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| Spinal Bifida |
| Etiology •Spina bifida is due to failure of the posterior neural tube to close properly during fetal life. |
| Pathogenesis •Spina bifida is due to a number reasons not all of which are known. Some of the known ones include folic acid deficiency, obesity, and Hypervitaminosis A., |
| Epidemiology •As in other neural tube defects, spina bifida is a sporadic disease seen in 1:1000 live births in the United States. •In further pregnancies, if the patient has one infant with a neural tube defect, her chance of having another affected infant is 1:50 and with a third pregnancy if the second infant manifests the defect her chance of another affected infant is 1:25. |
| General Gross Description •Spina bifida is an abnormality of development of the spinal cord which takes several forms. •The least severe form is spina bifida occulta in which the vertebral arches do not form in the lumbar area but the spinal cord is relatively normal. •The next most severe form is the meningocoele in which the meninges are in a skin covered sac but the cord is relativesly normal. •In the meningomyelocoele an abnormal spinal cord is present in a skin covered sac often but not always in the lumbar area. •In rachischsis much the spinal cord which is abnormal is open and covered by skin or meninges only. •In some cases the cord may be bifed, that is divided or there may be diplomyelia or a double cord. |
| General Microscopic Description •In spinal bifida occulta and the meningocoele, the spinal cord and meninges may be relatively normal. •In the meningomyelocoele, the cord is made up of a jumbled mass of vascular meninges with islands of neuronal-glial tissue. •Microscopically, the cord and meninges in rachischisis appear as a jumbled mass of vascular meninges and glial neuronal islands just as in the meningomyelocoele. |
| Clinical Correlation •The clinical symptoms depend on the severity of the spinal cord lesion. Often patients with spina bifida occulta have no symptoms but may have a lumbar dimple or lipoma. •Patients with lumbar meningomyelocoele have loss of function of lower extremities and may also have bowel and bladder dysfunction. •Patients with rachischisis rarely live. •Many patients with more severe forms of spina bifida have Arnold Chiari malformation of the cerebellum. |
| References • Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 1301. • Poirer J et.al. Manual of basic neuropathology. Philadelphia: Saunders, 1990, pp 195- 197. |
| Spinal Bifida |
| Synopsis by: M.L. Grunnet M.D. (TX7410M21510)[57] |
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