Definition

Encephalocele is a disorder of neural tube closure that affects the brain. It can be visible at birth, appearing as a sac connected to the head containing brain tissue and its membranes. Encephalocele occurs in 1 out of 10,000 live births. Its incidence is higher in developing countries compared to developed ones.

Causes

The neural tube is a narrow canal that folds and closes during the third to fourth week of pregnancy to form the brain and spinal cord. If the closure of the neural tube is disrupted due to various factors, various disorders can occur. These disorders may include encephalocele, meningocele (a sac outside the head containing brain membranes), spina bifida (a disorder of neural tube closure in the spinal cord), and anencephaly (failure of the formation of the brain, cerebellum, and skull bones). Disorders of neural tube closure can be caused by genetic and environmental factors. Genetic factors can be exacerbated by consanguineous marriage and a history of pregnancies with neural tube closure disorders. Environmental factors may include infections during pregnancy, such as TORCH infections (toxoplasmosis, rubella, cytomegalovirus, herpes simplex). There are more than 30 syndromes (a collection of signs and symptoms that may be related to each other as part of a disorder or disease) associated with encephalocele.

Disorders of neural tube closure resulting in encephalocele can occur at the front and back of the head. Based on the location of encephalocele, accompanying abnormalities can occur in the brain and surrounding tissues.

Risk factor

Encephalocele is more likely to occur in families with a history of other neural tube closure disorders such as spina bifida and anencephaly. Infections during pregnancy also increase this risk, especially TORCH infections. Individuals with encephalocele are at risk of death if born premature, have low birth weight, and have other body abnormalities.

Symptoms

Encephalocele can be recognized as a mass or lump on the front or back of the head covered by skin. Based on the location, encephalocele is divided into two types: anterior (front) encephalocele and posterior (back) encephalocele.

Anterior encephalocele may involve the nasal bridge, the middle of the eyebrows, and the middle of the eyes. If it involves the inside of the nose, this type of encephalocele may cause several symptoms, such as:

• Blocked nose
• Snoring
• Leakage of brain fluid near the brain (also known as cerebrospinal fluid, which is clear and has a liquid texture)
• Leakage of clear fluid from the nose (which is actually cerebrospinal fluid leaking)

Posterior encephalocele usually occurs above the nape of the neck. In this type of encephalocele, several symptoms may occur, such as:

• Abnormal facial shape and wide distance between the eyes (hypertelorism)
• Seizures
• Leakage of clear fluid from the nose or ears

Diagnosis

Diagnosis of encephalocele can begin with a physical examination. A protruding mass from the head, when illuminated, may appear translucent. This occurs when the sac contains a lot of fluid such as cerebrospinal fluid. 

Subsequently, imaging tests can be performed, such as magnetic resonance imaging (MRI) to visualize the tissues inside the sac protruding from the head, or computed tomography (CT) scans to view missing parts of the skull and excessive fluid in the brain (hydrocephalus). If brain tissue enters the nose, direct examination may show results similar to nasal polyps. However, nasal polyps are very rare in babies, so the presence of a mass inside the nose in a baby may raise suspicion of encephalocele.

Diagnosis of encephalocele can also be made during pregnancy. The preferred examination is ultrasound (USG), which is performed between the 9th and 11th weeks of pregnancy. In the USG examination, a fluid-filled sac penetrating the skull bones may be visible. If this examination is repeated in the 13th week of pregnancy, this sac may be filled with brain membranes alone (meningocele) or with brain tissue as well (encephalocele). Additionally, other examinations that can be performed include genetic testing to detect genetic abnormalities.

If the USG examination suggests the possibility of encephalocele, examinations of other organs may also be conducted to determine the possibility of syndromes present in the fetus.

Management

The management of encephalocele is surgical. The goal of surgery is to close the opening in the skull and the layers beneath it, remove excess skin tissue and remove non-functional brain tissue. If surgery is performed on a baby or child with anterior encephalocele, the facial bones will eventually form on their own. However, if the distance between the eyes is too wide, surgery may be performed to correct facial shape and eye position. Surgery is usually performed openly but can be done with endoscopic tools if it involves the area near the nose.

Surgery is performed depending on the size, location, associated complications, and the presence of skin covering the encephalocele. If there is a protective skin layer, surgery may be postponed for several months or years. Usually, surgery is performed at the age of 2-3 years. Meanwhile, if there is no protective skin layer covering the encephalocele, surgery should be performed immediately after birth. If the encephalocele occurs at the base of the head, surgery is better performed quickly to prevent infection and brain tissue from entering the nose.

Closure of the skull bones is done using self-transplantation (autologous) bone, titanium, and other materials. However, if the skull hole is small, closure may not be necessary.

Complications

The most common complications of encephalocele are leakage of cerebrospinal fluid from the nose and/or ears and meningitis. Meningitis or infection of the brain membranes can be characterized by fever, headache, seizures, and decreased consciousness. Other complications of encephalocele include seizures, excessive cerebrospinal fluid in the brain (hydrocephalus), and growth and developmental disturbances or delays.

Prevention

Encephalocele may not be preventable, but several related conditions can be avoided, such as infections during pregnancy. The following steps can be taken to prevent infections during pregnancy:

• Protect yourself from Zika infection. If you are pregnant, avoid traveling to areas with high rates of Zika infection.
• Regularly wash your hands, especially after using the bathroom, handling raw meat, eggs, or vegetables, preparing and eating food, touching soil, playing with pets, contacting sick people, being exposed to saliva, playing with or caring for young children, and changing diapers.
• Reduce contact with baby or young child's saliva and urine, as they may contain cytomegalovirus (CMV), which can cause inhibited brain growth and deafness in fetuses. This can be done by not sharing food and utensils with babies and young children and washing hands after changing diapers.
• Avoid unpasteurized dairy products. Unpasteurized dairy products may contain bacteria harmful to fetuses.
• Do not touch or clean cat feces, as they may contain toxoplasma, a parasite that can affect fetuses. If you must clean the feces yourself, use gloves and wash your hands afterwards.
• Stay away from rodents, both pets and wild, such as rats, hamsters, and guinea pigs, as they may carry lymphocytic choriomeningitis virus (LCMV).
• Visit the nearest healthcare facility for screening for sexually transmitted diseases such as HIV, hepatitis B, syphilis, gonorrhea, and others. These diseases sometimes do not cause symptoms, so their presence is often unknown. Early screening before pregnancy is excellent for ensuring a safe pregnancy.
• Visit the nearest healthcare facility for vaccinations, such as tetanus vaccination, which is essential to fulfill before pregnancy and childbirth.
• Avoid contact with infected individuals, regardless of the type of infection. Rubella, for example, can cause fever accompanied by a rash, but not always. However, this virus is very dangerous for fetuses as it can cause congenital abnormalities.

When to see a doctor?

Seek medical attention promptly if your child has a mass protruding from the head since birth. This mass could be an encephalocele, but it could also be caused by other factors. Management may be possible immediately or may require some time, and this should be discussed with a doctor. Untreated encephalocele can result in a range of complications from cosmetic issues to life-threatening meningitis.

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