What is fibromyalgia?

What is Fibromyalgia?

Fibromyalgia is a common rheumatological condition characterized by chronic widespread pain and reduced pain threshold, with hyperalgesia and allodynia, accompanied by fatigue, depression, anxiety, sleep disturbance, headache, migraine, variable bowel habits, diffuse abdominal pain, and urinary frequency. 1

Pathophysiology

Fibromyalgia involves several key pathophysiological mechanisms:

• Central sensitization: Hyperexcitability at spinal or brainstem level causing amplified pain processing 1, 2
• Peripheral sensitization: Alterations in peripheral nociceptor signaling 3
• Neurotransmitter imbalances: Deficiencies in serotonergic and noradrenergic transmission, with increases in pronociceptive neurotransmitters like glutamate and substance P 2
• Contributing factors: Genetic predisposition, psychological factors, and altered pain perception 1, 4

The condition is characterized by widespread pain and reduced pain threshold, with hyperalgesia (heightened response to painful stimuli) and allodynia (pain from normally non-painful stimuli) 1, 2.

Epidemiology

• Third most common musculoskeletal disorder after lower back pain and osteoarthritis 3
• Affects approximately 2-8% of the population 5, 6
• More prevalent in women than men 3
• Can occur at any age but most common between 30-35 years 3
• Healthcare utilization averages over $2000 per patient per year 1

Clinical Features

Fibromyalgia presents with a constellation of symptoms:

• Primary symptom: Chronic widespread musculoskeletal pain lasting more than 3 months 1
• Associated symptoms:
  • Fatigue
  • Sleep disturbances
  • Cognitive dysfunction ("fibro fog")
  • Depression and anxiety
  • Headaches and migraines
  • Irritable bowel symptoms
  • Urinary frequency
  • Muscle and joint stiffness 1, 3, 6

Diagnosis

Diagnosis is based on clinical criteria as there are no specific diagnostic biomarkers:

• American College of Rheumatology (ACR) classification criteria: Most commonly used in clinical and research settings 1

  • History of widespread pain for 3 months
  • Pain present at 11 or more of the 18 specific tender point sites 1, 7

• Screening tools: The Fibromyalgia Rapid Screening Tool can help identify potential cases 6

• Differential diagnosis: Important to rule out other conditions that may cause similar symptoms, such as:

  • Inflammatory rheumatic diseases
  • Hypothyroidism
  • Myopathies
  • Neuropathic pain conditions

Treatment Approaches

Treatment should be multidisciplinary, focusing on symptom management and improving quality of life:

Non-pharmacological Interventions (First-line)

• Patient education: Positive diagnosis and management can reduce healthcare utilization 1
• Exercise therapy: Both land-based and water-based exercise programs show benefit 3, 5, 6
• Cognitive behavioral therapy: Helps address psychological aspects and improves coping strategies 5, 6
• Physical therapy: Including manual therapy and electrotherapy 3

Pharmacological Interventions

• FDA-approved medications:

  • Pregabalin: Effective at doses of 300-450 mg/day, showing reduction in pain and improvement in function 7
  • Duloxetine: SNRI that improves pain, though may cause side effects like nausea, dry mouth, and somnolence 8, 6
  • Milnacipran: Another SNRI approved for fibromyalgia 6

• Other medications with evidence:

  • Amitriptyline: Tricyclic antidepressant that may help with pain and sleep 6
  • Cyclobenzaprine: Muscle relaxant with evidence for effectiveness 1

• Medications to avoid:

  • NSAIDs: Not effective for fibromyalgia specifically 1, 6
  • Opioids: Not recommended due to lack of demonstrated benefit and significant risks 1, 6

Common Pitfalls in Management

1. Delayed or missed diagnosis: Many physicians still fail to recognize the syndrome, leading to unnecessary testing and delayed treatment 4

2. Over-reliance on medications: The most effective approach combines pharmacological and non-pharmacological interventions 3, 5

3. Inappropriate use of opioids: These have not demonstrated benefits for fibromyalgia and carry significant risks 6

4. Failure to address comorbidities: Conditions like depression, anxiety, and sleep disorders need concurrent management 1, 6

5. Unrealistic expectations: Setting realistic treatment goals is important as complete resolution of symptoms is uncommon 4

A positive diagnosis and appropriate education about the condition can significantly improve outcomes and reduce unnecessary healthcare utilization 1.