Hydrocephalus Water on Head

Saturday 8 April 2023 2

A 9 year old boy was brought to his GP by his parents who noted that he was having difficulty with balance and was complaining of head aches.

Warm UP

CSF is a clear fluid produced by dialysis of blood in the choroid plexus.Once produced, CSF is then circulated, due to hydrostatic pressure, from the choroid plexus of the lateral ventricles, through the inter-ventricular foramina into the 3rd ventricle. CSF then flows through the cerebral into the 4th ventricle. From the 4th ventricle the CSF circulate in the subarachnoid space in the brain and spinal cord

Large amounts of CSF are drained into venous sinuses through arachnoid granulations in the dorsal sagittal sinus. The dorsal sagittal sinus is located between the folds of dura, known as the falx cerebri, covering each of the cerebral hemispheres.

Arachnoid granulations contain many villi that are able to act as a one way valve helping to regulate pressure within the CSF, and these arachnoid villi push through the dura and into the venous sinuses.

The CSF volume, estimated to be about 150 ml in adults, is distributed between 125 ml in cranial and spinal subarachnoid spaces and 25 ml in the ventricles, but with marked interindividual variations.

CSF secretion in adults is around 500 ml per day, depending on the subject and the method used to study CSF secretion. 

When cerebrospinal fluid pressure increases, arachnoid villi develop, thereby increasing their surface of exchange.

Physiological values of CSF pressure vary according to individuals and study methods between 10 and 15 mmHg in adults and 3 and 4 mmHg in infants. Higher values correspond to intracranial hypertension.

CSF pressure varies with the systolic pulse wave, respiratory cycle, abdominal pressure, jugular venous pressure, state of arousal, physical activity and posture.

Take off

Definition

Hydrocephalus is a disorder in which an excessive amount of cerebrospinal fluid (CSF) accumulates within the cerebral ventricles and/orsubarachnoid spaces, which are dilated [1,2].

Aka Hydrodynamic disorder of CSF.

1-Fishman MA. Hydrocephalus. In: Neurological pathophysiology, Eliasson SG, Prensky AL, Hardin WB (Eds), Oxford, New York 1978.2-Carey CM, Tullous MW, Walker ML. Hydrocephalus: Etiology, Pathologic Effects, Diagnosis, and Natural History. In: Pediatric Neurosurgery, 3 ed, Cheek WR (Ed), WB Saunders Company, Philadelphia 1994.

Epidemiology

The prevalence of congenital and infantile hydrocephalus in the United States and Europe has been estimated as 0.5 to 0.8 per 1000 live and still births.

Mortality/Morbidity

In untreated hydrocephalus, death may occur by tonsillar herniation secondary to raised ICP with compression of the brain stem and subsequent respiratory arrest.

Sex

Males = females.

EXCEPT in Bickers-Adams syndrome ,an X-linked hydrocephalus transmitted by females and manifested in males.

NPH has a slight male preponderance.

Age

bimodal age curve. One peak occurs in infancy and is related to the various forms of congenital malformations. Another peak occurs in adulthood, mostly resulting from NPH. Adult hydrocephalus represents approximately 40% of total cases of hydrocephalus.

Hydrocephalus results from an imbalance between the intracranial cerebrospinal fluid (CSF) inflow and outflow.

It is caused by1- obstruction of CSF circulation2- by inadequate absorption of CSF3- or (rarely) by overproduction of the CSF.

Regardless of the cause, the excessive volume of CSF causes increased ventricular pressure and leads to ventricular dilatation

ClassificationA*

High pressure hydrocephalus

Normal pressure hydrocephalus

B*

Communicating HC = ventricular sys communicating with SA space

Noncommunicating HC = blockage within the ventricular system

Normal pressure hydrocephalus (NPH) describes a condition that rarely occurs in patients younger than 60 years. 

Enlarged ventricles and normal CSF pressure at lumbar puncture (LP) in the absence of papilledema led to the term NPH.

intermittent intracranial hypertension has been noted during monitoring of patients in whom NPH is suspected, usually at night.

The classic Hakim triad of symptoms includes gait apraxia, incontinence, and dementia. Headache is NOT a typical symptom in NPH

NPH

Communicating hydrocephalus occurs when full communication occurs between the ventricles and subarachnoid space. It is caused by

1. defective absorption of CSF (most often).

2. venous drainage insufficiency (occasionally).

3. overproduction of CSF (rarely).

MCC : infection/ SAH.

Noncommunicating hydrocephalus occurs when CSF flow is obstructed within the ventricular system or in its outlets to the arachnoid space, resulting in impairment of the CSF from the ventricular to the subarachnoid space.

The most common form: obstructive and is caused by intraventricular or extraventricular mass-occupying lesions that disrupt the ventricular anatomy. Other causes:

congenital malf. (Aqueduct stenosis).

Inflammation.

Hemorrhage.

Noncommunicating obstructive hydrocephalus caused by obstruction of the foramina of Luschka and Magendie. This MRI sagittal image demonstrates dilatation of lateral ventricles with stretching of corpus callosum and dilatation of the fourth ventricle.

Noncommunicating obstructive hydrocephalus caused by obstruction of foramina of Luschka and Magendie. This MRI axial image demonstrates dilatation of the lateral ventricles.

Communicating versus non -communicating hydrocephalus 

 Brain imaging can help to distinguish obstructive (non-communicating) from absorptive (communicating) hydrocephalus.

The site of obstructed CSF flow may be suggested by the pattern of ventricular dilatation. Stenosis of the aqueduct (a common type of obstructive hydrocephalus) typically results in dilated lateral and third ventricles and in a fourth ventricle of normal size.

In contrast, communicating hydrocephalus (eg, caused by either extraventricular obstruction or by impaired CSF absorption) in neonates and infants usually results in symmetric dilatation of all four ventricles.

If extraventricular obstruction or impaired CSF absorption occurs in children and adults, it may cause benign intracranial hypertension (pseudotumor cerebri) without ventricular dilatation, because of reduced compliance of the brain tissue

LOOK!!

These forms of hydrocephalus are distinct from two radiographic findings that include the same word.

The term “hydrocephalus ex-vacuo” refers to dilatation of the ventricles secondary to brain atrophy or loss of brain tissue secondary to an insult; hydrocephalus ex-vacuo is not accompanied by increased ICP.

The term “external hydrocephalus” or “benign enlargement of the extra-axial spaces” refers to excessive fluid, usually CSF, in the subarachnoid spaces

associated with familial macrocephaly

Seen in infant and early children.

The ventricles usually are not enlarged significantly

resolution within 1 year is the rule.

 Hydrocephalus can be congenital or

acquired. Both categories include a diverse group of conditions.

applies to the ventriculomegaly that develops in the fetal and infancy periods

often associated with macrocephaly.

The most common causes of congenital hydrocephalus are obstruction of the cerebral aqueduct flow, Arnold-Chiari malformation or Dandy–Walker malformation.

 these patients may stabilize in later years due to compensatory mechanisms but may decompensate, especially following minor head injuries.

Congenital hydrocephalus :

Infants : S & S

Signs :

Head enlargement: Head circumference is at or above the 98th percentile for age.

Dysjunction of sutures: This can be seen or palpated.

Dilated scalp veins: The scalp is thin and shiny with easily

visible veins.

Tense fontanelle: The anterior fontanelle in infants who are held erect and are not crying

may be excessively tense.

Setting-sun sign: In infants, it is characteristic of increased intracranial pressure (ICP). Ocular globes are deviated downward, the upper lids are retracted,

and the white sclerae may be visible above the iris.

Increased limb tone: Spasticity preferentially affects the lower limbs. The cause is stretching of the periventricular pyramidal tract fibers by hydrocephalus.

Symptoms :

Poor feeding

Irritability

Reduced activity

Vomiting

Setting-sun sign

Adults : S & S

Symptoms: Cognitive deterioration: This can be confused with other types of dementia

in the elderly.

Headaches: more prominent in the morning because cerebrospinal fluid (CSF) is resorbed less efficiently in the recumbent position. This can be relieved by sitting up. As the condition progresses, headaches become severe and continuous. Headache is rarely if ever present in normal pressure hydrocephalus (NPH).

Neck pain: If present, neck pain may indicate protrusion of cerebellar tonsils into the foramen magnum.

Nausea that is not exacerbated by head movements

Vomiting: Sometimes explosive, vomiting is more significant in the morning.

Blurred vision (and episodes of "graying out"): These may suggest serious optic nerve compromise, which should be treated as an emergency.

Double vision (horizontal diplopia) from sixth nerve palsy

Difficulty in walking

Drowsiness

Incontinence (urinary first, fecal later if condition remains untreated): This indicates significant destruction of frontal lobes and advanced disease.

Signs :

Papilledema: If raised ICP is not treated, it leads to optic atrophy.

Failure of upward gaze and of accommodation indicates pressure on the tectal plate. The full Parinaud syndrome* is rare.

* Parinaud's Syndrome, also known as dorsal midbrain syndrome is a group of abnormalities of eye movement and pupil dysfunction. It is caused by lesions of the upper brain stem and is named for Henri Parinaud(1844–1905), considered to be the father of French ophthalmology

Unsteady gait is related to truncal and limb ataxia. Spasticity in legs also causes gait difficulty.

Large head: The head may have been large since childhood

Unilateral or bilateral sixth nerve palsy is secondary to increased ICP.

NPH : S & S Gait disturbance is usually the first symptom and may

precede other symptoms by months or years. Magnetic gait is used to emphasize the tendency of the feet to remain "stuck to the floor" despite patients’ best efforts to move them.

Dementia should be a late finding in pure (shunt-responsive) NPH. It presents as an impairment of recent memory or as a "slowing of thinking." Spontaneity and initiative are decreased. The degree can vary from patient to patient.

Urinary incontinence may present as urgency, frequency, or a diminished awareness of the need to urinate.

Other symptoms that can occur include personality changes and Parkinsonism. Seizures are extremely rare and should prompt consideration for an alternative diagnosis.

Signs : Muscle strength is usually normal.

NO SENSORY LOSS IS NOTED.

Reflexes may be increased, and the Babinski response may be found in one or both feet. These findings should prompt search for vascular risk factors (causing associated brain microangiopathy or vascular Parkinsonism), which are common in NPH patients.

Difficulty in walking varies from mild imbalance to inability to walk or to stand. The classic gait impairment consists of short steps, wide base, externally rotated feet, and lack of festinating (hastening of cadence with progressively shortening stride length, a hallmark of the gait impairment of Parkinson disease). These abnormalities may progress to the point of apraxia. Patients may not know how to take steps despite preservation of other learned motor tasks.

Frontal release signs such as sucking and grasping reflexes appear in late stages.

Congenital causes in infants and children:

Brainstem malformation causing stenosis of the aqueduct of Sylvius: This is responsible for 10% of all cases of hydrocephalus in newborns.

Dandy-Walker malformation: This affects 2-4% of newborns with hydrocephalus.

Arnold-Chiari malformation type 1 and type 2

Agenesis of the foramen of Monro

Congenital toxoplasmosis

Bickers-Adams syndrome: This is an X-linked hydrocephalus accounting for 7% of cases in males. It is characterized by stenosis of the aqueduct of Sylvius, severe mental retardation, and in 50% by an adduction-flexion deformity of the thumb.

Acquired causes in infants and children:

Mass lesions account for 20% of all cases of hydrocephalus in children. These are usually tumors (eg, medulloblastoma, astrocytoma), but cysts, abscesses, or hematoma also can be the cause.

Haemorrhage: Intraventricular hemorrhage can be related to prematurity, head injury, or rupture of a vascular malformation.

Infections: Meningitis (especially bacterial) and, in some geographic areas, cysticercosis can cause hydrocephalus.

Increased venous sinus pressure: This can be related to achondroplasia, some craniostenoses, or venous thrombosis.

Iatrogenic: Hypervitaminosis A, by increasing secretion of CSF or by increasing permeability of the blood-brain barrier, can lead to hydrocephalus. As a caveat, hypervitaminosis A is a more common cause of idiopathic intracranial hypertension, a disorder with increased CSF pressure but small rather than large ventricles.

Idiopathic

Causes of hydrocephalus in adults:

Subarachnoid hemorrhage (SAH) causes one third of these cases by blocking the arachnoid villi and limiting resorption of CSF. However, communication between ventricles and subarachnoid space is preserved.

Idiopathic hydrocephalus represents one third of cases of adult hydrocephalus.

Tumors can cause blockage anywhere along the CSF pathways. The most frequent tumors associated with hydrocephalus are ependymoma, subependymal giant cell astrocytoma, choroid plexus papilloma, craniopharyngioma, pituitary adenoma, hypothalamic or optic nerve glioma, hamartoma, and metastatic tumors.

Head injury, through the same mechanism as SAH, can result in hydrocephalus.

Prior posterior fossa surgery may cause hydrocephalus by blocking normal pathways of CSF flow.

Meningitis, especially bacterial, may cause hydrocephalus in adults.

All causes of hydrocephalus described in infants and children are present in adults who have had congenital or childhood-acquired hydrocephalus.

Causes of NPH

Most cases are idiopathic and are probably related to a deficiency of arachnoids granulations:

SAH

Head trauma

Meningitis

Differential diagnosis Brainstem Gliomas

Childhood Migraine Variants

Craniopharyngioma

Epidural Hematoma

Frontal and Temporal Lobe Dementia

Frontal Lobe Epilepsy

Frontal Lobe Syndromes

Glioblastoma Multiforme

Intracranial Epidural Abscess

Intracranial Hemorrhage

Meningioma

Mental Retardation

Migraine Headache

Migraine Variants

Oligodendroglioma

Pituitary Tumors

Primary CNS Lymphoma

Pseudotumor Cerebri

Pseudotumor Cerebri: Pediatric Perspective

Subdural Empyema

Subdural Hematoma

Imaging studies

CT scan:

Advantages: fastreliable does not interfere with implanted medical devices

Disadvantage : radiation exposure 

U/S: In a newborn, ultrasonography is the preferred

technique for the initial examination because it is portable and avoids ionizing radiation.

Ultrasound is good for imaging the lateral ventricles but does not assess the posterior fossa well-to assess ventricular size

( through the open fontanelle).

MRI:MRI is generally the imaging modality of choice in patients with unexplained hydrocephalus

Procedures

Lumbar puncture (LP)

is a valuable test in evaluating NPH.

only in communicating

should be performed only after CT or MRI of the head.

Normal LP opening pressure (OP) should be less than 180 mm H2 O (ie, 18 cm H2 O). Patients with initial OP greater than 100 mm H2 O have a higher rate of response to CSF shunting than those with OPs less than 100 mm H2 O.

Continuous CSF drainage through external lumbar drainage (ELD) is a highly accurate test for predicting the outcome after ventricular shunting in NPH, although false negative results are not uncommon.

EEG if the patient has seizures .

ManagementMEDICAL :

1-drugs (Diuretics and fibrinolytics) :They have been used for short periods in slowly progressive hydrocephalus in patients too unstable for surgery

2- Repeat lumbar punctures (LPs):can be performed for cases of hydrocephalus after intraventricular hemorrhage, since this condition can resolve spontaneously. If reabsorption does not resume when the protein content of cerebrospinal fluid (CSF) is less than 100 mg/dL, spontaneous resorption is unlikely to occur.

LP can be performed only in cases of communicating hydrocephalus.

Surgical

Shunting :

allows CSF to flow from the ventricles into the systemic circulation or to the peritoneum where it

is absorbed, bypassing the site of mechanical or functional obstruction to absorption.

Types of shunting

Ventriculo-peritoneal shunting (VP shunting):

Most commonly used.

It is preferred for growing children and most adults.

Lateral ventricle is the usual proximal location.

Advantages:

The ability of the peritoneal cavity to accept a large loop of tubing and to

accommodate the axial growth.

Specific complications:

Inguinal hernia in > l5%

Hydrocele

Peritonitis.

Volvulus

Peritoneal cyst

Intestinal obstruction.

2. Ventriculo-atrial shunting (VA shunting)

3. Lumbo-peritoneal shunting (LP shunting)

VP shunt VA shunt

Contraindications:

Active ventriculitis.

Fresh ventricular hemorrhage

Active systemic infection.

Open meningeocele (source of infection if not closed)

Complication of shunt

o Infections:

2-3 months post-op

Staph. Epidermis and Staph. Aureus.

o Obstruction of the catheter

o Intracerebral /subdural Hemorrhage

o Over shunting (VP shunts)

o Misplacement

o Seizures

Approximately 40 percent of standard shunts malfunction within the first year after placement

Third ventriculostomy — Endoscopic third ventriculostomy (ETV) is a procedure in which a perforation is made to connect the third ventricle to the subarachnoid space.

This has been used in the initial treatment of selected cases of obstructive hydrocephalus and as an alternative to shunt revision. Some experts consider it the treatment of choice for aqueductal stenosis, although about 20 percent of patients still require shunting.

ETV is not useful for patients with communicating hydrocephalus. The success of the procedure depends upon the cause of hydrocephalus and upon previous complications .

When successful, ETV provides a treatment for hydrocephalus that is relatively low-cost and durable.

Complications of third ventriculostomy

are mainly perioperative

and include inability to complete the procedure, hemorrhage, hypothalamic dysfunction (diabetes insipidus, syndrome of inappropriate antidiuretic hormone secretion, or precocious puberty), meningitis, and cerebral infarction.

In a systematic review, permanent morbidity after the procedure was 2.1 percent, and mortality was 0.22 percent

Complications of hydrocephalus Related to progression of hydrocephalusVisual changes

Occlusion of posterior cerebral arteries secondary to downward transtentorial herniation

Chronic papilledema injuring the optic disc

Dilatation of the third ventricle with compression of optic chiasm

Cognitive dysfunction

Incontinence

Gait changes

Related to medical treatmentElectrolyte imbalance

Metabolic acidosis

Prognosis Long-term outcome is related directly to the cause of

hydrocephalus.

Survival in untreated hydrocephalus is poor. Approximately 50 percent of affected patients die before three years of age, and 77 to 80 percent die before reaching adulthood [27].

Treatment markedly improves the outcome for hydrocephalus not associated with tumor

Functional outcome depends upon factors including :degree of prematurity central nervous system (CNS) malformationsother congenital abnormalities and epilepsy, as well as sensory and motor impairments

Saturday 8 April 2023 59

A 9 year old boy was brought to his GP by his parents who noted that he was having difficulty with his balance and was complaining of head aches.

He was referred to the neurosurgical unit and a CT scan was perform of his head region.

This showed the presence of dilated lateral and III ventricles with a normal IV ventricle. There was effacement of the overlying cortical sulci in the brain and a diagnosis of Hydrocephalus was made.

MRI showed the cerebral aqueduct was stenosed.

The boy subsequently had a III ventriculostomy performed, and his symptoms resolved rapidly.

Reference: http://www.uptodate.com/contents/search?sp=0&so

urce=USER_PREF&search=Hydrocephalus&searchType=PLAIN_TEXT

http://emedicine.medscape.com/article/1135286-overview

http://www.sciencedirect.com/science/article/pii/S1879729611001013

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