Microcephaly (microcephaly) is a congenital malformation that leads to a reduction in the size of the head, and thus also of the brain. Consequently, microcephaly is often accompanied by features of intellectual disability, as well as other dysfunctions of the nervous system. What are the causes and symptoms of microcephaly? Is it possible to cure this developmental defect? ​​

Microcephaly( microcephaly ) iscongenital developmental defectleading to a decrease in the normal size of the head , and thus - the brain (in microcephaly, the weight of the brain is less than 900 g). Therefore, people with microcephaly in most cases show developmental delay (intellectual disability).

The head is measured right after delivery - between the area just above the browguard to the most posterior part of the occipital bone. If the measurement result is significantly lower than the established norm for a given age and gender, it means microcephaly.

The prevalence of microcephaly is estimated at around 1/1000 of people.

Microcephaly (microcephaly): causes

1. GENETIC FACTORS

  • numerical and structural chromosome aberrations, incl. trisomy, that is, the presence of an additional - third - chromosome. Therefore, microcephaly may appear in the course of diseases such as: Edwards' syndrome (trisomy 18), Down syndrome (trisomy 21 - moderate microcephaly) or Patau syndrome (trisomy 13), cat scream syndrome (5p deletion), Wolf's syndrome. Hirschhorn (4p deletion);
  • diseases conditioned by mutations of single genes, e.g. Rett syndrome, Seckel syndrome, Smith-Lemli-Opitz syndrome, familial autosomal dominant microcephaly, autosomal recessive familial microcephaly;
  • diseases conditioned by genetic predisposition and environmental factors (multifactorial diseases);

2. NONGENETIC FACTORS

  • non-infectious diseases of the central nervous system of the fetus in the pre- and postnatal period (ischemia and hypoxia, bleeding into the nervous system, perinatal injuries);

The cause of microcephaly may be the Zika virus, transmitted by tiger mosquitoes, warn the medical services of Brazil,where, since the beginning of 2015, 3,174 cases of the birth of children with microcephaly have been reported.

  • congenital intrauterine infections of the fetus (cytomegaly, toxoplasmosis, rubella, herpes);
  • chemicals and drugs (tobacco, alcohol, drugs - especially cocaine and opiates, some drugs, e.g. antiepileptic drugs, such as hydantoin or phenobarbital derivatives, carbamazepine);
  • maternal diseases (diabetes and maternal phenylketonuria - microcephaly is the most common and most serious complication in children of mothers suffering from this disease);
  • malnutrition;

Microcephaly (microcephaly): symptoms

Microcephaly is often associated not only with features of intellectual disability, but also with other disorders of the central nervous system. They can lead to them, among others intrauterine infections. For example, congenital cytomegaly is characterized, apart from microcephaly, by low birth weight, microgyria, microgyria, retinitis and choroiditis, hearing loss, and psychomotor retardation. In turn, congenital rubella is the cause of, among others, heart and middle ear defects as well as cataracts and skeletal system dysfunctions.

Research shows that alcohol consumption during pregnancy causes an almost 2-fold increase in the risk of microcephaly with accompanying other malformations. This includes the so-calledFetal Alcohol Syndrome , in which microcephaly coexists with significant cognitive dysfunctions, impaired physical development, and facial dysmorphic features.

In turn, women who smoked during pregnancy give birth to babies whose birth weight is 150-250 grams less than that of newborns from non-smoking mothers.

In contrast, infants of mothers taking more than one antiepileptic drug during pregnancy are more frequently observed, inter alia, serious malformations, intrauterine hypotrophy (abnormal growth of the baby in the womb), hypoplasia (insufficient development) of the middle part of the face and fingers.

Microcephaly (microcephaly): diagnosis

In addition to the physical examination (head measurement) and imaging (computed tomography of the head, magnetic resonance imaging), blood tests are also performed (to exclude infection). If genetically related microcephaly is suspected, the child is referred for karyotype testing.

Microcephaly (microcephaly): treatment

Treatment of microcephaly is not possible.

According to an expertbow. Maciej Pawłowski, resident doctor - paediatrics

Microcephaly is one of the more common clinical symptoms found in practicepediatric. They are found when the greatest circumference of the head (measured between the area just above the browguard to the most posterior occipital bone) is less than minus 3 standard deviations. The prevalence is estimated at about 1 / 1,000 newborns. The most common causes of microcephaly include: non-infectious diseases of the central nervous system of the fetus, congenital intrauterine infections of the fetus, chemicals / drugs, diseases of the pregnant mother and sociodemographic factors. Microcephaly can also be genetically determined, requiring karyotype analysis. Unfortunately, it often turns out that too small head circumference leads to intellectual disability and other dysfunctions of the central nervous system.

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