Normal Pressure Hydrocephalus
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Transcript of Normal Pressure Hydrocephalus
A Sharing Session on
Normal Pressure Hydrocephalus(NPH)
Suhaila Mohamed Usuludin17 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
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)
• 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)
NPH
• 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
Symptoms of NPH
• 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
• Timed walking test• GAITRite gait analysis
Assessment: Impaired gait
Urinary Incontinence
• Usually 2nd 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
• MMSE• AMT• Neuropsychological tests:
– Trail Making Test– Digit/Letter Cancellation– Kendrick Object Learning Test (KOLT): visual
memory
Assessment of Impaired Cognitive Functions
NOT Expected Symptoms
• 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
How is it Diagnosed?
• MRI– Ventricles (lateral, 3rd and 4th) and Sylvian fissure
dilated with normal hippocampus
MRI showing ventriculomegaly
• CT scan– Rounding of horns– Thinning of corpus
callosum
How is it Diagnosed?
Surgical Management
• 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.
Venticuloatrial Shunt (VA Shunt)
• CSF is shunted from the cerebral ventricles into the right atrium of the heart.
• 2nd 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
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.
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.
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
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.
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.
Thank You