Brain Abnormality (developmental/genetic & metabolic disorders) Flashcards
what is the most common cause of CNS malformation?
neural tube defects
anencephaly
absence of brain except basal ganglia, cerebellum, brainstem
ant. neuropore failure to close
usually an absent skull too
Myelomeningocele
meninges + spinal cord protrude through vertebral column defect
- often presents with hydrocephalus and Arnold-chiari malformation
- most common non-lethal malformation
encephalocele
meninges + brain through skull
-less serious, sinus probs
polymicrogyria
increased # of small, irregular gyri
4 cortical layers instead of the usual 6
pachygyria
flat, thick gyri
due to a migratory problem; usually results in mental retardation
heterotopias
Abnormal clusters of neurons due to a partially failed migration from subependymal (germinal) matrix
Seizures often occur
usually due to DCX (doublecortin) gene mutation
holoprosencephaly
failure of hemispheres to separate (resulting in frontal lobe fusion)
Sonic hedgehog defect
sometimes no corpus callosum either
Arnold-chiari malformation
SMALL posterior fossa resulting in a slightly deformed brain stem (type 2 most common)
associated with meningomyelocele and hydrocephalus due to aqueductal stenosis
Dandy-walker malformation
LARGE posterior fossa (foxc1 gene mutation)
Cerebellar vermis replaced with midline cyst
lateral displacement of cerebellar hemispheres
also can cause hydrocephalus
Syringomyelia
a cavity that forms in the spinal cord (usually cervical)
onset at ANY age
presents as loss of PTT symetrically in hands with hand muscle wasting (C8ish)
Cerebral Palsy
Non-progressive neurologic MOTOR deficits
90% congenital, 10% acquired
Can NOT be diagnosed in utero nor at birth:
- floppy/stiff arms legs in first months
- poor head control at 5 mo
- inability to sit after 8mo
- difficulty standing 12mo
- probs walking 12-18 mo
What are the 3 types of cerebral palsy and what is characteristic of each?
1) Spastic = stiff and jerky movements
2) ataxic = decreased muscle tone and poor coordination
3) athetoid = difficulty maintaing posture & involuntary movements (usually due to hyperbilirubinemia)
Germinal Matrix Hemorrhage
attributed to cerebral hypoxia
usually occurs between 25-35 weeks gestation
preemie baby with blood in CSF
Periventricular leukomalacia
INFARCTS in periventricular white matter of cerebral hemispheres.
cyst formation may occur
Non-ketotic hyperglycinemia
causes imprecise eye movements/nystagmus
Freidrich Ataxia
MOST common inherited ataxia
due to frataxin gene defect
onset 2-16yrs
95% show first sign being “clumsiness”, slurred speech follows, and 55% form pes cavus deformity
hypertrophic cardiomyopathy key sign
Tay-Sachs disease
neuronal storage disease caused by accumulation of GM2 gangliosides
hexosaminidase A deficiency
3-8months onset, “cherry red spot” in macula, exaggerated startle reflex
Krabbe Disease
aka globoid cell leukodystrophy
galactocerebroside B-galactosidase deficiency***
accumulation of psychosine
motor decline, and difficulty feeding
onste at 3-6months with mult-nucleated Macrophages!!!
Metachromatic leukodystrophy
arylsulfatase A deficiency —> accumulation of sulfatide
onset usually in later infant years (6-8)
presents as mental & motor decline with peripheral neuropathy (widespread myelin deficit in white matter)
leukocoria (white pupil)
No red reflex… infantile cataract is most common (galactosemia)
but could be a RB1 mutation resulting in retinoblastoma
Adrenoleukodystrophy
x-linked
presents in early school years (with adrenal insufficiency too)
rapid/progressive and fatal
pelizaeus-merzbacher disease
x-linked, fatal leukodystrophy
-proteolipid protein deficit (PLP gene important for CNS myelin)
