Fibromyalgia: Update on Understanding Pathophysiology and Treatment Approaches

With treatment approaches for fibromyalgia evolving over the course of modern medicine, many clinicians are reviewing the way they address potential symptoms of the common chronic, widespread pain condition.

“We as clinicians have to be proactive but also be advocates for patients with this condition,” said Steven Stanos, DO, medical director of Swedish Pain Services at the Swedish Health Systems/Swedish Medical Group, at PAINWeek.

What many may not realize is that fibromyalgia overlaps with related syndromes including chronic fatigue syndrome, regional pain syndromes such as tension headache, temporomandibular joint disorder, and idiopathic low back pain; psychiatric disorders such as major depressive disorder, obsessive-compulsive disorder, bipolar disorder, posttraumatic stress disorder, and general anxiety disorder;  and somatoform disorders.1

The pathophysiology of fibromyalgia includes central sensitization (amplification of pain in the spinal cord via spontaneous nerve activity, expanded receptive fields, and augmented stimulus responses), abnormalities of descending inhibitory pain pathways (dysfunction in brain centers that regularly downregulate pain signaling in the spinal cord), neurotransmitter abnormalities (where decreased serotonin in the central nervous system could lead to aberrant pain signaling), neurohumoral abnormalities (dysfunction in the hypothalamic-pituitary-adrenal [HPA] axis), and comorbid psychiatric conditions (persons with fibromyalgia have increased rates of psychiatric comorbid conditions).2

Clinical features of fibromyalgia include widespread pain, sleep disturbances, tenderness, and fatigue. Pain characterizations in patients with fibromyalgia include an increase in brain activity related to anticipation of pain, attention to pain, emotional aspects, and motor control.3

Fibromyalgia shares several features with depression, said Dr. Stanos.  These include a strong genetic predisposition and similar comorbidity; coaggregation in families; cognitive disturbances; dysfunction of the HPA axis; chronic stress-induced cytokine expression in the brain; and central monoaminergic neurotransmission.

Dr. Stanos described the stepwise treatment algorithm for fibromyalgia: confirm the diagnosis of fibromyalgia; recommend treatment based on the individual evaluation; and if the patient is not responding to medication alone, consider cognitive behavioral therapy or group education.4

Patients living with fibromyalgia may undergo a range of physical, cognitive, social, and activity changes. For example, a patient could feel fatigued, experience memory problems, witness disruption in family relationships, and admit to a reduction in activities of daily living. Patients with fibromyalgia also report abnormal sleep characteristics: delayed sleep onset, more frequent arousals, sleep disordered breathing,  and changes on electroencephalography.

Dr. Stanos recommended that clinicians use both nonpharmacologic  and pharmacologic therapies to address increased distress, decreased activity, isolation, poor sleep, and maladaptive illness behaviors.

Nonpharmacologic therapies can alleviate pain in fibromyalgia, but not all options are as evidence-based as others. Cognitive behavioral therapy and aerobic exercise are commonly recommended for these patients, and there is strong evidence in support of their use. Tender point injections and flexibility exercises, however, are less common.5,6

Pharmacologic therapies for fibromyalgia include dual-reuptake inhibitors, anticonvulsants, and selective serotonin reuptake inhibitors (SSRIs). There is weak evidence supporting the use of growth hormones or tropisetron, and little evidence to support the use of nonsteroidal anti-inflammatory agents or opioids in these patients.5,6

The new American College of Rheumatology (ACR) criteria for fibromyalgia require that other potential causes be ruled out and that a patient has been experiencing symptoms for at least 3 months. It also includes two new methods of assessment: the widespread pain index (WPI) and the symptom severity (SS) scale score.

Dr. Stanos concluded that fibromyalgia is best understood from a multidisciplinary perspective because of its complexity.

References

  1. Clauw DJ, Chrousos GP. Chronic pain and fatigue syndromes: overlapping clinical and neuroendocrine features and potential pathogenic mechanisms. Neuroimmunomodulation. 1997;4:134-153.
  2. Abeles AM, Pillinger MH, Solitar BM, et al. Narrative review: the pathophysiology of fibromyalgia. Ann Intern Med. 2007;146:726-734.
  3. Graceley RH, Geisser ME, Giesecke T, et al. Pain catastrophizing and neural responses to pain among persons with fibromyalgia. Brain. 2004;127:835-843. doi: 10.1093/brain/awh098.
  4. Arnold LM. Biology and therapy of fibromyalgia. New therapies in fibromyalgia. Arthritis Res Ther. 2006;8:212.
  5. Burckhardt CS, Goldenberg D, Crofford L. Guideline for the Management of Fibromyalgia Syndrome Pain in Adults and Children. Glenville, Ill: American Pain Society; 2005.
  6. Goldenberg DL, Burckhardt C, Crofford L. Management of fibromyalgia syndrome. JAMA. 2004;292:2388-2395.

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