Pitfalls Associated with Diagnosing Polymyalgia Rheumatica and Fibromyalgia in Young Obese Patients

July 30, 2019

Fibromyalgia and polymyalgia rheumatica are distinctly different, but in a case report described in the May 8 issue of the American Journal of Case Reports, Fawad Aslam, M.D., of Mayo Clinic in Arizona, and colleagues describe a confusing case of a 30-year-old woman.

Fibromyalgia and polymyalgia rheumatica are distinctly different, but in a case report described in the May 8 issue of the American Journal of Case Reports, Fawad Aslam, M.D., of Mayo Clinic in Arizona, and colleagues describe a confusing case of a 30-year-old woman.

In this article we summarize the case report, but also highlight the features that distinguish fibromyalgia and polymyalgia rheumatica.

THE CASE

This was a 30-year-old African-American woman with a year-long history of dysphagia, generalized muscle tenderness, tender neck lymphadenopathy, plus hypertension, asthma, gastroesophageal reflux disease, migraines, obesity (BMI of 41), and obstructive sleep apnea.

Her inflammatory markers were high. ESR was 100 mm/h as compared to a normall of less than 29. And, CRP was 35 mg/L as compared to a normal of less than eight.

Her symptoms included sudden onset of dysphagia, generalized muscle tenderness, and tender neck lymphadenopathy. She was initially diagnosed with polymyalgia rheumatica and was prescribed prednisone as long-term therapy at 20 mg daily.The treatment successfully resolved her symptoms, but they returned when the treatment stopped. Prednisone was resumed with methotrexate, but her mylagia symptoms worsened due to severe chronic steriod use.

At times, the pain and fatigue was so severe, she could not get out of bed, the authors reported.

Although initially diagnosed with polymyalgia rheumatica, doctors ultimately concluded she had fibromyalgia.

"Fibromyalgia is usually a diagnosis of exclusion in patients who present with chronic myalgias. Rendering a diagnosis of fibromyalgia requires a careful clinical
evaluation for any underlying condition that may be responsible for the fibromyalgia," the authors wrote.

NEXT PAGE: How are polymyalgia rheumatica (PMR) and fibromyalgia different?

Source: Rabia Cheema, April Chang-Miller, Fawad Aslam. "Myalgia with Elevated Inflammatory Markers in an Obese Young Female: Fibromyalgia or Polymyalgia Rheumatica?" American Journal of Case Reports. 2019; 20:659-663. DOI: 10.12659/AJCR.915564

How are polymyalgia rheumatica (PMR) and fibromyalgia different?

Polymyalgia rheumatica is most commonly associated with pain and stiffness, primarily of the joint and hip. For a diagnosis, the patient must be 50 years old or older. It is extremely rare in African-Americans populations.

Polymyalgia rheumatica patients usually have a rapid and effective therapeutic response to low-dose glucocorticoids, up to 75 percent within seven days with a 15 mg dose.

Fibromyalgia manifests as chronic widespread musculoskeletal pain often accompanied by fatigue, cognitive disturbance, psychiatric symptoms, and multiple somatic symptoms. It primarily afflicts women between 20 and 55 years old, but can occur at any age.

A key difference is that fibromyalgia is not associated with high inflammatory markers and steroids are not known to be effective for fibromyalgia.

NEXT PAGE:  OBESITY AS CONFOUNDER

How can obesity make arriving at an accurate diagnosis even more difficult?

Obesity can elevate inflammatory markers, but the elevated levels are not always due to obesity. Obesity is also more prevelant among patients with fibromyalgia, but a full work-up is recommended to rule out rheumatologic disorders, such as rheumatoid arthritis, spondyloarthritis, connective tissue diseases or rare disorders like Takayasu arteritis. And, even thought ESR and CRP are not typically elevated in fibromyalgia cases, this case illustrates an exception to the rule.

NEXT PAGE:  AGE AS CONFOUNDER

At what age does polymyalgia rheumatica (PMR) usually manifest?

It usually occurs in people over age 50.

NEXT PAGE:  HALLMARK DISEASE FEATURES

What are the hallmark features of polymyalgia rheumatica?

Elevated erythrocytes sedimentation rate (ESR) and/or C-reactive protein (CRP), which are normal in fibromyalgia.

NEXT PAGE:  LABORATORY TESTING

A diagnosis of fibromyalgia requires laboratory testing. Which tests are recommended?

Laboratory testing to rule out other conditions are recommended. Specifically, the following conditions: spondyloarthritis, systemic autoimmune disorders, polymyalgia rheumatica, inflammatory myopathy, and hypothyroidism.

 

REFERENCE: Rabia Cheema, April Chang-Miller, Fawad Aslam. "Myalgia with Elevated Inflammatory Markers in an Obese Young Female: Fibromyalgia or Polymyalgia Rheumatica?" American Journal of Case Reports. 2019; 20:659-663. DOI: 10.12659/AJCR.915564