What is Hydranencephaly?
Hydranencephaly is a rare condition in which the brain’s cerebral hemispheres
are absent and replaced by sacs filled with cerebrospinal fluid. An infant with
hydranencephaly may appear normal at birth. The infant’s head size and
spontaneous reflexes such as sucking, swallowing, crying, and moving the arms
and legs may all seem normal. However, after a few weeks the infant usually
becomes irritable and has increased muscle tone. After a few months of life,
seizures and hydrocephalus (excessive accumulation of cerebrospinal fluid in the
brain) may develop. Other symptoms may include visual impairment, lack of
growth, deafness, blindness, spastic quadriparesis (paralysis), and intellectual
deficits. Hydranencephaly is considered to be an extreme form of porencephaly (a
rare disorder characterized by a cyst or cavity in the cerebral hemispheres) and
may be caused by vascular infections or traumatic disorders after the 12th week
of pregnancy. Diagnosis may be delayed for several months because early behavior
appears to be relatively normal. Some infants may have additional abnormalities
at birth including seizures, myoclonus (spasm or twitching of a muscle or group
of muscles), and respiratory problems.
Is there any treatment?
There is no definitive treatment for hydranencephaly. Treatment is symptomatic
and supportive. Hydrocephalus may be treated with a shunt (a surgically
implanted tube that diverts fluid from one pathway to another).
What is the prognosis?
The outlook for children with hydranencephaly is generally poor, and many
children with this disorder die before age 1. However, in rare cases, children
with hydranencephaly may survive for several years or more.
What research is being done?
The NINDS conducts and supports a wide range of studies that explore the complex
mechanisms of normal brain development. The knowledge gained from these
fundamental studies provides the foundation for understanding how this process
can go awry and, thus, offers hope for new means to treat and prevent
developmental brain disorders, including hydranencephaly.
Organizations
March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
askus@marchofdimes.com
http://www.marchofdimes.com
Tel: 914-428-7100 888-MODIMES (663-4637)
Fax: 914-428-8203
National Organization for Rare Disorders (NORD)
P.O. Box 1968
(55 Kenosia Avenue)
Danbury, CT 06813-1968
orphan@rarediseases.org
http://www.rarediseases.org
Tel: 203-744-0100 Voice Mail 800-999-NORD (6673)
Fax: 203-798-2291
National Dissemination Center for Children with Disabilities
U.S. Dept. of Education, Office of Special Education Programs
P.O. Box 1492
Washington, DC 20013-1492
nichcy@aed.org
http://www.nichcy.org
Tel: 800-695-0285
Fax: 202-884-8441
Source: National Institutes of Health; National Institute of
Neurological Disorders and Stroke
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