Fibromyalgia: A Diagnosis of Exclusion No Longer

LAS VEGAS—A diagnosis of fibromyalgia is not one of exclusion but based on clinical characteristics, the primary hallmark of which is chronic, widespread pain of 3 months or more in duration, Gary W. Jay, MD, FAAPM, a pain medicine and management consultant from Raleigh-Durham, North Carolina, said in providing a comprehensive, practical approach to the disorder.

Emphasizing that patients with fibromyalgia must be treated within a medical model, he said American College of Rheumatology (ACR) diagnostic criteria for the disorder requires three conditions be met: 1) a widespread pain index (WPI) ≥7 and symptom severity (SS) scale score ≥5 or WPI 3 to 6 and SS scale score ≥9; 2) symptoms have been present at a similar level for at least 3 months; and 3) the patient doe not have a disorder that would otherwise explain the pain.

The pain can wax and wane and intensity may vary, as may physical location. Fibromyalgia is associated with fatigue and sleep disorder, as well as tenderness, stiffness, mood disturbances, and cognitive difficulties, and can be the cause of multiple areas of functional impairment. Patients with fibromyalgia have reported difficulty climbing stairs, walking two blocks, and with activities of daily living.

Fibromyalgia has a negative effect on careers, mental health, and personal relationships, with increased work absences, decreased productivity, and higher direct/indirect medical and other costs. Fibromyalgia is currently a clinical entity within the spectrum of central sensitivity syndromes, which includes chronic fatigue syndrome, irritable bowel syndrome, temporomandibular disorder, restless leg syndrome and periodic limb movements in sleep, idiopathic low back pain, multiple chemical hypersensitivity, headache (tension-type, migraine, mixed), interstitial cystitis, chronic pelvic pain and endometriosis, and myofascial pain syndrome.

Dr. Jay provided three hypotheses for the disorder's pathophysiology: central sensitization secondary to constant peripheral nociception (pain amplification); failure of the descending pain pathway; and mu opioid receptors not functioning properly, possibly contributing to failure of the descending pain pathway.

Primary fibromyalgia is more difficult to treat because patients commonly have significant hypersensitivity to the prescribed medications. Better treatment outcomes may result if patients are first subgrouped, possibly on the basis of psychosocial/behavioral or genomic/metabolic characteristics. FDA-approved agents to treat fibromyalgia are pregabalin, a gabapentinoid, and two serotonin–norepinephrine reuptake inhibitors, duloxetine and milnacipran. These drugs should be started low and slowly titrated in patients. In patients with secondary fibromyalgia, the treatment is directed at the primary illness.

Fibromyalgia affects approximately 10 million Americans and is most prevalent in women (75% to 90%), although it does occur in men and children. Typically, a diagnosis of fibromyalgia is made between the ages of 20 and 50 years. Incidence increases with age; therefore, by 80 years, approximately 8% of adults meet ACR criteria for fibromyalgia, according to the National Fibromyalgia Association.