Myelomeningocele

Myelomeningocele is the most common physically disabling birth defect in humans. The incidence is 1/1000 births. It is caused by the failure of the neural tube to close and is most common in the lumbosacral area (75%). There is a genetic risk with 3-4% incidence when a previous child has had a MM. There has been some association with folic acid deficiency and it is recommended that all woman start folate prior to conception and continue for the first 12 weeks of pregnancy. There is also an association with mothers taking valproic acid. In general, the higher the lesion, the more serious the neurological symptoms.

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Diagnosis

  1. Prenatally, the diagnosis may be made by measuring alpha fetoprotein in maternal serum or amniotic fluid. It is elevated because of leaking of AFP through the open skin. AFP may also be elevated with twins, abdominal wall defects, or after fetal demise.
  2. After delivery, the diagnosis will be obvious by the presence of a midline sac-like cystic mass with a layer of skin covering it. There may be decreased movement of the lower extremities and loss of sensation.

Immediate Treatment

  1. Immediately after delivery, the infant should be placed in the prone position and sterile gauze soaked with saline placed over the open area. The infant must be transferred to a center that has experience treating infants with MM.
  2. The opening is usually surgically closed by 48 hours of age unless the child is medically unstable.

Complications

  1. Neurological
    1. Hydrocephalus- there is a high association of a type II Arnold Chiari malformation with kinking of the hindbrain. Patients must be monitored for increased intracranial pressure by checking head circumference, EOMs, alteration in conciousness, and vomiting. If there are signs of increased intracranial pressure an ultrasound and head CT must be performed, If there is evidence of hydrocephalus, a ventriculo-peritoneal shunt is inserted.
    2. Shunt malfunction due to infection or obstruction. Presents with fever, irritability, vomiting, eye changes, and headaches.
    3. As the child grows, there may be tethering of the cord leading to changes in bladder and bowel habits and loss of strength.
    4. Arnold Chiari Crisis- herniation through the foramen magnum causing hoarseness, stridor, apnea, and respiratory arrest.
    5. Increased incidence of seizures
    6. Loss of sensation.
  2. Orthopedic
    1. Club feet
    2. dislocations
    3. Contractures
    4. Scoliosis and kyphosis
  3. Urologic
    1. Neurogenic bladder leading to urinary retention, increased risk of UTIs, and reflux
  4. Gastrointestional
    1. Constipation is a common problem
  5. Educational and Social
    1. 70% of children with MM are of normal intelligence although there is a high percentage of children with learning problems
    2. As the children get older, the incidence of psychological problems increase. In addition to the problems encountered with any disability or chronic disease, the need for bladder catherization and sexual dysfunction increases the incidence of poor self esteem and depression.
    3. There is a high incidence of latex sensitivity and products containing latex should be avoided

Management

  1. The role of the pediatrician is to be the coordinator of care for the child with myelomeningocele. They must insure that the patient gets to a center that offers all the services needed. Also, the pediatrician must provide routine care that as well as knowing how to deal with the common complications like increased intracranial pressure, UTIs, and emotional difficulties. Giving support to the parents and family is also very important.
  2. Orthopedics
    1. early surgical corrections of club feet and hips
    2. monitor for scoliosis and kyphosis
    3. Work with OT and PT to optimize chances for ambulation and providing braces and wheelchairs.
  3. Urology
    1. Catherization programs to eliminate residual urine and decrease chances of UTIs
    2. Antibiotic prophylaxis
    3. Sexual dysfunction issues when the children become adolescents
  4. Neurosurgery
    1. Maintain good shunt care and watch for changes of neurologic function.
  5. Because of high incidence of MR and school problems, early intervention strategies may be necessary and arrangements for special eduacation prepared
  6. Stool softeners, laxatives, and suppositories.

References

  1. Dias M.S. and Li V. Pediatric Neurosurgical Disease. Pediatric Clinics of North America 1998
  2. Botto L. et al. Neural-Tube Defects. NEJM Nov 1999.
  3. Dias M. and Skaggs D. Neurosurgical Management of Myelomenogocele Pediatrics in Review February 2005
  4. Liptak G.S. and Dosa N.P. Myelomenogocele. Peds in Review 2010
  5. Adzick A et al.  Randomized trial of preatal versus postnatal repair of myelomeningocele.  NEJM 2011

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