INTRODUCTION TO NEURAL TUBE DEFECTS (NTD)

Neural tube defects ( NTDs ) are abnormalities that can occur in the developing brain, spinal cord, or spine.

Discovered very early in fetal development, certain cells form a tube (called a neural tube) that later becomes the spinal cord, brain and nearby structures that protect it. they, including the backbone (also called the spine or vertebra). As development progresses, the upper part of the tube becomes the brain and the rest becomes the spinal cord. An NTD occurs when the tube does not close completely somewhere along its length, resulting in a hole in the spine or another type of problem.  

These defects occur during the first month of pregnancy, usually before the woman knows she is pregnant. Because they are present at birth, they are classified as birth defects .   

There are several types of neural tube defects ( NTD ) , described here.

* Spina bifida

Spina bifida is the most common type of NTD. It occurs when the neural tube does not close completely. Infants with spina bifida often suffer from nerve paralysis below the affected area of ​​the spinal cord, which can cause lifelong problems with mobility and other difficulties. Because the bladder and bowel function is controlled by the lowest spinal nerves, bowel and urinary dysfunction is common with spinal spine disease. Many babies with spina bifida have normal intelligence, but some children will have learning or intellectual disabilities . There are several common types of spine spinal disease:           

– Spina bifida Occulta is the lightest form. In fact, it’s so light that most experts don’t consider it a real consumer. With this condition, there is a small space in the spine but no openings or pockets in the back. The nerves and spinal cord are not damaged, and defects often do not cause any defects. Therefore, sometimes spinal bony disease is sometimes called obscured muscle.      

– A closed neural tube defect is a malformation of the fat, bone or lining in the spine. In some people, closed NTD causes little or no symptoms, but others may be partially paralyzed or other symptoms. In some cases, the only external sign of a closed consumer may be a dimple or a bun in the spine.    

– Meningocele describes cases in which a fluid bag protrudes through a hole in the back, but the spinal cord is unrelated or damaged. For this reason, some people with meningocele will have no symptoms, while some people will have more serious problems.  

– Myelomeningocele is the most severe form and is also the most common form of spinal spine disease. In this condition, the bones of the spine are not fully formed, which causes some of the spinal cord and tissues covering the spinal cord to bulge out of a hole in the back. A person with this disease often has partial or complete paralysis in parts of the body below the spinal problem. Intestinal and urinary problems are common. Children with marrow can also have hydrocephalus (excess fluid in the brain), which can lead to learning and mental retardation. Some babies with myelosuppression have serious intellectual disabilities .        

* Anencephaly

Anencephaly is a more serious type of NTD, but less common. This condition occurs when the neural tube does not close at the head. As a result, most or all of the brain is missing, and parts of the skull may also be missing. Babies with this condition are often unconscious and deaf, blind and unable to feel pain because the brain structures associated with those functions do not exist. They may have reflexive actions, such as breathing and reaction. Infants with brain disease or die prematurely or die shortly after birth.      

* Encephalocele

Encephalocele another rare type of NTD, which occurs when the tube doesn’t close near the brain and has an opening in the skull. The brain and membrane covering it can protrude through the skull, forming a sac-like bulge. In some cases, only a small hole in the nasal cavity or the frontal area is not noticeable. Babies with brain disease may have other problems, such as hydrocephalus, paralysis of limbs, developmental delays, mental retardation, seizures, vision problems, head abnormalities, face and skull and inconsistent movements (ataxia). Although there are many different developmental disabilities and effects, some children with this disease have normal intelligence.    

* Iniencephaly

Iniencephaly, another rare but serious NTD, describes a head that is bent backwards. The spine is specially deformed. Usually, babies lack a neck, with the face skin connected to the chest and scalp connected to the back. Other abnormalities may also exist, such as cleft lip and palate, cardiovascular abnormalities, psychosis and malformed bowels. Babies with this disease usually do not live longer than a few hours.    

What are the symptoms of neural tube defects?

The symptoms associated with neural tube defects ( NTD ) vary depending on the specific type of defect. 

Symptoms include physical problems (such as paralysis and urinary and bowel control issues), blindness, deafness, mental retardation, lack of consciousness and, in some cases, death. Some people with NTD have no symptoms. Most children with certain types of consumers die or become severely disabled.  

What causes neural tube defects (NTD)?

The exact cause of neural tube defects ( NTD ) is not known. Many different factors, including genetics, nutrition and environmental factors, all play a role. 

Research shows that getting enough folic acid (also known as folate or vitamin B9) before conception and early in pregnancy can significantly reduce the risk of spinal cord disease and other NTD.

In addition, evidence suggests that women who are obese, have poorly controlled diabetes, or take certain anti-seizure medications, such as phenytoin (Dilantin), carbamazepine (Tegretol) and valproic acid (Depakote) or antifolate. (like aminopterin) the risk is higher than for other women who have a baby with spina bifida or encephalopathy.

Some studies have shown that NTD and miscarriage are more common in women who have high temperatures (such as using a hot tub or sauna or have a fever) in the first 4 to 6 weeks of pregnancy. . For this reason, healthcare providers often advise women who may be pregnant or pregnant to avoid using hot tubs or saunas. 

How many people are at risk for neural tube defects (NTD)?

NTD is a major cause of death and disability throughout the world. Parents who have a child with spine spondylitis or other NTD are at a slightly higher risk (less than 5%) compared to other parents with a second child with spine spine. Families with two children with spine spine have 1 in 10 chance of having another child with this condition. To help prevent NTD in later pregnancies, health care providers may recommend higher amounts of folic acid for these women, starting well before conception.  

How do healthcare providers diagnose neural tube defects (NTD)?

NTD is usually diagnosed during pregnancy, through imaging tests or tests.

Prenatal laboratory tests may include:

– Blood tests triple test : A blood test part of the triple test search for alpha-fetoprotein levels (AFP) increases, related to a higher risk of NTD. AFP testing can also be done by itself . The other two parts of the triple test involve testing of human chorionic gonadotropin (hCG) and estriol. This test is usually done during the second trimester.     

– Amniotic fluid test Amniotic fluid test can also show high levels of AFP, as well as high levels of acetylcholinesterase. Health care providers can perform this test to confirm the high AFP level seen in a triple test . Amniotic fluid can also be checked for chromosomal abnormalities, which can also be a cause of abnormal AFP levels.    

Prenatal ultrasound images often detect most types of NTD.

As soon as an infant with NTD is diagnosed or suspected, the health care provider will perform tests to assess the severity of the consumer and any complications. These tests may include x-rays, magnetic resonance imaging (MRI), computerized tomography (CT or CAT) exams for spinal defects or excess fluid ; measuring head circumference; evaluate the power, movement and sensory function of newborns; and observe the infant’s urine stream.    

People with milder spine spines may not be diagnosed until later in childhood or in adulthood.

Infants with NTD may have other conditions that require treatment. Such conditions vary from infant to infant, and some developmental conditions must either be addressed over time or later in life. 

The most serious problems tend to develop in newborns with myelosuppression, the most severe form of spinal cord disease. A. Conditions relating may include the following.

Hydrocephalus

Many babies with spina bifida have fluid that builds up in and around the brain, a condition called hydrocephalus. Excess fluid can cause swelling that pushes some brain structures against the skull or away from where they are usually located, which can lead to brain injury. 

Chiari II malformation

In many children with myelosuppression, the brain is abnormal located. The lower part of the brain is farther than usual, partly in the upper spinal canal. This abnormal position can block cerebrospinal fluid and cause hydrocephalus. Although most affected children do not have any other symptoms, a few may develop upper muscle weakness, difficulty breathing and swallowing.   

Spinal cord forced

Unlike a normal spinal cord, freely floating in the spinal canal, in the spine, the spinal cord is attached to the spinal cord. This means that the spinal cord stretches as a person grows, which can cause spinal nerve damage. The person may have back pain, scoliosis (scoliosis), weakness in the legs and feet, bladder or bowel control problems and other problems.  

Paralysis and restraint in movement

People with high spina bifida (for example near the head) may not be able to move their legs, torso or arms. People with low spine spines in the back (for example, near the hip) may have some foot movement and may walk unsupported or with crutches, braces or walking. 

Lack of bladder and bowel control

People with spinal spine usually cannot control their bladder or intestinal motility. They may also have a urinary tract infection. 

Latex allergy

Many people with spine spine may have three-quarters of those with allergies to latex or natural rubber. Although researchers still do not fully understand why this rate is so high, some experts believe that regular exposure to latex can cause allergies. Latex exposure is common among people with shunt who have undergone multiple surgeries.  

Learning disabilities

Studies have shown a large change in deficit related to learning disabilities in patients with spinal cord disease. These include intellectual disabilities, non-standard scores on certain types of memory tests, and tasks related to executive function and non-verbal learning issues. This syndrome shares some of its characteristics with autism spectrum disorders, namely Asperger’s syndrome.  

Other conditions

Some people with myelosuppression have additional physical or psychological conditions, including digestive, vision, sexual, social and emotional problems; fat; and depression.  

What are the treatments for neural tube defects (NTD)?

The method of treatment depends on the severity of the condition and the presence of complications. For some people, the need for treatment may change over time, depending on the severity or complication of the condition.  

– Open the spine: An infant with myelosuppression, in which the spinal cord is exposed, may have surgery to close the hole in the back before birth or for the first few days after birth.  

– Hydrocephalus: If an infant with spina bifida spills with hydrocephalus (excess fluid that surrounds the brain), the surgeon may implant a shunt tube into a small hollow tube to drain fluid to reduce pressure on the brain. . Treating hydrocephalus can prevent problems like blindness.   

– Encephalocele: People with aneurysms resemble encephalocele, where the brain and surrounding membranes protruding through the skull are sometimes treated with surgery. During surgery, the bulge of the tissue is placed back into the skull. Surgery can also help correct abnormalities in the skull and face.   

– The spinal cord is tightly tied: Surgery can remove living tissue from surrounding tissues.  

– Paralyzed and limited in moving. People with spinal cord disease use different means of transportation, including braces, crutches, walkers and wheelchairs. 

– Urinary tract infection and lack of bladder and bowel control: People with myelosuppression often suffer nerve damage that causes the bladder to not be completely empty. This can cause urinary tract infections and kidney damage. Health care providers can solve this problem by using a tube to completely empty the bladder. Medications, injections and surgery can also help prevent accidental leakage of urine and keep the kidneys and bladder long-term.    

There is no treatment for encephalopathy or iniencephaly. Babies with these diseases usually die soon after birth.

 References:

  1. Moretti, ME, Bar-Oz, B., Fried, S., & Koren, G. (2005). Maternal hyperthermia and risk of neural tube defects in newborns: Systematic assessment and meta-analysis. Epidemiology 16 (2), 216 From219. Retrieved August 6, 2018, from https://journals.lww.com/epidem/fulltext/2005/03000/M Parental_Hyperthermia_and_the_Risk_for_Neural_Tube.10.aspx
  2. Chescheir, N., & American College of Obstetricians and Gynecologists (ACOG) on the Practice of Obstetrics and Gynecology. (2003, reaffirming 2016). ACOG Practical News: Neural tube defect, No. 44. International Journal of Gynecology and Obstetrics, 83 , 123 Reflective 133.     
  3. Centers for Disease Control and Prevention. (2016). Prickly spine disease . Retrieved February 23, 2017, from http://www.cdc.gov/ncbddd/spinabifida/facts.html
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  8. Centers for Disease Control and Prevention. (2016). Spina bifida: Health problems & treatments for spine Retrieved February 23, 2017, from http://www.cdc.gov/NCBDDD/spinabifida/treatment.html     
  9. Spina Bifida Association. (the second time). Natural latex allergy: People with spina bifida are at a higher risk of latex allergy. Retrieved February 23, 2017, from http://spinabifidaassociation.org/project/natural-rubber-latex-allergy-2/    
  10. Alriksson-Schmidt, A., Thibadeau, JK, Swanson, ME, Marcus, D., Carris, KL, Siffel, C., et al. (two thousand and thirteen). The natural history of spine spine disease in a pilot child project: Research protocol. Research protocols of JMIR, 2 (1), e2. Accessed March 23, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/23612276    
  11. National Institute of neurological disorders and stroke. (the second time). Spina bifida information page. Retrieved February 23, 2017, from https://www.ninds.nih.gov/Disnings/All-Disnings/Spina-Bifida-In information-Page  
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