CD-ROM Today 1996 January/CD-ROM Today 1996 January.iso/dp/0383/03836.txt

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$Unique_ID{BRK03836}
$Pretitle{}
$Title{Hydrocephalus}
$Subject{Hydrocephaly Water on the Brain Communicating Hydrocephalus
Non-Communicating Hydrocephalus Obstructive Hydrocephalus Internal
Hydrocephalus Normal Pressure Hydrocephalus Spina Bifida Meningitis Epilepsy
Arnold-Chiari Syndrome Encephalocele Cardio-Facio-Cutaneous Syndrome
Walker-Warburg Syndrome}
$Volume{}
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Copyright (C) 1984, 1985, 1987, 1988, 1989, 1992 National Organization
for Rare Disorders, Inc.

10:
Hydrocephalus

** IMPORTANT **
It is possible that the main title of the article (Hydrocephalus) is
not the name you expected.  Please check the SYNONYMS listing to find the
alternate name and disorder subdivisions covered by this article.

Synonyms

     Hydrocephaly
     Water on the Brain

Disorder Subdivisions:

     Communicating Hydrocephalus
     Non-Communicating Hydrocephalus
     Obstructive Hydrocephalus
     Internal Hydrocephalus
     Normal Pressure Hydrocephalus
     Benign Hydrocephalus

Information on the following diseases can be found in the Related
Disorders section of this report:

     Spina Bifida
     Meningitis
     Epilepsy
     Arnold-Chiari Syndrome
     Encephalocele
     Cardio-Facio-Cutaneous Syndrome
     Walker-Warburg Syndrome

General Discussion

** REMINDER **
The Information contained in the Rare Disease Database is provided for
educational purposes only.  It should not be used for diagnostic or treatment
purposes.  If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section of this report.


Hydrocephalus is a condition in which abnormally dilated (widened)
ventricles (cerebral spaces in the brain) inhibit the normal flow of
cerebrospinal fluid (CSF).  The cerebrospinal fluid accumulates in the skull
and puts pressure on the brain tissue.  An enlarged head in infants and
increased cerebrospinal fluid pressure are frequent findings but are not
necessary for the diagnosis of Hydrocephalus.  There are several different
forms of Hydrocephalus:  communicating hydrocephalus, non-communicating
hydrocephalus or obstructive hydrocephalus, internal hydrocephalus, normal
pressure hydrocephalus and benign hydrocephalus.

Symptoms

Hydrocephalus is characterized in children with an unusually large head
(cephalomegaly), a thin, transparent scalp, a bulging forehead with prominent
fontalelles (space between the bones of the skull) and a downward gaze.
Other symptoms may include convulsions, abnormal reflexes, a slowed heartbeat
and respiratory rate, headache, vomiting, irritability, weakness and problems
with vision.  Blindness and continuing mental deterioration may occur if
treatment is not administered.

When hydrocephalus begins as an adolescent or a young adult, the facial
abnormalities (physiognomic) are less obvious than in children with
congenital or early onset hydrocephalus.  Many of the other mental and
physiologic symptoms are the same, with the added loss of previously acquired
coordinated movement (motor coordination).  Acquired hydrocephalus in
children and adolescents is often associated with symptoms of hypopituitarism
(under-active pituitary gland) such as delayed growth and obesity, and
general weakness.

Hydrocephalus is subdivided according to the particular defect that
exists in the brain and whether or not the cerebrospinal fluid pressure is
high or normal.

In "communicating hydrocephalus" there is no blockage (obstruction) in
the cerebral spaces of the brain (ventricular system); the cerebrospinal
fluid flows readily into the subarachnoid space (the space between the
arachnoid and pia mater membranes in the brain), but the fluid is not
absorbed readily, or perhaps produced in too great a quantity to be absorbed.

In "noncommunicating (obstructive) hydrocephalus", the cerebrospinal
fluid is blocked causing dilation (widening) of the pathways upstream of the
block, leading to increased cerebrospinal fluid pressure in the skull.

"Normal-pressure hydrocephalus", which affects middle-aged and older
persons, is characterized by dilated ventricles but normal pressure within
the spinal column (lumbar pressure).  This type of hydrocephalus may be
detected by a diagnostic test known as pneumoencephalography.  A
pneumoencephalography is a procedure in which air is injected into certain
spaces in the brain (lumbar subarachnoid spaces) and X-ray (radiographic)
studies are done.  Other symptoms of normal-pressure hydrocephalus include
loss of memory and intellectual capacity (dementia), loss of muscle
coordination (ataxia) and loss of bladder control (urinary incontinence).

Causes

The cause of hydrocephalus is not known.  Some cases are caused by a birth
defect; others can follow hemorrhage, viral infection, or meningitis.  A
genetic predisposition has been proposed, with transmission through autosomal
recessive or X-linked genes.

Human traits, including the classic genetic diseases, are a product of
the interaction of two genes, one received from the father and one from the
mother.

In recessive disorders, the condition does not appear unless a person
inherits the same defective gene for the same trait from each parent.  If a
person receives one normal gene and one gene for the disease, the person will
be a carrier for the disease, but usually will show no symptoms.  The risk of
transmitting the disease to the children of a couple, both of whom are
carriers for a recessive disorder, is twenty-five percent.  Fifty percent of
their children will be carriers, but healthy as described above.  Twenty-five
percent of their children will receive both normal genes, one from each
parent, and will be genetically normal.

X-linked recessive disorders are conditions which are coded on the X
chromosome.  Females have two X chromosomes, but males have one X chromosome
and one Y chromosome.  Therefore, in females, disease traits on the X
chromosome can be masked by the normal gene on the other X chromosome.  Since
males only have one X chromosome, if they inherit a gene for a disease
present on the X, it will be expressed.  Men with X-linked disorders transmit
the gene to all their daughters, who are carriers, but never to their sons.
Women who are carriers of an X-linked disorder have a fifty percent risk of
transmitting the carrier condition to their daughters, and a fifty percent
risk of transmitting the disease to their sons.

Affected Population

Most cases of hydrocephalus are diagnosed in the first 2 years of life, but
onset may occur at any age, depending on the cause.  This disorder seems to
affect males and females equally, except those inherited as an X-linked
genetic traits which affects males.

Related Disorders

The following disorders can occur in conjunction with Hydrocephalus.
Comparisons may be useful for differential diagnosis.

Spina Bifida is a condition in which the spinal cord is not properly
closed and part of the contents of the spinal canal may protrude through this
opening.  In its mildest form, this condition may go undetected.  The lack of
closure may affect a very small area of the spine.   In the more severe form
of Spina Bifida, a sac (meningocele) may be present on the back containing
parts of the spinal canal.  Fluid may then accumulate in the cavities in the
brain, leading to hydrocephalus.  (For more information on this disorder,
choose "Spina Bifida" as your search term in the Rare Disease Database).

Arnold-Chiari syndrome is a rare disorder that is characterized by the
displacement of the brain stem (distal medulla).  The brain stem becomes
elongated and flattened and protrudes into the area of the upper spinal
canal.  In infants, Arnold-Chiari syndrome is associated with the presence of
a sac or hernia (myelomeningocele) from the spinal cord which may contain the
spinal cord and the membranes that surround the spinal cord (meninges).
Hydrocephalus is commonly present.  In infants, vomiting, mental impairment,
head and facial muscle weakness, and difficulties in swallowing may be
present.  (For more information on this disorder, choose "Arnold-Chiari" as
your search term in the Rare Disease Database).

Epilepsy is a disorder of the central nervous system.  It is
characterized by recurrent electrical disturbances in the brain.  Symptoms of
this disorder may include loss of consciousness, convulsions, spasms, sensory
confusion and disturbances in the autonomic nervous system.  Attacks are
frequently preceded by a feeling of uneasiness, discomfort or strange
behavior.  If the electrical disturbances or symptoms respond to medication,
the patient can expect an otherwise normal life.  Some types of epilepsy are
characterized by absent staring and an apparent disinterest in the
surrounding environment, which can happen repeatedly throughout the day.
Hydrocephalus can occur with or possibly result in epilepsy.  (For more
information on this disorder, choose "Epilepsy" as your search term in the
Rare Disease Database).

Meningitis is an infection that causes inflammation of the membranes that
surround the brain (meninges).  In its milder form, the cause is thought to
be viral.  Bacterial meningitis is generally a more severe disease.  Symptoms
may include a general feeling of ill health (malaise), nausea, abdominal
pain, and stiffness in the back and neck.  Meningitis can occur in
conjunction with hydrocephalus.  (For more information on this disorder,
choose "Meningitis" as your search term in the Rare Disease Database).

Encephalocele is a rare disorder in which an infant is born with a gap in
the skull.  The membranes that cover the brain (meninges), and the brain
tissue protrude through this gap.  Infants with an encephalocele may develop
hydrocephalus.  (For more information on this disorder, choose
"Encephalocele" as your search term in the Rare Disease Database).

Cardio-Facio-Cutaneous Syndrome is a rare disorder in which an infant is
born with multiple physical deformities and mental retardation.  The common
symptoms of this disorder include abnormal skin conditions (including patchy
and unusually dry skin), an unusual face, sparse and curly hair and heart
defects.  Infants with Cardio-Facio-Cutaneous syndrome have a characteristic
face in which the opening between the upper and lower eyelids slants
downward.  It is not uncommon for patients with this disorder to have an
excess amount of spinal fluid in the head causing a widening of the
ventricles of the brain (Hydrocephalus).  (For more information on this
disorder, choose "Cardio-Facio-Cutaneous Syndrome" as your search term in the
Rare Disease Database).

Walker-Warburg syndrome (WWS) is a very rare genetic disorder in which an
infant is born with congenital hydrocephalus, "smooth" brain tissue
(lissencephaly) that is greatly reduced in size, severe developmental
retardation and multiple brain malformations.  Developmental abnormalities if
the Retina (retinal dysplasia) also occur.  Walker-Warburg syndrome is also
known as HARD Syndrome +/-E.

Therapies:  Standard

Standard treatment for Hydrocephalus is the insertion of a shunt or tube into
the head cavity which drains the excess cerebrospinal fluid into a part of the
body that can absorb it.  In growing children the shunt may have to be
lengthened periodically.  Complications may arise if the shunt becomes clogged
or stops functioning.  At times a new shunt may have to be reimplanted.

Therapies:  Investigational

At the present time, there are several new surgical procedures being
perfected for the treatment of Hydrocephalus.  More research will be needed
to determine the safety and effectiveness of these procedures.

This disease entry is based upon medical information available through
September 1992.  Since NORD's resources are limited, it is not possible to
keep every entry in the Rare Disease Database completely current and
accurate.  Please check with the agencies listed in the Resources section for
the most current information about this disorder.

Resources

For more information on Hydrocephalus, please contact:

     National Organization for Rare Disorders (NORD)
     P.O. Box 8923
     New Fairfield, CT  06812-1783
     [phone]

     Hydrocephalus Parent Support Group
     225 Dickinson St., H-893
     San Diego, CA 92103

     National Hydrocephalus Foundation
     400 N. Michigan Ave., Suite 1102
     Chicago, IL  60611-4102

     Hydrocephalus Association
     870 Market St., Suite 955
     San Francisco, CA  94102
     [phone]

     NIH/National Institute of Neurological Disorders & Stroke (NINDS)
     9000 Rockville Pike
     Bethesda, MD  20892
     [phone]
     [phone]

     Association for Retarded Citizens of the U.S.
     P.O. Box 6109
     Arlington, TX  76005
     [phone]
     [phone]

For information on genetics and genetic counseling referrals, please
contact:

     March of Dimes Birth Defects Foundation
     1275 Mamaroneck Avenue
     White Plains, NY 10605
     [phone]

     Alliance of Genetic Support Groups
     35 Wisconsin Circle, Suite 440
     Chevy Chase, MD 20815
     (800) 336-GENE
     [phone]

References

MENDELIAN INHERITANCE IN MAN 9th Ed.:  Victor McKusick; Johns Hopkins
University Press, 1990.  Pp. 1248-1250, 1635-1636.

INTERNAL MEDICINE, 2nd Ed.:  Jay H. Stein, ed.-in-chief; Little Brown and
Co., 1987.  P. 2213

CECIL TEXTBOOK OF MEDICINE, 19th Ed.:  James B. Wyngaarden, and Lloyd H.
Smith, Jr., Editors; W.B. Saunders Co., 1990. Pp. 2223-2224.

HYDROCEPHALUS IN INFANCY AND CHILDHOOD, H.E. James; American Family
Physician (Feb. 1992; 45(2)).  Pp. 733-742.