NINDS Hydranencephaly Information Page: NINDS

Article title: NINDS Hydranencephaly Information Page: NINDS
Main condition: Hydranencephaly
Conditions: Hydranencephaly

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 poor. Death generally occurs before age 1.

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.

Selected references

Bradley, W, et al (eds).
Neurology in Clinical Practice: Principles of Diagnosis and Management. vol. I, 2nd edition, Butterworth-Heinemann, Boston, pp. 551, 553f (1996).

Dixon, A.
Hydranencephaly. Radiography, 54:613; 12-13 (January/February 1988).

Doi, H, et al.
The Use of Two-dimensional Doppler Sonography (Color Doppler) in the Diagnosis of Hydranencephaly. Child's Nervous System, 6; 456-458 (1990).

Hanigan, W, and Aldrich, W.
MRI and Evoked Potentials in a Child With Hydranencephaly. Pediatric Neurology, 4:3; 185-187 (1988).

Poe, L, and Coleman, L.
MRI of Hydranencephaly. American Journal of Neuroradiology, 10; S61 (September/October 1989).

Organizations

March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
resourcecenter@modimes.org
http://www.modimes.org/
Tel: 914-428-7100 888-MODIMES (663-4637)
Fax: 914-428-8203

National Organization for Rare Disorders (NORD)
P.O. Box 8923
(100 Route 37)
New Fairfield, CT 06812-8923
orphan@rarediseases.org
http://www.rarediseases.org/
Tel: 203-746-6518 800-999-NORD (6673)
Fax: 203-746-6481

This fact sheet is in the public domain. You may copy it.Provided by:
The National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892

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