MIDTERMS: Spina Bifida & Hydrocephalus Flashcards
What is the second most common childhood disability?
Spina bifida (neural tube defect).
When does the failure of neural tube closure occur in spina bifida?
On the 28th day of gestation.
What ultrasound markers are associated with spina bifida?
Lemon sign: Lemon-shaped cranial vault
Banana sign: Banana-shaped cerebellum
Which environmental factors are associated with spina bifida?
Low socioeconomic status
Maternal obesity
Heat exposure (e.g., maternal fever, hot environments)
Exposure to anticonvulsant drugs (Valproic acid, Carbamazepines)
What is the banana sign in spina bifida?
The cerebellum assumes a banana shape due to downward traction of the spinal cord in neural tube defects.
What distinguishes Spina Bifida Occulta from other types?
There is no herniation of neural elements, and it may present with skin markers like pigmented nevi, hirsute patches, or dimples.
Which CNS malformation is commonly associated with spina bifida?
Arnold-Chiari malformations.
What is the difference between meningocele and myelomeningocele?
Meningocele: Herniation of meninges filled with CSF, no neural tissue.
Myelomeningocele: Herniation includes dysplastic neural tissue, causing sensorimotor deficits and bowel/bladder dysfunction.
What is the best time to perform an amniocentesis for spina bifida diagnosis?
Between 16-18 weeks of gestation.
What is the significance of Alpha-fetoprotein (AFP) in spina bifida diagnosis?
Elevated AFP levels in amniotic fluid (13-15 weeks) indicate open neural tube defects due to CSF leakage.
What is the lemon sign, and how is it related to spina bifida?
The lemon sign refers to an abnormally shaped fetal head (frontal bones flattened), seen in 98% of open spina bifida cases.
What is Spina Bifida Aperta/Cystica?
An open defect where the contents of the spinal cord herniate through the vertebral opening. It includes meningocele (herniation of meninges) and myelomeningocele (herniation of neural tissue and meninges).
What factors contribute to spina bifida in prenatal diagnosis?
Genetic predisposition
Environmental influences (e.g., maternal diet, heat exposure)
Maternal obesity
Prenatal drug exposure
What are common presentations of post-neurulation defects?
Skin-covered lesions associated with malformations of the conus, filum terminale, or caudal spinal canal tumors.
What is Spina Bifida Occulta?
A condition where the vertebrae are affected, but the neural and meningeal elements are not herniated. It occurs with incomplete closure of posterior vertebral structures.
What are the neural tube defects resulting from failed neurulation during the 3rd and 4th weeks after conception?
Spina bifida
Craniorachischisis
Anencephaly
What are the warning signs of Spina Bifida Occulta?
Pigmented nevus
Angioma
Hirsute patch (faun’s tail)
Dimple or dermal sinus on overlying skin
What occurs during the post-neurulation phase (4th to 7th weeks)?
Canalization and retrogressive differentiation of the caudal portion of the spinal cord.