Fibromyalgia is a clinical syndrome wherein the patient experiences generalized pain and fatigue that cannot be explained by the presence of any other disorder.
It is often considered to be psychosomatic or psychogenic in nature.
It is found in approximately 2% of the population and the prevalence increases with age, most common in women 20-55 year of age


  • The 2010 American College of Rheumatology (ACR) classification criteria have been used in most clinical & therapeutic trials
  • Based on expert opinions regarding the optimal historical & physical findings that could differentiate patients w/ FM from those w/ other rheumatic disease & forms of chronic pain
  • A diagnosis of fibromyalgia is given to patients who have all 3 conditions:
    • Widespread pain index (WPI) ≥7 and symptom severity (SS) scale score ≥5 or WPI of 3-6 and SS scale score of ≥9
    • Symptoms present for at least 3 months
    • No other disorder/disease that can explain the pain
  • It does not require a physical or tender point exam, but does provide a scale for measurement of the severity of symptoms that are characteristic of FM
  • May be used in patients w/ symptoms present at a similar level for at least 3 mth, & there is no other disorder that would otherwise explain the pain
  • Particularly useful in clinicians who are inexperienced in performing tender point exam or as additional points in difficult cases
  • Showed a good correlation w/ the 1990 ACR criteria & it correctly classifies 88.1% of cases
  • Combine the widespread pain index (WPI) & the symptom severity (SS) scale for making the diagnosis
    • WPI is a measure of the number of painful body regions from a defined list of 19 areas
      • Shoulder girdle, left
      • Shoulder girdle, right
      • Lower arm, left
      • Lower arm, right
      • Hip (buttock, trochanter), left
      • Upper arm, left
      • Upper arm, right
      • Lower leg, left
      • Lower leg, right
      • Hip (buttock, trochanter), right
      • Upper leg, left
      • Upper leg, right
      • Jaw, left
      • Neck
      • Upper back
      • Lower back
      • Abdomen
      • Chest
    • SS score is the sum of the severity of the 3 symptoms (fatigue, unrefreshed sleep & cognitive symptoms) plus the severity or extent of somatic symptoms in general
    • Scale for the level of severity for each of the 3 symptoms over the past week:
      • 0 no problem
      • 1 slight or mild problems, generally mild or intermittent
      • 2 moderate, considerable problems, often present and/or at a moderate level
      • 3 severe: pervasive, continuous, life-disturbing problems
    • Scale for presence of somatic symptoms in general:
      • 0 no symptoms
      • 1 few symptoms
      • 2 a moderate number of symptoms
      • 3 a great deal of symptoms
    • Final score is between 0 and 12
    • The SS score allows assessment of patients w/ current or previous FM, & in those in whom the classification criteria have not been applied
    • It is particularly useful in longitudinal evaluation of patients w/ marked symptom variability


  • Diagnosis is based primarily on history of widespread pain, defined as axial, bilateral, upper & lower body pain, for at least 3 consecutive mth
  • Pain assessment w/ particular focus on the type, quality, source, location, duration, time course, pain affect & effects on patient’s quality of life
  • Evaluate severity of other symptoms
    • Refer patients w/ suspected mood disorders for formal psychological testing
  • Evaluate for conditions that mimic, complicate or coexist w/ FM: Hypothyroidism, ankylosing spondylitis, tendonitis, bursitis, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), osteoarthritis (OA), polymyalgia rheumatica, irritable bowel syndrome, chronic fatigue syndrome, temporomandibular dysfunction, vulvodynia & irritable bladder
  • Review social & development history
  • Previous treatment & efficacy, opioid prescription

Physical Examination

  • Perform a complete joint exam, manual muscle strength testing & neurological exam
  • Perform manual tender point exam on the 18-paired muscle-tendon sites including the control areas (eg thumbnail, forehead, mid forearm) w/ pressure that is approx 4 kg/cm2
    • Can be influenced by external factors
  • Usually within normal limits except for soft tissue tenderness

Laboratory Tests

  • There are no pathognomonic lab tests or imaging studies for FM
  • Lab tests should only be performed to exclude associated disease or illness that may mimic, complicate or coexist w/ FM
    • CBC to rule-out infectious etiologies & multi-system disease
    • ESR is almost always elevated in polymyalgia rheumatica
    • Creatine phosphokinase (CPK) is elevated in inflammatory myopathy
    • Thyroid function tests, LFT, C-reactive protein (CRP)
  • Overnight polysomnogram is performed in patients suspected of sleep disorders
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