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30 Cards in this Set
- Front
- Back
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Nociception
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Nociception: Defined as recognition and transmission of painful stimuli
Modulation can occur at different levels: -Peripheral -Spinal cord -Supraspinal |
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Trigger point definition
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Taut band of skeletal muscle or muscle fascia (if muscle accessible)
A hyperirritable focus Painful on compression Local twitch response on muscle manipulation (‘snapping’) or needling Compression can give rise to the sensory, motor, and/or autonomic changes Think of myofascial pain syndrome |
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Integrated trigger point hypothesis
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Muscular overload due to overuse or trauma causes dysfunction at the neuromuscular endplate
Excessive release of acetylcholine, prolonged depolarization, and sustained, focal sarcomere contraction, or contraction knot Compression of small blood vessels, local tissue ischemia, release of bradykinin, and excitation of nociceptors Multiple knots in an area summate to form the trigger point, within a ‘taut band’ of muscle |
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Myofascial pain syndrome: clinical features
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Predisposition to muscle trauma / microtrauma
-deconditioned state, -poor posture, -underlying arthritis, -certain occupations, recreational activities Persistent pain at rest Weakness or restricted movement Referred pain -Does not follow dermatome or nerve distribution |
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Myofascial pain syndrome: ddx
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Regional:
-Bursitis, -Tendinitis, -Axial radiculopathy, -Peripheral entrapment syndromes Diffuse: -Fibromyalgia (FM) Overlapping syndromes -Trigger point area may entrap a nerve -20% of patients with MPS have FM; 70% of patients with FM have active trigger points (IMPORTANT) |
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Myofascial pain syndrome: treatment
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Physical Therapy
-Identify predisposing musculoskeletal abnormalities -Correct posture and/or other abnormal mechanics -Transcutaneous electrical stimulation (TENS) -Thermal modalities -Ultrasound Invasive: -Trigger point injection |
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Fibromyalgia: definition
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Widespread pain for > 3 months
All must be present: -Pain on L and R side of body -Pain above and below waist -Axial pain must also be present (cervical spine, anterior chest, thoracic spine, or low back) 11/18 tender points must be present |
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Fibromyalgia ddx
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Systemic rheumatic diseases
Infections -Hepatitis C? Chronic fatigue syndrome Hyper or hypothyroidism Fibromyalgia |
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Fibromyalgia: pathophysiology overview
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Central sensitization
-Abnormalities of descending inhibitory pain pathways Neurotransmitter abnormalities Neurohumoral abnormalities Psychiatric comorbid conditions |
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Fibromyalgia: central sensitization
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“Turning up the volume” on an amplifier with a result that ….
Sensations that formerly were non-painful now become painful (allodynia) Sensations that formerly were mildly painful now become excessively painful (hyperalgesia) After an initial painful stimulus, subsequent equal stimuli are perceived to be more intensely painful (wind-up phenomenon) Abnormalities of descending inhibitory pain pathways |
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Fibromyalgia: neurotransmitter abnormalities
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Decreased cerebrospinal fluid serotonin in FM compared to lower back pain and pain-free persons
Decreased dopamine transmission in the brain may lead to chronic pain |
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Fibromyalgia: neurohormornal abnormalities
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Dysfunction in the hypothalamic-pituitary-adrenal axis
-Blunted cortisol responses -Lack of cortisol diurnal variation |
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Fibromyalgia: genetics
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Trace amine-associated receptor-1 (OR=3.8)
-Modulate dopaminergic activity Guanylate binding protein-1 (OR=1.7) -Induced by interferon and other cytokines Regulator of G-protein Signaling-4 (OR=1.5) -Overexpression may down-regulates mu opioid receptor function in the noradrenergic nucleus of the locus coeruleus |
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Fibromyalgia: role of stress/psychosocial factors
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1. Predisposing factors (e.g., physical abuse, trauma and injuries)
2. Triggering factors (e.g., life threatening events) 3. Perpetuating factors: -The alarming portrayal of the condition as catastrophic and disabling -Pain signifies damage and that activity should be avoided -One is unable to function because of pain -Higher body-related attention |
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Fibromyalgia: epidemiology
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80% to 90% are women.
Peak age: 30-50 Can have its onset in childhood and can be present over the age of 60. -Rare to onset after age of 60... think of PMR instead Secondary fibromyalgia more likely to affect men as well as women. |
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Fibromyalgia: associated symptoms
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Fatigue
Sleep disturbances Stiffness Paresthesias Headaches (50%) Irritable bowel syndrome (50-80%) Depression (40%) -Presence of depression worsens pain outcomes and vice versa. Anxiety |
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Secondary fibromyalgia
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Secondary FM can occur in the following clinical settings:
Hepatitis C and HIV infections Rheumatoid arthritis, lupus, scleroderma and other connective tissue diseases Multiple sclerosis |
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Fibromyalgia: laboratory tests
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IMPORTANT
Primarily done to exclude medical condition that may be presenting as FM Basic tests: -Thyroid test -Glucose -Creatinine and SGPT -Blood count -Other tests should be ordered as indicated by their history and/or physical |
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Fibromyalgia: treatment education
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Discuss the nature of the illness
-Diagnosis is “empowering” to most patients Set realistic expectations -Improve physical function -Reduce pain severity Stress management -Pleasant activity scheduling -Relaxation -Join FM support group |
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Fibromyalgia: treatment sleep hygiene
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Written advise to improve sleep hygiene
Use of drugs to induce restorative sleep Consider ruling out coexisting sleep apnea |
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Fibromyalgia: treatment physical activity
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Activity pacing
-Avoid post-exertional exacerbation of pain Encourage aerobic exercise -Graded aerobic exercise is preferred -Exercise prescription should be individualized -No differences between land-based vs. water-based exercise |
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Fibromyalgia: treatment CBT
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4-week program
-CBT vs. Usual care CBT: 6 one-hour sessions -1st –4th sessions: muscle relaxation; activity pacing; pleasant activity scheduling -5th session: cognitive restructuring, appraisals and beliefs that could sabotage coping attempts -6th session: problem solving skills in anticipation of relapse |
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Fibromyalgia: drugs used in treatment
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Tricyclic compounds
Muscle relaxants Serotonin norepinephrine reuptake inhibitor (SNRI) Analgesics (tramadol/acetaminophen) Anti-convulsants |
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Tricyclics in FM
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Significantly more effective than placebo in reducing pain
Low dose Proposed mechanisms: -Activity on noradrenergic and serotonergic systems subsequently modulating pain perception. -Amelioration of comorbid psychiatric disorder. -Potentiation or enhancement of opioid analgesia. |
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Duloxetine in FM
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Potent serotonin and NE reuptake inhibitor
Evenly balanced Combined drug better than just SSRI The inhibitory effects of antidepressants on 5-HT and NE reuptake processes have been implicated in the mediation of endogenous analgesic mechanisms via the descending inhibitory pain pathways in the brain and spinal cord |
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Tramadol in FM
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Centrally acting analgesic
Binds to mu-opioid receptors -Inhibition of ascending pain pathways activity Inhibit the uptake of norepinephrine and serotonin Risk of abuse and dependence: -1 per 100,000 patient exposures |
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Anticonvulsant (pregabalin, gabapentin) in FM
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Analgesic and anxiolytic-like activity
Restricted to neurons -Reduces the release of glutamate, noradrenaline and substance P Gabapentin is now being widely used in various pain conditions, particularly in neuropathic pain. Efficacious in reducing pain from diabetic neuropathy and postherpetic neuralgia. (+) effects on mood and quality of life |
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NSAIDs and opiates in FM
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No data to support efficacy
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FM comorbid psychiatric disorder
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Difficult to distinguish cause and effect within the pain-depression-insomnia cycle.
Clinician must actively screen for its presence repeatedly during the course of pain treatment Anxiety -Pain causes anxiety; reducing anxiety in pain states may prevent the negative psychophysiological sequelae of chronic pain. -Causes autonomic nervous system (ANS) arousal, leading to skeletal muscle tension; precipitates episodic muscle spasm. -Interferes with effective cognitive and behavioral coping. |
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WHO pain guidelines
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Nonpharm modalities and/or acetaminophen
Low-dose ibuprofen or nonacetylated salicylates Full-dose NSAIDs Weak opioids Strong opioids |
