Diffuse Soft Tissue Pain

A 38 year-old accountant notes persistent joint pain and fatigue that have worsened over the past several months. She has had similar but milder pain for the past four to five years. She notes pain in her neck, shoulders, arms, back and knees. The pain interferes with her sleep most nights and she never awakens feeling rested. She has trouble making it through a full day at work because she is so tired. She has tried various over-the-counter non-steroidal anti-inflammatory therapies along with sleep aids, all without significant improvement. She denies depression but does admit to a fair amount of stress at work trying to keep up with the work load. The only past medical history is a prior diagnosis of irritable bowel syndrome. The rest of her review of systems is negative.

On joint exam, there is no synovitis or joint deformity. She has full range of motion of all extremities and passive joint movement does not reproduce her pain. On palpation though, she displays increased tenderness over multiple juxta-articular muscle groups, including over her upper trapezius, posterior cervical muscles, lumbar, paraspinous, greater trochanter, medial knees, and lateral epicondyles. There is discomfort with examiner resistance during strength testing, but normal strength of the upper and lower extremity muscles throughout. The rest of her examination is normal including head and neck, skin, cardiac, pulmonary, abdominal, and neurologic testing.

Laboratory evaluation is notable for CBC, CMP, ESR, thyroid studies, and vitamin D levels that are normal. Hepatitis B and C testing is negative.

This patient’s presentation and clinical findings are consistent with a diagnosis of fibromyalgia as the cause of her widespread chronic pain and fatigue.

In addition to fibromyalgia, what other disorders might present with chronic widespread pain and fatigue?

The differential for diffuse pain is broad. Rheumatologic causes include polymyalgia rheumatica, lupus, rheumatoid arthritis, myositis, vasculitis and scleroderma. Infectious entities that can cause chronic widespread pain include hepatitis C and HIV. Endocrinopathies such as hypothyroidism and hyperparathyroidism should be considered. Drug toxicity as a cause is best exemplified by the muscle pain complicating statin therapy.

Other considerations include malignancy, neurologic disorders, sleep apnea and psychogenic pain from mood disorders.

What clinical and/or laboratory features from above are most helpful in identifying the diagnosis?

The presence of widespread tender points, along with a concurrent history of irritable bowel syndrome (IBS), is suggestive of fibromyalgia. Concurrent functional disorders such as IBS, interstitial cystitis, and TMJ syndrome may be present. In addition, there is a high prevalence of comorbid depression among patients with fibromyalgia. The syndrome can develop without a precipitating event, but has been reported following injury/trauma as well as in the setting of physical/emotional abuse (highlighting the importance of a full history during the initial encounter).

The lack of joint swelling, muscle weakness or other objective exam findings, coupled with lack of end-organ disease by lab testing, suggest a diagnosis other than a systemic inflammatory process. In general, the absence of clinical, radiographic and laboratory evidence of an inflammatory process after > 2 years of symptoms suggests a non-inflammatory etiology. The utility of laboratory testing is to rule out other etiologies. How extensive this testing should be is debatable.

Preliminary diagnostic criteria for fibromyalgia were updated in 2010 and do not include reliance upon tender points on exam. 

The patient returns to review the results of her studies. Extra time is spent counseling her on the diagnosis of fibromyalgia, explaining what it is and how it can be managed. She is reassured that this is not a progressively destructive or life-threatening illness. The need for regular, daily exercise and lifestyle modification is stressed. The diagnosis and treatment of any barriers to sleep is also essential, and referral to a sleep physician may be warranted. Therapeutic options are discussed and a trial of low dose, nighttime amitriptyline is begun.