31st January 2024

Fibromyalgia

Diagnosis can be challenging due to the heterogeneous nature of the condition. Diagnosis is based on symptoms, with the principal feature being widespread pain. However, sleep disturbance, fatigue, cognitive impairment such as memory loss or poor concentration, and bladder and bowel abnormalities can also occur. The American College of Rheumatology have laid out diagnostic criteria for fibromyalgia:

• Widespread pain index of at least 7, defined as the number of areas in which the patient has experienced pain in the last week (out of 19)
• Symptom severity score of 5 or more, based on the sum of severity of fatigue, waking unrefreshed and cognitive symptoms
• Symptoms lasting for at least 3 months 
• No other disorder diagnosed to otherwise explain the pain

On physical examination, there is usually tenderness present without erythema or swelling of soft tissues or joints. The condition is thought to be caused by a central nervous system dysfunction; there are no routine laboratory tests or imaging modalities to diagnose fibromyalgia. 

Investigations should be guided by the history; routine tests such as FBC and CRP/ESR are used to rule out other causes of inflammatory pain. More specialist testing, such as autoimmune or viral screening, should be considered if the history is suggestive. It should be noted that patients with rheumatological diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), ankylosing spondylitis or osteoarthritis are at higher risk for fibromyalgia.