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