Developmental defects of the central nervous system

Central nervous system (CNS) malformations are a broad group of conditions that result from abnormalities in the developmental process of the brain and spinal cord. Knowledge of the underlying mechanisms is crucial for their early diagnosis and effective treatment. The development of the central nervous system in humans is a very complicated process. If there are abnormalities in organ differentiation at the embryonic stage, or if the structures of the nervous system mature at different rates at the fetal stage, CNS defects may develop. The incidence of most of these is believed to be multifactorial, with factors influencing their development:

- genetic,
- Infectious (rubella virus, influenza, mumps, hemiplegia, and the parasite toxoplasmosis),
- Physical (high temperature; ionizing radiation; mechanical trauma),
- chemical (drugs, such as valproic acid; toxins),
- environmental affecting the fetus during pregnancy (e.g., lack of nutrient supply to the fetus).

Depending on the week of gestation in which the teratogenic agent occurs, as well as on the duration of its effect on the fetus, various developmental defects of the central nervous system can develop. Determining their causes is very often impossible.

The risk of central nervous system disorders in infants increases:

- The presence of diabetes, circulatory disorders, ischemic heart disease in the mother;
- a history of pregnancy poisoning.

Since the various components of the central nervous system take a long time to develop, the incidence of CNS defects in newborns is high compared to other systems. It depends on ethnicity and environmental conditions, among other factors.

Disorders of the central nervous system are isolated defects, although they sometimes co-occur with defects of the heart, kidneys, abdominal shells or genital organs. They are among the most common nervous system disorders and account for 40% of all deaths in the first year of life. Children who survive a brain malformation can present neurological disorders of varying severity, drug-resistant epilepsy, psychomotor developmental delay, and intellectual disability.

The complex development of the CNS is responsible for a wide variety of developmental defects of the central nervous system in children. They can be divided into several groups:

Brain malformation syndrome:

- Brainlessness - involves the absence of the brain or most of its structures;
- Acrania - involves the absence of the bones of the skull lid; the brain is shielded only by soft meninges;
- Cerebral hernias - are defects in which the meninges and parts of the brain are protruded through a congenital opening in the skull;
- Cerebral hernia - results from a defect in the occipital bone and a failure to close the spine in the cervical and thoracic regions;
- True smallbrain - consists of primary underdevelopment of the cerebral hemispheres;
- Large-brained - involves an increase in the mass of the brain in all or part of it;
- Arnold-Chiari syndrome - involves displacement of the brainstem and medulla into the spinal canal;
- Absence of cerebral cortex - the apparent absence of furrows and corners of the cerebral cortex, resulting from impaired neuronal migration and associated with mental retardation;
- Agenesis/hypoplasia of the corpus callosum - various degrees of underdevelopment of the great cerebral spiracle (corpus callosum).

Congenital CNS defects of the spinal cord:

- Spinal epidural - in its typical form, consists of a lack of closure of the posterior laminae at any level of the spinal canal;
- Meningeal hernia - is the protrusion of the dura and arachnoid meninges through the cleft canal, while the spinal cord remains in the spinal canal;
- Meningeal hernia - involves the presence of a herniated sac with the spinal cord and/or its roots; the non-skinned surface of the meninges is in direct contact with the environment;
- Spinal herniation - consists of the spinal cord and its direct contact with the external lumen (no meningeal sac); there is a direct leakage of cerebrospinal fluid;
- Hydrocephalus - is a neurological condition characterized by accumulation of fluid in the central canal of the spinal cord;
- Spinal bifurcation - involves the division of the spinal cord into two separate structures corresponding to the two halves of the spinal cord. These are usually located in one, sometimes in two separate sacs of the dura;
- Cavernosity of the medulla - involves the presence of cavities in the medulla, usually located dorsal to the central canal;
- Hydrocephalus - involves an increase in the amount of cerebrospinal fluid throughout the fluid spaces, especially in the ventricles.

Each disease of the central nervous system is different and requires different management. The doctor's role is to determine the causes of the disorder and select the appropriate treatment method. In the case of a developmental defect of the central nervous system, drug treatment and physiotherapy are used. These are designed to stimulate the brain and help compensate for the child's developmental delays. It is also important to remember the right diet, rich in nutrients, to support the CNS.

We invite you to schedule a consultation at Paley European Institute - the European representative of the world-renowned center specializing, among other things, in the treatment of developmental defects of the central nervous system with a variety of symptoms. Serving children and adults from Poland and Europe, Paley European Institute offers comprehensive, coordinated care from an experienced team of specialists designed to meet the specific needs of each patient. Within pediatric orthopedics, we treat the most common developmental defects of the central nervous system.