What are the diagnostic criteria and first-line management for fibromyalgia in adults?

Fibromyalgia: Diagnostic Criteria and First-Line Management

Diagnostic Criteria

Diagnose fibromyalgia when a patient presents with chronic widespread pain affecting all four body quadrants for at least 3 months, accompanied by fatigue, sleep disturbances, and cognitive dysfunction, without requiring tender point examination. 1

Clinical Features Required for Diagnosis

• Pain characteristics: Chronic widespread pain present in all four body quadrants for a minimum of 3 months, characterized by hyperalgesia (increased pain response) and allodynia (pain from normally non-painful stimuli) 2
• Associated symptoms: Fatigue disproportionate to activity level, non-restorative sleep, and cognitive dysfunction ("fibro fog") must be present 2
• Symptom severity: Pain must be disproportionate to any identifiable tissue damage or inflammation 1
• Common comorbidities: Mood disturbances including anxiety and depression frequently accompany fibromyalgia 2

Essential Laboratory Testing to Exclude Mimics

Order only the following tests to rule out conditions that mimic fibromyalgia—not to confirm the diagnosis itself: 1

• Complete blood count (CBC) 1
• Erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) 1
• Thyroid-stimulating hormone (TSH) 1
• Creatine kinase (CK) 1
• Rheumatoid factor and anti-CCP antibodies (only if inflammatory arthritis is suspected) 1

Avoid extensive imaging or additional laboratory work, as fibromyalgia is a clinical diagnosis based on symptoms, not laboratory abnormalities. 3

First-Line Management Algorithm

Step 1: Immediate Patient Education (Required for All Patients)

Begin immediately with patient education explaining fibromyalgia as a central nervous system pain processing disorder—not tissue damage or inflammation—before initiating any other treatment. 1

• This education is foundational and significantly reduces healthcare utilization when patients understand their condition 2
• Explain that the primary problem is inadequate filtering of pain signals by descending antinociceptive pathways (central sensitization) 4

Step 2: Initiate Non-Pharmacological Treatment (Primary Intervention)

Start aerobic and strengthening exercise immediately as the primary intervention (Level Ia, Grade A evidence). 1

• Exercise has the strongest evidence base for fibromyalgia management 1, 5
• Begin with low-intensity aerobic exercise and gradually increase intensity as tolerated 5

Add one or more of the following complementary therapies based on patient preference and availability: 1

• Cognitive behavioral therapy (CBT) (Level Ia, Grade A evidence) 1, 5
• Heated pool therapy/hydrotherapy (Level Ia, Grade A evidence) 1, 5
• Yoga, tai chi, or qigong (Level Ia, Grade A evidence) 1, 5
• Mindfulness-based stress reduction (Level Ia, Grade A evidence) 1, 5
• Manual acupuncture (Level Ia, Grade A evidence) 1, 5

Step 3: Select First-Line Pharmacological Treatment Based on Predominant Symptoms

Choose ONE of the following medications based on the patient's primary symptom profile (Level Ia, Grade A evidence): 1

If Pain with Sleep Disturbance is Predominant:

• Amitriptyline (low dose) 1, 5
• Start at low doses and titrate gradually to minimize side effects 5

If Pain with Depression/Anxiety is Predominant:

• Duloxetine 1, 5
• Do not escalate beyond 60 mg/day 1
• Alternative: Milnacipran 5

If Pain is the Primary Symptom (without significant mood or sleep issues):

• Pregabalin 1, 5
• Do not escalate beyond 450 mg/day 1
• Adjust dose for creatinine clearance <60 mL/min 1
• FDA-approved for fibromyalgia with demonstrated efficacy in reducing pain scores 6

Alternative First-Line Options:

• Tramadol (weak opioid with SNRI properties) 4, 5
• Cyclobenzaprine (muscle relaxant) 4, 5

Critical Medications to NEVER Prescribe

Never prescribe the following as monotherapy for fibromyalgia, as they have no demonstrated benefit with significant potential for harm (Level Ia, Grade A evidence): 1

• Strong opioids: No evidence of efficacy and high risk of addiction and adverse effects 4, 1, 3
• Corticosteroids: No benefit for fibromyalgia 1
• NSAIDs as monotherapy: No demonstrated benefit for fibromyalgia pain 1, 3, 7

Monitoring and Follow-Up

Reassess every 4-8 weeks initially to evaluate treatment efficacy using standardized measures. 1

• Use the Fibromyalgia Impact Questionnaire (FIQ) to measure functional impact on daily activities, pain, fatigue, sleep quality, and functioning 2
• Use Visual Analogue Scale (VAS) to assess pain intensity 2
• Adjust the treatment plan based on response, tolerability, and patient goals 1

Common Pitfalls to Avoid

• Delaying diagnosis: Average time to diagnosis is over 2 years with 3.7 consultations with different physicians, leading to high healthcare utilization 2
• Over-testing: Ordering extensive laboratory work or imaging delays diagnosis and increases costs without benefit 1, 3
• Monotherapy approach: Using only pharmacological OR only non-pharmacological treatment is usually unsuccessful 8
• Prescribing opioids: Strong opioids are recommended only as second-line for neuropathic pain, not fibromyalgia 4
• Exceeding maximum effective doses: Duloxetine >60 mg/day and pregabalin >450 mg/day provide no additional benefit with increased adverse effects 1