Fibromyalgia vs Polymyalgia rheumatica
How to tell Fibromyalgia and Polymyalgia rheumatica apart when a board question makes them look alike.
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Elevated ESR or CRP in a patient older than 50 with proximal morning stiffness points to polymyalgia rheumatica.
Side by side
Chronic widespread pain with fatigue and nonrestorative sleep in a younger or middle-aged patient, with normal inflammatory studies.
Age older than 50 years with abrupt bilateral shoulder and hip girdle morning stiffness plus elevated ESR or CRP.
Central pain amplification with altered nociceptive processing causes diffuse tenderness without inflammatory muscle injury.
Inflammatory periarticular synovitis and bursitis of proximal girdle structures causes systemic inflammation and stiffness.
ESR and CRP are typically normal, CK is normal, CBC and TSH are usually normal, and serologies such as RF and anti-CCP are negative unless another diagnosis coexists.
ESR is commonly above 40 mm/hr and CRP is elevated, CK remains normal, and rapid clinical improvement within 48 to 72 hours after prednisone 12.5 to 25 mg/day strongly supports the diagnosis.
The trap
Diffuse pain plus fatigue is often labeled fibromyalgia even in older adults with marked morning stiffness. The resolving clue is objective inflammation, especially ESR or CRP elevation with normal CK, which should trigger steroid treatment and screening for giant cell arteritis symptoms such as jaw claudication or visual change.
The repair move
Next best step: start oral prednisone 15 mg daily now, then reassess pain and morning stiffness in 48 to 72 hours with repeat CRP or ESR in 1 to 2 weeks. If response is brisk, taper slowly by 1 to 2.5 mg every 2 to 4 weeks once at 10 mg/day, and at each visit ask about headache, jaw claudication, or vision loss that would require urgent high-dose steroids for possible giant cell arteritis.
Try a free question
CoreA 70-year-old woman has 2 months of bilateral shoulder and hip pain with morning stiffness lasting 90 minutes. BP 150/84 mm Hg, HR 86/min, temp 37.3 C. ESR is 68 mm/hr, CRP is elevated, and CK is normal. What is the next best step in management?
Show answer and explanation
Answer: A. Start prednisone 15 mg orally daily. Older age, prolonged proximal stiffness, high ESR or CRP, and normal CK are classic for PMR and warrant immediate low-dose oral prednisone.
Why the other choices are tempting
- B. Wrong. This fits PMR, not isolated fibromyalgia, because inflammatory markers are clearly elevated.
- C. Wrong. Pulse-dose IV steroids are for vision-threatening giant cell arteritis, not uncomplicated PMR.
- D. Wrong. Muscle biopsy is not required for PMR and delays effective treatment.
- E. Wrong. Observation with NSAID alone is inadequate when PMR features are strong and function is impaired.
Flashcards
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Which objective finding distinguishes polymyalgia rheumatica from fibromyalgia in a patient with diffuse pain?
Elevated ESR or CRP with normal CK in an older patient with proximal morning stiffness supports polymyalgia rheumatica.
What bedside pattern supports fibromyalgia rather than polymyalgia rheumatica?
Widespread tenderness with fatigue and poor sleep but normal ESR, CRP, and CK supports fibromyalgia.
Quick answers
What is the fastest way to tell Fibromyalgia from Polymyalgia rheumatica?
Elevated ESR or CRP in a patient older than 50 with proximal morning stiffness points to polymyalgia rheumatica.
What is the key clue for Fibromyalgia?
Chronic widespread pain with fatigue and nonrestorative sleep in a younger or middle-aged patient, with normal inflammatory studies.
What is the key clue for Polymyalgia rheumatica?
Age older than 50 years with abrupt bilateral shoulder and hip girdle morning stiffness plus elevated ESR or CRP.
What is the common trap with Fibromyalgia vs Polymyalgia rheumatica?
Diffuse pain plus fatigue is often labeled fibromyalgia even in older adults with marked morning stiffness. The resolving clue is objective inflammation, especially ESR or CRP elevation with normal CK, which should trigger steroid treatment and screening for giant cell arteritis symptoms such as jaw claudication or visual change.