The symptoms of an encephalocele can vary from one individual to another depending upon many different factors including size, location and the amount and kind of brain tissue protruding from the skull. Encephaloceles are congenital malformations i.e. present at birth. The location of the encephaloceles is very important since there are distinct clinical implications for treatment and prognosis for anterior and posterior encephaloceles. Posterior encephaloceles are more often associated with neurological problems. Encephaloceles toward the front of the skull usually do not contain brain tissue and generally have a better prognosis.
Most registries and epidemiological studies classify encephaloceles using broad categories like frontal, parietal, occipital and sphenoidal.
The most common area of skull for the development of an encephalocele is the upper portion from the forehead to the lower back of the skull in the area of the occipital bone. Encephaloceles can also occur near the sinuses, forehead and nose or near the base of the skull.
Symptoms that can develop include delays in reAching developmental milestones, intellectual disability, learning disabilities, growth delays, seizures, vision impairment, uncoordinated voluntary movements (ataxia), and hydrocephalus, a condition in which excess cerebrospinal fluid in the skull causes pressure on the brain. Hydrocephalus can result in a variety of symptoms. Some affected individuals develop microcephaly, a condition that indicates that head circumference is smaller than would be expected for an infant’s age and sex. Also in some cases, affected individuals experience progressive Weakness and loss of strength in the arms and legs due to increased muscle tone and stiffness (spastic paraplegia). However it is important to note that not all affected individuals may have the symptoms discussed above and some children may have normal intelligence, while others experience intellectual disability. Parents should talk to their child’s physician and medical team about their specific case, associated symptoms and overall prognosis.
In some cases, encephaloceles occur in association with other neurological conditions such as Dandy-Walker malformation or Chiari malformation. Dandy-Walker malformation is a brain malformation with partial or complete absence of the cerebellar vermis and enlargement of the fourth ventricle. Chiari malformation of the brain is characterized by a downward displacement of the cerebellar tonsils through the opening at the base of the skull (foramen magnum) which may result in the obstruction of cerebrospinal fluid (CSF) circulation leading sometime to a non-communicating hydrocephalus.
According to data from the Metropolitan Atlanta Congenital Defects Program, the majority of deaths of children with encephalocele occurred during the first day of life and the estimated survival probability to 20 years of age was 67.3%, In addition, factors associated with increased mortality were low birth weight, presence of multiple defects instead of single defect, and Black or African American ancestry.