Normal pressure hydrocephalus

DR PRAVEEN K TRIPATHI
02-Dec-15 1

 In 1964, Colombian
neurosurgeon Salomón
Hakim and colleagues
described a syndrome of
Progressive cognitive
decline
Gait difficulties
Urinary incontinence
Ventricular dilatation
Normal cerebrospinal
fluid (CSF) pressure
during lumbar puncture
02-Dec-15 2

1982, CM Fisher underscored the importance of
the gait disturbance in the description of NPH.
1986, Graff-Radford and Godersky correlated
clinical symptoms and shunt responsiveness.
The term idiopathic adult hydrocephalus
syndrome may be more accurate, because
intracranial pressure is not always normal in
NPH.
02-Dec-15 3

 elderly individuals (age >65 y) the prevalence of
NPH was 1.4%
 Incidence -1.4 per 1,00,000
 No race or gender prediliction
 more than 60% of patients with iNPH had
cerebrovascular disease.
 In another similar study, more than 75% had
Alzheimer disease pathology at the time of shunt
surgery.
02-Dec-15 4

IDIOPATHIC – 50 %
SECONDARY CAUSES
 subarachnoid hemorrhage (23%),
 meningitis (4.5%)
 and traumatic brain injury (12.5%)
Secondary NPH has higher response rate to
shunting than idiopathic NPH
02-Dec-15 5

 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
02-Dec-15 6

Ventricle enlargement leads to periventricular
ischemia regardless of etiology
Compression and stretching of arterioles and
venules
Arterial hypertension and cerebral
arteriosclerosis increased in NPH
02-Dec-15 8

Increased subarachnoid space volume does not
accompany increased ventricular volume.
Symptoms result from distortion of the central
portion of the corona radiata by the distended
ventricles. Interstitial edema of the white matter
The periventricular white matter anatomically
includes the sacral motor -abnormal gait and
incontinence.
Dementia results from distortion of the
periventricular limbic system.02-Dec-15 9

Kiefer, M; Unterberg, A
The Differential Diagnosis and Treatment of Normal-Pressure Hydrocephalus
Dtsch Arztebl Int 2012; 109(1-2): 15-26; DOI: 10.3238/arztebl.2012.0015
02-Dec-15 10

CLASSIC TRIAD
 GAIT DISTURBANCE -is typically the earliest feature
noted and considered to be the most responsive to treatment
 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
 Hyperreflexia
 Apraxia of gait – no weakness or ataxia.
02-Dec-15 11

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
02-Dec-15 13

DEMENTIA
 Usually mild
 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
 prominent memory loss and bradyphrenia.
 Frontal and subcortical deficits
 forgetfulness, decreased attention,
 Aphasia /agnosia – alternate diagnosis -Alzheimer
02-Dec-15 14

 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
02-Dec-15 15

AD NPH
Impaired
Memory
Learning
Orientation
Attention/concentration
Executive function
Writing
Psychomotor slowing
Fine motor speed
Fine motor accuracy
Borderline
Impaired
Motor and psychomotor skills
Visuospatial skills
Language
Reading
Auditory memory
Attention/concentration
Executive function
Behavior/personality
changes
02-Dec-15 16

 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
02-Dec-15 17

 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
02-Dec-15 18

 Depression
 Subcortical arteriosclerotic encephalopathy
 Multi-infarct encephalopathy
 Chronic alcoholism
 B12, Folate deficiency
 Electrolyte abnormalities
 Cervical or lumbar stenosis
 Peripheral neuropathy
02-Dec-15 19

 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
02-Dec-15 20

 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 02-Dec-15 21

 Angle of roof of lateral ventricles in A-P projection
02-Dec-15 23

 Loss of MRI signal due to flow of CSF
Normal aqueduct Abnormal aqueduct
02-Dec-15 24

Normal fourth ventricle Abnormal fourth ventricle
02-Dec-15 25

 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
02-Dec-15 26

 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
02-Dec-15 27

 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
02-Dec-15 28

 Physiological
 Opening pressure 70-240 mmH2O
02-Dec-15 29

 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
02-Dec-15 30

 Brain imaging- Ventricular enlargement
associated with following
 Cerebral atrophy of sufficient severity to
explain ventricular enlargement
 Structural lesion that may increase
ventricular size
02-Dec-15 31

 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
02-Dec-15 32

No ventriculomegaly
Signs of increased intracranial pressure
such as papilledema
No component of clinical triad
Symptoms explained by other causes (eg,
spinal stenosis)
02-Dec-15 33

- Vit B12 , Thyroid profile
- CSF – analysis –
opening pressure – 11 +/- 3 mm hg (150 mm H2o)
slightly higher than normal
- Transient high pressure B waves may be detected
- (CSF) protein Lipocalin-type prostaglandin D
synthase (L-PGDS) – marker of Frontal lobe
dysfunction in iNPH – decreased due to damage
of arachnoid cells
02-Dec-15 34

 Ventriculomegaly that is out of proportion to sulcal
atrophy.
 differentiates NPH from ex vacuo
ventriculomegaly,
 Frontal and occipital periventricular
hypoattenuating areas, represent transependymal
CSF flow -infrequent and often may represent
periventricular leukoencephalopathy
 corpus callosal thinning, -nonspecific
02-Dec-15 35

 Rounding of frontal horns
 clinical picture and ventriculosulcal
disproportion on either CT or MRI
scans, 50-70% of patients are likely to
respond to a CSF-shunting procedure.
02-Dec-15 36

disproportionately enlarged temporal
horns of the lateral ventricles compared
with the relatively normal sulcal size.
02-Dec-15 37

The Evans index (EI), a linear ratio
between the maximal frontal horn width
and the cranium diameter,
signifies ventriculomegaly if it is 0.3
02-Dec-15 38

 Temporal horns out of proportion to hippocampal
atrophy
 MRI provides additional physiologic information on
NPH
 T2-weighted images, regions of moving CSF
demonstrate no signal, instead of the increased
signal observed in slow-moving CSF,
 CSF flow studies- jet of turbulent CSF flow may be
observed distal to the aqueduct
 Cine phase-contrast MRI quantifies CSF flow in
terms of stroke volume
 - significant corelation to shunt responsiveness02-Dec-15 39

 Most prefer 45 -50 ml removal
 Csf pressures may be transiently elevated
 Improvement may be delayed and appear 1-2
days after
 Sensitivity of test – 62 % and 33 % specificity
 However it has been listed in guidelines of
prognostic evaluation of NPH
02-Dec-15 41

 greater impact on brain volume expansion
 300 ml drained for 5 days
 Complications -including headache,
radiculopathy, and bacterial meningitis
 More sensitive than csf tap test
 sensitivity, specificity, and negative predictive
value were 95%, 64%, and 78%, respectively.
 PPV 80 -100 %
 Requires hospitalisation specialised care
02-Dec-15 42

 CSF infusion testing.- One drain is used for
continuous pressure monitoring while the other drain
is used to continuously infuse solution into the CSF
space.
 Ro – impedance of flow offered by csf absorption
 Isotopic cisternography is no longer in frequent use
 Acqueductal CSF flow – not of much diagnostic use
02-Dec-15 44

 Neuropsychological evaluation (eg, Folstein test
or formal neuropsychological evaluation)- not
validated
 Timed walking test.
 Videotaping the gait evaluation before and after
the large volume lumbar puncture.- IS
PREFERABLE
 Reduction in bladder hyperactivity also may be a
sign of good outcome from shunting.
02-Dec-15 46

 No prospective, double blind, randomized, controlled
clinical triaL
 Medical management – levodopa trial to rule out
idiopthic parkinson disease
 No drug is known to work in NPH
 Surgical Management – mainstay
 Benefit expected from shunt surgery in probable case
of NPH 50 %- 61 %
02-Dec-15 47

 Adjustable shunt valves – adjusts the opening
pressure
 Gravity-controlled valves - low valve opening
pressure when the patient is lying down.
 G valves lower the risk of overdrainage by 90%
02-Dec-15 51

 Endoscopic third ventriculostomy (ETV).
 Alternative to shunt placement for treatment
of hydrocephalus.
 Effective in obstructive hydrocephalus.
Efficacy in NPH not known
02-Dec-15 52

 Routine follow up 2 to 3 times per year
 Earlier if shunt inection/failure
 Bedside clinical examination follow up CTScan
within few weeks
 D Dimer ,CRP in case of ventriculoatrial shunts
for subclinical septicemia and
thromboembolism
02-Dec-15 53

 High CSF pressure should prompt investigation
for a secondary cause of NPH
 Response to a 40-mL to 50-mL (high-volume)
lumbar tap suggests a potential benefit to shunting
 An ELD may be used to evaluate those who do
not respond to a high-volume tap
 There is no substantial predictive value to MRI
CSF flow studies
 IF multi-infarct or Alzheimer’s disease
dementia ??
02-Dec-15 54

 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
02-Dec-15 55

Enlarged
Ventricles
02-Dec-15 57

Enlarged
Ventricles
02-Dec-15 58

 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.
02-Dec-15 59

 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
02-Dec-15 60

 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 02-Dec-15 61

 Poor response to shunting
 Severe dementia
 Dementia presenting symptom
 MRI abnormalities
 Cerebral atrophy
 Multiple white matter lesions
02-Dec-15 62

 Indeterminate significance
 Patient age
 Duration of symptoms
 Lack of response to removal CSF
02-Dec-15 63

Normal pressure hydrocephalus: an update, Stein, SC, Neurosurgery
Quarterly (2001)11(1):26–35
02-Dec-15 64

Normal pressure hydrocephalus: an update, Stein, SC, Neurosurgery
Quarterly (2001)11(1):26–35
02-Dec-15 65

 Externally programmable valve allows
transcutaneous adjustment CSF outflow resistance
02-Dec-15 66

 Monitoring of mental function
 Patients should have neuropsychiatric testing
prior to shunt
 Periodic testing post shunt to document
improvement
02-Dec-15 68

 Monitor for complications of shunt
 Infection
 Shunt malfunction
 Excessive CSF drainage
 Subdural hematoma
02-Dec-15 69

 The INPH is a syndrome, characterized by gait
impairment, cognitive decline and urinary
incontinence
 Associated with ventriculomegaly in the absence of
elevated CSF pressure.
 Pathogenesis is not understood; intermittent
intracranial hypertension, decreased CSF
absorption and cerebral ischemia have been
blamed.
 Hallmark of neuroimaging in NPH is
ventriculomegaly out of proportion with sulcal
atrophy 02-Dec-15 71

 MRI is the choice of imaging; CSF flow in NPH is
hyperdynamic, with an increase in the amount and
velocity of CSF passing rostrally, then caudally, through
the cerebral aqueduct with each cardiac cycle.
 Clinical improvement after CSF drainage implies good
response to shunting.·
 The best results are found in the subjects treated with
low-pressure valves.·
 Increased use of adjustable valve seems to be beneficial.
 Gait is most likely to improve. Postoperative reduction
in ventriculomegaly is not always seen or proportionate
to the clinical improvement.
02-Dec-15 72

Normal pressure hydrocephalus

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