Polymicrogyria: causes, symptoms and effects
Normally, during the normal development of the brain a series of folds or turns are formed that serve so that the surface of the brain occupies less space and fits inside the skull. Like any other organ, the brain also suffers malformations. An example of this is polymicrogyria, which affects the morphology of the cerebral cortex folds .
It is a disease that causes severe neurological symptoms due to the malformations that occur during fetal development. Let's see briefly what kind of training problems we find in polymicrogyria, what is its cause and what is possible to do with those people who suffer it.
What is the polimicrogiria?
The etymology of the word poly- (multiple) micro- (small) -giria (folds) indicates it clearly: it is a defect of the morphology in which a greater number of smaller folds is observed. This genetic defect of the cortex can be clearly observed through radiodiagnostic tests such as magnetic resonance imaging (MRI). In these images you can see how the cortex is thicker and more intense, indicating a higher density, and how the folds form superficially, different from that of a normal brain.
There are different forms of polimicrogiria, to which more serious. When it only affects one part of the brain, it is called unilateral. It is called bilateral, however, when both hemispheres are affected. The nomenclature does not refer only to symmetry, but also to how many areas of the brain are affected. Thus, a brain with only one affected area would suffer focal polimicrogiria, versus generalized polymicrogyria when it affects almost all or all of the cortex.
The polimicrogiria patterns have a predilection for some lobes over others . The lobes most frequently affected are the frontal lobes (70%), followed by the parietal lobes (63%) and then the temporal lobe (18%). Only a small portion (7%) has affected occipital lobes. Also, it seems that it tends to deform the lateral fissures that separate the frontal and parietal lobes from the temporal ones (60%) more frequently.
- Related article: "The lobes of the brain and its various functions"
Signs and symptoms
While focal and unilateral forms do not usually give more problems than controllable seizures through medication, when they are bilateral the severity of the symptoms soars. Some symptoms include:
- Epilepsy
- Delay of development
- Squint
- Speech and swallowing problems
- Muscle weakness or paralysis
The global affectations of polimicrogiria have profound mental retardation, serious movement problems , cerebral palsy and seizures impossible to control with medication. For this reason, while the milder forms of polymicrogyria allow a very long life expectancy, people who are born with a severe affliction die when they are very young due to the complications of the disease.
Often the polimicrogiria does not occur alone or purely, but together with other syndromes such as:
- Variants of Adams-Oliver syndrome
- Arima syndrome
- Galoway-Mowat syndrome
- Delleman syndrome
- Zellweger syndrome
- Fukuyama muscular dystrophy
Causes
In most cases the cause is unknown. There is a percentage of cases that occur because the mother suffers an intrauterine infection during pregnancy. Some viruses that are related to the development of polymicrogyria are cytomegalovirus, toxoplasmosis , syphilis and the varicella virus.
Hereditary causes include both chromosomal syndromes, that is, affecting several genes at the same time, as syndromes of a single gene. There are many genetic disorders that modify the way in which the brain is formed. Because of this, many genetic diseases are accompanied by polymicrogyria among other manifestations.
The GPR56 gene has been identified as one of the main causes of polymicrogyria in its global and bilateral versions. In one study it was found that all the patients examined had some modification in this gene, which resulted in an affectation of the central nervous system. It is known that this gene is very involved in the formation and development of the cerebral cortex of the fetus during its gestation.
Therefore, it is important that parents who suffer or are at risk of polymicrogyria are informed of the hypothetical risk of transmitting their disease to the child and determine through a genetic study what is the real probability of occurrence before starting pregnancy.
Management of the patient after diagnosis
After diagnosis through image, It will be necessary to carry out a complete evaluation in the domains affected by polymicrogyria . Paediatricians, neurologists, physiotherapists and occupational therapists must intervene to assess the risk of a developmental delay, intellectual disability or even cerebral palsy. In this sense, special educational needs will be indicated so that the patient can learn at the speed that their illness allows. Speech will be evaluated in those who have the affected lateral cleft, vision and hearing.
Symptoms will be treated through physiotherapy, pharmacological intervention with antiepileptic drugs, orthopedic products and surgery for patients suffering from stiffness due to muscle spasticity. When there are speech problems, a speech therapy and occupational intervention will be carried out.
Ultimately, parent training is a cornerstone of symptom management. It will be necessary to train them on issues related to how seizures occur and what to do when one occurs. Also, support measures can be used to prevent the appearance of joint problems or decubitus ulcers due to the patient sitting too long in the same position.
