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| Meningomyelocele |
| Etiology |
•due to
failure of the posterior
neural tube to close properly during fetal life. |
| Pathogenesis |
•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 |
•sporadic disease
•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. |
| Clinical |
•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. |
| 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 is 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 Micro 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. |
| Reference |
• 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.
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