Myelodysplasia Flashcards
Define spina bifida (general definition).
Defective development of any part (especially the lower segments) o the spinal cord.
Pathophysiology of spina bifida.
Embryo (20 days after conception) the neural groove becomes the neural crest, then we have closure of the neural tube. By day 23, the tube has completely closed except for a hole at the top for the brain and a hole at the bottom for the spinal cord. There are also errors in the development of vertebral architecture. Infants are usually present with loss of neurologic function (sensory and motor) below the level of the lesion.
Etiology of spina bifida.
Multifactorial (possible environmental and genetic factors): folic acid deficiency (important first 6 weeks); lower SES; teratogenic agents; hyperthermia during early pregnancy; vitamin A deficiency; Rh factor; alcohol ingestion; genetic link (parents with one child with myelodysplasia have 50 times the higher chance of having another sibling).
Are females or males more affected by spina bifida?
Females
How do you diagnose spina bifida?
Pre-natal detection: ultrasonic scanning is able to detect NTD prenatally; serum alpha-fetoprotein (AFP) testing.
Prenatal diagnosis: planned c-section to avoid trauma to the neural sac during vaginal delivery.
Post-natal detection: observation (except occulta).
Describe myelodysplasia occulta.
Failure of one or more vertebral arches to meet and fuse in the 3rd month of development. Spinal cord and meninges are unharmed and remain in the vertebral canal. Midline over area. Bony defect is covered by skin. Most common in lumbosacral area. No disturbance in neurological or MSK function. May present with depression or dimple, cafe au lait spot, fatty deposit, or tuft of hair.
Describe myelodysplasia aperta - cystica.
Neural tube and vertebral arches fail to close appropriately. There is cystic protrusion of material through defective arches. There are two types: meningocele and myelomeningocele.
Describe meningocele.
Protrusion of meninges and CSF into cystic sac. Spinal cord remains within vertebral column. May exhibit some abnormalities but less common.
Describe myelomeningocele.
Protrusion of both spinal cord and meninges into cystic sac. Can be opened or closed. If closed, covered with a combination of skin and membranes. If open, nerve roots and spinal cord may be exposed with dura and skin at edge of lesion.
Meningocele and closed myelomeningocele are most common at what areas of the spine?
Thoracic and lumbosacral areas.
2/3 of open myelomeningocele occur where in the spine?
T-L junction
Lipoma
Fatty tumor on spinal cord
Myelocystocele
Cystic like tumor of spinal cord
Anencephaly
Failure of closure of cranial end of neural tube; some brain tissue may be evident but forebrain usually absent; lack of sustained life.
Clinical picture of occulta.
Usually does not cause neurologic dysfunction. Occasional disturbances in bowel and bladder function or foot weakness.
Clinical picture of myelomeningocele.
Motor dysfunction: myotomal loss
Sensory loss: dermatomal loss
Skeletal deformity
Hydrocephalus: 90% develop
ID: low percentage; LD: high percentage
Motor function prognosis: depends on level of lesion
Medical management of myelomeningocele.
Surgical repair: can repair lesion; place the spinal cord back into the spinal canal, seal the meninges, build the bony structures around. Can happen pre or post-natally.
Following surgery of myelomeningocele, 90% of infants develop _______ from next few days to weeks.
Hydrocephalus.
If not taken care of, what can individuals with myelomeningocele develop?
Tethered cord syndrome, where the cord becomes tethered or scarred down, putting tension on the cord.
Signs and symptoms of hydrocephalus.
Full, bulging, tense soft spot (fontanel) on top of the child’s head.
Large prominent veins on the scalp.
“Setting sun sign”: child appears to only look down. The whites of the eyes are obvious above the colored portion of the eyes.
Behavioral changes.
High-pitched cry.
Seizures.
Vomiting or change in appetite.
Management of hydrocephalus.
Ventriculoperitoneal shunt: shunt-thin tube with a small pump attached, which diverts CSF from lateral ventricles to a location where the fluid can be managed.
You can also place do a ventriculo-atrial pump.
Shunt malfunction for hydrocephalus - signs and symptoms.
Firm fontanels
Listlessness, drowsiness, irritability
Vomiting, change in appetite
Increasing head circumference
Swelling along the trunk
Disturbance of bowel and bladder problems
Seizures
Older child/adult: headaches, blurring, vision, seizures, decrease in school performance, decrease in sensory and motor functions.
Arnold-Chiari Malformation
Brainstem is displaced through the foramen magnum.
Defect in formation of the brainstem; may result from myelomeningocele.
Frequently contributes to development of hydrocephalus.
Signs and symptoms of Arnold Chiari.
Brainstem dysfunction and cranial nerve involvement: feeding difficulties; choking; pooling of secretions; repeated aspirations, apnea, neck pain, vocal cord paralysis; stridor breathing; UE weakness, spasticity, weakness, incoordination.
