Spina Bifida Flashcards
In what countries does the majority of Spina Bifida occur? Why?
In developing countries due to malnutrition
What ethnicity in the US has the highest prevalence rate of spina bifida?
Hispanics
How does a common genetic polymorphism in Hispanics pre-dispose them to having children with spina bifida?
It is associated with lower plasma and RBC folate concentrations making them susceptible to folate insufficiency
What is the recommended daily folate intake for women of childbearing age?
400mcg (µg)
What is the recommended daily folate intake for women with high risk of having a child with spina bifida? (Previous pregnancy, self or partner with SB)
4 mg
How long before pregnancy should folate supplementation start?
1-3 months
When does primary neurulation take place?
From 18-28 days after fertilization
What do defects that occur during primary neurulation cause?
Open neural tube defects, most commonly MMC
What is craniorachischisis?
Completely open brain and cord
What is anencephaly?
Open brain and lack of skull vault
What is an encephalocele?
Herniating of the meninges and brain through a posterior defect
What is iniencephaly?
Occipital skull and spine defects with extreme retroflexion of the head
What is a closed spinal dysraphism?
Deficiency of at least two vertebral arches
What are 3 variants of a closed spinal dysraphism?
Lipomyelomeningocele, low-lying conus, thickened film terminale
Why do antiepliptic drugs increase the risk of SB?
They alter folate metabolism in the embryo and decrease plasma folate concentration
Besides medications, what are four maternal risk factors for SB?
Obesity, diabetes, cigarette smoking, and hyperthermia (hot tub)
Beside Hispanics, people of what ancestry have a higher proportion of SB?
Irish and German
What is the difference between and open and closed neural tube defects?
In an open defect, there is leakage of the CSF and protrusion of neural elements. A closed defect shows no involvement of the neural elements and thus minimal to no neurological involvement.
What is the cause of Chiari II malformations and hydrocephalus with neural tube defects?
Loss of CSF in an open defect
What is the most accurate method for diagnosing SB?
Prenatal US
When can SB first be detected when using prenatal US?
Late first trimester
When is delivery by C-section for a child with SB preferred?
After intrauterine repair
What are 3 benefits to intrauterine repair with SB treatment?
Decreased Chiari II malformation, decreased need for shunts, and improved lower extremity motor function
What are four increased risks of intrauterine repair when treating SB?
Tethered cord, spontaneous rupture of membranes, premature delivery, subsequent obstetric complications with future pregnancies
What is the gold standard for treatment of hydrocephalus in SB?
VP shunt
What characterizes Chiari II malformations?
Elongation and caudal displacement of the medulla and cerebella vermis into the spinal canal
What are 5 signs of tethered cord?
Change in bowel/bladder function, back pain, increased upper motor signs, change in strength, rapid progression of scoliosis
What percentage of children with MMC have detrusor sphincter dyssynergia?
50%
When should a child with SB first have a urologic work up (labs, RBUS, Urodynamics)?
Within the first 3 months of life.
What are the two types of urologic procedures for children with SB?
Continent and incontinent
What type of laxatives should be avoided in SB?
Lubricant (mineral oil) because they loosen stool and increase fecal incontinence
What are two osmotic laxatives used in the SB population?
PEG and lactulose
What two types of enemas should be avoided in the SB population?
Sodium phosphate, magnesium-based
If there is concern for scoliosis, how often should X-rays be obtained?
Every 1-2 years
What preventable abnormality has the most significant impact on gait in SB?
Hip contracture
When can surgery for a dislocated hip in the SB population be considered?
A unilateral dislocation in a low lumbar or sacral patient with good quadriceps power
When is a tibial derotation osteotomy indicated in a SB patient? (Two indications)
Interfering with bracing, limiting motor development
What are the two most common sites for fracture in a child with SB?
Femoral neck, distal femur
Why do fractures in children with SB heal with exuberant callous formation?
There is extensive subperiosteal hemorrhage due to flaccid muscles
At what age should a child with SB start a standing program of at least one hour a day?
6
At what age is manual muscle testing usually reliable?
5
What is the functional hallmark for a lower thoracic level SB patient?
No lower limb motor function
What is the functional hallmark for a L1 motor level in SB?
Iliopsoas with 2/5 strength or better
What is the functional hallmark of a L2 motor level in SB?
Iliopsoas and adductors have at least 3/5 strength
What defines an L3 motor level in SB?
At least 3/5 knee extension strength
What is the functional hallmark of L4 motor level in SB?
Strong knee extension but lack hip abduction
What movements does a L5 motor level SB patient lack?
Ankle plantarflexion/eversion, hip extension
At what age range does walking decline in SB?
18-25
What are the cognitive strengths of children with SB?
Rule-based processing, vocabulary, math facts
What are the cognitive weaknesses of SB patients?
Problem-solving, reading comprehension
What are risk factors for more intellectual disability in the SB population? (4)
Severe hydrocephalus, repeated shunt malfunctions, higher level lesions, severe brain malformations
What part of the brain is relatively spared in SB?
Frontal lobes
What are two cross-reacting foods with latex allergy?
Bananas and avocados
What are 4 risk factors for pressure injury in the SB population?
higher level lesion, shunt, WC use, urinary incontinence
What can help prevent skin injury in the setting of incontinence?
Barrier creams
At what age should children start being involved in skin inspection?
3
What is the most common presenting sign for symptomatic Chiari II malformation?
Dysphagia
When should screening for diabetes start in the SB population?
10 years old
What are children with SB being treated with growth hormone at increased risk for?
Scoliosis progression and spinal cord tethering
What is the definition of precocious puberty?
Development of secondary sexual characteristics before the age of 8 in girls and 9 in boys
What intervention can help with improving self-management in the SB population?
Camp-based interventions
What should pregnant patients with SB be monitored for?
shunt malfunction due to increased intra-abdominal pressure (headache, nausea, vomiting)
By age 30, what portion of SB patients are independent?
1/3
By age 30, what portion of SB patients are independent?
1/3
What is diastematomyelia?
Spinal cord longitudinally split
What is diplomyelia?
Spinal cord longitudinally duplicated
What is spina bifida cystica?
An open defect with herniating cord
Besides folate, what other nutritional deficiencies are implicated in SB?
B6, B12
Why is hyperinsulinemia and hyperglycemia a strong risk factor for neural tube defects?
Hyperglycemia can cause cell death in the neuroepithelium
What two antiepileptics are established risk factors for neural tube defects?
Valproic acid and carbmazepine
What are signs of increased ICP in infants?
Bulging fontanel, sunset eyes, vomiting, respiratory arrest
What provides the best chance for favorable lower urinary tract function in the SB population?
Spinal lesion closure in first 24 hours
What are indications for prophylactic antibiotics in infants with SB?
Hydronephrosis or reflux
What are the two most common shunt complications?
Infection and obstruction
What are 5 signs of a shunt malfunction seen in toddlers and older?
Headaches, vomiting, lethargy, irritability, seizures
What is the cause of sunsetting eyes in an infant with shunt malfunction?
Cranial nerve VI palsy
What is the most common cause of shunt infection in SB?
Steph epidermidis
What percentage of children with a shunt require revision due to obstruction in the first year of life?
50%
What is the leading cause of death in infants with MMC?
Symptomatic Chiari II malformation
Besides tethered cord, what presents with rapid progression of scoliosis and change in strength in the SB population?
Hydromyelia
Besides MMC, what are three other lesions that can lead to tethering of the spinal cord?
Lipomyelomeningocele, tight film terminale, and diastematomyelia (division of the cord)
What percentage of SB patient have an incompetent urethral sphincter?
85%
How often should infants with SB get a renal bladder US?
Twice a year
Why should surgical correction of the ankle in a SB patient be delayed until they are walking?
Crawling has a deforming force that leads to recurrence
What can a lower extremity fracture in a SB patient mimic?
Cellulitis or osteomyelitis
What are the 3 most important predictors of ambulation in the spina bifida population?
Hip flexor power, quadriceps power, and ability to achieve independent sitting
What is the Hoffer ambulation classification?
Community ambulatory, household ambulatory, nonfunctional ambulatory, nonambulators
What area in the world has the highest incidence of spina bifida?
British Isles, Ireland, Wales, Scotland
What area in the world has the lowest incidence of spina bifida?
Japan
What is the general spinal cord level involved in the majority of patients with spina bifida?
lumbar/lumbosacral (75%)
How often is Arnold Chair type II malformation seen in MMC?
about 80-90% of the time
What is the most common complication of VP shunts?
infection
Spinal level of somatic innervation to the bladder?
S2-S5 through the pudendal plexus
What complication is seen with proteus UTI’s?
calcinosis
Presence of what is associated with greater chance of bowel continence?
bulbocavernosus or anocavernous reflex
Is there generally anal sphincter tone in lesions above L2?
Yes, due to intact spinal reflex arc
What residual bladder volume level is an indication for starting CIC?
greater than 20 ml
Surgical treatment for calcaneus foot deformity?
posterior transfer of tibialis anterior
Surgical treatment for equines foot deformity?
achilles tendon lengthening
Adolescent functional motor activity for L3-L4 motor level?
50% WC, house-hold ambulation with crutches
Adolescent functional activity for L5 motor level?
community ambulation with crutches
At what age can a child learn crutch walking?
2 - 3 year old (mental age)
What percentage of low lumbar lesions achieve functional community ambulation before 15 years old?
40%
What is the employment rate for those with spina bifida?
25-50%
What pregnancy complication are pregnant women with spina bifida at increased risk for?
premature labor
At what motor level is male sexual function preserved?
L5 and below
What level spina bifida can be a community ambulator?
L5
What is the likely adolescent activity for a L3-L4 spina bifida patient?
50% WC, house-hold ambulation with crutches
What spina bifida level has early hip dislocation?
upper lumbar
What spina bifida level has late hip dislocation?
lower lumbar
What is the foot deformity in lower lumbar spina bifida lesions?
calcaneus or calcaneovarus
What is the foot deformity in thoracic or upper lumbar spina bifida lesions?
equinus
What is the foot deformity in sacral level spina bifida lesions?
cavus
Is prophylactic shunt removal recommended if hydrocephalus is arrested?
no
What is the incidence of retethering in spina bifida?
10-15%
At what spinal level does syringomyelia usually occur?
cervical
What is the functional mobility in childhood of a high lumbar level spina bifida patient?
WC for distance, limited household ambulation
What is the difference between hydromyelia and syringomyelia?
With hydromyelia, the cyst form within the central canal of the spinal cord with communication to the 4th ventricle. In syringomyelia, the cyst forms next to the central canal and does not contain ependymal cells
What should be imaged when hydromyelia is suspected?
the entire neuraxis
Cause of hydrocephalus in spina bifida?
obstruction of outflow from 4th ventricle due to aqueductal stenosis or Chiari II malformation
What should be ruled-out before preforming a hindbrain decompression in a patient with a symptomatic Chiari II malformation?
shunt malfunction
Equation for bladder volume
Bladder volume (in ounces) = age in years +2
Why are only about ¼ of spina bifida patients continent with CIC alone?
Due to a combination of low outlet resistance and small bladder volume
When should diabetes screening be started in a spina bifida patient?
age 10 or high BMI
What should be suspected in a spina bifida patient with cardiac dysfunction?
sleep-related breathing disorder
