HPA Axis Flashcards
What is the normal response in an acute stress situation
a reaction associated with fear which prepares the body to flee or fight
general steps in the HPA
stress –> CRH relased from the hypothalamus –> ACTH released from the pituitary into the peripheral circulation–> cortisol released by the adrenal cortex –> cortisol binds to glucocorticoid receptors taht are present in every nucleated cell
what are the effected regions in chronic stress situations
the hippocampus and cerebral cortex
what are some effects of chronic stress
decreased number of glucocorticoid receptors in the hypothalamus
change in size of adrenal cortex via hypertrophy
decreased number of glial cells
effect on mood control and ability to experience pleasure
role of glial cells
important for controlling fear, regulating motivation and controlling impulses
steady state and how chronic stress affects it
The HPA axis potentiates inhibition of actions when a new acute stressor occurs in the state of chronic stress so that when it is removed the body will stay at this new increased or decreased steady state value. Once equilibrium has been established, the body seeks to stay near this new point.
important findings of chronic stress and depression
One does not lead to the other; there is just more vulnerability for depression with chronic stress. There has been hippocampal atrophy shown in individuals with depression
Those with chronic stress have difficulty changing the way they think to get out of the depression
forms of treatment for chronic stress and depression
• Antidepressants are able to increase neurogenesis (increase the rate of formation of new neurons) and synaptogenesism in the hippocampus
• Exercise can improve mood and promote neurogenesis in hippocampus
o Serves as a neural protective factor
• Electroshock therapy
what is the most effective treatment for depression and chronic stress
talk therapy, exercise and medication combo
physiology of anxiety involving the prefrontal cortex
• The prefrontal cortex has become impaired by high levels of glucocorticoids
o Therefore stress control mechanism is damaged and any new emotional stimulus is resistant to extinction
role of the prefrontal cortex
acts as a brake on the amygdala
fear modulation and emotional balance
treatment for anxiety
o Treatment involves cognitive behavioral therapy that “extinguish” the underlying fear; not by getting rid of it but associating it with a good stimulus
cause of FM
Genetic factors
“environmental” factors such as external stressors (man made)
cause of chronic fatigue syndrome
No cause has been determined
Current theory focuses on interplay between infections, immune system and HPA
pathophysiology of FM
Pathophysiology Pain or early life stress leads to HPA dysfunction/neuroendocrine abnormalities
• Childhood stressors and “adult” stresses
o Exposure amount and time increase the risk of FM
o “man-made” are more likely to trigger
o Time off from work/inactivity can trigger FM
o Victims of unavoidable accidents have higher frequency of FM
o Daily hassles are more capable of causing symptoms
• Stress response is inappropriately triggered by everyday occurrences that change the “set point”
• Absence of descending pain
o Normal EK but decreased serotonin
• Increased central sensitization
o 3x amount of substance P
o Glutamate levels 2x higher
hallmarks of FM and chronic fatigue
pain and fatigue
symptoms of FM
Pain
• Diffuse
• waxes and wanes
• Migratory
• Dysthesisas/parasthesia
Fatigue
Chronic widespread pain (primary symp)
Sleep disturbance/ waking unrefreshed
Cognitive symptoms
• Problems with attention and memory
Diffuse hyperalgesia
-increased pain to normally painful stimuli
Allodynia
-pain to normally nonpainful stimuli
criteria for chronic fatigue syndrome
Unexplained, persistent disabling fatigue for at least 6 months that is not alleviated by rest
Short term memory impairments
Sore thoart
Tender lymph nodes
Muscle pain without swelling or redness
Headaches of a new type
Unrefreshing sleep
20-50% have one or more of the following symptoms such as abdominal pain, alcohol intolerance, bloating, chest pain…..
prognosis for FM
Depends;
Some have very good while others have long-term disability
prognosis for chronic fatigue
Highly variable
Some will be homebound
Some will improve so they can return to work
But full recovery is in only 5-10%
treatment for FM
Strong evidence for tricyclics, SNRI/NSRI, cardiovascular exercise, cognitive behavior therapy, pt. education (some strength training is ok)
Opioids, NSAIDS, corticosteroids , acupuncture, massage therapy are NOT effective
treatment for Chronic fatigue
Combination of drug and nondrug treatment
Never overdo it during exercise
Gentle stretching
Nutritional supplementation
FM ratio
Women more likely in clinical samples because they tend to seek treatment more than men; overall population based samples are equal in diagnosis
