Fibromyalgia: Diagnosis

Pain symptoms are often symmetric. Screening for psychiatric conditions is appropriate, but a positive diagnosis does not exclude fibromyalgia as a separate diagnosis.

Physical examination reveals characteristic tender points. Palpation causes pain that is disproportionate to the stimulus intensity. Apart from muscle and tendon pain, the examination is otherwise normal except for coexisting conditions, such as rheumatoid arthritis, osteoarthritis, and lupus.

The diagnosis of fibromyalgia requires 11 of 18 bilateral tender points.² Pressure should be applied gradually and with a dolorimeter (4kg/cm), or by using a finger to the point of whitening of the fingertip.³

The sites of palpation are:

Superolateral quadrant of gluteus maximus.
Supraspinatus origin.
Superior half of trapezius.
Suboccipital insertion.
Sternocleidomastoid (posteroinferior).
Second costochondral junction.
Lateral epicondyle (approximately 2 cm distal).
Greater trochanter.
Medial knee (fat pad).

No abnormal laboratory or imaging findings are diagnostic of fibromyalgia, and inappropriate use of tests can lead to misdiagnosis. Initial laboratory tests that could help rule out other etiologies include erythrocyte sedimentation rate, complete blood count, thyroid function tests, Lyme disease titer, and creatine kinase.