Initial Workup for Suspected Fibromyalgia
The initial workup for suspected fibromyalgia should include a comprehensive assessment of pain, function, and psychosocial context to establish diagnosis, while excluding other conditions that may mimic its symptoms. 1
Diagnostic Approach
Clinical Assessment
- Confirm widespread pain present in all four quadrants of the body for at least three months 1, 2
- Evaluate for associated symptoms including fatigue, non-refreshed sleep, mood disturbance, and cognitive impairment 1, 3
- Document tender points - traditionally 11 out of 18 specific tender points, though newer criteria focus more on symptom patterns 1, 2
- Assess impact on quality of life and daily functioning 1
Key Differential Diagnoses to Rule Out
- Rheumatic disorders affecting the spine 4
- Systemic inflammatory conditions 4, 3
- Endocrine disorders, particularly hypothyroidism 4, 5
- Neurologic disorders that may present with widespread pain 5, 2
- Medication-related side effects that may mimic fibromyalgia symptoms 5
Laboratory Testing
- Complete blood count to rule out inflammatory conditions 5, 6
- Erythrocyte sedimentation rate and C-reactive protein to assess for inflammation 4, 2
- Thyroid function tests to exclude hypothyroidism 4, 5
- Creatine kinase to rule out myopathies 6
- Vitamin D levels (often deficient in fibromyalgia patients) 2
Additional Considerations
- Unlike other rheumatic conditions, fibromyalgia is not associated with radiological or laboratory abnormalities - normal results support the diagnosis 4, 3
- Consider sleep study if significant sleep disturbances are present 5, 6
- Evaluate for comorbid mood disorders (anxiety, depression) which frequently accompany fibromyalgia 1, 5
Important Diagnostic Principles
- Fibromyalgia is primarily diagnosed by excluding other conditions - it is a diagnosis of exclusion 4, 2
- Recognition of central sensitization as the key pathogenic mechanism helps frame the diagnostic approach 3
- Diagnosis is clinical and does not require specialized testing beyond ruling out other conditions 1, 2
- Early diagnosis is important to avoid unnecessary investigations and inappropriate treatments 1
Common Pitfalls to Avoid
- Failing to acknowledge the reality of the patient's pain, which can worsen patient outcomes 4, 6
- Over-reliance on tender point examination alone, which may miss atypical presentations 3, 2
- Excessive diagnostic testing beyond what's needed to rule out reasonable alternatives 1, 6
- Not recognizing overlapping conditions that commonly occur with fibromyalgia (irritable bowel syndrome, chronic fatigue syndrome, temporomandibular disorder) 3
Once diagnosed, management should follow a graduated approach starting with patient education and non-pharmacological therapies, particularly exercise which has the strongest evidence for effectiveness 1, 7.