BRS Neurology Flashcards
central vs. peripheral hypotonia
central- UMN, altered level of consciousness, increased DTRs, ankle clonus
peripheral- LMN, consciousness not affected, muscle bulk and DTRs are decreased
weak cry, decreased spontaneous movement, frog-leg posture, muscle contractures are signs of ______
hypotonia
when you suspect central hypotonia you should get these tests
head CT
serum electrolytes
genetic study (Down syndrome, Prader-Willi)
when you suspect peripheral hypotonia, get these labs
serum CK
DNA test for spinal muscular atrophy
EMG and nerve conduction studies
muscle biopsy
weak cry, tongue fasciculations, bell shaped chest ,frog-leg posture, normal extraocular movements and normal sensory exam
spinal muscular atrophy- anterior horn cell degeneration (hypotonia, weakness, tongue fasciculations)
classification of SMA
type 1: infantile form, onset < 6 months, aka Werdnig-Hoffman dz
type 2: intermediate form, onset 6-12 months
type 3: juvenile form, onset > 3 years
______ is the second most common inherited neuromuscular disorder after Duchenne muscular dystrophy
SMA
how is SMA inherited and where is the gene
AR
mutation of survival motor neuron gene (SMN1) on chromosome 5
how to dx SMA
DNA testing for abnormal gene is diagnostic in > 90% of cases
muscle bx shows characteristic atrophy of muscles innervated by the degenerating axons
how to tx SMA
what’s the prognosis
supportive care: G tube, monitor for respiratory infections, PT
prognosis: type 1 does not survive past year 1, type 2 survives to adolescence, type 3 survives to adulthood
constipation –> weak cry and suck, loss of previously obtained motor milestones, ophthalmoplegia, hyporeflexia
-paralysis is symmetric and descending
infantile botulism- bulbar weakness and paralysis that develops during year 1 secondary to ingestion of clostridium botulinum spores and absorption of botulinum toxin
what does botulinum toxin do
prevent presynaptic release of ACh
when do sxs of infantile botulism occur in relation to spore ingestion
12-48 hours afterwards
what does EMG show with infantile botulism
incremental response during high-frequency stimulation
how to tx infantile botulism
what’s the prognosis
treatment is supportiv: +/- NG feeding, ventilator
-botulism immune globulin improves clinical course
-do NOT give abx, they might make it worse
prognosis is excellent!
as a neonate
- polyhydramnios
- feeding and respiratory problems as a neonate
- facial diplegia (bilateral weakness), hypotonia, areflexia, arthrogryposis (multiple joint contractures)
- myotonia develops later on
congenital myotonic dystrophy
in an adult, myotonic facies (atrophy of masseter and temporalis muscles), prosis, stiff straight smile, inability to release grip after handshaking
congenital myotonic dystrophy
define myotonia
inability to relax contracted muscle
inheritance of congenital myotonic dystrophy
AD trinucleotide repeat disorder- mostly through the affected mother
chromosome 19
how to dx congenital myotonic dystrophy
DNA testing
how to tx congenital myotonic dystrophy
what’s the prognosis
treatment is supportive
prognosis is guarded… infant mortality can be as high as 40%
all survivors are mentally retarded with average IQ of 50-65
feeding problems subside with time
noncommunicating vs. communicating vs. ex vacuo hydrocephalus
- noncommunicating- enlarged ventricles caused by obstruction of CSF flow
- communicating- enlarged ventricles as a result of increased CSF production or decreased CSF absorption
- ex vacuo- not true hydrocephalus, ventricular enlargement due to brain atrophy
downward displacement of cerebellum and medulla through foramen magnum
what is it and what is it associated with often?
chiari type II malformation
often associated with lumbosacral myelomeningocele
absent or hypoplastic cerebellar vermis and cystic enlargement of the 4th ventricle –> block of CSF flow
Dandy Walker malformation