Diagnosis of Fibromyalgia

Diagnostic Evaluation of Fibromyalgia

Patient History and Physical Examination

The diagnostic evaluation of fibromyalgia begins by taking a careful patient history and establishing the presence of the primary signs and symptoms of the syndrome. Fibromyalgia should be suspected in any patient with a long-standing history (3 months or longer) of widespread musculoskeletal pain, persistent fatigue, generalized stiffness (especially in the morning), and sleep disturbances. Patients with fibromyalgia may also complain of associated symptoms (e.g., headaches; irritable bowel syndrome; cognitive dysfunction; mood disorders; hypersensitivity to cold temperatures; among others).

The diagnostic evaluation of the patient with suspected fibromyalgia continues with a physical examination that focuses on locating and assessing the patient's tender points for pain. Tender points are regions of the body that evoke severe pain upon gentle digital palpation. The level of pain experienced by patients with fibromyalgia is out of proportion to what would otherwise be expected by gentle digital palpation of the tender point regions.

In 1990, the American College of Rheumatology established the following diagnostic criteria for patients with fibromyalgia:

• Long-standing, widespread musculoskeletal pain of at least 3 months duration.

• Pain must be present in all four body quadrants

  • pain in the left side of the body
  • pain in the right side of the body
  • pain above the waist
  • pain below the waist
  • axial skeleton pain (cervical spine, anterior chest, thoracic spine or low back)

• Painful response upon gentle digital palpation must be elicited in 11 of 18 tender point regions:

  • occiput (back of the head): both sides at the sites of muscle insertions
  • low cervical: both sides (C5-C7)
  • trapezius: both sides
  • supraspinatus: both sides
  • second rib: both sides
  • lateral epicondyle (elbow): both sides
  • gluteal (buttocks): both sides
  • greater trochanter (hip): both sides
  • knee: both sides, inner aspects

The pain may be described as a deep aching, radiating, gnawing, shooting or burning. It can range from mild to severe and is felt deep within muscles, ligaments or tendons. Typically, the body aches with stiffness upon awakening; the aches may improve during the day and increase again toward the evening. Symptoms are made worse by exertion, cold, damp weather, changes in barometric pressure, anxiety and stress. Muscle spasm and cramping are more common at night.

Laboratory Evaluation

The diagnosis of fibromyalgia can usually be established on the basis of signs and symptoms and a physical examination using the 1990 American College of Rheumatology classification criteria with documentation of a painful response upon gentle digital palpation in 11 of 18 designated tender points.

Expensive imaging studies, electrical nerve conduction studies, or invasive diagnostic procedures are rarely necessary or justified. X-Rays, MRIs and nerve conduction studies are usually normal in people with fibromyalgia and tend to be used only if other disorders are suspected.

There are no specific laboratory blood tests that can diagnose fibromyalgia. Blood tests may be performed primarily to rule-out other conditions that may be the cause of the patient's signs and symptoms. Blood tests that may be performed as part of the diagnostic "work-up" for fibromyalgia may include:

• Complete blood count (CBC)
• Blood chemistries
• Erythrocyte sedimentation rate
• Antinuclear antibodies
• Rheumatoid factor
• Thyroid function tests
• Serum iron levels
• Creatinine phosphokinase (CPK)
• Vitamin B12
• Folate