16 - Chronic Pain Flashcards
What is a functional GI disorder?
Chronic, usually more than 2-3 month, set of GI symptoms without clear anatomical, inflammatory, or infectious cause.
Does NOT mean that it’s in the patient’s head- what we call functional today may be considered organic when we find the cause or explain the pathophysiology.
What are a few disorders that were once thought to be “in the patient’s head”?
Chrons and MS.
What is the prevalence of functional gastrointestinal disorders (FGID)?
6% of middle schoolers and 15% high schoolers fulfill IBS criteria.
IBS effects 20% of adults.
What are some functional somatic disorders?
Pelvic pain, fibromyalgia, chronic fatigue syndrome, back pain, migraine.
Usually have no “finding” when evaluating the end organ.
What is the difference between nociception and pain?
Nociception is an input signal (notification)
Pain is a summated neural output that attributes meaning - the decision that the incoming signal is indeed dangerous to the organism.
What are the difference physiological implications of acute vs chronic pain?
Acute: self-limited, action done to escape danger
Chronic: self-reinforcing signal, mental state (akin to depression), no action (learned passivity).
What are three components to the sensitized state?
Hyperalgesia: increased pain sensitivity
Allodynia: perceived painful response to non-noxious stimulus
Spontaneous pain: in absence of stimulus
Describe the two routes of the network gating anatomy that modulates pain and other signals?
Ascending: spinothalamic tract
Descending: modulating system
Describe the DNIC - descending modulating system gating function that modules pain?
Called diffuse noxious inhibitory control (DNIC)
DNIC non-functional in IBS and predicts post-op pain.
What are drugs that effect the descending modulating system? Where does each act?
PAG: opioids and NSAIDs
RVM: opiods and cannabinoids, blocks by nalaxone
Dorsal horn: tricyclic agents, SNRIs, a-2-agaonists, opioids.
Are functional GI disorders (FGIDs) limited to the GI tract?
No, 91% of subjects with IBS will have at least 1 comorbidity.
Patients with IBS report an avg of 5 comorbidities.
What are comorbidities?
Disagnosis that overlap with the specific disorder.
What are chronic overlapping pain disorders? What are other names for this?
Conditions characterized by symptoms such as chronic pain, fatigue, sleep disturbances, and often disability.
Also called functional somatic syndromes or somatoform disorders.
How is heart rate variability (HRV) related to chronic pain? What does HRV provide information about?
HRV gives info about vagal/parasympathetic function.
Vagal tone is decreased in many chronic syndromes.
Not clear if it’s an associated, cause, or consequence of chronic pain.
What is the function of the periaqueductal gray (PAG) structure in the brain when stimulated?
When stimulated, PAG decreaes pain as part of the descending pain modulating system.
It increases vagal tone, and also modulates BP.
