Encephalocele

Encephalocele
Synonyms	Cranium bifidum
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Field	Neurosurgery, Pediatrics, Medical genetics
Symptoms	Visible sac-like protrusion on the head, hydrocephalus, developmental delay, seizures, vision problems
Complications	Neurological deficits, motor impairment, intellectual disability, infection
Onset	Present at birth
Duration	Lifelong (chronic condition)
Types	Frontal encephalocele, occipital encephalocele, parietal encephalocele, basal encephalocele
Causes	Failure of the neural tube to close completely during fetal development
Risks	Folate deficiency, maternal exposure to teratogens, family history of neural tube defects
Diagnosis	Prenatal ultrasound, MRI or CT scan after birth
Differential diagnosis	Meningocele, arachnoid cyst, dermoid cyst
Prevention	Adequate folic acid intake before and during pregnancy
Treatment	Surgical repair, supportive therapy, shunt placement if hydrocephalus is present
Medication	Symptomatic management (e.g. antiepileptic drugs for seizures)
Prognosis	Depends on size, location, and brain involvement; can range from mild to severe disability
Frequency	Rare; estimated incidence is 1 in 10,000 live births worldwide
Deaths	Can be fatal if severe or untreated

Neonate with encephalocele

Encephalocele, 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.

Signs and 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.

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. ^{(August 2015)}

Proper levels of folic acid have been shown to help prevent such defects when taken before pregnancy, and early in pregnancy.

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.

Classifications

Encephaloceles of the face are generally classified as nasofrontal, nasoethmoidal, or naso-orbital, however, there can be some overlap in the type of encephalocele. They can also appear along any part of the cranial vault, as they result from abnormal closure of cranial bones; the most common location for encephaloceles is the occipital region. If the bulging portion contains only cerebrospinal fluid and the overlying membrane, it may be called a meningocele. If brain tissue is present, it may be referred to as a meningoencephalocele. When the head size or occipitofrontal circumference is smaller than the herniating sac, then it is termed as giant encephalocele.

Prevention

It is recommended that women who may become pregnant take 400 micrograms of folic acid daily. ^{(December 2011)}

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.

Gallery

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  A neonate with a large encephalocele.

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  Encephalocele on the head of a two-year-old.

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  Baby with encephalocele.

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  Encephalocele.

See also

• Cephalic disorder
• Knobloch syndrome

External links

• encephaloceles at NINDS