Differentiating Fibromyalgia from other diseases

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aditya Ganti M.B.B.S. [2]

Overview

Fibromyalgia must be differentiated from other diseases that present with pain, fatigue and sleep disturbance, and symptoms of cognitive dysfunction and psychiatric disease such as rheumatoid arthritis, SLE, chronic fatigue syndrome, spondyloarthritis, and polymyalgia rheumatica.

Differentiating Fibromyalgia from other Diseases

Fibromyalgia must be differentiated from other diseases that present with pain, fatigue and sleep disturbance, and symptoms of cognitive dysfunction and psychiatric disease such as rheumatoid arthritis, SLE, chronic fatigue syndrome, spondyloarthritis, and polymyalgia rheumatica.

Disease	Differentiating signs and symptoms	Diagnostic findings
Fibromyalgia	Symptoms have been present at a similar level for at least 3 months. Chronic musculoskeletal pain with multiple tender points Stiffness, numbness, and fatigue Headaches Sleep disorder	All lab tests are normal
Rheumatoid arthritis	Multiple joint swelling Morning stiffness Rheumatoid nodules	RF or anti-cyclic citrullinated protein (CCP) antibody is positive. Markers of systemic inflammation (ESR, CRP) are typically elevated.
SLE	Maculopapular rash Multi-system involvement	Positive anti-Smith antibodies
Chronic fatigue syndrome	Fatigue plus 4 of the following symptoms: Short-term memory loss Sore throat Tender lymph nodes in the neck or armpit Muscle pain Joint pain without swelling or redness Headaches Insomnia Malaise	Diagnosis of exclusions Symptoms must present for more than 6 months
Spondyloarthritis	Axial skeletal pain and stiffness Restricted spinal motion	Elevated ESR or CRP Negative RF Bamboo spine on x-ray
Polymyalgia rheumatica	Older at onset Generalized stiffness	An elevated erythrocyte sedimentation rate (ESR) OR C-reactive protein (CRP) Response to corticosteroids
Osteoarthritis	Localized joint pain Restricted to affect joints Older at onset	X-ray of the involved joints demonstrate degenerative changes
Hypothyroidism	Systemic symptoms such as weight gain, constipation, dry skin Muscular aching and prominent fatigue that improves on replacement of thyroid hormone.	TSH is elevated and free T4 is low.
Myopathaies (polymyositis and dermatomyositis)	Pelvic and shoulder girdle muscle weakness Rash	Muscle biopsy confirms the diagnosis Elevated CPK enzyme
Neuropathy	Numbness and tingling Paresthesia	Abnormal EMG