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Meningoencephalocele


Other Names for this Disease

  • Encephalomeningocele
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Overview

What is meningoencephalocele?

What causes meningoencephalocele?

Is meningoencephalocele inherited?

What is the long-term prognosis for individuals with meningoencephalocele?

What is meningoencephalocele?

Meningoencephalocele is a type of encephalocele, which is an abnormal sac of fluid, brain tissue, and meninges (membranes that cover the brain and spinal cord) that extends through a defect in the skull.  There are two main types of meningoencephalocele, which are named according to the location of the sac. The frontoethmoidal type is located at the frontal and ethmoid bones while the occipital type is located at the occipital bone.  Hydrocephalus, abnormalities of the eyeball and tear duct, and other findings have been associated with the condition.[1][2] Some affected individuals have intellectual or physical disabilities while others have normal development and abilities.[3]  The condition is typically congenital (present at birth) but has been reported to develop by chance in older individuals in rare cases.[4] The underlying cause of the condition is uncertain, but environmental factors are thought to play a role. Treatment depends on the size, location and severity of the defect but mainly includes magnetic resonance imaging (MRI) to determine the severity of the defect, followed by surgery to repair it.[1][2]
Last updated: 8/27/2014

What causes meningoencephalocele?

The exact cause of meningoencephalocele is not known. Some studies have suggested that environmental factors could play a role in causing the condition. Exposure during pregnancy to aflatoxins, toxins produced by a mold that grows in nuts, seeds, and legumes, has been proposed to be a possible cause in some cases. However, its potential role in causing the condition is unclear. It has also been suggested that folate deficiency during pregnancy might play a role, because the condition is so closely related to spina bifida, which can be caused by folate deficiency. However, there have been no studies regarding the relationship of maternal folate deficiency and meningoencephalocele. Further studies are needed to to clarify what may cause the condition.[1]
Last updated: 9/21/2011

Is meningoencephalocele inherited?

Meningoencephalocele is not thought to be an inherited condition. Studies have proposed that meningoencephalocele is likely a multifactorial defect. This means that both environmental factors and multiple genes may interact with each other to cause the condition. Studies have suggested that environmental factors probably play an important role. This information is supported by the fact that several studies have not identified the condition among close relatives of affected individuals. To date, there have been no genes identified that are likely to play a strong part in causing the condition.[1]
Last updated: 9/21/2011

What is the long-term prognosis for individuals with meningoencephalocele?

The prognosis for each individual with meningoencephalocele depends on the size and location of the sac, whether brain tissue is present in the sac, and if other brain abnormalities are also present.[2]  Survival is generally better when brain tissue is not involved in the sac.[5]  Individuals with encephaloceles located in the face (at the frontal and nasal bones) tend to have better survival and development than those located at the back of the head (at the occipital and parietal bones).[6][5]  Several studies have found that approximately two-thirds (66%) of individuals with meningoencephalocele in the back of the head survive[5][2]; of those survivors, approximately half have normal intelligence.[5]  Infections, such as meningitis, may develop and could also affect the outcome.  

Following treatment, individuals with small meningoencephaloceles and no other brain abnormalities may survive and may not have major disabilities, while those with large and/or severe meningoencephaloceles have lower survival or may continue to suffer from intellectual and physical disabilities.
Last updated: 8/27/2014

References
  1. Sitthiporn Agthong and Viroj Wiwanitkit. Encephalomeningocele cases over 10 years in Thailand: a case series. BMC Neurology. 2002; 2:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC113760/?tool=pubmed. Accessed 9/19/2011.
  2. Kiymaz N, Yilmaz N, Demir I, Keskin S. Prognostic Factors in Patients with Occipital Encephalocele. Pediatric neurosurgery 2010. 2010; 46(1):6-11.
  3. Meling TR, Due-T√łnnessen BJ, Helseth E, Skjelbred P, Arctander K. [Frontoethmoidal meningoencephaloceles]. Tidsskr Nor Laegeforen. August 20, 2000; 120(19):2250-2252.
  4. Nahas Z. Spontaneous meningoencephalocele of the temporal bone: clinical spectrum and presentation. Arch Otolaryngol Head Neck Surg. May 1, 2008; 134(5):509-518.
  5. Mealey J, Dzenitis AJ, Hockey AA. The prognosis of encephaloceles. Journal of Neurosurgery. 1970; 32(2):209-218. http://www.ncbi.nlm.nih.gov/pubmed/5411997. Accessed 8/27/2014.
  6. Hoving EW. Nasal encephaloceles. Childs Nerv Syst. November 2000; 16(10-11):702-706.


Other Names for this Disease
  • Encephalomeningocele
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.