Fibromyalgia—worth a diagnosis?

Fibromyalgia (FM) is a protean chronic pain syndrome. In its pathophysiology the dysregulation of central pain processing ( ‘ central sensitization ’ ) is of pivotal importance, but peripheral input of nociceptic information, especially if chronic, also contributes to the development of full-blown FM (1). Although chronic widespread pain and allodynia (decreased threshold to painful stimuli, excessive tenderness) are the hallmarks of FM, other core symptoms include debilitating fatigue, non-refreshed sleep, cognitive problems, and excessive somatic symptoms reporting. FM patients are frequently also co-morbid with psychiatric conditions such as depression and anxiety as well as stress-related disorders (2), but usually these are not the most emergent problems. Chronic pain is prevalent. In epidemiological studies approximately 10% – 15% of the population in Western countries of both genders suffer from chronic widespread musculoskeletal pain (CWP) (3). FM is signifi cantly more common in females (3% – 5%) than in males (0.2% – 0.5%) (4). The gender differential for CWP and FM may be due to the American College of Rheumatology (ACR) 1990 classifi cation criteria requiring at least 11/18 tender points (5), whose presence also correlates with psychological distress (1). Physicians are trained to do diagnostics. Nevertheless, the majority of patients at primary care present symptoms which cannot be explained by any disease (6). On the other hand, authorities in rheumatology still debate whether the diagnosis of FM is justifi ed (7), although most admit that ‘ pain is real ’ (8). Further, many physicians are reluctant to diagnose FM, since they are taught in medical schools to diagnose diseases, not obscure sets of symptoms. In fact, according to a survey amongst Norwegian physicians, the doctors rank FM as the least ‘ prestigious ’ illness (9). Nevertheless, FM is worth a diagnosis. FM decreases function (10) and is costly both by increasing all kind of health service utilization (11) as well as work disability (10,12). The diagnosis does not affect adversely (13) but helps the patient to cope with the symptoms (14). More importantly, the diagnosis of a true case of FM leads to savings mostly due to decrease in health service utilization (15). Further, the patients with FM appear to be at increased risk to commit suicide (16,17). In the present issue of Annals of Medicine , Wolfe and H ä user (18) put excellently into perspective the evolvement of the concept fi bromyalgia from fi brositis, the confl ict this chronic pain syndrome has generated and still generates within the medical community, as well as how various criteria to classify or diagnose a patient with FM have emerged. The authors compare the recent ACR 2010 preliminary diagnostic criteria for fi bromyalgia, compiled by a group of fi bromyalgia specialists (19), with the previously composed ACR 1990 fi bromyalgia classifi cation criteria (5). The latter consist only of the recognition of CWP (at least for 3 months) and tender point palpation, while the 2010 criteria ignore manual physical examination. On the other hand, the 2010 criteria include the presence of CWP and emphasize the importance of other key features of FM: fatigue, unrefreshed sleep, cognitive problems, and extensive somatic symptom reporting. Expectedly, the criteria for the most part catch the same patients, although a total of 25% of the patients classifi ed to have FM according to the ACR