The Clinical Syndrome

Fibromyalgia is a chronic pain syndrome that affects a focal or regional portion of the body. Fibromyalgia of the cervical spine is one of the most common painful conditions encountered in clinical practice. The sine qua non for diagnosis is the finding of myofascial trigger points on physical examination. These trigger points are thought to be the result of microtrauma to the affected muscles. Stimulation of the myofascial trigger points reproduces or exacerbates the patient’s pain. Although these trigger points are generally localized to the cervical paraspinous musculature, the trapezius, and other muscles of the neck, the pain is often referred to other areas. This referred pain may be misdiagnosed or attributed to other organ systems, thus leading to extensive evaluation and ineffective treatment.

The pathophysiology of the myofascial trigger points of fibromyalgia of the cervical spine remains unclear, but tissue trauma seems to be the common denominator. Acute trauma to muscle caused by overstretching commonly results in fibromyalgia. More subtle muscle injury in the form of repetitive microtrauma, damage to muscle fibers from exposure to extreme heat or cold, overuse, chronic deconditioning of the agonist and antagonist muscle unit, or other coexistent disease processes such as radiculopathy may also produce fibromyalgia of the cervical spine.

Various other factors seem to predispose patients to the development of fibromyalgia of the cervical spine. For example, a weekend athlete who subjects his or her body to unaccustomed physical activity may develop fibromyalgia. Poor posture while sitting at a computer or while watching television has also been implicated as a predisposing factor. In addition, previous injuries may result in abnormal muscle function and increase the risk of developing fibromyalgia. All these predisposing factors may be intensified if the patient also suffers from poor nutritional status or coexisting psychological abnormalities including depression and alexithymia, a personality disorder of altered emotional self-awareness.

Often, stiffness and fatigue accompany the pain of fibromyalgia of the cervical spine. These symptoms increase the functional disability associated with this disease and complicate its treatment. Fibromyalgia may occur as a primary disease state or in conjunction with other painful conditions, including radiculopathy and chronic regional pain syndromes. Psychological or behavioral abnormalities, including depression and alexithymia frequently coexist with the muscle abnormalities, and the management of these concurrent conditions must be an integral part of any successful treatment plan. Studies have suggested that an abnormality in the serotonin transport gene may predispose patients to the development of fibromyalgia as a result of abnormal pain processing.

Signs and Symptoms

As noted earlier, the sine qua non of fibromyalgia of the cervical spine is the myofascial trigger point. This trigger point represents the pathologic lesion and is characterized by a local point of exquisite tenderness in the affected muscle. Mechanical stimulation of the trigger point by palpation or stretching produces not only intense local pain but also referred pain. Taut bands of muscle fibers are often identified when myofascial trigger points are palpated. In addition, involuntary withdrawal of the stimulated muscle, called a jump sign, is often seen ( Fig. 17.1 ). A positive jump sign is characteristic of fibromyalgia of the cervical spine, as are stiffness of the neck, pain on range of motion, and pain referred to the upper extremities in a nondermatomal pattern. Although this referred pain has been well studied and occurs in a characteristic pattern, it often leads to misdiagnosis.

Palpation of a trigger point results in a positive jump sign.

Testing

Biopsies of clinically identified trigger points have not revealed consistently abnormal histologic features. The muscle hosting the trigger points has been described either as “moth eaten” or as containing “waxy degeneration.” Increased plasma myoglobin has been reported in some patients with fibromyalgia of the cervical spine, but other investigators have not corroborated this finding. Electrodiagnostic testing has revealed an increase in muscle tension in some patients, but again, this finding has not been reproducible. Thus, the diagnosis is based on the clinical findings of trigger points in the cervical paraspinous muscles and an associated jump sign, rather than on specific laboratory, electrodiagnostic, or radiographic testing.