NORMAL PRESSURE HYDROCEPHALUS

Transcription

1 NORMAL PRESSURE HYDROCEPHALUS Roy Yaari, MD Neurologist, Dementia Specialist & Associate Director, Memory Disorders Clinic Banner Alzheimer s Institute Objectives: Understand the diagnostic evaluation of normal pressure hydrocephalus Assess the benefits and risks of shunt placement in treatment of normal pressure hydrocephalus Identify the etiologies of vascular dementia. DISCLOSURE OF COMMERCIAL SUPPORT Roy Yaari, MD does not have a significant financial interest or other relationship with manufacturer(s) of commercial product(s) and /or provider(s) of commercial services discussed in this presentation 2009 All Rights Reserved 22

2 Slide 1 Normal Pressure Hydrocephalus Roy Yaari, MD Banner Alzheimer s s Institute Slide 2 Introduction Normal Pressure Hydrocephalus (NPH) pathologically enlarged ventricular size normal opening pressures on lumbar puncture distinguished from obstructive or noncommunicating hydrocephalus structural blockage of cerebrospinal fluid (CSF) circulation Slide 3 Triad Urinary Incontinence (UI) Gait disturbance Dementia 2009 All Rights Reserved 23

3 Slide 4 The Good, the Bad, and the Ugly The Good News potentially reversible The Bad News little consensus regarding NPH diagnosis selection of patients for shunt placement The Ugly News Relatively high complication rate of treatment Krauss JK and Halve B, Acta Neurochir Apr;146(4): Slide 5 Epidemiology Prevalence varies by study Estimate: ~175,000 in US in 2000 ~4.5 million Alzheimer s s disease in 2000 Discrepancies reflect: Inconsistent definitions of NPH Different population samples Slide 6 Trenkwalder C et al, Arch Neurol 1995;52: Hebert LE et al, Arch Neurol 2003;60: Source: Flow of CSF 2009 All Rights Reserved 24

4 Slide 7 Etiology Impaired absorption of CSF Secondary Subarachnoid hemorrhage (aneurysm/trauma) Meningitis (infection, cancer, inflammatory dz) Inflammation fibrosis of arachnoid granulations Increased pressure not measured on LP Local pressure effect on periventricular white matter tracts Idiopathic Previous head injury Subclinical viral meningeal infection Slide 8 Gait Disturbance Most prominent feature of early NPH Most responsive to shunt Magnetic Gait / gait apraxia Feet stuck to the floor Short steps Decreased stride length and height Broadened base Outwardly rotated feet Sudarsky L and Simon S, Arch Neurol Mar;44(3):263-7 Stolze H et al., Neurol Neurosurg Psychiatry Mar;70(3): Slide 9 This patient provided assent, and his legal power of attorney provided consent for use of this video for educational purposes 2009 All Rights Reserved 25

5 Slide 10 This patient provided assent, and his legal power of attorney provided consent for use of this video for educational purposes Slide 11 Dementia of NPH Psychomotor slowing Decreased attention and concentration Impaired executive function Naming generally preserved Iddon JL et al., Neurol Neurosurg Psychiatry Dec;67(6): Slide 12 Urinary Incontinence Urinary urgency may be present early Gait disorder may impede getting to the restroom In later stages, lack of concern 2009 All Rights Reserved 26

6 Slide 13 Basic Dementia Workup Cognitive testing B12 TSH CMP CBC Structural brain imaging (MRI or CT) Slide 14 MRI Ventriculomegaly in NPH in the absence of sulcal enlargement or out of proportion to sulcal enlargement Ventricular enlargement in other dementia occurs with progressive cortical atrophy hydrocephalus ex vacuo Barron SA et al. Neurology 1976 Nov;26(11): Slide 15 A: AD T2 MRI showing ventriculomegaly in proportion to sulcal dilatation B: NPH T2 MRI showing ventriculomegaly out of proportion to sulcal dilatation Source: UpToDate Online 2009 All Rights Reserved 27

7 Slide 16 Evans Ratio Evans ratio > 0.31 Ratio of the maximum width of the frontal horns of the lateral ventricles divided by the diameter of the skull measured from the two sides of the inner table at the same level. Gyldensted C, Neuroradiology Dec 31;14(4): Slide 17 Other MRI Findings Thinning or elevation of the corpus colosum. Distention of the third ventricle. Dilated Aqueduct of Sylvius is often seen Slide 18 Source: Kasper DL et al, Harrison s Principles of Internal Medicine, 16 th Edition 2009 All Rights Reserved 28

8 Slide 19 Other Neuroimaging Cisternography Injection of radioisotope in lumbar area Radioisotope in ventricles 48-72hrs later Did not improve accuracy of predicting surgical improvement Cine-MRI Measures CSF flow rate in cerebral aqueduct Mixed or negative results Vanneste JA, J Neurol Jan;247(1):5-14 Dixon GR et al., Mayo Clin Proc Jun;77(6): Slide 20 Large Volume Spinal Tap cc CSF Document before and after Cognitive function Gait Benefit from shunt Positive predictive value % Negative predictive value 30-50% Wikkelso C et al., Acta Neurol Scand 1986 Jun;73(6): Slide 21 Lumbar Drain CSF drainage 5-10cc/hour5 Temporary catheter in lumbar CSF space Hospitalization days One small series 17 patients 100% sensitivity 100% specificity Complications (meningitis, hemorrhage) Haan J and Thomeer RT, Neurosurgery Feb;22(2): All Rights Reserved 29

9 Slide 22 Why is the Diagnosis Difficult? Gait difficulty 20% over age 75yrs Cognitive decline 4.5 million over 65yrs with AD in 2000 Incontinence 38% in elderly women 17% in elderly men Enlarged ventricles Increases with age Occurs in AD No decisive test Graff-Radford NR, AAN Continuum. 2007; 13(2) Slide 23 Treatment Ventriculoperitoneal shunting only treatment Source: Slide 24 Shunting Data supporting efficacy of shunting is limited Small case series (n=20 to 30) Frequently retrospective No placebo group Short follow-up time Unstandardized outcome measures 2009 All Rights Reserved 30

10 Slide 25 Literature Review 44 articles Degree of hydrocephalus not correlated with clinical improvement Overall, 59% (range, %) improved after shunting Complications occurred in 38% (range, 5-100%) 5 Additional surgery required in 22% (range, %) 6% (range, 0-35%) 0 rate of permanent neurological deficit and death Slide 26 Favorable Indicators Any one factor is not decisive in selecting patients for surgery Gait disturbance preceding cognitive problems. Cognitive deficits are mild Short duration of cognitive deficits (<2 years) Clinical improvement after lumbar puncture or drainage Graff-Radford NR, AAN Continuum. 2007; 13(2) Slide 27 Unfavorable Indicators Any one factor is not decisive in selecting patients for surgery Moderate to severe cognitive impairment Dementia for > 2 years Cognitive impairment preceding gait disturbance History of ETOH abuse MRI showing significant white matter involvement or diffuse cerebral atrophy. Graff-Radford NR, AAN Continuum. 2007; 13(2) All Rights Reserved 31

11 Slide 28 Shunt Complications 38% complication rate 6% with permanent sequelae or death Subdural effusion Subdural hematoma Intracranial infection Seizure Intracerebral hemorrhage Mechanical shunt failure/blockage Abdominal injury Slide 29 Summary Triad: gait disturbance, dementia, UI MRI: ventriculomegaly out of proportion to degree of atrophy No good diagnostic test Shunt is only treatment Shunts have high complication rate 2009 All Rights Reserved 32