Muscle morphology after SCI

Question 1

What are one of the most obvious muscular abnormalities associated with SCI?

Answer 1

profound muscular atrophy

Question 2

Muscle fibre cross sectional area after SCI is approximately?

Answer 2

30-80% of that in the able bodied

Question 3

When is atrophy more pronounced?

Answer 3

after LMN injury (cauda equina)

Question 4

What fibre types is atrophy most profound in?

Answer 4

type IIa fibre types

Question 5

When does atrophy approximately level off?

Answer 5

after 2 years

Question 6

What is the decrease in fibre CSA accompanied by?

Answer 6

increases in interstitial fat

Question 7

What muscle is the major player in the storage of glucose and the maintenance of normal glucose regulation/metabolism?

Answer 7

Skeletal muscle

Question 8

What is type II diabetes?

Answer 8

(A.k.a. non insulin dependent diabetes mellitus)
-is a condition characterized by increased blood glucose levels (hyperglycemia) resulting from the bodys inability to store glucose
-the pancreas doesn’t produce enough insulin OR the body has an impaired response to insulin (insulin resistance)

Question 9

What is type I diabetes?

Answer 9

the pancreas no longer produces insulin

Question 10

The ingestion of CHO leads to

Answer 10

the secretion of insulin from pancreas which leads to the storage of CHO in muscle (and liver) and fat (in adipose tissue)

Question 11

Bauman and Spungen, 1994:

Answer 11

100 individuals with SCI (50 paraplegia, 50 tetraplegia)
50 age matched able bodied controls
22% of those with SCI were classified as NIDDM compared to 6% of controls (worse glucose tolerance in those with tetraplegia)

Question 12

Why is there an increased risk of diabetes in individuals with SCI:

Answer 12

1. loss of muscle mass and ability to contract
2. increased insulin resistance

Question 13

The higher your injury the higher the increase for type 2 diabetes because:

Answer 13

There is more muscle to be affected
Is a bigger problem for those with tetraplegia

Question 14

What is glucose intolerance?

Answer 14

an inability to properly store/metabolize glucose
62% of individuals with tetraplegia
50% of individuals with paraplegia
18% of able bodied

Question 15

What is insulin resistance?

Answer 15

An inability to respond to, and use insulin
i.e. any given amount of insulin secreted from the pancreas results in a lesser transport of glucose into muscle and liver and fat into adipose tissue
-individuals with SCI have greater insulin resistance than the able bodied (approx 3-4 times) due to decreased muscle mass

Question 16

SCI leads to:

Answer 16

decreased muscle mass and paralysis which leads to type II diabetes

Type II diabetes branches off into secondary problems due to increased blood glucose which leads to kidney failure and peripheral neuropathy. Peripheral leads to somatic which leads to weakness and decrease in sensation and neuropathy leads to autonomic which leads to UTI and ED

Type II diabetes also branches off into secondary problems due to increased fat in blood which leads to the conversion to LDL which leads to increased risk of CVD

Question 17

Exercise training may partially reverse the atrophy that is associated with SCI:

Answer 17

25-50% is realistic:
-resistance training
-FES (functional electrical stimulation- involuntary)
-BWSTT (body weight support treadmill training)

Question 18

Exercise training may also partially reverse the glucose intolerance that is associated with SCI due to:

Answer 18

• increased muscle mass
  -decreased insulin resistance (increased insulin sensitivity)
  -increased GLUT4 content in muscle (with exercise)

Question 19

skeletal muscle in individuals with SCI is not only prone to atrophy and decreased strength but also to?

Answer 19

decreased fatigue resistance

Question 20

Why the decreased fatigue resistance in SCI?

Answer 20

reduction of aerobic enzymes- maybe
reduction in muscle capillarization- maybe
reduction in the NA+, K+ ATPase enzyme- (Yes 50%)

Question 21

muscle spasticity may?

Answer 21

preserve type I fibre representation in individuals with SCI

Question 22

What is spasticity?

Answer 22

involuntary, random, increase in muscle tone (agonists and antagonists) common in individuals with UMN SCI
-is velocity dependent and position dependent
-is tested via ashworth scale
-is random

Question 23

What is clonus?

Answer 23

-repetitive contraction of a muscle due to an uninhibited stretch reflex
-example: toe tap
-not random
-spinal cord injury is preventing this turn off (uninhibited)

Question 24

What is a contracture?

Answer 24

-reduced range of motion in a joint due to chronic shortening of a muscle
-muscle contraction, not spasticity
-can happen to any muscle that chronically shortened over time

Question 25

Ashworth test of spasticity:

Answer 25

• move the joints of the lower limb (hip, knee, ankle) and record the amount of resistance (spasticity) based on a 6 point scale
  -need a metronome

0. no increase in muscle tone
1. slight increase, catch and release.OR min resistance at end of ROM
   1+ slight increase, catch (no release) and min resistance for less than half of ROM
2. more marked increase, through most of ROM but still easily moved
   3.considerable increase, passive movement difficult
3. rigid in flexion or extension