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55 Cards in this Set
- Front
- Back
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CNS MALFORMATIONS - WILSON - FRIDAY JAN 26
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what is the most common CNS malformation type, and what do they result from?
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neural tube defects - failure of neural tube to close
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what are the two most common forms of NTDs?
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1) spina bifida; 2) anencephaly
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what is the incidence of these defects (considered together)?
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1 in 1000 (4000 fetuses annually in the US)
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what fraction are aborted (either spontaneously or electively)?
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one third
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what is an antenatal screening test for NTDs?
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elevated AFP in maternal serum
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what is a risk factor for NTDs?
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folate deficiency during initial weeks of gestation
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at what point in gestation is the neural tube closed?
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28 days into gestation
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what is the most common congenital malformation of the brain?
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anencephaly
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SPINA BIFIDA
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what is the most frequent site for spina bifida?
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lumbosacral region
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what is the mildest form of spina bifida called?
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spina bifida occulta
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what is the defect like, and where?
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vertebral defect (non-closed vertebral arches) without an externally visible cystic lesion on the back - variable and often asymptomatic
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what sign is frequently present on the skin?
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overlying cutaneous stigmata (e.g. hypertrichosis / skin dimple or sinus / lipoma / capillary nevus)
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what other associated defects may there be (3)?
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1) sacral; 2) anorectal; 3) urogenital
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what form is a step up in severity from spina bifida occulta, and what is it characterized by?
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spina bifida cystica - vertebral defect combined with a cystic lesion on the back
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what types of spina bifida cystica are there (2)?
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1) meningocele; 2) myelomeningocele
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what is a meningocele?
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protrusion (herniation) of the meninges through a vertebral defect
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what happens to the spinal cord in a meningocele?
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it remains in normal position in the vertebral canal
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what is a myelomeningocele (the most severe form of spina bifida)?
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protrusion (herniation) of both meninges and spinal cord through a vertebral defect
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what is a myelomeningocele almost invariably associated with?
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Arnold-Chiari type II malformation
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what are the essential components of this malformation (2)?
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1) elongation of the inferior vermis and brain stem associated with their displacement into the cervical spinal canal; 2) hydrocephalus (usually)
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what % of infants with spina bifida survive past one year?
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>90%
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what is a common complication of spina bifida?
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progressive deterioration secondary to various medical complications
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what % have other congenital anomalies?
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20%
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what severe, life long disabilities are usual (4)?
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1) paraplegia; 2) incontinence; 3) recurrent/chronic infection (meningitis; 4) learning disabilities
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ANENCEPHALY
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what is anencephaly, and what does it result from?
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absence of cerebrum and calvarium resulting from nicomplete closure of the anterior neural tube
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what is the rate per 1000 live births for anencephaly?
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1 to 5
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what happens to those affected?
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stillborn or early death
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PERINATAL BRAIN INJURY
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what is the msot common neonatal intracranial hemorrhage?
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intraventricular hemorrhage
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what type of infants are most susceptible?
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preterm infants (full term infants can get it too)
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what is the most frequent origin of IVH?
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periventricular germinal matrix (subependymal germinal matrix)
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how long does this matrix persist?
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34 weeks
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what type of activity and circulation was this matrix said to have?
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fragile microcirculation, high fibrinolytic activity
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what is the usual area of matrix to hemorrhage?
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ventrolateral to the lateral ventricles
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what does the extent of hemorrhage range from?
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small asymptomatic focus to massive IVH with or without hemorrhagic infarction in the periventricular white matter
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PERIVENTRICULAR LEUKOMALACIA
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what type of lesion is periventricular leukomalacia, and who gets it?
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common ischemic lesion of preterm infants (full term can get it also)
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where does it occur, and what type of damage occurs?
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infarction of periventricular white matter (cerebral)
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what is the vulnerable area of the centrum semiovale, and where is it located (between two things)?
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boundary zone between ventriculpetal and ventriculofugal arteries
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what % of hospital births have PVL?
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5%
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what % of LBW infants are affected?
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as many as 35%
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what are the initial manifestations of PVL like?
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relatively nonspecific
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what develops in most surviving infants?
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spastic motor dysfunction (paraplegia, quadraplegia)
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