Colpocephaly is a cephalic disorder involving the disproportionate enlargement of the occipital horns of the lateral ventricles and is usually diagnosed early after birth due to seizures. It is a nonspecific finding and is associated with multiple neurological syndromes, including agenesis of the corpus callosum, Chiari malformation, lissencephaly, and microcephaly. Although the exact cause of colpocephaly is not known yet, it is commonly believed to occur as a result of neuronal migration disorders during early brain development, intrauterine disturbances, perinatal injuries, and other central nervous system disorders. Individuals with colpocephaly have various degrees of motor disabilities, visual defects, spasticity, and moderate to severe intellectual disability. No specific treatment for colpocephaly exists, but patients may undergo certain treatments to improve their motor function or intellectual disability.
Symptoms
There are various symptoms of colpocephaly and patients can experience effects ranging from mild to severe. Some patients do not show most of the symptoms related to colpocephaly, such as psychomotor abnormalities and agenesis of the corpus callosum. In some cases, signs appear later on in life and a significant number of children only develop minor disabilities. The following list includes common symptoms of colpocephaly.
partial or complete agenesis of the corpus callosum
intellectual disability
motor abnormalities
visual defects such as, crossing of the eyes, missing visual fields, and optic nerve hypoplasia spasticity seizures cerebral palsy
Intracranial abnormalities include:
Microcephaly
Agenesis of the corpus callosum
Meningomyelocele
Lissencephaly
Periventricular leukomalacia (PVL) Enlargement of the cisterna magna Cerebellar hypoplasia
Causes
There is no known definitive single mechanism that causes colpocephaly. However, researchers believe there are many possible causes of colpocephaly. It is a common symptom of other neurological disorders in newborns, can be caused as a result of shunt treatment of hydrocephalus, developmental disorders in premature infants, due to intrauterine disturbances during pregnancy, genetic disorders, underdevelopment or lack of white matter in the cerebrum, and exposure of the mother and the developing fetus to medications, infections, radiation, or toxic substances. Also, it is usually more common in premature infants than in full-term infants, especially in babies born with hypoxia or lung immaturity.
Some of the central nervous system disorders which are associated with colpocephaly are as follows: polymicrogyria Periventricular leukomalacia (PVL) intraventricular hemorrhage Hydrocephalus schizencephaly microgyria microcephaly Pierre-Robin syndrome Neurofibromatosis
Often colpocephaly occurs as a result of hydrocephalus. Hydrocephalus is the accumulation of cerebrospinal fluid (CSF) in the ventricles or in the subarachnoid space over the brain. The increased pressure due to this condition dilates occipital horns causing colpocephaly.
The most generally accepted theory is that of neuronal migration disorders occurring during the second to fifth months of fetal life. Neuronal migration disorders are caused by abnormal migration, proliferation, and organization of neurons during early brain development. During the seventh week of gestation, neurons start proliferating in the germinal matrix which is located in the subependymal layer of the walls of the lateral ventricles. During the eighth week of gestation, the neurons then start migrating from the germinal zone to cortex along specialized radial glial fibers. Next, neurons organize themselves into layers and form synaptic contacts with other neurons present in the cortex. Under normal conditions, the neurons forming a germinal layer around ventricles migrate to the surface of the brain and form the cerebral cortex and basal ganglia. If this process is abnormal or disturbed it could result in the enlargement of the occipital horns of the lateral ventricles. Common prenatal disturbances that have been shown to disturb the neuronal migration process include the following:
continuation of oral contraceptives
exposure to alcohol
intrauterine malnutrition
intrauterine infections such as toxoplasmosis
maternal drug ingestion during early pregnancy such as corticosteroids, salbutamol, and theophylline Researchers also believe that these factors can cause destruction of neural elements that have previously been normally formed.