Lecture 16 MSK Theme - Sarcopenia

Question 1

What is sarcopenia?

Answer 1

The age related progressive loss of muscle mass and strength.

Question 2

What is the main symptom of sarcopenia?

Answer 2

Muscle weakness.

Question 3

What is the main consequence of sarcopenia?

Answer 3

Increased risk of falls.

Question 4

What has the potential to mitigate against muscle loss with ageing?

Answer 4

Nutrients and lifestyle choices.

Question 5

What is a primary risk factor for sarcopenia?

Answer 5

Ageing

Question 6

What are secondary risk factors for sarcopenia?

Answer 6

Activity
Nutrition
Surgery
Inflammation

Question 7

What causes sarcopenia?

Answer 7

Loss of type II fast acting muscle fibres due to imbalances in oxidant and antioxidant status leading to increased production of ROS creating a catabolic environment.
Reduced satellite cells so less replacement and repair of damaged muscle cells seen.

Question 8

What is the SARC-F assessment tool?

Answer 8

SARC-F = strength, assistance walking, rise from chair, climb stairs and falls).
A simple questionnaire used as an initial screening tool for sarcopenia and quickly assesses function.
A score of four or greater indicates sarcopenia.

Question 9

What are the cut offs suggesting weak grip strength?

Answer 9

<27kg in men
<16kg in women

Question 10

What is the cut off for suggesting sarcopenia for chair rises?

Answer 10

More than 15 seconds to do 5 chair rises.

Question 11

How would you measure grip strength?

Answer 11

Forearm rested on arm of chair, support given for the dyanometer.
3 trials alternating between hands, max of 6 values used.

Question 12

How do you perform the chair stand test?

Answer 12

Standing and sitting down 5 times.
Normal = less than 15 seconds.
Sarcopenia indicator = more than 15 seconds due to muscle force and functioning decreasing.

Question 13

What is dual X-Ray absorptiometry (DXA)?

Answer 13

DXA measures precisely whole body and regional fat and lean mass using small doses of radiation.
Expressed as appendicular lean mass divided by height.

Question 14

What scans have more precise results compared to DXA?

Answer 14

CT and MRI.

Question 15

What are some other ways of measuring muscle mass?

Answer 15

Bioimpedance
Ultrasound
D3-creatine dilution method

Question 16

Describe bioimepdance.

Answer 16

Portable equipment that uses electrical current to estimate muscle mass. Built in equation estimates the muscle mass.

Question 17

Describe ultrasound.

Answer 17

Provides information similar to that obtained using MRI but cheaper and easier to acquire data on a specific body part.
Small electrical current sent through the tissue and resistance is measured.
Estimation of how much muscle tissue there is dependent on the resistance shown.

Question 18

Describe the D3-creatine dilution method.

Answer 18

Mass spectrometry used to determine total-body creatine pool size as a direct measure of skeletal muscle mass.
Uses a single dose of creatine followed by measurement of urinary D3 creatinine.
Only in research stages.