Subscription is FREE for qualified healthcare professionals in the US.

Fibromyalgia & Myofascial Pain Syndromes

A practical approach to the differential diagnosis and treatment of fibromyalgia and myofascial pain syndromes.

A bane in the practice of almost any clinician who treats chronic pain syndromes is the patient with chronic muscular pain, specifically fibromyalgia and myofascial pain syndromes.1 In general, musculoskeletal pain impacts greater than 40 million people in the United States, and is responsible for greater than 300 million physician visits, with a cost in the hundreds of millions of dollars.2 Musculoskeletal pain is divided into articular pain, such as osteo- and rheumatoid arthritis, as well as myofascial and fibromyalgia pain syndromes. The clinician should understand the differences, similarities, and interactions between these syndromes. For the purpose of this article, the majority of the focus will be on fibromyalgia and myofascial pain. It is quite common — though inaccurate — that these two terms are used interchangeably.

Fibromyalgia Diagnostic Considerations

A primary symptom for fibromyalgia is the widespread diffuse muscular pain and tenderness.3 In order to meet the criteria of the American College of Rheumatology, 11 of the 18 defined Tender Points (TePts) which are painful with a standard 4 kilograms of force, and present for greater than three months.4 A wide variety of other accompanying symptoms such as fatigue, generalized weakness, non restorative sleep, cognitive difficulties, and subjective swelling or stiffness, along with occasional paresthesias, dysthesias and allodynia may coexist to complicate diagnosis and treatment. These concurrent symptoms also support the belief that central sensitization mechanisms, similar to neuropathic pain syndromes, may play a role in fibromyalgia pathology. Moreover, it is not uncommon for the patient to have other associated syndromes including anxiety, depression, irritable bowel syndrome, migraine headaches and other rheumatologic disorders, further complicating the clinical situation.

At times, the accurate diagnosis may appear as one of exclusion, as the differential diagnosis is quite expansive. Extensive laboratory evaluation may help rule out syndromes as polymyositis, chronic Lyme disease, hepatitis C, osteomalacia, polymyalgia rheumatica, rheumatoid arthritis, Systemic lupus erythematosus, and various drug or nutritional induced myopathies. Like many of these other listed syndromes, myofascial pain should also be in the differential diagnosis, and may co-exist with fibromyalgia.

The difficulty in making an accurate diagnosis, along with often secondary behavioral issues in the patient, tends to promote the myth that fibromyalgia is a psychiatric or psychosomatic illness, akin to a “supratentorial” syndrome, as quoted by a regional HMO medical director. Specific laboratory studies tend to support the hypothesis of central sensitizations influence. CSF assays of fibromyalgia patients have found increased levels of substance P, and lower levels of serotonin, norepinephrine, and dopamine. ACTH and epinephrine release in response to hyperglycemia is blunted, as is sleep induced prolactin and growth hormone release. Moreover, heart rate response to exercise is diminished, as is vasoconstrictor responses to acoustic and cold stressors. More recent studies also report connective tissue collagen structure changes.

Diagnostic Criteria for Myofascial Trigger Points (TrPs)
All five of the following major criteria:
  1. 1. Regional pain complaint
  2. 2. Pain or parethesia in the typical distribution for that TrP
  3. 3. Taut band, if the muscle is accessible to palpation
  4. 4. Exquisite tenderness found in the taut band
  5. 5. Restricted range of motion in the involved muscles
One of three minor criteria:
  1. Reproduction of the clinical pain complaint by palpation of the TrP
  2. Local twitch response within the taut band with palpation or needle contact
  3. Spray & Stretch or injection alleviates TrP and Pain
Mechanisms of TrP Injections
  1. Mechanical disruption
  2. Release in intracellular K+
  3. Wash-out of sensitizing
  4. substances
  5. Local vasodilatation
  6. Interruption of feedback
  7. mechanisms
Figure 1. Mechanisms of Trigger Point Injections
Last updated on: May 16, 2011
First published on: July 1, 2004