Fibromyalgia Diagnosis

• Diagnosis is based primarily on history of widespread pain, defined as axial, bilateral, upper and lower body pain, for at least 3 consecutive months
• Pain assessment with particular focus on the type, quality, source, location, duration, time course, pain affect and effects on patient’s quality of life
• Evaluate severity of other symptoms
• Refer patients with suspected mood disorders for formal psychological testing

• Evaluate for conditions that mimic, complicate or coexist with fibromyalgia: 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 and irritable bladder
• Review social and development history
• Previous treatment and efficacy, opioid prescription

• Perform a complete joint exam, manual muscle strength testing and neurological exam
• Perform manual tender point exam on the 18-paired muscle-tendon sites including the control areas (eg thumbnail, forehead, mid forearm) with pressure that is approximately 4 kg/cm²
• Can be influenced by external factors
• Usually within normal limits except for soft tissue tenderness
• Repeated physical exams are generally avoided unless there are new reported symptoms or findings

• There are no pathognomonic lab tests or imaging studies for fibromyalgia
• Lab tests should only be performed to exclude associated disease or illness that may mimic, complicate or coexist with fibromyalgia
  
  • CBC to rule-out infectious etiologies and multi-system disease
  • Erythrocyte sedimentation rate (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

Classification Criteria

• The 2016 revision to the 2010/2011 American College of Rheumatology (ACR) classification criteria have been used in most clinical and therapeutic trials
• Based on expert opinions regarding the optimal historical and physical findings that could differentiate patients with fibromyalgia  from those with other rheumatic disease and forms of chronic pain
• A diagnosis of fibromyalgia is given to patients who have all the following conditions:
  • Widespread pain index (WPI) ≥7 and symptom severity scale (SSS) score ≥5 or WPI of 4-6 and SSS score of ≥9
  • Pain in at least 4-5 regions or generalized pain is present 
  • Symptoms present at a similar level for at least 3 months
  • Diagnosis of fibromyalgia does not exclude the presence of other disorders or coexistent conditions

• 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 fibromyalgia
  • Tender points, when associated with other functional disorders, may be useful in diagnosis
• Particularly useful in clinicians who are inexperienced in performing tender point exam or as additional points in difficult cases

• Combine the widespread pain index (WPI) and the symptom severity scale (SSS) score 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
    • Hip (buttock, trochanter), right
    • Upper arm, left
    • Upper arm, right
    • Lower leg, left
    • Lower leg, right
    • Upper leg, left
    • Upper leg, right
    • Jaw, left
    • Neck
    • Upper back
    • Lower back
    • Abdomen
    • Chest
  • SSS score is the sum of the severity of the 3 symptoms (fatigue, unrefreshed sleep and cognitive symptoms) plus the sum (0-3) of the following symptoms (headache, cramps or pain in the lower abdomen and depression) that the patient experienced during the previous 6 months
    • Scale for the level of severity for each of the 3 symptoms over the past week:

      Score	Symptoms
      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

      Reference: Dymon TE. Fibromyalgia. Ambulatory Care Self-Assessment Program. http://www.accp.com. 2015.

    • Final score is between 0 and 12
    • The SSS score allows assessment of patients with current or previous fibromyalgia, and in those in whom the classification criteria have not been applied
    • It is particularly useful in longitudinal evaluation of patients with marked symptom variability
  • Fibromyalgia severity (FS) scale is the sum of WPI and SSS and ranges from 0 (no symptoms) to 31 (most severe symptoms)
    • 92-96% of patients with scores ≥12 will satisfy the criteria for fibromyalgia and FS score will provide an approximate measure of fibromyalgia severity