Hydrocephalus

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Practice Essentials

Hydrocephalus can be defined broadly as a disturbance of cerebrospinal fluid (CSF) formation, flow, or absorption, leading to an increase in volume occupied by this fluid in the central nervous system (CNS).[1] This condition could also be termed a hydrodynamic CSF disorder.

Essential update: Endoscopic third ventriculostomy for hydrocephalus

In a study spanning nearly 2 decades and comprising 95 patients, investigators evaluating the indications for endoscopic third ventriculostomy (ETV) and its long-term effectiveness in hydrocephalus found the procedure to be effective and durable for select patients with this condition.[2] Moreover, in cases of successful ETV (75%), in which no subsequent surgery was required for hydrocephalus, none of the lifelong complications highly associated with conventional treatment for hydrocephalus using implanted ventricular shunts was observed. A significant factor in the success of ETV was the presence of preoperative inferior bowing of the third ventricle floor on magnetic resonance imaging (MRI).[2] Overall, patients had a mean follow-up period of 5.1 years (median, 4.7y), and follow-up data was available for up to 17 years.

Signs and symptoms

Clinical features of hydrocephalus are influenced by the patient's age, the cause of the hydrocephalus, the location of the obstruction, its duration, and its rapidity of onset.

Symptoms in infants include poor feeding, irritability, reduced activity, and vomiting.

Symptoms in children and adults include the following:

Children may also exhibit stunted growth and sexual maturation from third ventricle dilatation. Adults may also have nausea that is not exacerbated by head movements; incontinence (urinary first, fecal later if condition remains untreated) indicates significant destruction of the frontal lobes and advanced disease.

Symptoms of normal pressure hydrocephalus (NPH) include the following:

See Clinical Presentation for more detail.

Diagnosis

Examination in infants may reveal the following findings:

Children and adults may demonstrate the following findings on physical examination:

Children may also exhibit the Macewen sign, in which a "cracked pot" sound is noted on percussion of the head.

Patients with NPH may exhibit the following findings on examination:

Testing

No specific blood tests are recommended in the workup for hydrocephalus. However, consider genetic testing and counseling when X-linked hydrocephalus is suspected, and evaluate the CSF in posthemorrhagic and postmeningitic hydrocephalus for protein concentration and to exclude residual infection.

Obtain electroencephalography in patients with seizures.

Imaging studies

The following imaging studies may be used to evaluate patients with suspected hydrocephalus:

See Workup for more detail.

Management

Surgery

Surgical treatment is the preferred therapeutic option in patients with hydrocephalus.[5] Most patients eventually undergo shunt placements, such as the following:

Rapid-onset hydrocephalus with ICP is an emergency. The following procedures can be done, depending on each specific case:

Repeat LPs can be performed for cases of hydrocephalus after intraventricular hemorrhage (which can resolve spontaneously). If reabsorption does not resume when the CSF protein content is less than 100 mg/dL, spontaneous resorption is unlikely to occur. LPs can be performed only in cases of communicating hydrocephalus.

Alternatives to shunting include the following:

Conservative management

Medical treatment is not effective in long-term treatment of chronic hydrocephalus; it is used as a temporizing measure to delay surgical intervention. Medical therapy may be tried in premature infants with posthemorrhagic hydrocephalus (in the absence of acute hydrocephalus). Normal CSF absorption may resume spontaneously during this interim period.

Medication as treatment for hydrocephalus is controversial and should be used only as a temporary measure for posthemorrhagic hydrocephalus in neonates. Such agents include carbonic anhydrase inhibitors (eg, acetazolamide) and loop diuretics (eg, furosemide).

See Treatment and Medication for more detail.

Image library


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Noncommunicating obstructive hydrocephalus caused by obstruction of the foramina of Luschka and Magendie. This MRI sagittal image demonstrates dilatat....

Background

Hydrocephalus can be defined broadly as a disturbance of formation, flow, or absorption of cerebrospinal fluid (CSF) that leads to an increase in volume occupied by this fluid in the CNS.[1] This condition also could be termed a hydrodynamic disorder of CSF. Acute hydrocephalus occurs over days, subacute hydrocephalus occurs over weeks, and chronic hydrocephalus occurs over months or years. Conditions such as cerebral atrophy and focal destructive lesions also lead to an abnormal increase of CSF in CNS. In these situations, loss of cerebral tissue leaves a vacant space that is filled passively with CSF. Such conditions are not the result of a hydrodynamic disorder and therefore are not classified as hydrocephalus. An older misnomer used to describe these conditions was hydrocephalus ex vacuo.

Normal pressure hydrocephalus (NPH) describes a condition that rarely occurs in patients younger than 60 years.[6] Enlarged ventricles and normal CSF pressure at lumbar puncture (LP) in the absence of papilledema led to the term NPH. However, 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.

Benign external hydrocephalus is a self-limiting absorption deficiency of infancy and early childhood with raised intracranial pressure (ICP) and enlarged subarachnoid spaces. The ventricles usually are not enlarged significantly, and resolution within 1 year is the rule.

Communicating hydrocephalus occurs when full communication occurs between the ventricles and subarachnoid space. It is caused by overproduction of CSF (rarely), defective absorption of CSF (most often), or venous drainage insufficiency (occasionally). See the image below.


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Communicating hydrocephalus with surrounding "atrophy" and increased periventricular and deep white matter signal on fluid-attenuated inversion recove....

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 of noncommunicating hydrocephalus is obstructive and is caused by intraventricular or extraventricular mass-occupying lesions that disrupt the ventricular anatomy.[7] See the images below.


View Image

Noncommunicating obstructive hydrocephalus caused by obstruction of the foramina of Luschka and Magendie. This MRI sagittal image demonstrates dilatat....


View Image

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


View Image

Noncommunicating obstructive hydrocephalus caused by obstruction of foramina of Luschka and Magendie. This MRI axial image demonstrates fourth ventric....

Congenital hydrocephalus applies to the ventriculomegaly that develops in the fetal and infancy periods, often associated with macrocephaly.[8] The most common causes of congenital hydrocephalus are obstruction of the cerebral aqueduct flow, Arnold-Chiari malformation or Dandy–Walker malformation.[9] these patients may stabilize in later years due to compensatory mechanisms but may decompensate, especially following minor head injuries. During these decompensations, determining the extent to which any new neurological deficits may be due to the new acute event, compared with hydrocephalus that may have gone unnoticed for many years, is difficult.

Pathophysiology

Normal CSF production is 0.20-0.35 mL/min; most CSF is produced by the choroid plexus, which is located within the ventricular system, mainly the lateral and fourth ventricles. The capacity of the lateral and third ventricles in a healthy person is 20 mL. Total volume of CSF in an adult is 120 mL.

Normal route of CSF from production to clearance is the following: From the choroid plexus, the CSF flows to the lateral ventricle, then to the interventricular foramen of Monro, the third ventricle, the cerebral aqueduct of Sylvius, the fourth ventricle, the 2 lateral foramina of Luschka and 1 medial foramen of Magendie, the subarachnoid space, the arachnoid granulations, the dural sinus, and finally into the venous drainage.

ICP rises if production of CSF exceeds absorption. This occurs if CSF is overproduced, resistance to CSF flow is increased, or venous sinus pressure is increased. CSF production falls as ICP rises. Compensation may occur through transventricular absorption of CSF and also by absorption along nerve root sleeves. Temporal and frontal horns dilate first, often asymmetrically. This may result in elevation of the corpus callosum, stretching or perforation of the septum pellucidum, thinning of the cerebral mantle, or enlargement of the third ventricle downward into the pituitary fossa (which may cause pituitary dysfunction).

The mechanism of NPH has not been elucidated completely. Current theories include increased resistance to flow of CSF within the ventricular system or subarachnoid villi; intermittently elevated CSF pressure, usually at night; and ventricular enlargement caused by an initial rise in CSF pressure; the enlargement is maintained despite normal pressure because of the Laplace law. Although pressure is normal, the enlarged ventricular area reflects increased force on the ventricular wall.

The mechanism of NPH has not been elucidated completely. Current theories include increased resistance to flow of CSF within the ventricular system or subarachnoid villi; intermittently elevated CSF pressure, usually at night; and ventricular enlargement caused by an initial rise in CSF pressure; the enlargement is maintained despite normal pressure because of the Laplace law. Although pressure is normal, the enlarged ventricular area reflects increased force on the ventricular wall.

Frequency

United States

The incidence of congenital hydrocephalus is 3 per 1,000 live births; the incidence of acquired hydrocephalus is not known exactly due to the variety of disorders that may cause it.

International

Incidence of acquired hydrocephalus is unknown. About 100,000 shunts are implanted each year in the developed countries, but little information is available for other countries.

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.

Shunt dependence occurs in 75% of all cases of treated hydrocephalus and in 50% of children with communicating hydrocephalus. Patients are hospitalized for scheduled shunt revisions or for treatment of shunt complications or shunt failure. Poor development of cognitive function in infants and children, or loss of cognitive function in adults, can complicate untreated hydrocephalus. It may persist after treatment. Visual loss can complicate untreated hydrocephalus and may persist after treatment.

Sex

Generally, incidence is equal in males and females. The exception is Bickers-Adams syndrome, an X-linked hydrocephalus transmitted by females and manifested in males. NPH has a slight male preponderance.

Age

Incidence of human hydrocephalus presents a 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.

The outcome of pediatric hydrocephalus has been studied frequently, but much remains unresolved about long-term and social outcomes.[10]

History

Physical

Causes

Laboratory Studies

Imaging Studies

Other Tests

Procedures

Histologic Findings

Medical Care

Surgical Care

Consultations

Diet

Activity

Medication Summary

Acetazolamide (ACZ) and furosemide (FUR) treat posthemorrhagic hydrocephalus in neonates. Both are diuretics that also appear to decrease secretion of CSF at the level of the choroid plexus. ACZ can be used alone or in conjunction with FUR. The combination enhances efficacy of ACZ in decreasing CSF secretion by the choroid plexus. If ACZ is used alone, it appears to lower risk of nephrocalcinosis significantly.

Medication as treatment for hydrocephalus is controversial. It should be used only as a temporary measure for posthemorrhagic hydrocephalus in neonates.

Acetazolamide (Diamox)

Clinical Context:  Noncompetitive reversible inhibitor of enzyme carbonic anhydrase, which catalyzes the reaction between water and carbon dioxide, resulting in protons and carbonate. This contributes to decreasing CSF secretion by choroid plexus.

Class Summary

These agents inhibit an enzyme found in many tissues of the body that catalyzes a reversible reaction in which carbon dioxide becomes hydrated and carbonic acid dehydrated. These changes may result in a decrease in CSF production by the choroid plexus.

Furosemide (Lasix)

Clinical Context:  Mechanisms proposed for lowering ICP include lowering cerebral sodium uptake, affecting water transport into astroglial cells by inhibiting cellular membrane cation-chloride pump, and decreasing CSF production by inhibiting carbonic anhydrase. Used as adjunctive therapy with ACZ in temporary treatment of posthemorrhagic hydrocephalus in neonates.

Class Summary

These agents increase excretion of water by interfering with the chloride-binding cotransport system, which results from inhibition of reabsorption of sodium and chloride in the ascending loop of Henle and distal renal tubule.

Further Inpatient Care

Further Outpatient Care

Inpatient & Outpatient Medications

Transfer

Deterrence/Prevention

Complications

Prognosis

Author

Stephen L Nelson Jr, MD, PhD, Assistant Professor of Pediatrics, Neurology and Psychiatry, Uniformed Services University of the Health Sciences, F Edward Hebert School of Medicine; Attending Physician, Pediatric Emergency Medicine, Sinai Hospital and Shady Grove Hospital; Assistant Professor of Pediatrics and Neurology, Tulane School of Medicine

Disclosure: Nothing to disclose.

Specialty Editors

Anthony M Murro, MD, Professor, Laboratory Director, Department of Neurology, Medical College of Georgia

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

Richard J Caselli, MD, Professor, Department of Neurology, Mayo Medical School, Rochester, MN; Chair, Department of Neurology, Mayo Clinic of Scottsdale

Disclosure: Nothing to disclose.

Selim R Benbadis, MD, Professor, Director of Comprehensive Epilepsy Program, Departments of Neurology and Neurosurgery, Tampa General Hospital, University of South Florida College of Medicine

Disclosure: UCB Pharma Honoraria Speaking, consulting; Lundbeck Honoraria Speaking, consulting; Cyberonics Honoraria Speaking, consulting; Glaxo Smith Kline Honoraria Speaking, consulting; Sleepmed/DigiTrace Honoraria Speaking, consulting; Sunovion Consulting fee None

Chief Editor

Michael Hoffmann, MBBCh, MD, FCP(SA), FAAN, FAHA, Professor of Neurology, University of Central Florida College of Medicine; Director of Cognitive Neurology, Director of Stroke Program, James A Haley Veterans Affairs Hospital

Disclosure: Nothing to disclose.

Additional Contributors

Alberto J Espay, MD, MSc Associate Professor, Director of Clinical Research, Gardner Family Center for Parkinson's Disease and Movement Disorders, University of Cincinnati College of Medicine

Alberto J Espay, MD, MSc is a member of the following medical societies: American Academy of Neurology and Movement Disorders Society

Disclosure: Abbott Consulting fee Consulting; Chelsea therapeutics Consulting fee Consulting; Novartis Honoraria Speaking and teaching; TEVA Consulting fee Consulting; NIH Grant/research funds K23 Career Development Award; Eli Lilly Consulting fee Consulting; Great Lakes Neurotechnologies Other; Michael J Fox Foundation Grant/research funds Other; Lippincott Williams & Wilkins Royalty Book; American Academy of Neurology Honoraria Speaking and teaching

Eugenia-Daniela Hord, MD Instructor, Departments of Anesthesia and Neurology, Massachusetts General Hospital Pain Center, Harvard Medical School

Eugenia-Daniela Hord, MD is a member of the following medical societies: American Academy of Neurology and American Pain Society

Disclosure: Nothing to disclose.

References

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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.

Communicating hydrocephalus with surrounding "atrophy" and increased periventricular and deep white matter signal on fluid-attenuated inversion recovery (FLAIR) sequences. Note that apical cuts (lower row) do not show enlargement of the sulci, as is expected in generalized atrophy. Pathological evaluation of this brain demonstrated hydrocephalus with no microvascular pathology corresponding with the signal abnormality (which likely reflects transependymal exudate) and normal brain weight (indicating that the sulci enlargement was due to increased subarachnoid cerebrospinal fluid [CSF] conveying a pseudoatrophic brain pattern).

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.

Noncommunicating obstructive hydrocephalus caused by obstruction of foramina of Luschka and Magendie. This MRI axial image demonstrates fourth ventricle dilatation.

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.

Noncommunicating obstructive hydrocephalus caused by obstruction of foramina of Luschka and Magendie. This MRI axial image demonstrates fourth ventricle dilatation.

Communicating hydrocephalus with surrounding "atrophy" and increased periventricular and deep white matter signal on fluid-attenuated inversion recovery (FLAIR) sequences. Note that apical cuts (lower row) do not show enlargement of the sulci, as is expected in generalized atrophy. Pathological evaluation of this brain demonstrated hydrocephalus with no microvascular pathology corresponding with the signal abnormality (which likely reflects transependymal exudate) and normal brain weight (indicating that the sulci enlargement was due to increased subarachnoid cerebrospinal fluid [CSF] conveying a pseudoatrophic brain pattern).