What is fibromyalgia?

Fibromyalgia: Definition, Pathophysiology, and Management

Fibromyalgia is a common rheumatological syndrome characterized by chronic widespread pain with reduced pain threshold (hyperalgesia and allodynia), accompanied by fatigue, sleep disturbances, cognitive dysfunction, depression, anxiety, headaches, and various gastrointestinal and urinary symptoms. 1

Pathophysiology

Fibromyalgia involves complex mechanisms including:

• Central sensitization: Hyperexcitability at spinal or brainstem level leading to amplified pain perception 2, 1
• Peripheral sensitization: Alterations in peripheral nociceptor signaling 3
• Inflammatory and immune mechanisms: Contributing to pain processing abnormalities 3
• Genetic factors: Affecting serotonergic, dopaminergic, and catecholaminergic systems 1
• Psychosocial factors: Influencing pain severity and perception 1

While the exact cause remains unknown, these mechanisms collectively contribute to the syndrome's manifestation 2.

Diagnostic Criteria

The American College of Rheumatology (ACR) criteria are the most widely used for diagnosis:

• Classic criteria (1990): Requires history of generalized pain present for at least 3 months and pain upon digital pressure in at least 11 of 18 specific tender points 1
• Updated criteria: Focus on widespread pain index (WPI) and symptom severity scale (SS) 1

Key diagnostic features include:

• Chronic widespread musculoskeletal pain (≥3 months)
• Pain in all four body quadrants
• Tenderness at specific anatomical sites
• Associated symptoms (fatigue, unrefreshing sleep, cognitive issues) 1

Differential Diagnosis

Important conditions to rule out include:

• Inflammatory arthritis (check ESR/CRP, RF, anti-CCP)
• Polymyalgia rheumatica
• Myositis
• Hypothyroidism
• Multiple sclerosis
• Lyme disease 1

Targeted laboratory testing is recommended to exclude other conditions, but normal results in the appropriate clinical context support a fibromyalgia diagnosis. 1

Management Approach

Non-Pharmacological Therapies (First-Line)

• Exercise therapy:

  • Aerobic exercise and strength training (2-3 sessions/week, 10-30 minutes per session)
  • Start with low intensity and gradually increase 1

• Heated pool treatment/hydrotherapy: Shows significant benefits 1

• Cognitive Behavioral Therapy (CBT):

  • Addresses pain catastrophizing
  • Improves coping strategies
  • Typically 8-12 weekly sessions 1

• Mind-body approaches:

  • Mindfulness-based stress reduction
  • Meditation
  • Yoga, tai chi, qigong 1

• Dietary modifications:

  • Mediterranean-style diet
  • Emphasis on vegetables, fruits, whole grains
  • Limited processed foods and refined carbohydrates 1

Pharmacological Therapies

• First-line medications:

  • Amitriptyline: 10-25 mg at bedtime for pain and sleep disturbances 1
  • Pregabalin: 75 mg twice daily, shown to reduce pain and improve function in clinical trials 1, 4
  • Duloxetine: 30-60 mg daily, particularly effective when comorbid depression/anxiety exists 1

• Second-line options:

  • Cyclobenzaprine: For pain and sleep disturbances 1
  • Tramadol: For severe pain, use cautiously due to dependence risk 1

• Ineffective treatments (not recommended):

  • NSAIDs
  • Strong opioids
  • Corticosteroids 1

Treatment Algorithm

1. Initial approach:

   • Confirm diagnosis
   • Identify predominant symptoms
   • Begin with non-pharmacological therapies (exercise, education)

2. If insufficient response:

   • Add CBT, mindfulness, hydrotherapy based on patient preference and availability

3. Pharmacological treatment:

   • Select based on predominant symptoms:
     • Sleep disturbance → Amitriptyline or pregabalin
     • Depression/anxiety → Duloxetine
     • Severe pain → Consider pregabalin or tramadol

4. Monitoring:

   • Assess response every 4-8 weeks
   • A 30% reduction in symptoms is considered clinically significant
   • Set realistic expectations (modest benefits rather than complete resolution) 1

Impact and Prognosis

Fibromyalgia significantly impacts quality of life and healthcare utilization (averaging over $2000 per patient per year) 2, 1. However, proper diagnosis and management can reduce healthcare costs and improve outcomes 2.

Common Pitfalls to Avoid

1. Excessive testing: Once other conditions are ruled out, avoid repeated or unnecessary testing 1

2. Opioid prescribing: Strong opioids lack efficacy and carry significant risks 1

3. Focusing only on pain: Address all symptoms including sleep, fatigue, and mood disturbances 1

4. Unrealistic expectations: Set realistic goals for symptom improvement rather than promising complete resolution 1

5. Neglecting non-pharmacological approaches: These are foundational to effective management 1