Developmental CNS diseases Flashcards
What day does neural tube closure begin?
Day 22
Risk Factors for Neural Tube Closure defects?
How can you detect defects?
Maternal Diabetes
Valproic Acid (epilepsy meds)
Vitamin A
****LOW FOLIC ACID!!!
Materanl Serum AFP detects probelms
What can cause a phenocopy of Anencephaly?
Amniotic Strand disruption
Defects of Priamary Neurulation?
Anencephaly
Meningomyelocoele - spina bifida
Encephalocele
What is Encephaloceles?
***Herniation of intracranial contents through a skin covered neural tube defect **
Most cases are multifactorial - but there is a higher incidence of chromosomal/genetic syndromes with this than other neural tube closure defects (trisomies of chromosomes 13, 18)
Meckel-Gruber, Walker Warburg and Roberts Syndromes
FOLATE SUPPLEMENTATION UNASSOCIATED
Occult Spinal Dysraphic states? Features?
Defects of Secondary Neurulatoin: Group of conditions where there’s malformations in the caudal region of the developing fetus - Closed Spinal Dysraphism
Conditions involve abnormal development of lower sacral and coccygeal segments
Lumbosacral cutaneous findings: hair, dimples, tracts, hemangioma, etc
Neuromotor deterioration, worsening bladder or bowel problems and scoliosis **
What are the 5 disorders of secondary neurlation?
Liponmyelomeningocele - lipoma near SC and can tether SC
Split Cord malformation - Diaestematomyelia
Dermoid and Epidermoid Tumors
Dermal Sinus Tracts
Thickened Filum Terminale - assoc with tethered chord
What is holoprosencephaly? mutations? forms?
Holoprosencephaly - cleavage abnormalities that occur sagitally and result from fusion of cerebral hemispheres or horizontally with with weird optic and olfactory bulbs
Most are sporadic but can be Sonic Hedgehog on Chromosome 7! or from EtHO, Vintamin A, and Maternal Diabetes
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Microforms - less severe forms ; 1 incisor, Iris Coloboma, Hypotelorism, no frenulum
Lobar - Least Severe -
Semilobar - Anterior not cleaved but posterior normal - lack of frontal horn development and moderate midline craniofacial defects
Alobar - most severe - 1 ventricle, agenesis of corpus callosum, no 3rd ventrical or thalami and BG with significant facial defects
What is Lissencephaly?
Smooth brain with absence of normal gyral patterns
*Arrest of brain development at an immature level - Gene on Chromosome 17p
Frequently part of genetic or chromosomal Syndrome likes Miller dieker or Walker Warburg
Type 1 Lissencephaly
Miller-Dieker Syndrome - smooth primitive brain
Contiguous gene deletion syndrome on **chromosome 17p13.3 **
Smooth brain, Agenesis of Corpus callosum, Characteristic fact and genital anomalies
Lethal
FISH TESTING available
Type 2 Lissencephaly
Walker Warburg syndrome
Autosomal Recessive mapped to Chromosome 9q31
*Pachygyrira, cerebellar abnormalities (Dandy Walker), Hydrocehpalus, Muscular Dystrophy, Retina Dysplasia *
Periventricular Heterotopia?
Defect of neuronal migration where gray matter in the ventricle
can see on MRI
Associated with seizures
Polymicrogyria?
gyri that are too small and too numerous
lots of gyri partly fused with shallow sulci
Associated with Zellweger Syndrome, Viral infections and other abnormalities
What are the 3 Brain Disruptions?
Porencephaly - cystic cavities in brain from transient fetal hypotension or stroke or fetal infections
Hydranencephaly - total infarction of fetal cerebral hemispheres from hypotension, stroke, or infections–> Catastrophic
Schizencelphaly - split brain = XRay description of abnormality that results in deep “cleft” between frontal and temporal lobes from early arrest in development - pachygyria and seizures in kids often occur
POsterior Fossa Abnormalities: Chiari Malformations 1-3
Chiari 1: abnormally shaped cerebellar tonsils below the foramen magnum
Chiari 2: Downward displacement of cerebellar tonsils and vermis
- Beaked midbrain - brainstem malformation
*Spinal Myelomeningocele
Chiari 3 (rare) - small posterior fossa with high cervical or occipital encephaloecele
