Fibromyalgia

Fibromyalgia affects approximately 2-5% of the UK population, with a significant female predominance. It often co-exists with other functional syndromes such as Irritable Bowel Syndrome (IBS), chronic fatigue syndrome, and tension headaches. The diagnosis is clinical, based on the ACR criteria which assess the widespread pain index (WPI) and symptom severity (SS) score. Previously, 'tender points' were the focus, but current criteria emphasise the distribution of pain and the presence of associated symptoms. Patients often undergo extensive investigations which return negative results, leading to frustration. It is essential to explain that while the pain is real and disabling, it does not involve joint or muscle damage. Management emphasizes a biopsychosocial approach, where pharmacological treatments (like Amitriptyline or Duloxetine) are considered secondary to physical activity and psychological support.

Fibromyalgia is understood as a 'central sensitisation' syndrome or 'nociplastic' pain. There is an alteration in how the central nervous system processes sensory input. This involves an amplification of pain signals (hyperalgesia) and the perception of non-painful stimuli as painful (allodynia). Neurochemical studies show increased levels of Substance P (a pro-nociceptive neurotransmitter) in the cerebrospinal fluid and decreased levels of inhibitory neurotransmitters like serotonin and norepinephrine. Functional MRI studies show heightened activity in the 'pain matrix' of the brain (e.g., insula, anterior cingulate cortex) in response to minimal pressure.

The typical patient is a woman aged 30-50 presenting with 'hurting all over'. Pain is often described as burning or aching and is exacerbated by stress, cold, or over-exertion. Sleep is 'unrefreshing', meaning they wake up feeling as tired as when they went to bed. Physical examination is generally unremarkable except for multiple areas of tenderness. It is a 'diagnosis of exclusion' only in the sense that inflammatory mimics must be ruled out, but it should be diagnosed positively based on its own characteristic features. The impact on quality of life can be severe, often leading to work disability and social withdrawal.

- Bloods: Done to rule out mimics. FBC, ESR/CRP (should be normal), Bone profile, TSH (hypothyroidism can mimic fatigue/aching), CK (myopathy), Vitamin D.
- Imaging/Special: Not indicated for diagnosis; should only be performed if another pathology is suspected (e.g., MRI if focal neurological signs).

First-line: Patient education and reassurance. Aerobic exercise (e.g., swimming, walking) and tailored strengthening programs. NICE NG193 (Chronic Primary Pain) recommends: 1. Psychological therapies (CBT or ACT). 2. Acupuncture (short-term). 3. Pharmacological: Amitriptyline, Citalopram, Duloxetine, or Fluoxetine. (Note: Pregabalin and Gabapentin are used in some guidelines but NICE now restricts their recommendation in chronic primary pain unless part of a clinical trial). Avoid: Opioids, NSAIDs, and Steroids as they are ineffective for centrally mediated pain and carry high risks of harm.