Main Clinical Features of Fibromyalgia
Fibromyalgia is characterized by chronic widespread musculoskeletal pain, fatigue, unrefreshing sleep, and cognitive issues that persist for at least 3 months, with pain upon digital pressure in at least 11 of 18 specific tender points. 1
Core Diagnostic Features
According to the American College of Rheumatology (ACR) criteria, the main clinical features include:
- Widespread pain index (WPI): Pain must be present in multiple body regions
- Symptom severity scale (SS): Measures the intensity of associated symptoms
- Tender point examination: Classic diagnosis requires pain in at least 11 of 18 specific tender points when approximately 4 kg of pressure is applied 1
- Chronicity: Symptoms must be present for at least 3 months 1
Primary Symptom Clusters
Pain-Related Symptoms
- Chronic widespread musculoskeletal pain (hallmark feature)
- Muscle and joint stiffness
- Heightened pain sensitivity (allodynia and hyperalgesia)
- Pain that may fluctuate in intensity but remains persistent 1, 2
Sleep Disturbances
- Unrefreshing sleep
- Difficulty falling or staying asleep
- Sleep fragmentation
- Morning stiffness upon waking 1, 3
Cognitive Dysfunction ("Fibro Fog")
- Impaired concentration
- Memory problems
- Difficulty with mental clarity
- Reduced ability to multitask 1, 4
Fatigue and Energy Issues
- Persistent fatigue not relieved by rest
- Reduced physical endurance
- Post-exertional malaise
- General sense of low energy 1, 3, 2
Associated Symptoms
Fibromyalgia commonly presents with additional symptoms:
- Mood disorders (anxiety and depression)
- Headaches and migraines
- Irritable bowel syndrome
- Paresthesias (numbness and tingling)
- Sensitivity to environmental stimuli (light, sound, temperature)
- Dizziness 1, 2, 4
Clinical Pitfalls and Considerations
- Diagnostic challenges: Fibromyalgia lacks specific diagnostic biomarkers, making clinical evaluation crucial 2
- Symptom overlap: Many symptoms overlap with other conditions such as chronic fatigue syndrome, irritable bowel syndrome, and mood disorders 5
- Variable presentation: The heterogeneity of fibromyalgia presents a wide spectrum of symptoms that vary in severity and combinations 6
- Comorbidities: Frequently coexists with other conditions that must be identified separately 1
- Exclusion diagnosis: Requires ruling out other systemic and rheumatic diseases that could cause similar symptoms 5
Epidemiological Features
- Third most common musculoskeletal disorder after lower back pain and osteoarthritis 2
- More prevalent in women than men
- Can occur at any age but most commonly diagnosed between 30-35 years 2
- Significant impact on quality of life and healthcare utilization, with average costs exceeding $2000 per patient annually 1
Evolution of Diagnostic Criteria
The diagnostic approach has evolved from the original 1990 ACR criteria (focused on tender points) to more recent criteria that incorporate symptom severity scales and recognize the broader symptom profile beyond pain 5. Clinicians should be aware of the limitations of using tender points alone for diagnosis and should consider the full spectrum of symptoms 5.