Fibromyalgia

Overview

Fibromyalgia is a common, testable, and often misunderstood condition. On the PANCE, it shows up less as a diagnostic mystery and more as a pattern-recognition question. If you can recognize it quickly and avoid common traps, you’ll score easy points. This disorder affects pain processing and is a diagnosis of exclusion characterized primarily by chronic widespread musculoskeletal pain and fatigue.

Pathophysiology

Fibromyalgia is defined as a central pain processing disorder characterized by widespread musculoskeletal pain without an identifiable cause. This dramatic increase in pain perception is due to high levels of substance P which acts as both a neurotransmitter and neuromodulator responsible for transmitting pain signals through the body. This process is thought to be secondary to microtrauma within the body.

Clinical Manifestation

The female population between 20-50 years of age are the most commonly affected population. It is often associated with extreme fatigue, muscle tenderness, sleep disturbance, headache, cognitive dysfunction, and mood symptoms, sleep disturbance, and mental haziness often referred to as fibro fog.

Diagnosis

Since Fibromyalgia is a diagnosis of exclusion the provider must first rule out disorders such as rheumatoid arthritis, systemic lupus erythematous, thyroid disease, polymyositis, etc. Key features of fibromyalgia include normal lab values, pain along both sides of the body along the extremities and axial skeleton, and discomfort with palpation at 11 out of 18 tender points on exam. Symptoms must also be present for longer than 3 months.

A muscle biopsy can also be obtained which would show damage and a classic “moth eaten” appearance of the type I muscle fibers.

Treatment

Conservative treatments should be taken as first line for patients who are newly diagnosed with fibromyalgia such as exercise, stretching, heat, and massage. Cognitive behavioral therapy may also be helpful to provide reassurance and patient education while focusing on maintaining sleep hygiene. Several different classes of medication may be trialed in a effort to achieve symptoms management as well. Pregabalin is in the anticonvulsant class and if FDA approved for fibromyalgia. The SNRIs Duloxetine and Milnacipran also have FDA approval to treat these patients. Fluoxetine (SSRI), Amitriptyline (TCA), and cyclobenzaprine (muscle relaxant) may also be trialed on patients who have refractory symptoms.