What is Encephalocele?
Encephalocele, also referred to as cranium bifidum, is a type of birth defect and occurs very rarely where there is defect in the neural tube. The neural tube is a narrow canal that folds up and closes during the third and fourth weeks of pregnancy to form the spinal cord and brain. When the neural tube fails to close completely during fetal development in pregnancy, it leads to neural tube defect. Encephalocele is a sac-like projection or protrusion of the brain and its covering membranes through the skull’s opening. This results in an opening, which can be present anywhere, commonly at the back of the head, along the midline of the skull from the nose to the posterior side of the neck, the top of the head, or between the forehead and the nose. Patient has groove running down in the centre of the skull, or between the nose and forehead or on the posterior side of the skull. The severity of encephalocele depends on its location.
Classification of Encephalocele
Facial encephaloceles are classified as nasofrontal, naso-orbital and nasoethmoidal. Encephalocele can also develop along any region of the cranial vault, as they form due to failure or abnormal closure of the cranial bones. There can also be some overlapping in the type of encephalocele. Occipital region is the most common site for encephalocele. If the protrusion contains only the overlying membrane and cerebrospinal fluid, then it is termed as meningocele. If the protrusion contains brain tissue in it, then it may be called as meningoencephalocele.
Signs & Symptoms of Encephalocele
Craniofacial abnormalities or other malformations of the brain commonly accompany encephalocele. Patient has symptoms which include:
- Neurological problems.
- Hydrocephalus, where there is accumulation of the cerebrospinal fluid in the brain.
- Microcephaly, a condition where the patient has an abnormally small head.
- Spastic quadriplegia, which is the paralysis of the limbs.
- Ataxia where the patient has uncoordinated gait and muscle movement.
- Vision problems.
- Developmental delay.
- Growth and mental retardation.
Causes of Encephalocele
The exact cause of encephalocele is not clear, but when the neural tube fails to completely close during fetal development, it leads to encephalocele. According to studies, teratogens, which are substances or agents that cause embryo malformation or birth defects; trypan blue, which is a stain; and arsenic can cause damage to the developing fetus and cause the formation of encephalocele.
There is an inherited or genetic factor to this condition also, where there is increased risk for encephalocele if neural tube defects, such as anencephaly and spina bifida run in the family. It is also thought that certain types of environmental exposures during or before the pregnancy can also cause encephalocele.
Taking adequate amount of folic acid before and during the pregnancy helps in preventing neural tube defects including encephalocele.
Diagnosis of Encephalocele
As encephaloceles are noticeable deformities, they are diagnosed right after birth. However, in some cases, a small encephalocele in the forehead or nasal region can remain undetected. Different types of mental and physical developmental delays may indicate that the patient has encephalocele. Encephalocele which is present at the back of the skull can cause more problems with the nervous system, as well as other facial and brain defects. Other signs of encephalocele which will help with the diagnosis are:
- Accumulation of CSF in the brain.
- Abnormally small head.
- Complete loss of strength in the arms and legs.
- Developmental and intellectual delay.
- Vision problems.
Treatment for Encephalocele
As of now, surgery is the only effective treatment for encephalocele, which is done during the child’s infancy. The protruding section of the brain and its membranes are pushed back into the skull and the opening in the skull is closed. This relieves the pressure, which is exerted and hinders normal development of the brain. The degree of correction of the encephalocele depends on its size and location. Large protrusions can be repaired without causing any major disability. In some cases, shunts can also be placed to help drain the excess cerebrospinal fluid that has accumulated in the brain. However, the child still can suffer from neurologic problems, which are caused by the encephalocele. The condition of the child determines the long-term treatment of encephalocele. More than one surgery may also be needed. It depends on the location of the encephalocele and the parts of the face and head affected by the encephalocele. Daily intake of 400 micrograms of folic acid in pregnancy helps in preventing neural tube defects, including encephalocele.
The Aim of Treatment for Encephalocele Includes:
- Closing the defective opening on the skin to prevent desiccation of brain tissue and infection.
- Removing the nonfunctional extracranial cerebral tissue along with performing water-tight closure of the dura.
- Complete craniofacial reconstruction with special attention on avoiding the long-nose deformity. If proper care during treatment is not done, then the long-nose deformity becomes more obvious after the surgical repair.
Outcome & Recovery from Encephalocele
It is difficult to predict the outcome and recovery before the surgery and it depends on the type and location of the encephalocele and the type of brain tissue, which is involved. If the reparative surgery is successful, and patient has not had any developmental delays, then the patient can continue to develop normally. When there already has been developmental and neurologic damage, then the doctor will concentrate on minimizing both the mental as well as physical disabilities. A complete recovery is possible if the bulging sac mainly consists of cerebrospinal fluid. If the encephalocele consists of large amount of brain tissue, the risk of perioperative complication is more.