A Sharing Session on Normal Pressure Hydrocephalus (NPH) Suhaila Mohamed Usuludin 17 April 2008

Cerebrospinal Fluid (CSF) A clear, colourless fluid that contains small quantities of glucose and protein Fills the ventricles of the brain and the central canal of the spinal cord Production by choroid plexus in lateral ventricle at 20ml/hr

A clear, colourless fluid that contains small quantities of glucose and protein

Fills the ventricles of the brain and the central canal of the spinal cord

Production by choroid plexus in lateral ventricle at 20ml/hr

Cerebrospinal Fluid (CSF)

Cerebrospinal Fluid (CSF)

Functions drainage route for waste products of brain metabolism bouyancy electrolytes and nutrient exchange Pressure decrease from site of production -> site of absorption determined by venous pressure Cerebrospinal Fluid (CSF)

Functions

drainage route for waste products of brain metabolism

bouyancy

electrolytes and nutrient exchange

Pressure decrease from site of production -> site of absorption

determined by venous pressure

Pressure is raised if Brain volume increases Venous pressure increases Outflow obstruction At ventricles (non-communicating hydrocephalus) At absorptive site (communicating hydrocephalus) Cerebrospinal Fluid (CSF)

Pressure is raised if

Brain volume increases

Venous pressure increases

Outflow obstruction

At ventricles (non-communicating hydrocephalus)

At absorptive site (communicating hydrocephalus)

NPH Gradual decrease CSF absorption at arachnoid granulations back pressure effect Increase pressure in ventricles Compensatory mechanisms to maintain pressure Distension of ventricles

Gradual decrease CSF absorption at arachnoid granulations

back pressure effect

Increase pressure in ventricles

Compensatory mechanisms to maintain pressure

Distension of ventricles

NPH Slowly progressive Onset > 40 years Most common in elderly

Slowly progressive

Onset > 40 years

Most common in elderly

Symptoms of NPH Adams triad Impaired gait Urinary incontinence Impaired cognitive function

Adams triad

Impaired gait

Urinary incontinence

Impaired cognitive function

Impaired gait Usually first and prominent symptom reduced step height stride length velocity Shuffling gait wide-based trunk sway ‘ magnetic gait’ gait apraxia

Usually first and prominent symptom

reduced step height

stride length

velocity

Shuffling gait

wide-based

trunk sway

‘ magnetic gait’

gait apraxia

Timed walking test GAITRite gait analysis Assessment: Impaired gait

Timed walking test

GAITRite gait analysis

Urinary Incontinence Usually 2 nd symptom to follow Urgency and frequency Fecal incontinence Rare except in advanced cases

Usually 2 nd symptom to follow

Urgency and frequency

Fecal incontinence

Rare except in advanced cases

Impaired Cognitive Functions Reversible cause of dementia Subcortical dementia Inattention Delayed recent recall Delayed psychomotor functioning Behavioural changes Emotional instability Executive functioning may be affected as disease progresses

Reversible cause of dementia

Subcortical dementia

Inattention

Delayed recent recall

Delayed psychomotor functioning

Behavioural changes

Emotional instability

Executive functioning may be affected as disease progresses

MMSE AMT Neuropsychological tests: Trail Making Test Digit/Letter Cancellation Kendrick Object Learning Test (KOLT): visual memory Assessment of Impaired Cognitive Functions

MMSE

AMT

Neuropsychological tests:

Trail Making Test

Digit/Letter Cancellation

Kendrick Object Learning Test (KOLT): visual memory

NOT Expected Symptoms Seizures Signs and symptoms of increased ICP Headache Nausea Vomiting Altered level of consciousness Papilledema

Seizures

Signs and symptoms of increased ICP

Headache

Nausea

Vomiting

Altered level of consciousness

Papilledema

Differential Diagnoses Old age Parkinsonism Dementia – AD, vascular Depression Cerebellar/spinal cord involvement

Old age

Parkinsonism

Dementia – AD, vascular

Depression

Cerebellar/spinal cord involvement

How is it Diagnosed? MRI Ventricles (lateral, 3 rd and 4 th ) and Sylvian fissure dilated with normal hippocampus MRI showing ventriculomegaly

MRI

Ventricles (lateral, 3 rd and 4 th ) and Sylvian fissure dilated with normal hippocampus

CT scan Rounding of horns Thinning of corpus callosum How is it Diagnosed?

CT scan

Rounding of horns

Thinning of corpus callosum

Surgical Management Ventriculoperitoneal Shunt (VP shunt) Performed under general anaesthesia Catheter placed within a ventricle, and another end at the peritoneal cavity

Ventriculoperitoneal Shunt (VP shunt)

Performed under general anaesthesia

Catheter placed within a ventricle, and another end at the peritoneal cavity

VP Shunt Valve (fixed or programmable) ensures one-way flow and regulates CSF flow Permanent or temporary May need replacement or revision if not working properly With five pressure level settings, the programmable, adjustable Strata® valve (top) can be "fine-tuned" by the physician after shunt surgery for NPH. Adjusting the valve and verifying the setting is done quickly in the physician's office using a simple set of magnetic tools (bottom), eliminating the need for additional surgery.

Valve (fixed or programmable) ensures one-way flow and regulates CSF flow

Permanent or temporary

May need replacement or revision if not working properly

Venticuloatrial Shunt (VA Shunt) CSF is shunted from the cerebral ventricles into the right atrium of the heart. 2 nd preferred choice if VP shunt is not possible Eg. Infection of peritoneal cavity -> affects reabsorption rate of CSF

CSF is shunted from the cerebral ventricles into the right atrium of the heart.

2 nd preferred choice if VP shunt is not possible

Eg. Infection of peritoneal cavity -> affects reabsorption rate of CSF

To Shunt or Not To Shunt? High Volume Lumbar Tap test or External Lumbar Drainage (ELD) 40-50ml CSF-> beneficial from shunt Decrease atrophy/ischemia Prominent CSF flow void aqueductal stroke volume >42 Ym (Bradley, 1998) No known history of intracranial infection Pre-morbid functional status

High Volume Lumbar Tap test or External Lumbar Drainage (ELD)

40-50ml CSF-> beneficial from shunt

Decrease atrophy/ischemia

Prominent CSF flow void

aqueductal stroke volume >42 Ym (Bradley, 1998)

No known history of intracranial infection

Pre-morbid functional status

Operation Risks Ileus Slow gastric and bowel movement post operation and may feel nausea Infection Most common organisms are S. epidermidis and S. aureus Obstruction Most often due to the head tip is obstructed with cells, choroid plexus, or debris.

Ileus

Slow gastric and bowel movement post operation and may feel nausea

Infection

Most common organisms are S. epidermidis and S. aureus

Obstruction

Most often due to the head tip is obstructed with cells, choroid plexus, or debris.

Operation Risks Misplacement Occurs when the ventricular or peritoneal end of the shunt tubing is in a position which does not facilitate free flow of CSF Wound breakdown/shunt tube exposure Occurs when the wound does not heal well or the overlying skin is thin with minimal subcutaneous tissue layer resulting in wound breakdown.

Misplacement

Occurs when the ventricular or peritoneal end of the shunt tubing is in a position which does not facilitate free flow of CSF

Wound breakdown/shunt tube exposure

Occurs when the wound does not heal well or the overlying skin is thin with minimal subcutaneous tissue layer resulting in wound breakdown.

Prognosis Gait shows highest improvement rates Better gait does not correlate to better ADLs functioning All components of triad considered to achieve higher ADL scores Temporary improvements from 1 to 3 years May be substantial for improving QoL > 1 year, co-morbidities may affect effects of shunting

Gait shows highest improvement rates

Better gait does not correlate to better ADLs functioning

All components of triad considered to achieve higher ADL scores

Temporary improvements from 1 to 3 years

May be substantial for improving QoL

> 1 year, co-morbidities may affect effects of shunting

Rehabilitation Implications Difficulties in walking If given walking aid, may not know how to use it Gait apraxia Caregiver training on facilitation Changing the environment Urinary Incontinence Time scheduling Cognitive Issues Caregiver training on psychomotor dysfunctions, behavioural issues etc.

Difficulties in walking

If given walking aid, may not know how to use it

Gait apraxia

Caregiver training on facilitation

Changing the environment

Urinary Incontinence

Time scheduling

Cognitive Issues

Caregiver training on psychomotor dysfunctions, behavioural issues etc.

References Presentations from various professionals from the symposium Bradley, W.G. (1998). MR Prediction of Shunt Response in NPH: CSF Morphology versus Physiology. American Journal of Neuroradiology , 19 , 1285-1286. Department of Neurosurgery (2007). A Patient / Family Informed Consent Guide to Ventricular Peritoneal (VP) Shunt Insertion /Revision . Singapore: National Neuroscience Institute. Factora, R. (2006). When do common symptoms indicate normal pressure hydrocephalus?. Cleveland Clinic Journal of Medicine , 73 (5), 447-457. Gallia, G.L., Rigamonti, D., & Williams, M.A. (2006). The diagnosis and treatment of idiopathic normal pressure hydrocephalus. Nature Clinical Practice Neurology , 2 (7), 375-381.

Presentations from various professionals from the symposium

Bradley, W.G. (1998). MR Prediction of Shunt Response in NPH: CSF Morphology versus Physiology. American Journal of Neuroradiology , 19 , 1285-1286.

Department of Neurosurgery (2007). A Patient / Family Informed Consent Guide to Ventricular Peritoneal (VP) Shunt Insertion /Revision . Singapore: National Neuroscience Institute.

Factora, R. (2006). When do common symptoms indicate normal pressure hydrocephalus?. Cleveland Clinic Journal of Medicine , 73 (5), 447-457.

Gallia, G.L., Rigamonti, D., & Williams, M.A. (2006). The diagnosis and treatment of idiopathic normal pressure hydrocephalus. Nature Clinical Practice Neurology , 2 (7), 375-381.

Thank You