Clinical evaluation of

adult hydrocephalus

Youmans 6th editon

Out line

• Classification and etiology• Pathophysiology , Sign and Symptom• Normal pressure hydrocephalus• Neuroradiologic features of hydrocephalus• Physiologic testing of cerebrospinal fluid

dynamics• Management• Shunt

Classification and etiology

• Greek : Hydro(water) + Kefale(skull)• The state of excessive intracranial

accumulation of CSF that results from excessive production, circulation, or absorption of CSF

Classification and etiology

• Communicating Hydrocephalus• Panventricular dilation and occurs as a

result of obstruction to the flow of CSF in the subarachnoid space, distal to the foramina of Luschka and Magendie

• Noncommunicating or ObstructiveHydrocephalus• Pattern of ventricular dilation that reflects

the site of obstruction

Classification and etiology

• Long-Standing Overt Ventriculomegaly in Adults• This form of hydrocephalus develops

during childhood, with symptoms being manifested during adulthood

• Normal-Pressure Hydrocephalus• Gait disturbance, dementia, incontinence

with normal CSF pressure and dilate ventricles

Classification and etiology

• Isolated Fourth Ventricle Syndrome• fourth ventricle no longer communicates

with the third ventricle• prolonged infection or multiple shunt

operations

• Arrested Hydrocephalus• Hydrocephalus reach a state in which

ventricular size remains unchanged in the absence of a shunt or in the presence of a nonfunctioning one

Pathophysiology

Pathophysiology

• CSF obstruction transpendymal passage of CSF(periventricular edema ) + edematous white matter white matter damage cerebral atrophy

• Ventricular enlargement progress • distortion of tissue, white matter, blood vessel

damage ischemia• Loss elasticity tissue pressure gradient between

ventricle and periventricular tissue failure drainage of toxic metabolite

Initial feature of hydrocephalus

Normal Pressure hydrocephalus

Clinical finding

• Gait disturbance• Common initial symptoms : unsteadiness,

recurrent falls, shuffling, and reduced walking speed

• Advanced symptoms : difficulty initiating gait and imbalance on turning

• DDx : Parkisonism – tremor, lead pipe rigidity, poker face

• NPH : mobilize with a relatively preserve arm swing• UMN sign : cervical myopathy, lumbar canal stenosis

Clinical finding

• Urinary incontinence• Cognitive impairment

• memory loss, reduced attention, difficulty planning,

slowness in thought, and apathy• Ddx : Alzheimer’s disease –

neurolopsychological testing, aphasia, apraxia, agnosia

• Binswanger’ disease : frontal cognitive disteriotation , gait disturbance

Neuroradiologic features

• Evans’ index : maximal width of the anterior ventricular horn / maximal width of the calvaria at the level of Foramen of Monroe

• >0.3 ventricular enlargement

Neuroradiology features

• Bicaudate ratio : minimal

intercaudate distance / by the

brain width along the same line• > 0.25

ventriculomegaly

Neuroradiology features

• One of the following support• enlargement of the temporal horns of the lateral

ventricles not entirely attributable to hippocampus atrophy

• callosal angle of 40 degrees or greater• evidence of altered brain water content,

including periventricular signal changes not attributable to microvascular ischemic changes or demyelination

• aqueductal or fourth ventricular flow void on MRI

Supplementary Prognostic testing

• Lumbar puncture “tap test”• Specifity 100 % , Sensitivity 26 %

• External lumbar drainage• specificity 80% , sensitivity 50-80%

• Measures of CSF outflow resistance• specificity 87% ,sensitivity 46%

Neuroradiologic features of hydrocephalus

Physiologic testing of cerebrospinal fluid dynamics

Cerebrospinal Fluid DrainageandDynamics

• Communicating hydrocephalus• Intrathecal injection of radioisotropes• Ventricular > 48 hr ventricular stasis

or reflux

Mathematical Modeling of the Cerebrospinal Fluid Circulation—a Platform forInterpretationof Pressure-Volume

Monitoring of Intracranial pressure

• Overnight monitoring : Lundberg “B waves.”• B waves are slow waves of ICP lasting 20 seconds to 2 minutes• Intraparenchymal probe• Normal : < 15 mmHg• Vasogenic wave : greater • than 25 mmHg, for a period • around 10 min

Monitoring of Intracranial pressure

• The average overnight RAP index should be less than 0.6 in patients with good compensatory reserve.

• The overnight magnitude of slow waves is considered increased when their average value is greater than 1.5 mm Hg.

Clinical tests of cerebrospinal fluid dynamics

• The computerized infusion test

• Resistance to CSF outflow

= Plateau P – Resting P infusion rate

NPH and Brain atrophy

NPH Brain atrophy1.Baseline ICP2.Resistance to CSF outflow3.AMP4.RAP5.Elastance coefiicient

normal (<18 mmHg)

Increase (>13 mmHg/ml /minute)

Correlated with Mean ICP

Good (< 0.6 )Increase (E > 0.2

1/ml)

Low (<12 mmHg)Low (<12

mmHg/ml /minute)Low (<2mmHg)

Good (<0.5)Low (E < 0.2 1/ml)

NPH and Brain atrophy

NPH and Brain atrophy

Noncommunicating and acute hydrocephalus

Noncommunicating

acute hydrocephalus

1.Baseline ICP increase increase

2.Resistance to CSF outflow

increase increase

3.AMP increase increase

4.RAP > 0.6 normal

5.Elastance coefiicient

high low

Testing of Cerebrospinal Fluid Dynamics in Shunted Patients

Testing of Cerebrospinal Fluid Dynamics in Shunted Patients

Management

Management

• Surgical Management• Shunt insertion• Endoscopic third

ventriculostomy

• Medical Management• Acetazolamide• Repeated lumbar

puncture

Shunt insertion

• VP shunt : most common• Lumboperitoneal shunt• Lumbopleural shunt• Ventriculoatrial shunt

Endoscopic third ventriculostomy

• Obstructive hydrocephalus• Passage an endoscopre through lateral

ventricle to third ventricle create stoma at floor of 3rd ventricle

• Advantage : prevent shunt infection, lifelong risk for revision

Shunt

Mechanism of Shunt

• Fixed differential pressure valves• Adjustable differential pressure valves• Flow-regulating valves• Accerory device

Valve classification

• 1. Silicon membrane

• 2. Ball-on-spring • 3. Miter valve • 4. Proximal or distal slit valves.• 5. Moving diaphragm

Shunt

• Magnetric programming : prevent magnetric field near

• Overdrainage : dependence on diameter and length of the distal drain

• Membrane device : impede CSF flow by skin tense

• A flow –regulating : may permanent increase hydrodynamic resistance

Complication

• Surgery• Infection• Bleeding• CSF leakage• Seizure• Neurological deficit

• Intracerebral hemorrhage

Complication

Complication

• Excessive drainage SDH 2-17% neurological deficit,coma,death• Conservative c serial scanning• Symptomatic : evacuation, ligation of shunt

tubing

• Shunt malformation• blockage, malpositon from peristalsis,

disconnect in movement disorder or seizure• Revision surgery

Complication

• Shunt infection• Meningtis, peritonitis,subacute bacterial

endocarditis follow

• Shunt hardware adverse effect• Intestinal obstruction or volvulus• Wound breakdown• CSF leakage• Hernias

Thanks you