Gowers, a neurologist, first described FMS in 1904 as a possibly inflammatory condition. When no evidence of inflammation could be found an association was noted with depression and stress, the concept of “psychogenic rheumatism” was advanced (Boland 1947). A number of studies have since established that FMS is neither a psychosomatic nor somatiform disorder and that when present, anxiety and depression are more likely to be the result than the cause of FMS (Goldenberg 1989, Yunus 1994). Although FMS is now a better defined clinical syndrome, comprehensive patient evaluation continues to include a wide differential diagnosis including many diverse and sometimes obscure neurological and neuromuscular conditions.

Pathological findings in muscle in painful neuromuscular syndromes and neurophysiological abnormalities of sleep in FMS will be reviewed. Although there have been many abnormalities of laboratory and other tests reported in FMS, none is sufficiently sensitive or specific to be useful diagnostically. Patients with FMS should have a comprehensive medical evaluation as part of their work-up. A preliminary lab screening should include CBC, ESR, Rheumatoid factor, ANA, SPEP, IFE, Thyroid function testing (T₄, TSH), Hgb A1C, and CK (x3). Both prescribed and surreptitious drug use should be explored. Sleep and exercise behaviors should be examined. Clinical consideration of a wide range of diagnostic possibilities may include: Acute or chronic inflammatory demyelinating or axonal polyneuropathy, autonomic neuropathy, secondary hyperparathyroidism, obstructive sleep apnea, periodic limb movements, restless legs syndrome, Chiari I malformation, cervical spinal stenosis, polymyalgia rheumatica, polymyositis, inclusion body myositis, nodular fasciitis, steroid withdrawal syndrome, chronic antacid use (milk-alkali syndrome), myoadenylate deaminase deficiency or other metabolic myopathies, periodic paralysis, and myasthenia gravis.

Presented at the National Fibromyalgia Research Association's Subgroups in Fibromyalgia Symposium, September 26-27, 1999, in Portland, Oregon.