Myelodysplasia

Question 1

Myelodysplasia general definition

Answer 1

-defective development of any part (especially lower segments) of the spinal cord ~ thoracic, lumbar,sacral-congenital neural tube defect (NTD)(lack closure of tubes and deformities of skeletal structures)

Question 2

Meningomyelocoele

Answer 2

-defective closure of the neural tube-incomplete development of the neural arches

Question 3

Pathophysiology

Answer 3

-degree of resulting dysfunction is related to the anatomical level of the defect-usually present w/ loss of neurological function (sensory and motor) below the level of the lesion(children born w/ spina bifida likely have hydrocephalus as well)

Question 4

Eitology

Answer 4

Multifactorial: possible environmental and genetic causes:- folic acid deficiency( impt in first 6 weeks)-lower SES-teratogenic agents-hyperthermia during early pregnancy( fever, hot tub)-Vitamin A deficiency-Rh factor-Alcohol ingestion-genetic link ; parents w/ one child w/ myelodysplasia have a 50 times higher chance of having another sibling affected)

Question 5

Pathophysiogy

Answer 5

-embryo(20 days after conception) neural groove–> neural crest–> closure of neural tube-day 23 completely closed except for hole at top-> brain, and hole at bottom-> spinal cord-also errors in development of vertebral architecture(lack of closure of vertebral arches)

Question 6

diagnosis

Answer 6

-prenatal detection -ultrasound scanning is able to detect NTD prenatally - Serum alpha-fetoprotein(AFP) testing ( produced by infants at 10-13 weeks, w/ Meningomyelocoele-increased AFP, in circulatory system ->placenta->mother)-Prental diagnosis-> lanned cesarean section to avoid trauma to neural sac during vaginal birth-post natal detection- observation( except occult)

Question 7

Myelodysplasia-Types

Answer 7

-Occulta (hidden, not visible)-Aperta( cystica)-myleomenigocele

Question 8

Occulta

Answer 8

-failure of one or more vertebral arches to meet and fuse in 3rd month of development (cord lacks pot. protection)-spinal cord and meninges are unharmed and remain in the vertebral canal -midline over area-bony defect covered by skin-most common in the lumbosacaral region-no disturbance in neurological or musculoskeletal function-may present w/ depression or dimple, cafe au lait spot, soft fatty deposit or tuft of hair (fawns beard)

Question 9

Aperta-Cystica

Answer 9

-neural tube and vertebral arches fail to close appropriately-there is cystic protrusion of material through defective arches-2 types: -meningocele (herniation of meningeal sac) -myleomeningocele ( herniation of meninges, cord and nerves in sac)

Question 10

Myelodysplasia-meningocele

Answer 10

-protrusion of meninges and CSF into cystic sac-spinal cord remains within vertebral column-may exhibit some abnormalities but less common(minor losses in sensation/strength (vary w/ levels_typically none)

Question 11

Myelodysplasia- Myelomenigocele

Answer 11

-protrusion of both spinal cord and meninges into cystic sac-can be open or closed -closed: covered w/ a combination of skin and membranes( meningoceles and closed myelomeningoceles are most common at the thoracic and lumbosacral areas) -Open: nerve roots and spinal cord may be exposed with dura and skin at edge of lesion(2/3rds of open type occur at T-L junction, increased risk of infection or further damage(open to environment)

Question 12

myelodysplaasia other types

Answer 12

-lipoma: fatty tumor on spinal cord- within tissue( likely not visible, arches closed, pain/motor/sensory changes over time)-myelocystocele: cystic like tumor of spinal cored( fluid filled)( likely not visible, arches closed, pain/motor /sensory changes over time)-anencephaley-failure of closure of cranial end of neural tube ( some brain tissue may be evident but forebrain is usually absent, lack of sustained life)

Question 13

Clinical Pic of Occulta

Answer 13

-usually does not cause neurological dysfunction-occasional disturbances in bowel and bladder function or foot function (depends on level, most common in L-S level)

Question 14

Clinical Picture of Myelomeningocele

Answer 14

-motor dysfunction: myotomal loss-sensory loss: dermatomal loss- skeletal deformity: lack of formation of arches(not complete vertebrae-hemi)-hydrocephalus: 90% develop over time-MR: low percentage -LD: high percentage-motor function prognosis-depends on level of lesion-pt presents as if he or she has a dx & presentation consistent w/ a pt who has a SCI(not recovery of functions~compensations)

Question 15

medical management of Myelodysplasia

Answer 15

team of physcians and healthcare providers-surgical repair; prenatal and postnatal-postnatal -closure usually within 72 hrs - place neural tissue into vertebral canal -cover and repair vertebral defect -achieve a flat , watertight closure of the thecal sac ( no leaking of CSF)

Question 16

medical management of Myelodysplasia- surgical outcomes

Answer 16

-10% of infants recover after surgery and are d/c w/out further medical complications-90% begin to develop hydrocephalus from the next few days to weeks-can develop tethered cord( if scared down) later as a result and could experience similar signs and symptoms as Arnold Chiari- also would require surgery( cord unable to move within canal)

Question 17

Hydrocephalus

Answer 17

abnormal accumulation of CSF in cranial vault caused by:- overproduction of CSF-failure of absorption of CSF-obstruction in normal flow of CSF through brain and spinal cordaccumulation of CSF causes increase ICP, can lead to cerebral damage & celular death(increased fluid within ventricles(dilation of ventricles))

Question 18

signs and symptoms of hydrocephalus

Answer 18

-full, bulging, tense soft soft (fontanel) on top of the child’s head-large prominent veins on the scalp-“setting sun sign”-child appears to only look down, whites of the eyes are obvious above the colored portion of the eyes-behavioral changes( irritability, lethargy)-high pitched cry-seizures-vomiting or change in appetite

Question 19

Management of Hydrocephalus

Answer 19

-shunt thin tube with a small pump attached which diverts CSF from lateral ventricles to a location where the fluid can be managed-ventriculoperitoneal is most common, ventriculo-atrial also possible-need permanent solution (pump fluid out)-often goes behind ear (protected/out of the way)-over time shunt may need to be revised due to growth or clogged/kinked tube or malfunction of shunt

Question 20

Shunt malfunction: Signs and Symptoms

Answer 20

-firm fontanels-listlessness, drowsiness,irritability-vomiting, change in appetite-increasing head circumference-swelling along trunk( where tube is in place due to infection)-distribance of bowel or bladder patterns-seizures-older child/adult; headaches, blurring vision, seizures, decrease in school performance, decrease in sensory and motor functions

Question 21

Arnold Chiari Malfunction

Answer 21

-defect in formation of brainstem-hindbrain is displaced through the foramen magnum-frequently contributes to the development of hydrocephalus (brainstem/ CN symptoms, life threatening, CSF unable to circulate properly to cord, may not be dx’d until adult, can occur with tetheredcord)

Question 22

Signs of Arnold Chiari Malfunction

Answer 22

hindbrain dysfunction and cranial nerve involvement- feeding difficulties-choking-pooling of secretions-repeated aspirations, apnea, neck pain, vocal cord paralysis-stridor breathing (noisy breathing)-UE weakness, spasticity, weakness, incoordination

Question 23

Signs and Symptoms of tethered cord

Answer 23

-scoliosis (sudden onset)-increased spasticity (babinski, mm stretch reflex)-increased asymmterical postures or movements-altered gait pattern( if affecting LE innervation)-decreased UE coordination-changes in mm. strength at or below lesion-back pain