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Normal Pressure Hydrocephalus
 

Normal Pressure Hydrocephalus

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  • Very nice study. I recently provided a consult for an 89 yr old patient. He mostly had CT brain scans. But I was able to draw favorable conclusions for him by comparing his chages in prominence of the cortical sulci & amount of extracranial CSF to changes in ventricular size, and match this with his changes in gait. The key concern to his nsg was brain atrophy, but I think my report answered that - and I host it here on SlideShare.
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    Normal Pressure Hydrocephalus Normal Pressure Hydrocephalus Presentation Transcript

    • Normal Pressure Hydrocephalus Jerry Ryan MD University of Wisconsin - Madison
    • Objectives
      • 1. Evaluate patients suspected of having NPH and distinguish NPH from other causes of gait disturbance, incontinence and dementia
      • 2. Identify patients who need referral for consideration of treatment of NPH.
      • 3. Understand treatment of NPH and follow patients who have received neurosurgical interventions for NPH in the office.
      • 4. Educate patients with NPH and their families about the disorder.
    • How big is the problem?
      • Prevalence Normal Pressure Hydrocephalus (NPH)
        • Estimates vary from 0- 5% as a cause for dementia
        • Some of variation due to inconsistent definition of NPH
        • 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
      J Vanneste, P Augustijn, C Dirven, WF Tan and ZD Goedhart Neurology 1992;42:54–9
    • So why do I need to know about NPH?
      • Potentially reversible cause of significant morbidity
      • Recent direct to consumer advertising
    • What should Family Physicians know about NPH?
      • Diagnostic features
      • Diagnostic studies
      • Limitations of prognostic studies
      • Patients likely to benefit from treatment
      • Complications of treatment
      • Patient follow up
    • Etiology
      • 50% cases idiopathic
        • Leading theory is impairment of CSF outflow
        • Intraventricular pressure studies reveal waves of increased pressure- B-waves
          • Adult hydrocephalus syndrome
          • Adult symptomatic hydrocephalus
    • Etiology
      • 50% cases NPH secondary to other illnesses
        • Subarachnoid hemorrhage
        • Meningitis
        • Cranial trauma
      • Secondary NPH has higher response rate to shunting than idiopathic NPH
    • Pathophysiology
      • Ventricle enlargement leads to periventricular ischemia regardless of etiology
      • Compression and stretching of arterioles and venules
      • Arterial hypertension and cerebral arteriosclerosis increased in NPH
    • CSF pathway
      • CSF produced by choroid plexus at rate approximately 20 ml/hr
      • Flows from lateral ventricles through foramina of Monro into third ventricle
      • Enters fourth ventricle through aqueduct of Sylvius
      • Enters subarachnoid space
      • Resorbed by arachnoid villi at top of brain
    • CSF pathway
    • Diagnostic Triad
      • Gait Disturbance
      • Urinary Incontinence
      • Dementia
    • Diagnostic Triad
      • Gait disturbance
        • No classic gait disturbance
        • Gait may be wide based, shuffling
        • More severely affected patients have “magnetic gait”- feet stuck to ground and difficult to initiate walking
        • Difficulties with walking motions resolve with minimal support of patient or lying patient down
        • May resemble Parkinson’s gait
        • Not associated with limb weakness
        • Hyperreflexia
    • Diagnostic Triad
      • Urinary Incontinence
        • True incontinence found only in severely affected patients
        • Urinary urgency in most patients with NPH
        • Due to stretching of periventricular nerve fibers and loss of detrusor inhibition
        • Bladder sphincter muscle unaffected
    • Diagnostic Triad
      • Dementia
        • Presence of dementia in NPH extremely variable
          • Some shunt responsive patients have little or no dementia
          • Dementia usually least responsive of symptoms to intervention
        • Mental status changes may resemble depression
    • Differential Diagnoses- Alzheimer’s (AD)
      • Both AD and NPH cause memory impairment
        • AD- “cortical” abnormalities
          • Aphasia, Apraxia, Agnosia
          • Impaired recognition and encoding deficits
        • NPH- “subcortical” abnormalities
          • Memory impairment but intact recognition
          • Slow information processing
          • Difficulty with complex tasks
    • 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
    • Differential Diagnoses- Alzheimer’s (AD)
      • AD and NPH can usually be distinguished with formal neuropsychological testing
      • Primary care office testing may not be adequate to distinguish
      • Mental impairment early in course of AD but usually late in course of NPH and often minimal impairment
      • AD often associated with hippocampal atrophy on imaging studies
    • Differential Diagnoses- Parkinson’s Disease
      • Both NPH and Parkinson’s Disease (PD) can have similar gait disturbances
        • Hypokinesia
        • Freezing
        • Imbalance
        • Extrapyramidal symptoms
      • Trial of levadopa can help distinguish between PD and NPH
    • Differential Diagnoses- Other
      • Depression
      • Subcortical arteriosclerotic encephalopathy
      • Multi-infarct encephalopathy
      • Chronic alcoholism
      • B 12 , Folate deficiency
      • Electrolyte abnormalities
      • Cervical or lumbar stenosis
      • Peripheral neuropathy
    • Diagnostic studies
      • Ventricle enlargement on CT or MRI
        • Severity graded by ratio of maximal frontal horn width divided by transverse inner diameter of skull
        • 0.32 minimal for NPH but 0.40 more typical
      • Lack of hippocampus or cortical atrophy
      • Periventricular and cortical white matter lesions may be found in patients with NPH
      • Large number white matter lesions may be marker for poor response to shunting
    • Normal Ventricles
    • Enlarged Ventricles
    • Enlarged Ventricles
    • Enlarged Ventricles
    • Enlarged Ventricles
    • So now that I know it’s NPH what next?
      • Response to shunting varies significantly between patients
        • Study 166 shunted NPH patients
        • Overall response 36%, only 21% significant improvement
        • Only 15% of patients with idiopathic NPH showed marked improvement
      J Vanneste, P Augustijn, C Dirven, WF Tan and ZD Goedhart Neurology 1992;42:54–9
    • Any Problems With Shunting?
      • Complications of shunting
        • Low immediate post-surgical risks
        • Severe to moderate shunt related morbidity of 28%
          • Infection
          • Shunt malfunction
          • Intracranial bleed
        • Death or severe morbidity 7%
      J Vanneste, P Augustijn, C Dirven, WF Tan and ZD Goedhart Neurology 1992;42:54-9
    • Overdrainage
    • Are Benefits of Shunting Long Lasting?
      • Most studies show fairly significant decline in benefits over time
        • Initial improvement 60-75% of patients
        • Sustained improvement only 24-42%
      • Results confounded due to high mortality from co-morbid conditions
        • 57% patients dead within 5 years in study by Raftopoulos et.al.
    • How can I tell who will benefit?
      • Good response to shunting
        • Clinical presentation
          • Gait disturbance preceded mental impairment
          • Short duration of mild mental impairment
          • Known cause of NPH- e.g. infection, bleed
    • How can I tell who will benefit?
      • Good response to shunting
        • Special studies
          • Lack of white matter lesions on MRI
          • Marked resolution of symptoms with CSF drainage
            • One time removal 30-50 cc CSF
            • Multi-day drainage of 100-150 cc CSF
          • B-waves greater than 50% of time with continuous intracranial pressure (ICP) monitoring
          • Resistance to CSF outflow greater than 18 mmHg
    • How can I tell who will benefit?
      • Poor response to shunting
        • Severe dementia
        • Dementia presenting symptom
        • MRI abnormalities
          • Cerebral atrophy
          • Multiple white matter lesions
    • How can I tell who will benefit?
      • Indeterminate significance
        • Patient age
        • Duration of symptoms
        • Lack of response to removal CSF
    • How accurate are predictors of response to shunting? Normal pressure hydrocephalus: an update, Stein, SC, Neurosurgery Quarterly (2001) 11 (1):26–35
    • How accurate are predictors of response to shunting? Normal pressure hydrocephalus: an update, Stein, SC, Neurosurgery Quarterly (2001) 11 (1):26–35
    • NPH Guidelines
      • Worldwide group of experts assembled to develop guidelines for diagnosis and treatment of NPH
      • Meetings supported by shunt manufacturer
      • Limited number of RCT’s noted by group
      • Report published in Neurosurgery: Vol. 57 (3), Sept 2005 Supplement
    • Diagnosis- Probable Idiopathic NPH
      • History
        • Insidious onset
        • Age over 40
        • Symptom duration 3-6 months
        • No antecedent event known to cause secondary NPH
        • Progressive over time
        • No other medical, psychiatric or neurological condition that could cause symptoms
    • Diagnosis- Probable Idiopathic NPH
      • Brain imaging
        • Ventricular enlargement not attributable to cerebral atrophy or congenital disorder
        • No macroscopic obstruction present
        • At least one of the following
          • Enlargement of lateral horns not attributable to hippocampus atrophy
          • Callosal angle greater or equal to 40 degrees
          • Evidence of altered brain water content on imaging not attributable ischemia or demylination
          • An aqueductal or fourth ventricular flow void on MRI
    • Callosal angle
      • Angle of roof of lateral ventricles in A-P projection
    • MRI flow void
      • Loss of MRI signal due to flow of CSF
      Normal aqueduct Abnormal aqueduct
    • MRI flow void Normal fourth ventricle Abnormal fourth ventricle
    • Diagnosis- Probable Idiopathic NPH
      • Clinical
        • Gait/Balance- at least two of following present
          • Decreased step height
          • Decreased step length
          • Decreased cadence/speed
          • Decreased trunk sway
          • Widened stance
          • Toes turned outward while walking
          • En bloc turning- turns take three or more steps
          • Impaired balance- two or more corrective steps for eight steps on tandem gait testing
    • Diagnosis- Probable Idiopathic NPH
      • Cognition- two of following present
        • Psychomotor slowing
        • Decreased fine motor speed
        • Decreased fine motor accuracy
        • Difficulty dividing or maintaining attention
        • Impaired recall especially for recent events
        • Impairment of executive functions- multi-step procedures, working memory, formulation of abstractions, insight
        • Behavioral or personality changes
    • Diagnosis- Probable Idiopathic NPH
      • Urinary Symptoms- one of following
        • Episodic urinary incontinence not attributable to other causes
        • Persistent urinary incontinence
        • Fecal and urinary incontinence
      • OR
      • One of following
        • Urinary urgency
        • Urinary frequency- 6 or more voids in 12 hour period
        • Nocturia- more than two voids in night
    • Diagnosis- Probable Idiopathic NPH
      • Physiological
        • Opening pressure 5-18 mmHg
    • Possible INPH
      • History- Symptoms are
        • Subacute or indeterminate onset
        • Onset any time after childhood
        • <3 months or indeterminate duration
        • May follow trauma, hemorrhage or meningitis
        • Symptoms not entirely explained by co-existing neurological conditions
        • Non-progressive or not clearly progressive
    • Possible INPH
      • Brain imaging- Ventricular enlargement associated with following
        • Cerebral atrophy of sufficient severity to explain ventricular enlargement
        • Structural lesion that may increase ventricular size
    • Possible INPH
      • Clinical
        • Incontinence and/or cognitive impairment in absence of gait or balance dysfunction
        • Gait disturbance or dementia alone
      • Physiological
        • Opening pressure unavailable or outside of range for probable NPH
    • Unlikely INPH
      • No ventriculomegaly
      • Signs of increased intracranial pressure such as papilledema
      • No component of clinical triad
      • Symptoms explained by other causes (eg, spinal stenosis)
    • UCLA workup for NPH and selecting shunt candidates
      • Ventricular enlargement by CT or MRI (Evans Index >0.3)
      • Complete history and neurological exam, neuropsychiatric testing and gait analysis
      • Patients with significant dementia component referred for more extensive evaluation to rule out Alzheimer’s Disease of other forms of dementia
    • UCLA workup for NPH and selecting shunt candidates
      • Patients felt at risk for NPH undergo intracranial pressure monitoring
        • Inserted with local anesthesia
        • Fine wire placed just under calvarium
      • Elevated pressure- shunt
      • B-waves- further evaluation
    • UCLA workup for NPH and selecting shunt candidates
      • Cerebrospinal Fluid Outflow Resistance
        • Lumbar puncture performed
        • Artificial spinal fluid infused
        • Rise in ICP recorded by previously inserted ICP monitor
        • Resistance to absorbtion of infused fluid calculated
          • High resistance- shunt
          • Normal resistance- further testing
    • UCLA workup for NPH and selecting shunt candidates
      • Trial CSF drainage
        • 3 day trial
        • Small volumes removed- 30-50 cc
      • Improved symptoms- shunt
      • No improvement- no further studies, shunt no longer considered
    • UCLA workup for NPH and selecting shunt candidates
      • Studies not performed
        • Cisternogram
        • High volume CSF drainage
        • PET scan
        • SPECT scan
      • Tests felt not warranted due to expense or increased patient risk
      • MRI flow void not routinely done as felt to be non-specific
      • Further testing felt to add minimal additional prognostic information
    • Yet another workup Treating Normal Pressure Hydrocephalus, Luciano, M, AAFP CME Bulletin, 2004, Vol. 3 (4)
    • Yet another workup Treating Normal Pressure Hydrocephalus, Luciano, M, AAFP CME Bulletin, 2004, Vol. 3 (4)
    • What kind of shunt is used?
      • Externally programmable valve allows transcutaneous adjustment CSF outflow resistance
    • What kind of shunt is used?
    • Shunt placement
    • Shunt Valve Adjustments
    • Now that my patient has had a shunt what happens next?
      • Monitoring of mental function
        • Patients should have neuropsychiatric testing prior to shunt
        • Periodic testing post shunt to document improvement
    • Now that my patient has had a shunt what happens next?
      • Monitor for complications of shunt
        • Infection
        • Shunt malfunction
        • Excessive CSF drainage
        • Subdural hematoma
    • Summary
      • Best patients for shunt have gait disturbance with mild mental impairment
      • Improvement with CSF drainage predict good response to shunt but lack of improvement of limited prognostic value
      • Patients with significant dementia and limited gait disturbance unlikely to benefit from shunt.
    • Cochrane Database
      • Conclusion: There is no evidence to indicate whether placement of a shunt is effective in the management of NPH.
      • Conclusion based upon lack of randomized controlled trials
    • Suggested references
      • Diagnosis and management of normal pressure hydrocephalus, Vanneste, JA, JNeurol (2000) 247:5–14
      • Neurosurgery: Vol. 57(3) Supplement, September 2005
      • Normal pressure hydrocephalus: an update, Stein, SC, Neurosurgery Quarterly (2001) 11 (1):26–35
      • University of California- Los Angeles- http://www.neurosurgery.ucla.edu/Diagnoses/Adult/AdultDis_1.html
      • University of Virginia- http://www.healthsystem.virginia.edu/internet/neurogram/neurogram3_3_nph.cfm
    •