SMA Flashcards
what does spinal muscular atrophy (SMA) affect?is it an upper or lower motor neuron disease
anterior horn cell and motor neurons
LMN disease
symptoms of SMA
- muscle wasting/weakness
- hypotonia, fasciculations, arreflexia
is muscle weakness in SMA greater proximally or distally
proximally
T or F: children with SMA have impaired cognition
F: normal cognition
T or F: all states in the US screen for SMA
T
how is SMA inherited
autosomal recessive
SMN1 gene
chromosome 5
SMN1 gene
survival motor neuron 1 gene that is esential for all nerves/tissues and needed for mRNA funciton
what protein can help compensate for lack of SMN1
SMN2
T or F: everyone has the same amount of SMN2
F: this may explain variation in seen in SMA… some people can compensate for SMN1 better than others
what is the most common type of SMA
type 1
what is the leading genetic cause of infant mortality
SMA
how many types of SMA are there and how are they determined
5 types
determined by clinical presentation and copies of SMN2 gene
when is the onset of type 0 SMA? before current treatments, what was the highest function of infants with this type? prognosis?
- pre-natal
- respiratory support
- live less than a month
when is the onset of type 1 SMA? before current treatments, what was the highest function of infants with this type? prognosis?
- 0-6 months
- never sit
- live less than 2 years w/o ventilator
When is the onset of type 2 SMA? Before current treatments, what was the highest function of infants with this type? Prognosis?
- 7-18 months
- sits, never stand
- live less than 2 years
when is the onset of type 3 SMA? what about type 4?
3 = >18 months
4= >21 years
T or F: people with type 3 and 4 SMA can stand/walk and live into adulthood
T
*difficulty with stairs is common
type _____ SMA has the least copies of SMN2 while type ________ has the most
0
4
*the more copies, the better the prognosis
what are symptoms of type 1 SMA
- hypotonia
- difficulty feeding/managing secretions/respiratory distress
- lack of head control
- small amplitude movements
- early scoliosis
children with type 1 SMA have greatly _______ bone mineral density. why
- reduced b/c they aren’t WB and they don’t have strong muscles pulling on the bones
- atraumatic fx common
what are the most common contractures in SMA
LE: hip flexion, knee flexion, PF (more variable)
UE: elbow flexors, pronators, internal rotators
what kind of breathing is common in SMA. Why
- paradoxical breathing
- the diaphragm is spared but the intercostals are weak and not able to stabilize so during inhalation the ribs go in
what are some common medical interventions for children with SMA
- bi-pap/ventilator
- percussion vest
- cough assist
- suction
- pulse ox
- g-tube
what is a medication the has shown positive results in SMA and how does it work
spinraza
it enhances SMN2
