Presenter :Krishna Bihari

GautamHema Bharwani Nandini Dubey

Batch- March 2011

Coordinator: Dr. Vishnu Patel(MS)

HOD: Dr. G. P. Shrivastava (M.S)

HYDROCEPHALUS term is derived from Greek word,Hydro-water and cephalous-head.

It is excessive accumulation of fluid in brain,also known as water on the brain,Here water signifies CSF.

Excessive accumulation of CSF

Abnormal widening or ventricles

Harmful pressure on brain tissues

Signs and symptoms of hydrocephalus

Affects both pediatric and adult age group patient.

It has been estimated that 7,00,000 children and adults are living with hydrocephalus.

Incidence in pediatric age group 1 in 500 live births hence making it one of the most common disabilities even more common than Down syndrome and Deafness.

Also it is the leading cause of brain surgery for children.

Pediatrics hydrocephalus may also be a heritable condition mainly affecting males.

Refrences have been found in ancient egyptian medical literature from 2000 B.C.to 500A.D.

First described by HIPPOCRATES in 4th centuryB.C.

But more accurate description given by roman physician GALEN in 2nd century A.D.

First clinical description and operative procedure for hydrocephalus appears in Al-Tasrif(1000A.D.)by Arab surgeon Abu-al-Qasim who clearly described the evacuation of superficial intracranial fluid in hydrocephalic children.

Set of structures containing CSF in brain which is continuous with central canal of spinal cord.Composed of 4 ventricles: 2 Lateral ventricles Third ventricle Fourth ventricle

Derived embryologically from central canal of neural tube

ANTERIOR HORN

POSTERIOR HORN

INFERIOR HORN

THIRD VENTRICLE

INTERVENTRICULAR FORAMEN

CEREBRAL AQUEDUCT

FOURTH VENTRICLE

SPINAL CANAL

It is produced by ependymal cells of choroid plexus found in components of ventricular system except from cerebral aqueduct and occipetal and frontal horns of lateral ventricle

Lateral ventricle

Foramen of Monro

3rd ventricle

Aqueduct of Sylvius

4rth ventricle

central canal of spinal cord

Lumbar cistern Cisterns of sub arachnoid space

Around cerebral cortex

3 foramina

The fluid then flows around the superior sagittal sinus.

It reabsorbed via arachnoid villi into venous system.

ARACHNOID GRANULATIONS-these are small protrusions of arachnoid which protrude into the venous sinuses of brain allows csf exit from brain and enter blood.

The largest arachnoid granulation lies along the superior sagittal sinus.

The arachnoid villi act as a one way valve.Normally PRESSURE OF CSF >PRESSURE OF VENOUS SYSTEM.So CSF is drained through villi into venous blood.

Some amount of CSF is also drained through lymphatics assossiated with extra cranial nerves,ex.-through axons of olfactory nerve via cribriform plate.

VOLUME 150ml

PRODUCTION 20ml/hr(80% by choroid plexus)

ABSORBTION Arachnoid villi(pressure dependent)

RELATIVE TO PLASMA Reduced K and Ca ions

Increased Cl and Mg ions

pH=7.33 to 7.35

PRESSURE 5 to 15 mmHg(6 to 18cm of water)

1. PROTECTION- It acts as a shock absorber.

2. TRANSPORT-Act as a vehicle for delivering nutrients and removing waste.

3. It flows between the cranium and spine and compensates for changes in intra cranial blood volume.

Normal ventricles Dilated ventricles

In foetus fontanelle and sutures are opened.

Posterior fontanel - at birth.

Anterior fontanel – at 18 months.

In initial 6 months of life brain expands at a greater rate.

Opened sutures and fontanelle provide proper space for growth of brain and make the skull pliable.

If ther is accumulation of fluid in brain of neonate,the increased pressure causes whole skull to swell.

Fontanelle bulges and sutures remain seperated and this presents as macrocephaly.

Hence MACROCEPHALY and OPEN FONTANELLE provide EARLY DIAGNOSIS in infants.

There are basic three mechanism involved in hydrocephalus

1. Over production of CSF.

2. Defective absorption of CSF into circulation

3. Blockage of CSF outflow in ventricle or subarachnoid space.

As a result fluid accumulated in the ventricles will lead to brain damage either through formation of internal or external hydrocephalus

Subarachnoid hemorrhage

Block the return of CSF to circulation

CSF accumulation in sub arachnoid space

Pressure applied to brain externally

Compresses neural tissue and hence brain damage

Foramina of 4th ventricle or cerebral aqueduct blocked

CSF accumulated within the ventricles

Compression of nervous tissue

Irreversible brain damage and severely enlarged head

1. COMMUNICATING HYDROCEPHALUS

Non-obstructive hydrocephalus

It is caused by impaired cerebrospinal fluid resorption due to obstruction of CSF flow outside the ventricular system,usually at the level of basal sub arachnoid cistern or at the arachnoid granulations.

2. NON COMMUNICATING HYDROCEPHALUS

Obstructive hydrocephalus

It is caused by a CSF-flow obstruction with in the ventricular system ultimately preventing CSF from flowing into the subarachnoid space (either due to external compression or intraventricular mass lesions).

Both communicating and non communicating can be congenital or aquired.

CONGENITAL HYDROCEPHALUS

Intrauterine infection-

Rubella

Cytomegalo virus

Toxoplasmosis

Intra cranial and Intra ventricular haemorrhage

Congenital malformations-

Aqueduct stenosis,

Dandy Walker Syndrome,

Arnold Chiari Syndrome,

Midline tumors obstructinc CSF flow

ACQUIRED HYDROCEPHALUS

Tuberculosis,Chronic & pyogenic Meningitis

Post IVH

Posterior Fossa tumors-Medulloblastoma,Astrocytoma,Ependymoma

Arterio-Venous malformation,Intra cranial haemorrhage,ruptured aneurysm.

Hydrocephalus ex vacuo

•Chiari type I malformation is the caudal displacement of the cerebellar tonsils below the foramen magnum.•Gives symptoms in adolescence or adult life(headache,neck pain, myelopathy)•The brain stem and lower cranial nerves are normal .

CHIARI TYPE II MALFORMATION

•Progressive hydrocephalus and myelomeningocele.•Elongation of IV ventricle•Involves caudal displacement of the lower brain stem and stretching of lower cranial nerves•Symptomatic patients may be treated with suboccipital craniectomy.

CHIARI TYPE I MALFORMATION

Spina bifida is a developmental birth defect caused by incomplete closure of embryonic neural tube.

Cystic expansion of 4th ventricle in the posterior fossa

Developmental failure of roof of the 4th ventricle during embryogenesis.

90% have hydrocephalus.

Prominent occiput.

DANDY WALKER SYNDROME

•Hydrocephalus ex vacuo

•Normal pressure hydrocephalus

It is compensatory enlargement of cerebral ventricles and subarachnoid space due to brain atrophy or loss of brain parenchyma not the result of increased ICP.

Can occur in post traumatic brain injuries and even in some psychiatric disorders, such as schizophrenia

A chronic type of communicating hydrocephalus

Presents mainly in elderly

The increase in intracranial pressure (ICP) due to accumulation of cerebrospinal fluid (CSF) becomes stable and that the formation of CSF equilibrates with absorption.

CSF pressure reaches a high normal level of 150 to 200 mm of H2O.

Because of this equilibration, patients do not exhibit the classic signs of increased intracranial pressure such as headache, nausea, vomiting, or altered consciousness. patients do exhibit the classic triad of gait difficulties, urinary incontinence, and mental decline It is often misdiagnosed as Parkinsons disease, Alzhiemer disease, and senility due to its chronic nature and its presenting symptoms 2 types a) Idiopathic b) Secondary is due to subarachnoid haemorrhage, head injury, cranial surgery, or CNS infection.

The patient of hydrocephalus develop symptoms due to raised ICP.

Headache which is raised in early morning or on lying down .

Vomiting, nausea, papilledema, sleepiness, or coma.

Elevated intracranial pressure may result in uncal and/or cerebellar tonsil herniation, with resulting life threatening brain stem compression.

Further symptoms depend on the cause of the blockage, the person's age, and how much brain tissue has been damaged by the swelling.

In infants with hydrocephalus, CSF fluid builds up in the central nervous system, causing the fontanelle (soft spot) to bulge and the head to be larger than expected.

Eyes that appear to gaze downward

Seperated sutures

Diplopia and blurred vision

Irritability

Seizures

Sleepiness

Symptoms that may occur in older children The presentation in older children is more acute.Features include:Brief shrill and high pitched cry

Changes in personality, memory and ability to think or reason

Changes in facial expression and eye spacing

Crossed eyes and uncontrolled eye movements

Difficult feeding, Excessive sleepiness

Loss of bladder control

Loss of coordination and trouble walking

Muscle spasticity

Slow growth(0-5years) and restricted movements

•Papilledema (more in old children)

•Cracked pot/Macewan sign(old children)

•Sixth nerve palsy

•Impaired upgaze

•Focal neurological deficits

•Impaired concious level

IN INFANTS

Patient of hydrocephalus develop raised ICP

•Progressive macrocephaly

•Bulging anterior fontanelle

•Dilated scalp veins

•Sun setting signs

NPH may exhibit the classic triad (also known as Adam's triad) of urinary incontinence, gait disturbance, and dementia

1)Gait disturbance and Ataxia

is the first symptom of the triad

Progressive

Occurs due to expansion of the ventricular system(particularly at the level of the lateral ventricles)

traction on the lumbosacral motor fibers

unsteadiness and impaired balance, especially on stairs and curbs.

NPH gait disturbance is often characterized as a "magnetic gait," in which feet appear to be stuck to the walking surface until wrested upward and forward at each step.

2) Dementia

is predominantly frontal lobe in nature,

with apathy, dullness in thinking, slight inattention. and Memory problems.

The dementia is thought to result from traction on frontal and limbic fibers that also run in the periventricular region

3) Urinary incontinence

appears late in the illness,

consisting of increased frequency and urgency.

A physician selects the appropriate diagnostic tool based on an individual’s age, clinical presentation or type of hydrocephalus and the presence of known or suspected abnormalities of the brain or spinal cord.

Hydrocephalus is diagnosed through

1. Clinical neurological evaluation

2. Lumbar puncture

3. Cranial imaging techniques

• ultrasonography,

• computed tomography (CT),

• magnetic resonance imaging (MRI) and T2 weighted MRI

4. Other ICP-monitoring techniques.

1) CLINICAL NEUROLOGICAL EVALUATION

Signs symptoms and neurological examination with accurate serial recording of head circumference will point towards the diagnosis.

An increase in head circumference in 1st three months of life >1cm every fortnight should arouse suspicion of hydrocephalus

Persistent widening of squamo parietal sutures is not physiological and should arouse suspicion of hydrocephalus.

2)LUMBAR PUNCTURE

a)Obstructive hydrocephalus- This is a contraindication for LP because of the risk of causing tonsillar

herniation and death.

b)Non Obstructive hydrocephalus-LP here may be both diagnostic-by measurement of opening pressure therapeutic-by draining volume of csf c) NPH LP is usually the first step in diagnosis. In most cases, CSF pressure is

usually above 155 mmH2O.i) CSF tap test: Clinical evaluation is done before and after removal of CSF (30

ml or more).It has a high predictive value for subsequent success with shunting. This is called the "lumbar tap test" or Miller Fisher test. A "negative" test has a very low predictive accuracy, as many patients may improve after a shunt in spite of lack of improvement after CSF removal.

ii) CSF infusion studies :Infusing saline into the thecal sac while measuring tha pressure to obtain and estimate of resistance to CSF outflow>14mmHg/ml/min have a positive predictive value for responsiveness to ventriculoperitoneal shunt insertion.

3) IMAGING STUDIES:

a) Uitrasonography(USG)

Serial USG helps to support the clinical diagnosis and to evaluate serial ventricular size.

b) CT Scan and MRI

Ventricular size can be assessed more accurately with CT scan.

Information about cortical mantle, periventricular ooze and etiology of hydrocephalus like Arnold chiari and dandy walker malformation

In children CT shows COPPER BEATING of skull because of chronic raised ICP.

MRI/CT may be necessary to determine site of obstruction and in congenital hydrocephalus to identify associated malformation.

MRI provide better anatomical detail of lesion and is particularly helpful in diagnosis of aqueductal stenosis

Imaging however cannot differentiate between pathologies with similar clinical picture like Alzheimer's dementia, vascular dementia or Parkinson's disease.

Copper beating appearence

Arnold chiari malformation

c) MID LINE T2 WEIGHTED MRI scan

Can be used to assess the suitability of patient for third ventriculostomy by identifying the relationships of floor of third ventricle,basilar artery and clivus.

d) ICP MONITORING

With a parenchymal probe placed into the frontal lobe via a twistdrill burrhole is a useful diagnostic tool for patients in whom hydrocephalus or CSF shunt dysfunction is suspected.

Hydrocephalus is to be differentiated from conditions manifesting as large head-

a) MEGANCEPHALY-causes include-

Hurlers syndrome

Metachromatic leukodystrophy

Taysachs disease

b)CHRONIC HAEMOLYTIC ANAEMIA-(widening of diploic bones)

c) VITAMINE D DEFICIENCY

d) SUB DURAL EFFUSION

e) CEPHALHEMATOMA

f) CAPUT SUCCEDENUM

g)OTHER CAUSES- HYDRANENCEPHALY,RICKETS,FAMILIAL MACROCEPHALIES

Management of hydrocephalus depends on the underlying cause and severity of symptoms

MEDICAL MANAGEMENT

This is a conservative approach for mild & slowly progressive hydrocephalus or cases where surgery is not indicated

Acetazolamide[25 -100mg/kg/min].

Oral glycerol

SURGICAL MANAGEMENT

It includes-

a)Removing of a causative mass leisonIntracranial mass lesion usually present with obstructive hydrocephalusIt includes tumor removal and decompression of CSF pathway using EVD(External ventricular drainage) to cover early post operative period.

b) Ventricular shunting

c) 3rd ventriculostomy

WHAT IS SHUNT?

This system diverts the flow of CSF from the CNS to another area of the body where it can be absorbed as part of the normal circulatory process.

A shunt is a flexible but sturdy plastic tube. A shunt system consists of the shunt, a catheter, and a valve. One end of the catheter is placed within a ventricle inside the brain or in the CSF outside the spinal cord. The other end of the catheter is commonly placed within the abdominal cavity, but may also be placed at other sites in the body such as a chamber of the heart or areas around the lung where the CSF can drain and be absorbed. A valve located along the catheter maintains one-way flow and regulates the rate of CSF flow.

CHABBRA V P SHUNT

CHABBRA V P SHUNT

WHAT IS VENTRICULO PERITONEAL SHUNT

It involves shunt between lateral ventricle and peritoneal cavity.

Here there occurs the insertion of a catheter into lateral ventricle{usually right frontal or occipital}.The catheter is then connected to a shunt valve under the scalp and finally to a distal catheter,which is tunnelled subcutaneously down to abdomen and inserted into the peritonial cavity.if the CSF pressure > the shunt valve pressure then CSF will flow out of the distal catheter and can be absorbed by peritonial lining.

OTHER SHUNT SYSTEMS-

Ventriculo atrial shunt

Ventriculo pleural shunt.

Lumbar peritonial shunt.

MECHANISM OF SHUNT VALVES

-Diaphragm system

-Ball in cone system

These are pressure regulated which are sucseptible to SIPHONING.

There are three performance settings of shunts-high,medium,low.

Shunt valves usually have an in-built CSF reservoir on the ventricular side of the valve,which may be useful for shunt taping.WHEN IS THE SHUNTING DONE

If the head size enlarges rapidly or is associated with a progressive symtoms,where vision or life is endangered it is desirable to treat surgically before irreparable damage occurs specially in congenital obstructive hydrocephalus,aquired hydrocephalus or periventricular ooze with hydrocephalus and patients with tubercular meningitis.

An alternative procedure called third ventriculostomy. In this procedure, a neuroendoscope — a small camera that uses fiber optic technology to visualize small and difficult to reach surgical areas — allows a doctor to view the ventricular surface. Once the scope is guided into position, a small tool makes a tiny hole in the floor of the third ventricle, which allows the CSF to bypass the obstruction and flow toward the site of resorption around the surface of the brain.

External drains can be placed within the ventricle (EVD) or the Lumbar Thecal Sac (Lumbar drain).

Useful for temporary CSF drainage.

Can be also used to administer Intrathecal antibiotics to treat CSF infections.

Possible complications include

shunt malfunction

shunt blockage

shunt failure

shunt infection.

Over draining of shunts

CSF leak

Stroke & intracranial haemorrhage

Shunt blockage may affect the ventricular catheter,shunt valve or distal catheter.Causes include choroid plexus adhesion,blood or cellular debris or misplacement of the distal catheter in the pre peritoneal space.

Shunt infection usually caused by skin commensals such as staphylococcal epidermitis.Neonates are susceptible to E.coli and hemolytic streptococcal infections.Risk factors for infections include- Very young children Open myelomeningocele Longer operative time Excessive staff movement into & out of theater90% infections become apparent clinically within 6 months.Treatment-Removal of shunts, External drainage treatment of infection prior to re-insertion of shunt at a different site.Shunt system may overdrain leading to subdural haemorrhage.

The prognosis for individuals diagnosed with hydrocephalus is difficult to predictPrognosis depends the time of diagnosis and type of hydrocephalus.Cognitive abilities appear to be better in non communicating hydrocephalus and those with myelomeningocoele or chiari malformation type IICommunicating hydrocephalusis associated with more cognitive impairment.Hydrocephalus due to intrauterine CNS infections have grim developmental prognosis.If left untreated progressive hydrocephalus may be fatal.With good medical care & if there are no severe underlying brain disorders that affect intelligence, patients of Hydrocephalus can expect to live a productive & relatively normal life with adequately functioning shunt.

CASE FROM DEPARTMENT OF SURGERY,SGMH

As we have seen that due to blockage of CSF outflow or defective absorbtion or overproduction of CSF,there is accumulation of fluid in ventricles which leads to brain damage and produce signs and symptoms of increased ICP.

Only congenital form can be screened by proper antenatal check ups & investigaions.

It is diagnosed by neurological evaluation, Imaging, Lumbar Puncture, & ICP monitoring.

Only definitive treatment is SHUNTING of CSF either into Peritoneal(VP shunt) or Pleural cavity.

A team work of Gynaecologist, Paediatrician, Psychiatrist, Physiotherapist and most importantly Parents is required to combat this problem.

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2. Sabiston textbook of surgery Vol.II ,17th Edi.(2004)

3. Schwartz’s Principles of surgery,8th Edi.(2005)

4. B.D.Chourasia’s Human Anatomy Vol.III ,4th Edi.(2009)

5. Concise textbook of surgery,S.Das,3rd Edi.(2001)

6. Rob and Smith’s Paediatrics operative surgery,5th Edi.(1995)

7. Harrison’s Principles of Internal Medicine,17th Edi.(2008)

8. Internet: www.wikipedia.com