Neural Tube Defects

Types of Neural Tube Defects

1. Spina Bifida -Spina bifida occulta -Closed NTD -Meningocele -Myelomeningocele 2. Anencephaly 3. Encephalocele 4. Iniencephaly

Prevention

B-Vitamin folic acid Have enough folic acid in women's system before pregnancy and during early pregnancy Multivitamin with at least 400 micrograms of folic acid every day before pregnancy and during early pregnancy Do not take more than 1,000 micrograms/day

Risk Factors to have a child with NTD

Couples with family history of NTD -A couple with 1 child with NTD has 4:100 chance of having another baby with NTD -A couple with 2 children with NTD has a 1:10 chance of having another baby with NTD Obesity Anti-seizure medication during pregnancy (may need more folic acid) Diabetes (may need more folic acid) Hispanic population more likely to have a baby with NTD Least common in Ashkenazi Jews, African Americans, Asians

Neural Tube

Embryonic structure *Neurulation*: formation of the neural tube Primary: shaping, folding, midline fusion of neural plate Secondary: most caudal portion of the spinal cord is formed Birth defect Affects the brain, spine or spinal cord Occurs during *first* *month* of pregnancy Neural tube normally develops into the brain and spinal cord NTD will occur when the neural tube does not close completely Causes a hole in the spinal column or another type of defect May occur before mother even knows she is pregnant

Causes

Genetic Environmental -Teratogens

Closed Neural tube defect

Malformation of the fat, bone, or membranes May cause no or few symptoms Can cause partial paralysis Dimple or tuft of hair on the spine

Medical Considerations

Medications Problems controlling bowels Paralysis Depression due to isolation and low self esteem Allergies (latex) due to overexposure Hydrocephalus Sleep apnea Higher risk for wounds (unable to feel, feet, legs, back, buttocks) Chiari malformation type II. Chiari malformation (kee-AH-ree mal-for-MAY-shun) type II is a common brain abnormality in children with the myelomeningocele form of spina bifida. The brainstem, or lowest part of the brain above the spinal cord, is elongated and positioned lower than usual. This can cause problems with breathing and swallowing.

Spina Bifida Occulta

Mildest form of spina bifida Not a true NTD Small gap in the spine but no opening or sack on the back Nerves/spinal cord not damaged Does not usually cause disability "Hidden" spina bifida

Spina Bifida

Most common NTD Affects 1,500 babies a year in the US (CDC) Neural tube does not close completely Congenital cleft in the bony encasement of the spinal cord Infant usually has paralysis of nerves below affected are of spine

Myelomeningocele

Most severe type Most severe form Spinal column does not form completely Spinal cord and tissue covering it bulges out of the opening Partial or complete paralysis of parts below affected area Hydrocephalus, learning or intellectual disability

Folic Acid

Needed to make new cells "Enriched" "Fortified" have folic acid added Corn products are NOT fortified with folic acid Beans Egg yolks Leafy green vegetables (broccoli and spinach) Citrus fruits and juices

Dental Considerations

Possible pre-medication for ventriculoatrial, ventriculocardiac, or ventriculovenous shunts for hydrocephalus Consultation with physician Latex allergy (up to 70%) Vac-Pac or pillows to alleviate pressure on sensitive areas Evaluate tissues and skin for wounds Gag reflex Dysphagia Craniofacial abnormalities: cleft lip/palate, bifida uvula, poorly defined philtrum, nasal cleft

Detection of NTD

Quad Screen- blood test to measure substances in mother's blood, can show if there is increased risk for NTD, but not for encephalocele Maternal serum -fetoprotein (MSAFP) Ultrasound - detect pregnancies with higher risk for NTD's (increased MSAFP level) Detailed ultrasound of baby's skull and spine Amniocentesis- amniotic fluid test; fluid is taken and DNA is tested for abnormalities Recommended if quad screen and/or ultrasound show increased risk

Iniencephaly

Rare but severe Infant's head is bent severely backward Spine is distorted May lack a neck Likely not to live longer than a few hours Cleft lip/palate, cardiovascular irregularities, anencephaly "open skull", malformed intestines

Encephalocele

Rare: 375 babies a year in US Neural tube fails to close near the brain Opening in the skull Brain and membranes can protrude through the skull Some cases may have small opening in the nasal or forehead area Hydrocephaus, intellectual disabilities, seizure, vision problems, small head, facial and skull abnormailites, ataxia May have normal intelligence

Meningocele

Sack of fluid that protrudes through the opening in the back Spinal cord is not involved Some may not have symptom, other may have severe symptoms Paralysis is uncommon because neural elements are not involved May experience complete paralysis of bladder and bowel dysfunction

Anencephaly

Severe, but less common Affects 1,000 babies each year Females are three times more likely than males Neural tube fails to close at the top Fetus will have little or no brain matter Lacks part of the skull Infants born with this are usually unconscious, deaf, blind, and unable to feel pain All infants will die soon after birth or are still born

Treatment

Surgical interventions -Post-natal -Immediate, if possible -May require multiple surgeries

SUMMARY

There are 4 different types of NTD (spina bifida, anencephaly, encephalocele, and iniencephaly). There are 4 types of spina bifida (spina bifida occulta, closed neural tube defect, meningocele, and myelomeningocele). Folic acid daily intake of 400-800 mcg is said to help prevent against NTD however taking too much folic acid can lead to increased risk of having a child with autism according to recent research.