Fatigue

Question 1

What are the causes of fatigue?

Answer 1

CNS
Neuromuscular
endocrine dysfunction 
sleep pattern
psychological 
immunological 
Autonomic nervous system

Question 2

CNS

Answer 2

dysfunction in premotor cortex, limbic system, basal ganglia and brainstem.
Reduced frontal lobe activity and deficits in perfusion and glucose uptake
dysfunction in areas related to hypothalamus and endocrine system

Question 3

Neuromuscular

Answer 3

Changes in the Na pump at the nodes of Ranvier can result in nerve conduction block.
– impaired muscular excitation, contraction and metabolism. Fall in muscle PCr, accumulation of H+ ions and reduced pH

Question 4

endocrine dysfunction

Answer 4

hypothalamic-pituitary-adrenal (HPA) axis is the body’s stress regulator. Normally stress leads to release of various hormones which eventually release cortisol which reduces stress response.
In abnormal systems – low levels of cortisol so highly sensitive to stress. In fatigued people with MS often abnormally high level of ACTH.

Question 5

immunological

Answer 5

immune system is
abnormally active. Several of these abnormally body chemicals are raised in people with MS with fatigue compared to people with MS without fatigue.

Question 6

Autonomic nervous system

Answer 6

reduced activity leads to fatigue due to effect of lowering BP.

Question 7

Sleep

Answer 7

many people with MS have disrupted sleep patterns

Question 8

Psychological

Answer 8

association of higher fatigue in people with depression/ anxiety