Introduction

When there is disturbed or incomplete closure of the neural tube during embryonic life it leads to a developmental congenital defect called spina bifida (SB). Some of the vertebrae of the spinal cord are not completely formed and remain open to produce a defect in the vertebral column that may or may not be covered by the skin. The most common site of this defect is the lumber or the sacral segment of the spinal cord. The incidence of SB is about one in every 1000 births1,2.

 Disorders associated with spina bifida

There are various disorders which are similar to SB or which may be associated with SB. These disorders include:

1. Anencephaly

anencephaly1

This disorder refers to the absence of a large portion of the brain or the skull. It is also termed as aprosencephaly or with an open cranium. It is the neural defect that occurs when the superior portion of neural the tube fails to close. The possible risk factors for this abnormality include low folic acid level in pregnant mothers and exposure to certain toxins or drugs during pregnancy. Its incidence is one in 10,000 births3.

Clinical features of anencephaly include:

  • Absence of the skull or a part with exposure of brain tissue
  • Absence of the brain or a portion
  • Facial abnormalities
  • Valvular defects of the heart3

Diagnosis: The following tests can be carried out to diagnose this defect in a pregnant mother:

  • Abdomenial ultrasonography
  • Amniocentesis
  • Alpha-fetoprotein level
  • Test of pre-pregnancy serum folate level
  • Urine estriol level3

Treatment: There is no current therapy except genetic counseling.

Prognosis: The anomaly usually results in death within a few days of birth.

Prevention: Adequate folic acid intake may prevent this malformation from developing3.

2. Encephalocele

Encephalocele

This is another of the neural tube defects which result from the incomplete closure of superior part of the neural tube. Its other name is cranium bifidum. It sticks out of the skull through openings in the form of protrusions of brain tissue with its covering membranes. It has many similarities with spina bifida. It is a rare anomaly that occurs at a rate of one in 5000 live births4,5.

Types: If the protruded part of encephalocele contains only CSF along with membranes, it may be termed as meningocele and if the brain tissue also protrudes with it, it is called encephalomeningocele.  Encephaloceles include the following types4:

  • Naso-frontal
  • Naso-ethmoidal
  • Naso-orbital

Risk factors: Recent studies show an association of these congenital anomalies with the following risk factors:

  • Exposure to cancer causing agents
  • Exposure to tryptan blue- a stain used to color dead tissues
  • Decreased level of folic acids5

Clinical manifestations: Patients with this malformation can have following features:

  • Hydrocephalus
  • Weakness of  lower limbs
  • An abnormally small sized head
  • Disturbed muscle movement
  • Developmental delay
  • Vision problems
  • Mental and growth retardation
  • Seizures5
  • Meningitis, both pre-operative and post operative
  • Hydrocephalus
  • Blindness6

Complications: These include:

Management: The following investigations are conducted with pregnant women  to diagnose this anomaly:

  • Ultrasonography of the abdomen
  • MRI
  • AFP-level5,6

Reparative surgery is the treatment of choice at an early stage. Other treatment options are supportive therapy, counseling, physical therapy, psychotherapy etc5, 6.

3. Tethered Cord Syndrome

Tethered Cord Syndrome

This syndrome is characterized by pulling of the spinal cord at the base of the spinal canal along with consequent clinical manifestations. It has many different forms like:

  • Dermiods
  • Dermal sinus tracts
  • Cystoceles
  • Tight filum terminale
  • Lipomenengiomyelocele
  • Split cord malformation 7

.

Aetiology: Causes of TCS include:

  • Disturbed growth of the neural tube during fetal development
  • Spina bifida
  • Later spinal cord injury
  • Syringomyelia8

Clinical manifestations: Clinical manifestations of this anomaly include:

  • Skin lesions like hairy patches, dimples, or fatty tumors on the lower back
  • Paralysis of both lower limbs
  • Spine and feet deformities
  • Kyphoysis and scoliosis
  • Backache
  • Urinary incontinence
  • Urinary retention
  • Weakness of muscle and loss of sensations of touch, vibration, temperature, pain and proprioception
  • Urinary frequency, urgency, feeling of incomplete urination
  • Rectal prolapse
  • Constipation
  • Bowel control dysfunction
  • Motor neuron findings like amyotrophy, hypereflexia and up-going planter
  • Chronic recurrent kidney infections and stones9, 10

Treatment: Treatment options include:

  • Untethering by surgery
  • NSAIDS and opiates to relieve the pain
  • Antidepressants for severe pain
  • Muscle relaxing exercises
  • Treatment of urinary tract infection
  • Physiotherapy9,10

4. Chiari Malformation

Chiari Malformation

This is another medical condition associated with neural tube defects. In this instance there is an extension of the cerebellum into the spinal canal and thus blocking the flow of CSF. There may be associated symptoms of upper body weakness, difficulty in swallowing and breathing and hydrocephalus5.

5. Meckel syndrome

Meckel syndrome

This problem is associated with neural tube defects and it has following features:

·         Occipital encephalocele along with micrecephaly

·         Cleft palate

·         Polycystic kidney disease

·         Polydactyly

·         Ambiguous genitals5

6. Dandy-Walker-Malformation

220px-Dandy-Walker-Variante_-_MRT_T2_sagittal

It is characterized by enlargement of the 4th ventricle along with a cyst that extends into the posterior cranial fossa. This malformation is also associated with neural tube defects5.

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References

1. Davies RW. Congenital vertebral anomalies: aetiology and relationship to spina bifida cystica. J Med Genet 1975;12(3):280-8.
2. Moris G. Adult Complications of Spina Bifida Occulta [internet]. [last updated 2011 March 25; cited 2013 Aug 23]. Available from:

http://www.livestrong.com/article/244091-adult-complications-of-spina-bifida-occulta/.

Anencephaly [internet]. [last updated 2011 May 1; cited 2013 Aug 23]. Available from:
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002547/.
3. Khan AN, Turnbull I, MacDonald S. Encephalocele imaging: review [Internet]. 2011 [lasted updated 2011 May 25; cited 2013 Aug 17]. Available from: http://emedicine.medscape.com/article/403308-overview.
4. Anthony D, John G, Adam R, Jeffrey V, Geoffrey L. Frontoethmoidal encephaloceles: reconstruction and refinements. J Caraniofac Surg 2011;12(1):6-18.
5. What are Encephaloceles? [Internet]. [Cited 2013 Aug 17]. Available from: http://www.bandbacktogether.com/encephalocele-resources/.
6. Yamada S, Lonser RR. Adult tethered cord syndrome. J spinal Disord 2000;13(4):319-23.
7. Agarwalla PK, Dunn IF, Scott RM, Smith ER. Tethered cord syndrome. Neurosurg Clin N Am 2007;18(3):531-47.
8. Pang D, Wilberger JE. Tethered cord syndrome in adults. J Neurosurg 1982;57(1):32-47.
9. Ratliff J, Mahoney PS, Kline DG. Tethered cord syndrome in adults. South Med J 1999;92(12):1199-203.

 

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