water content on imaging not attributable ischemia or demylination </li></ul></ul></ul><ul><ul><ul><li>An aqueductal or fourth ventricular flow void on MRI </li></ul></ul></ul>
  39. 39. Callosal angle <ul><li>Angle of roof of lateral ventricles in A-P projection </li></ul>
  40. 40. MRI flow void <ul><li>Loss of MRI signal due to flow of CSF </li></ul>Normal aqueduct Abnormal aqueduct
  41. 41. MRI flow void Normal fourth ventricle Abnormal fourth ventricle
  42. 42. Diagnosis- Probable Idiopathic NPH <ul><li>Clinical </li></ul><ul><ul><li>Gait/Balance- at least two of following present </li></ul></ul><ul><ul><ul><li>Decreased step height </li></ul></ul></ul><ul><ul><ul><li>Decreased step length </li></ul></ul></ul><ul><ul><ul><li>Decreased cadence/speed </li></ul></ul></ul><ul><ul><ul><li>Decreased trunk sway </li></ul></ul></ul><ul><ul><ul><li>Widened stance </li></ul></ul></ul><ul><ul><ul><li>Toes turned outward while walking </li></ul></ul></ul><ul><ul><ul><li>En bloc turning- turns take three or more steps </li></ul></ul></ul><ul><ul><ul><li>Impaired balance- two or more corrective steps for eight steps on tandem gait testing </li></ul></ul></ul>
  43. 43. Diagnosis- Probable Idiopathic NPH <ul><li>Cognition- two of following present </li></ul><ul><ul><li>Psychomotor slowing </li></ul></ul><ul><ul><li>Decreased fine motor speed </li></ul></ul><ul><ul><li>Decreased fine motor accuracy </li></ul></ul><ul><ul><li>Difficulty dividing or maintaining attention </li></ul></ul><ul><ul><li>Impaired recall especially for recent events </li></ul></ul><ul><ul><li>Impairment of executive functions- multi-step procedures, working memory, formulation of abstractions, insight </li></ul></ul><ul><ul><li>Behavioral or personality changes </li></ul></ul>
  44. 44. Diagnosis- Probable Idiopathic NPH <ul><li>Urinary Symptoms- one of following </li></ul><ul><ul><li>Episodic urinary incontinence not attributable to other causes </li></ul></ul><ul><ul><li>Persistent urinary incontinence </li></ul></ul><ul><ul><li>Fecal and urinary incontinence </li></ul></ul><ul><li>OR </li></ul><ul><li>One of following </li></ul><ul><ul><li>Urinary urgency </li></ul></ul><ul><ul><li>Urinary frequency- 6 or more voids in 12 hour period </li></ul></ul><ul><ul><li>Nocturia- more than two voids in night </li></ul></ul>
  45. 45. Diagnosis- Probable Idiopathic NPH <ul><li>Physiological </li></ul><ul><ul><li>Opening pressure 5-18 mmHg </li></ul></ul>
  46. 46. Possible INPH <ul><li>History- Symptoms are </li></ul><ul><ul><li>Subacute or indeterminate onset </li></ul></ul><ul><ul><li>Onset any time after childhood </li></ul></ul><ul><ul><li><3 months or indeterminate duration </li></ul></ul><ul><ul><li>May follow trauma, hemorrhage or meningitis </li></ul></ul><ul><ul><li>Symptoms not entirely explained by co-existing neurological conditions </li></ul></ul><ul><ul><li>Non-progressive or not clearly progressive </li></ul></ul>
  47. 47. Possible INPH <ul><li>Brain imaging- Ventricular enlargement associated with following </li></ul><ul><ul><li>Cerebral atrophy of sufficient severity to explain ventricular enlargement </li></ul></ul><ul><ul><li>Structural lesion that may increase ventricular size </li></ul></ul>
  48. 48. Possible INPH <ul><li>Clinical </li></ul><ul><ul><li>Incontinence and/or cognitive impairment in absence of gait or balance dysfunction </li></ul></ul><ul><ul><li>Gait disturbance or dementia alone </li></ul></ul><ul><li>Physiological </li></ul><ul><ul><li>Opening pressure unavailable or outside of range for probable NPH </li></ul></ul>
  49. 49. Unlikely INPH <ul><li>No ventriculomegaly </li></ul><ul><li>Signs of increased intracranial pressure such as papilledema </li></ul><ul><li>No component of clinical triad </li></ul><ul><li>Symptoms explained by other causes (eg, spinal stenosis) </li></ul>
  50. 50. UCLA workup for NPH and selecting shunt candidates <ul><li>Ventricular enlargement by CT or MRI (Evans Index >0.3) </li></ul><ul><li>Complete history and neurological exam, neuropsychiatric testing and gait analysis </li></ul><ul><li>Patients with significant dementia component referred for more extensive evaluation to rule out Alzheimer’s Disease of other forms of dementia </li></ul>
  51. 51. UCLA workup for NPH and selecting shunt candidates <ul><li>Patients felt at risk for NPH undergo intracranial pressure monitoring </li></ul><ul><ul><li>Inserted with local anesthesia </li></ul></ul><ul><ul><li>Fine wire placed just under calvarium </li></ul></ul><ul><li>Elevated pressure- shunt </li></ul><ul><li>B-waves- further evaluation </li></ul>
  52. 52. UCLA workup for NPH and selecting shunt candidates <ul><li>Cerebrospinal Fluid Outflow Resistance </li></ul><ul><ul><li>Lumbar puncture performed </li></ul></ul><ul><ul><li>Artificial spinal fluid infused </li></ul></ul><ul><ul><li>Rise in ICP recorded by previously inserted ICP monitor </li></ul></ul><ul><ul><li>Resistance to absorbtion of infused fluid calculated </li></ul></ul><ul><ul><ul><li>High resistance- shunt </li></ul></ul></ul><ul><ul><ul><li>Normal resistance- further testing </li></ul></ul></ul>
  53. 53. UCLA workup for NPH and selecting shunt candidates <ul><li>Trial CSF drainage </li></ul><ul><ul><li>3 day trial </li></ul></ul><ul><ul><li>Small volumes removed- 30-50 cc </li></ul></ul><ul><li>Improved symptoms- shunt </li></ul><ul><li>No improvement- no further studies, shunt no longer considered </li></ul>
  54. 54. UCLA workup for NPH and selecting shunt candidates <ul><li>Studies not performed </li></ul><ul><ul><li>Cisternogram </li></ul></ul><ul><ul><li>High volume CSF drainage </li></ul></ul><ul><ul><li>PET scan </li></ul></ul><ul><ul><li>SPECT scan </li></ul></ul><ul><li>Tests felt not warranted due to expense or increased patient risk </li></ul><ul><li>MRI flow void not routinely done as felt to be non-specific </li></ul><ul><li>Further testing felt to add minimal additional prognostic information </li></ul>
  55. 55. Yet another workup Treating Normal Pressure Hydrocephalus, Luciano, M, AAFP CME Bulletin, 2004, Vol. 3 (4)
  56. 56. Yet another workup Treating Normal Pressure Hydrocephalus, Luciano, M, AAFP CME Bulletin, 2004, Vol. 3 (4)
  57. 57. What kind of shunt is used? <ul><li>Externally programmable valve allows transcutaneous adjustment CSF outflow resistance </li></ul>
  58. 58. What kind of shunt is used?
  59. 59. Shunt placement
  60. 60. Shunt Valve Adjustments
  61. 61. Now that my patient has had a shunt what happens next? <ul><li>Monitoring of mental function </li></ul><ul><ul><li>Patients should have neuropsychiatric testing prior to shunt </li></ul></ul><ul><ul><li>Periodic testing post shunt to document improvement </li></ul></ul>
  62. 62. Now that my patient has had a shunt what happens next? <ul><li>Monitor for complications of shunt </li></ul><ul><ul><li>Infection </li></ul></ul><ul><ul><li>Shunt malfunction </li></ul></ul><ul><ul><li>Excessive CSF drainage </li></ul></ul><ul><ul><li>Subdural hematoma </li></ul></ul>
  63. 63. Summary <ul><li>Best patients for shunt have gait disturbance with mild mental impairment </li></ul><ul><li>Improvement with CSF drainage predict good response to shunt but lack of improvement of limited prognostic value </li></ul><ul><li>Patients with significant dementia and limited gait disturbance unlikely to benefit from shunt. </li></ul>
  64. 64. Cochrane Database <ul><li>Conclusion: There is no evidence to indicate whether placement of a shunt is effective in the management of NPH. </li></ul><ul><li>Conclusion based upon lack of randomized controlled trials </li></ul>
  65. 65. Suggested references <ul><li>Diagnosis and management of normal pressure hydrocephalus, Vanneste, JA, JNeurol (2000) 247:5–14 </li></ul><ul><li>Neurosurgery: Vol. 57(3) Supplement, September 2005 </li></ul><ul><li>Normal pressure hydrocephalus: an update, Stein, SC, Neurosurgery Quarterly (2001) 11 (1):26–35 </li></ul><ul><li>University of California- Los Angeles- </li></ul><ul><li>University of Virginia- </li></ul>