02b: CNS defects Flashcards
Neuropores (rostral and caudal) are closed by (X) (day/week) of gestation.
X = 25th-27th day
Spina Bifida oculta is caused by improper (X) and usually occurs at which vertebra level?
X = incomplete closure of vertebral arch
L5-S1
Meningocele contains (X) and myelomeningocele contains (Y).
X = meninges and CSF Y = meninges, CSF, neural tissue
70-90% of patients with myelomeningocele have associated (X), esp if located in thoracolumbar region.
X = hydrocephalus
There is up to 8% risk of (X) recurrence after birth of child with spina bifida.
X = myelodysplasia
How are neural tube defects diagnosed in antenatal period?
- Elevated alpha-fetoprotein in maternal serum
2. Ultrasound
Encephalocele is:
herniation of brain and intracranial contents through skull defect
Cranial meningocele is:
herniation of meninges and CSF through skull defect (no neural tissue)
Failure of the brain to divide is called (X); it arises before (Y) day/week of gestation.
X = holoproscencephaly; Y = 23 day
List the forms of holoproscencephaly, from least to most severe.
- Lobar
- Semilobar
- Alobar
Lobar holoproscencephaly: (X) brain ventricles are fused and the ventricular system is comprised of:
X = deeper
Two ventricles (lateral ventricle division is not formed)
Semilobar holoproscencephaly: (X) brain ventricles are fused and the ventricular system is comprised of:
X = anterior and deep
Two occipital horns only
Facial features such as single eye, nare, or incisor can be seen with which CNS defect?
Holoprosencephaly
Neurons normally migrate (inward/outward) starting from (X) to form the cortex layers. (Inner/outer) cortical layers form first.
Outward
X = periventricular zone
Inner (layer 1, most superficial, forms last)
Migration of neurons during cortex formation occurs via which two mechanisms?
- Somal translocation (cell body moves toward pial surface)
2. Radial glial cell guide/track
CNS deformity resulting in smooth brain is called:
Lissencephaly
Genetic syndrome particularly associated with lissencephaly involves (X) gene, responsible for regulating (Y).
X = LIS-1 Y = neuronal migration
Lissencephaly Type (I/II) shows severely disorganized cortex with areas of gyri that are:
II;
- Absent (agyria)
- Thick (Pachygyria)
- Excessive and small (Polymicrogyria)
Lissencephaly Type (I/II) occurs earlier than the other Type.
I (10-14 weeks gestation with completely smooth brain)
Double Cortex deformity is inherited via (X) pattern and presents with which which symptoms?
X = X-linked
Lissencephaly (males), seizures, developmental delays
Schizencephaly is flawed development of (X) during (Y) developmental event. This occurs in trimester (1/2/3).
X = cortical mantle
Y = neural cell migration
1
Schizencephaly: cleft is most commonly formed in (X). How does it differ from Porencephaly cleft?
X = sylvian fissure
Lined with grey matter (and abnormal gyri)
Corpus callosum originates from (X) (before/after) the neural tube closes.
X = rostral neuropore (lamina terminalis)
After (forms on days 74-115)
List some etiologies of CC agenesis.
Genetic, metabolic, toxic (fetal alcohol)
