Immobilization Syndrome Flashcards
effects of immobility
- weakness, atrophy, poor endurance
- postural hypotension
- dvt
- immobilization osteoporosis
main types of adverse effectts in msk
- muscle atrophy and weakness
- joint contracture
- immobilization osteoporosis
hallmark of muscle atrophy
- decrease in muscle fiber size
- reduced muscle mass
- lmn lesion: regional
- muscle disease: proximal and antigravity muscles
changes in sarcomere number
- shortened position: reduced
- elongated position: sarcomeres in series is increase and sarcomeres in parallel is reduced
muscle fiber changes
- atrophy of fibers type 1 and 2a
- prevention: gravity loading muscles for 10 hours per day
- reduced collagen synthesis
- titin
decreased growth factor release
- dec serum ck and fibroblast growth factor
- prevention: resistance exercise during bedrest
- myostatin inhibits muscle synthesis (inc in bedrest)
5 mechanisms by which disuse atrophy happens
- alteration of metabolism and muscle cell homeostasis
- changes in sarcomere number
- muscle fiber changes
- decreased growth factor release
- inc protein breakdown
t//f loss of strength is more prominent in lower limbs than upper limbs
true
major contributors of loss of strength
- reduced myofibril number per fiber volume
- reduced size/ number of mitochondria/ muscle fiber nuclei
- reduced sarcomeres in parallel
causes of reduced indurance
- reduced atp and glycogen storage sites
- rapid depletion of atp and glycogen
- reduced muscle protein synthesis and oxidative enzyme function
- premature anaerobic energy production with rapid lactic acid accumulation
ferreti et al study
- dec vo2 max by 16%
- dec cardiac output by 30%
- dec oxygen delivery by 40%
- dec oxidative enzyme activity by 11%
deconditioning process
read
loss of muscle mass -> reduced muscle strength and endurance ->
reduced:
- muscle blood flow
- rbc delivery
- oxidative enzyme activity
- o2 utilization in muscle
- decreased formation of fiber 1 and 2a
t/f lack of adequate muscle activity has no effect on cardio
false
minimum resistance exercise
- one a day contraction at 30-50% of maximal strength for 3-5 mins, 3x a week
pathology in joint contractures
- contributory conditions + lack of joint motion
- most common factor: lack of joint motion throughout full allowable range
types of joint contractures
arthrogenic, myogenic, soft tissue
what is myogenic contracture
- shortening of the resting muscle length
- limits full rom
- abnormal positioning of limbs or body
most common cause of myogenic contracture
- after multiple injuries
- chronic illness
- sedentary lifestyle
natural history of myogenic contracture
- joint muscles involved
- ue: internal rotators and elbow flexors
- le/core: hamstrings and back muscles
pathologic processes in arthrogenic contracture
- cartilage degeneration
- congenital incongruency
- synovial inflammation
- effusion
- pain
- joint immobility
acute arthritis
exercise -> short term immobilization to reduce inflammation
intense dynamic exercise + ordinary activity = most effective to improve physical function
chronic arthritis
short term immobilization showed increased destruction of joints and cartilage
t/f intensive exercise is more effective than conservative exercise in arthritis
true
what is soft tissue contracture
- cutaneous, sc, loose ct around joint
- limits movement in one plane only
- prevention: rigorous active and passive rom exercises, rest joint, compressive garmets
management of contractures
- prevention
- active and passive rom exercises with sustained terminal stretch on daily basis
- mild: 5-10 min
- severe: 20-30 min
- uts = most popular heat source
- sustained stretch (2+ hrs)
- last resort: tendon lengthening
what is disuse osteoporosis
- loss of ca and hydroxyproline in cancellous bone, epiphyses, metaphysis, cortical bone
non weight bearing over several weeks can cause ___
trabecular and endosteal mineral bone loss in tibia
can take 1-1.5 years to return to baseline
prevention and treatment of disuse osteoporosis
- isotonic exercises, weight bearing and functional training, ambulation
- tilt table
t/f resistance exercise can increase bone mass
true
prolonged bed rest increases resting heart rate by ___
1 beat/min every 2 days
after 3 days: 32%
(reduced stroke volume and co)
what is orthostatic intolerance
- prolonged bed rest = normal orthostatic response is compromised
- cannot maintain stable bp
- falls more than 20 mmhg
- rapid hr = prevents optimal filling of rv
s/sx of postural hypotension
- inc pulse rate >20 bpm
- dec systolic pressure >20 mmhg
- dec pulse pressure
virchow’s triad
venous stasis, hypercoagulability, blood vessel damage
most frequent time for dvt
1st week of bed rest
venous stasis in leg is due to ___
dec pumping activity of calf muscles and dec orthostatic pressure
prevention of dvt
- sc heparin injection (lmw heparin > sc heparin)
