What are the signs and symptoms of fibromyalgia?

Signs and Symptoms of Fibromyalgia

Fibromyalgia is characterized by chronic widespread pain lasting at least 3 months, accompanied by fatigue, sleep disturbances, cognitive dysfunction, and various somatic symptoms including headaches, bowel and bladder abnormalities. 1

Core Clinical Features

Pain Characteristics

• Widespread musculoskeletal pain present for at least 3 months 1
• Hyperalgesia (increased sensitivity to pain) and allodynia (pain from normally non-painful stimuli) 1
• Pain upon digital pressure in at least 11 of 18 specific tender points (according to classic ACR criteria) 1
• Pain that is typically bilateral, affecting both sides of the body 1, 2

Neurological and Cognitive Symptoms

• Fatigue that significantly impacts daily functioning 1, 2
• Sleep disturbances including non-restorative sleep 1, 3
• Cognitive dysfunction (often called "fibro fog") affecting memory and concentration 1, 4
• Headaches and migraines 1

Psychological Manifestations

• Anxiety and depression commonly co-occur 1, 2
• Mood disturbances 4
• Heightened stress response 5

Gastrointestinal and Urinary Symptoms

• Variable bowel habits and diffuse abdominal pain (similar to irritable bowel syndrome) 1
• Urinary frequency and other bladder symptoms 1, 5

Other Common Symptoms

• Morning stiffness 2, 4
• Paresthesias (abnormal sensations like tingling) 3
• Sensitivity to environmental factors (temperature, noise, bright lights) 3

Diagnostic Criteria

The American College of Rheumatology (ACR) diagnostic approach includes:

1. Widespread Pain Index (WPI): Assessment of pain in specific body regions
2. Symptom Severity Scale (SS): Evaluation of fatigue, waking unrefreshed, cognitive symptoms, and somatic symptoms
3. Tender point examination: Classically required pain in at least 11 of 18 specific tender points 1

Important Differential Considerations

Fibromyalgia must be distinguished from:

• Inflammatory arthritis (differentiated by elevated ESR/CRP and positive RF or anti-CCP) 1
• Polymyalgia rheumatica 1
• Myositis 1
• Hypothyroidism 1
• Multiple sclerosis 1
• Lyme disease 1
• Chronic fatigue syndrome 6

Clinical Pearls and Pitfalls

• Fibromyalgia is the third most common musculoskeletal disorder after lower back pain and osteoarthritis 2
• More prevalent in women than men 2
• Most commonly diagnosed between ages 30-35, though can occur at any age 2
• No specific laboratory biomarkers exist for diagnosis 2, 6
• Symptoms often fluctuate in intensity over time 3
• Diagnosis remains challenging and is often missed by physicians unfamiliar with the condition 3
• The condition significantly impacts quality of life and has substantial economic consequences 1

Pathophysiological Mechanisms

Current understanding suggests three main underlying processes:

1. Central sensitization with alterations in neurotransmitter release 2
2. Peripheral sensitization affecting nociceptor signaling 2
3. Inflammatory and immune mechanisms 1, 2

Additionally, genetic factors related to serotonergic, dopaminergic, and catecholaminergic systems may contribute to susceptibility 1