Malformations and Developmental Diseases Flashcards
How is a malformation caused?
intrinsic malformation
How is a deformation caused?
external force acts upon
How is a disruption caused?
a destructive force acts upon
When is the neurulation phase?
3-4wks
When is the prosencephalic phase?
2-3 mos
When is the neuronal proliferation phase?
3-4 mo
When is the neural migration phase?
3-5 mo
When is the organization phase?
5-postnatal years
When does myelination occur?
birth-postnatal years
When does neural tube closure occur?
28 days
What is the definition of a neural tube defect?
disurbance of formation of neuroectodermal and/or overlynig mesodermal structures or reopening or secondary rupture of closed tube
How can neural tube defects be detected?
prenatal folate supplement
What are the 3 main types of neural tube defects?
spina bifida
anencephaly
encephalocele
Which type of spina bifida causes neural defects?
myelomeningocoele
What drug can cause neural tube defects in 1-2% of pregnancies?
valproic acid
What are potential complications of myelomeningocoele?
hydrocephalus (type II chiari defect 80%)
meningitis
pneumonia
What is a chiari crisis?
downward herniation of the medulla and cerebellar tonsils
What is typically missing in anencephaly?
cerebral and cerebellar hemispheres
calvarium, meninges and scalp
What is an encephalocele?
broad-based pedunculated masses of cerebral tissue & dura protruding through cranial defect, covered by skin
Where is the most common site for an encephalocele?
occupital region, frontal/nasal location also common
What is meckel-gruber syndrome?
AR condition
occipital encephalocoele, cleft lip or palate, microcencephaly, micropthalmia, abnormal genitalia, polycystic kidneys and polydactyly
What is polymicrogyria?
too many irregular small fused gyri