Encephalocele

(medicine) Hernia of the brain through a congenital or traumatic opening in the cranium.

Definition

Encephaloceles refers to defects in the development of a fetal structure called the neural tube. The tube fails to close completely during development of the fetus, resulting in portions of the brain and its surrounding membranes that protrude from the skull in sac-like formations. Often, normal brain function is impaired and children with encephaloceles experience delays in development.

Description

In normal fetal development, the neural tube forms by the closure of the neural structure. When this does not occur in the case of an encephalocele, the result is a groove. The groove can form down the middle region of the upper part of the skull, or between the forehead and the nose, or down the back of the skull. The incomplete closure also creates areas where the brain and its overlaying membrane can bulge outward in sac-like protrusions. The larger deformities, in particular those that occur at the back of the skull, are readily evident and are recognized very soon after birth. These deformities are also associated with abnormal structure and functioning of the brain. Some encephaloceles are less evident, even to the point of being undetectable at birth. Defects in the region of the forehead and nose are examples.

Demographics

Encephaloceles occur rarely. At a rate of one per 5,000–10,000 live births, an encephalocele is less common than spina bifida, another neural tube defect. Geographical differences occur with respect to the type of encephalocele. Malformation of the back portion of the head is more common in Europe and North America, whereas involvement of the front portion of the head occurs more frequently in Southeast Asia, Malaysia, and Russia.

Causes and symptoms

The exact cause of encephaloceles is not yet known. The disorder is passed on from generation to generation, and is more prevalent in families where there is a history of spina bifida. It is clear that one or more genetic abnormalities lie at the heart of the condition. However, fetal development is an extremely complex process, with interactions between various genes, and influence of the external environment determining which genes are activated at which time. Thus, pinning down the crucial genes whose expression or changed activity produces abnormal neural tube formation is a difficult task.

Research using animal models has shown that teratogens, compounds like x rays, trypan blue, and arsenic, which can damage the developing fetus, cause encephaloceles in the animals. Whether exposure of a human fetus to such agents contributes to encephalocele formation in humans is not known.

Most often, the symptoms of encephaloceles are not difficult to recognize. These include the excessive build-up of cerebrospinal fluid in the brain (a condition called hydrocephalus), paralyzed arms and legs (spastic quadriplegia), an abnormally small head (microcephaly), difficulty in tasks like walking and reaching because of a lack of coordination (ataxia), delayed or impaired mental and physical development (although intelligence is not always affected), problems with vision, and seizures.

If the bulging portion contains only cerebrospinal fluid and the overlaying membrane, the malady can also be called a cranial meningocele or a meningocele. If brain tissue is also present, the malady can also be referred to as an encephalomeningocele.

Diagnosis

Diagnosis is based at the discovery of the physical abnormalities at birth or sometime later, and on the failure to attain the various physical and mental developmental milestones that are a normal part of early life.

Treatment team

Medical treatment involves family physicians, neurosurgeons, and nurses. Special education professionals, physical therapists, and caregivers are also an important part of the treatment team, as an affected person may require assistance in everyday activities throughout life.

Treatment

Treatment typically involves surgery. The surgery is usually accomplished soon after birth, and re-positions the bulging brain back into the skull, removes any of the sac-like protrusions, and corrects the skull deformities. Often, shunts are placed during surgery to drain excess cerebrospinal fluid from the brain. While delicate, the operation typically relieves the pressure that would otherwise impede normal brain development. Other treatment involves dealing with specific symptoms and producing as comfortable and satisfying everyday life as is possible.

Recovery and rehabilitation

Prospects for recovery are difficult to predict prior to surgery. Nonetheless, if surgery is successful, and other developmental difficulties have not occurred, an individual can develop normally. Where neurological and developmental damage has occurred, the focus shifts from recovery to maximizing mental and physical abilities.

Clinical trials

As of April 2004, no clinical trails for specific study of encephaloceles were being conducted. However, research is underway to more clearly define the mechanisms of brain development, and several clinical trials related to neural tube defects are recruiting participants. Updated information can be found at the National Institutes of Health clinical trials website at: http://clinicaltrials.gov.

Prognosis

As for recovery and rehabilitation, the prognosis is varies and cannot be predicted beforehand. In general, when the bulging material consists of mainly cerebrospinal fluid, a complete recovery can occur 60–80% of the time. However, the presence of brain tissue in the protruding material can reduce the chances of a complete recovery considerably.

Special concerns

Folic acid, a B vitamin, has been shown to help prevent neural tube defects when taken before and in early pregnancy. The March of Dimes organization and the United States Public Health Service recommend that all women who may become pregnant take a multi-vitamin that contains 400 micrograms of folic acid every day.

Resources

BOOKS

McComb, G. G., ed. Neural Tube Defects. American Association of Neurological Surgeons, 1998.

PERIODICALS

"Beaumont surgeons correct rare defect for Caribbean boy." Health Week (July 1, 2002): 17.

OTHER

NINDS Encephaloceles Information Page. National Institute of Neurological Disorders and Stroke. (April 7, 2004). http://www.ninds.nih.gov/health_and_medical/disorders/encephaloceles.htm

Prevention of Neural Tube Defects. The Arc. (April 10, 2004). http://www.thearc.org/faqs/folicqa.html

ORGANIZATIONS

Birth Defect Research for Children. 930 Woodcock Road, Suite 225. Orlando, FL 22808. (407) 895-0802 or (800) 313-2232; Fax: (407) 895-0824.

March of Dimes Birth Defects Foundation. 1275 Mamaroneck Avenue, White Plains, NY 10605. (914) 428-7100 or (888) 663-4637; Fax: (914) 428-8203. askus@ marchofdimes.com. http://www.marchofdimes.com.

National Institute for Neurological Diseases and Stroke (NINDS). 6001 Executive Boulevard, Bethesda, MD, 20892. (301) 496-5751 or (800) 352-9424. http://www.ninds.nih.gov.

National Organization for Rare Disorders. 55 Kenosia Avenue, Danbury, CT 06813-1968. (203) 744-0100 or (800) 999-6673; Fax: (203) 798-2291. orphan@rarediseases.org. http://www.rarediseases.org.

Brian Douglas Hoyle, PhD

Hernial protrusion of brain substance through a congenital or traumatic opening of the skull.

Encephalocele
Classification and external resources
A large encephalocele of a just born alive baby.
ICD-10	Q01.
DiseasesDB	29394
eMedicine	radio/246
MeSH	D004677

Encephalocele, sometimes known by the Latin name cranium bifidum, is a neural tube defect characterized by sac-like protrusions of the brain and the membranes that cover it through openings in the skull. These defects are caused by failure of the neural tube to close completely during fetal development. Encephaloceles cause a groove down the middle of the skull, or between the forehead and nose, or on the back side of the skull. The severity of encephalocele varies, depending on its location.^[1]

Contents 1 Classifications 2 Occurrence 3 Causes 4 Symptoms 5 Diagnosis 6 Treatment 7 Recovery 8 Notable cases 9 See also 10 References 11 External links

Classifications

Encephaloceles are generally classified as nasofrontal, nasoethmoidal, or naso-orbital, however, there can be some overlap in the type of encephalocele. If the bulging portion contains only cerebrospinal fluid and the overlaying membrane, it may be called a meningocele. If brain tissue is present, it may be referred to as an encephalomeningocele^[2].

Occurrence

Encephaloceles occur rarely, at a rate of one per 5,000 live births worldwide. Encephaloceles of the back of the head are more common in Europe and North America, while encephaloceles on the front of the head more frequently occur in Southeast Asia, Africa, Malaysia, and Russia. Ethnic, genetic, and environmental factors, as well as parental age, can all affect the likelihood of encephaloceles. The condition can occur in families with a family history of spina bifida^[3].

Causes

Although the exact cause is unknown, encephaloceles are caused by failure of the neural tube to close completely during fetal development. Research has indicated that teratogens (substances known to cause birth defects), trypan blue (a stain used to color dead tissues or cells blue), and arsenic may damage the developing fetus and cause encephaloceles.

Symptoms

Encephaloceles are often accompanied by craniofacial abnormalities or other brain malformations. Symptoms may include neurologic problems, hydrocephalus (cerebrospinal fluid accumulated in the brain), spastic quadriplegia (paralysis of the limbs), microcephaly (an abnormally small head), ataxia (uncoordinated muscle movement), developmental delay, vision problems, mental and growth retardation, and seizures.

Diagnosis

Usually encephaloceles are noticeable deformities and are diagnosed immediately after birth, but a small encephalocele in the nasal or forehead region can go undetected. Various physical and mental developmental delays can indicate the presence of encephaloceles.

Baby with encephalocele comes to Children's Hospital Boston for surgery	Child is prepped for surgery	Facial dissection of patient to remove encephalocele	Skull of same child with unrepaired encephalocele
Repaired skull	Tumor removed from patient	Patient post-surgery

Treatment

Currently, the only effective treatment for encephaloceles is reparative surgery, generally performed during infancy. The extent to which it can be corrected depends on the location and size of the encephaloceles; however large protrusions can be removed without causing major disability. Surgery repositions the bulging area back into the skull, removes the protrusions, and corrects the deformities, typically relieving pressure that can delay normal brain development. Occasionally, shunts are placed to drain excess cerebrospinal fluid from the brain.

The goals of treatment include:

• closure of open skin defects to prevent infection and desiccation of brain tissue
• removal of nonfunctional extracranial cerebral tissue with water-tight closure of the dura
• total craniofacial reconstruction with particular emphasis on avoiding the long-nose deformity (nasal elongation that results from depression of the cribiform plate and nasal placode). Without proper management, the long-nose deformity can be more obvious after repair^[4].

Proper levels of folic acid have been shown to help prevent such defects when taken before pregnancy, and early in pregnancy. It is recommended that women who may become pregnant take 400 micrograms of folic acid daily.

Baby with encephalocele	Same baby is prepaired for surgery at Children's Hospital Boston	Skull with encephalocele	cast of skull with encephalocele
Child's skull is surgically repaired	Same patient in Children's Hospital Boston Plastic Surgery operating room	Post encephalocele removal	After a period of healing from surgical removal of encephalocele

Recovery

Recovery is difficult to predict prior to surgery, and depends on the type of brain tissue involved and location of the encephaloceles. If surgery is successful, and developmental delays have not occurred, a patient can develop normally. Where neurologic and developmental damage has occurred, the specialists will focus on minimizing both mental and physical disabilities.

In general, when the bulging material consists of primarily cerebrospinal fluid, a complete recovery can occur. When a large amount of brain tissue is present in the encephaloceles, there is a higher chance of perioperative complication.

Notable cases

In November 2006, there was an hour-long documentary on the British television network Channel 4 about Facing the World, an organization that helps children with severe facial disfigurements in developing countries. One of the children featured on the documentary was Ney, a Cambodian boy who suffered from a severe form of encephalocele, wherein part of his brain protruded through his face.

In August 2008, Partners in Health along with surgeons in the Department of Plastic Surgery at Children's Hospital Boston brought a young boy named Dumanel Luxama from his home in Haiti to Boston for the repair of a frontal encephalocele as well as an arachnoid cyst. Dumanel and his father's trip to Boston was covered extensively by the Boston Globe, and his case was presented in a live webcast that aired on January 28 2009. Participating in the webcast and providing expert commentary were Dr. John Meara, Plastic Surgeon-in-Chief at Children's Hospital Boston, Dr. Edward Smith, Neurosurgeon at Children's Hospital Boston, and Dr. David Walton. Dr. Walton works with Partners in Health and was part of the team that arranged for Dumanel and his father's transportation to the United States.

See also

• Cephalic disorder

References

This article includes a list of references or external links, but its sources remain unclear because it has insufficient inline citations. Please help to improve this article by introducing more precise citations where appropriate. (July 2009)

1. ^ NINDS Encephaloceles Information Page, NINDS, February 12, 2007 . Retrieved on 2007-09-26.
2. ^ http://emedicine.medscape.com/article/403308-overviewAugust 21, 2009 . Retrieved on 2009-08-21.
3. ^ http://www.childrenshospital.org/az/Site833/mainpageS833P0.htmlAugust 21, 2009 . Retrieved on 2009-08-21.
4. ^ http://journals.lww.com/jcraniofacialsurgery/Fulltext/2001/01000/Frontoethmoidal_Encephaloceles__Reconstruction_and.3.aspx#,August 21, 2009 . Retrieved on 2009-08-21.

External links

• encephaloceles at NINDS
• Overview at ucsf.edu
• Surgical procedure done to repair an encephalocele at Children's Hospital Boston - Webcast
• The chance of two lifetimes Boston Globe
• A gift for an ailing Haitian boy: 2 cows Boston Globe

v • d • e Congenital malformations and deformations of nervous system (Q00-Q07, 740-742) Brain Neural tube defect Anencephaly (Acephaly, Acrania, Iniencephaly) · Encephalocele · Arnold-Chiari malformation Other Microcephaly · Congenital hydrocephalus (Dandy-Walker syndrome) other reduction deformities (Holoprosencephaly, Lissencephaly, Pachygyria, Hydranencephaly) Septo-optic dysplasia · Megalencephaly CNS cyst (Porencephaly, Schizencephaly) Polymicrogyria (Bilateral frontoparietal polymicrogyria) Spinal cord Neural tube defect Spina bifida · Rachischisis Other Currarino syndrome · Diastomatomyelia · Syringomyelia central nervous system navs: anat/physio/dev, noncongen/congen/neoplasia, symptoms+signs/eponymous, proc

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