Myelodysplasia test 3 Flashcards
Myelodysplasia general definition
-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)
Meningomyelocoele
- defective closure of the neural tube
- incomplete development of the neural arches
Pathophysiology
-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)
Eitology
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)
Pathophysiogy
-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)
Incidence
neural tube defects occur in 1-2 cases per 1,000 live births
- 6,000 to 10,000 children born each yr in US
- females >males
diagnosis
- 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)
Myelodysplasia-Types
- Occulta (hidden, not visible)
- Aperta( cystica)
- myleomenigocele
Occulta
- 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)
Aperta-Cystica
- 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)
Myelodysplasia-meningocele
-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)
Myelodysplasia- Myelomenigocele
-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)
myelodysplaasia other types
- 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)
Clinical Pic of Occulta
- 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)
Clinical Picture of Myelomeningocele
-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)
medical management of Myelodysplasia
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)
medical management of Myelodysplasia- surgical outcomes
- 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)
Hydrocephalus
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 cord
accumulation of CSF causes increase ICP, can lead to cerebral damage & celular death
(increased fluid within ventricles(dilation of ventricles))
signs and symptoms of hydrocephalus
- 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
Management of Hydrocephalus
- 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
Shunt malfunction: Signs and Symptoms
- 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
Arnold Chiari Malfunction
-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)
Signs of Arnold Chiari Malfunction
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
Signs and Symptoms of tethered cord
- 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
