Fibromyalgia

Definition/diagnostic criteria Fibromyalgia is a long-term condition characterised by widespread pain and profound fatigue. The American College of Rheumatology (ACR) 1990 criteria, widely accepted in the UK, define fibromyalgia as:

• Chronic widespread pain in combination with tenderness at 11 or more out of 18 specific tender point sites.
• The more recent 2016 revisions emphasise symptom severity, persistent symptoms for at least three months and the presence of cognitive symptoms, sleep disturbance, and somatic symptoms, alongside widespread pain.

Other potential causes need to be excluded, though clearly fibromyalgia can co-exist with other clinically important illness.

Epidemiology Fibromyalgia affects between 2-4.7% of the general population in the UK, with a higher prevalence in women. It is most commonly diagnosed in individuals between the ages of 30 and 50 but can occur in people of any age, including children and the elderly.

Diagnosis
Clinical features: Patients typically present with a history of widespread pain lasting more than three months, fatigue, sleep disturbance, and cognitive disturbances known as ‘fibro fog’, encompassing problems with concentration, memory and orientation.

Other symptoms may include irritable bowel syndrome, headaches and depression or anxiety.

Investigations: There is no specific laboratory or imaging test for fibromyalgia. Diagnosis is primarily based on clinical history and physical examination. The identification of tender points as part of the diagnostic criteria is key, although the emphasis on their number may vary.

Routine tests may be conducted to exclude other conditions, including complete blood count, erythrocyte sedimentation rate, thyroid function tests, and autoimmune screens, among others. Typical abnormalities are not found in these tests in fibromyalgia patients, often helping to rule out other conditions rather than confirming fibromyalgia itself.

Treatment Treatment of fibromyalgia requires a multidisciplinary approach, focusing on education, lifestyle modifications, physical therapies and pharmacological treatments.

• Non-pharmacological: Education about the condition, cognitive-behavioural therapies, and structured exercise programmes are recommended as first-line treatments. Hydrotherapy, relaxation techniques and acupuncture may also benefit some patients.
• Pharmacological: Amitriptyline, a tricyclic antidepressant, is often the first-line medication for treating pain, sleep disturbance and other symptoms. Other antidepressants can be trialled as part of a chronic disease management programme, even in the absence of overt depression. NICE no longer recommends initiating gabapentinoids, NSAIDs or opioids in chronic primary pain.

Prognosis Fibromyalgia is a chronic condition with a variable course. While it is not life threatening, it can lead to significant morbidity and impact on quality of life. Some patients may experience a spontaneous improvement in symptoms, while others may have persistent symptoms for many years. Early diagnosis and a comprehensive treatment plan can help manage symptoms and improve quality of life.