Fibromyalgia — Causes, Symptoms, Diagnosis & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

Fibromyalgia is a chronic pain syndrome characterised by widespread musculoskeletal pain, fatigue, sleep disturbance, and cognitive dysfunction (cognitive complaints — 'fibro fog'), resulting from central sensitisation — an amplification of pain signals in the central nervous system (CNS) that causes normally non-painful stimuli to become painful (allodynia) and normally painful stimuli to be perceived as more painful than expected (hyperalgesia). Fibromyalgia is no longer considered a diagnosis of exclusion or a psychosomatic condition — it is recognised as a distinct neurobiological disorder of central pain processing, with demonstrable neuroimaging abnormalities (increased activity in pain-processing regions on fMRI), abnormal temporal summation of pain, and neuroendocrine dysregulation (HPA axis, autonomic nervous system). Fibromyalgia affects approximately 2-4% of adults globally, with a strong female preponderance (7:1 female:male ratio), typically presenting between ages 30-60. It is the second most common rheumatological diagnosis after osteoarthritis. Fibromyalgia frequently coexists with irritable bowel syndrome (IBS — in 50-60%), migraine, interstitial cystitis, temporomandibular disorder, chronic fatigue syndrome (ME/CFS), and psychiatric conditions (depression in 30-50%, anxiety in 40-60%). These comorbidities share the pathophysiological mechanism of central sensitisation, collectively termed 'central sensitivity syndromes' (CSS).

Fibromyalgia results from central sensitisation — abnormal amplification of pain signals in the spinal cord and brain. Multiple mechanisms contribute: spinal cord sensitisation (increased excitability of dorsal horn neurons — 'windup' phenomenon; NMDA receptor overactivation; substance P and glutamate increase pain signal transmission); reduced descending pain inhibition (normal pain modulation by opioidergic, serotoninergic, and noradrenergic descending pathways is impaired — the basis for SNRI and tricyclic antidepressant use); functional neuroimaging differences (fMRI studies show greater activation of pain-processing areas at lower stimulus intensities); neuroendocrine dysregulation (HPA axis hyperreactivity with cortisol dysregulation; autonomic nervous system dysfunction with sympathetic predominance); and abnormal neurotransmitter levels (elevated substance P in CSF by 3x; reduced levels of serotonin and noradrenaline). Triggers and risk factors: prior physical trauma (traffic accidents, surgical procedures) or infection (Lyme disease, Epstein-Barr virus, COVID-19 — long COVID shares significant features with fibromyalgia); psychological trauma and adverse childhood experiences (ACE — highest risk factor — PTSD is a major risk factor); stress; sleep deprivation; genetics (heritability estimated 50% — serotonin transporter gene, catechol-O-methyltransferase/COMT polymorphisms, dopamine receptor variants); female sex (hormonal modulation of pain processing — oestrogen modulates substance P and serotonin); and pre-existing mood disorders (depression and anxiety lower the pain threshold through shared neurobiological mechanisms). Pre-existing chronic pain conditions (osteoarthritis, rheumatoid arthritis, lupus) frequently precipitate fibromyalgia.

Fibromyalgia presents with a complex of symptoms affecting multiple body systems. The core symptoms are: widespread chronic pain — the cardinal feature — felt in muscles and joints throughout the body (above and below the waist, bilateral, and axial); described as aching, burning, shooting, or stabbing; varies in intensity day-to-day; fatigue — profound, non-restorative fatigue disproportionate to activity; does not improve with rest; 'waking tired' despite sleeping; and cognitive dysfunction ('fibro fog') — difficulty with attention, concentration, short-term memory, word-finding, and processing speed — a major complaint affecting work and daily function. Sleep disturbances: non-restorative sleep (wake feeling unrefreshed); difficulty initiating and maintaining sleep; restless legs syndrome (frequently comorbid). Allodynia (pain from normally non-painful stimuli — light touch, pressure, cold): pressure allodynia most clinically relevant — pain on gentle palpation of specific tender point sites. Sensory hypersensitivities: light sensitivity (photophobia); noise sensitivity (phonophobia); chemical hypersensitivity. Additional common symptoms: headaches (including migraine — in 50%); IBS symptoms — bloating, cramping, altered bowel habits (in 50-60%); pelvic pain, painful menstruation, urinary frequency; temporomandibular pain (jaw pain); dry eyes and mouth; Raynaud's phenomenon; and depressed mood and anxiety (in 30-60%). Symptoms characteristically fluctuate (flares) and are exacerbated by: physical or mental stress; weather changes; disrupted sleep; inactivity (paradoxically, under-activity worsens pain); and hormonal changes.

Fibromyalgia is a clinical diagnosis based on symptom pattern — there is no confirmatory blood test or imaging finding. However, investigations are essential to exclude other causes of widespread pain. 2016 ACR Modified Criteria for fibromyalgia (revised from the 1990 tender point criteria): (1) Widespread pain index (WPI) of 7+ and Symptom Severity Score (SSS) of 5+; or WPI 4-6 and SSS 9+. (2) Generalised pain present in at least 4 of 5 regions (left/right upper, left/right lower, axial). (3) Symptoms present at similar level for at least 3 months. (4) A fibromyalgia diagnosis is valid irrespective of other diagnoses — fibromyalgia can coexist with rheumatoid arthritis, lupus, and other conditions. The 2010 ACR criteria replaced the 1990 tender point examination (18 tender points — 11/18 required) as tender points are unreliable (depend on examiner pressure and patient cooperation). Investigations to exclude differentials: FBC (anaemia, leucopenia — lupus, RA); ESR and CRP (elevated in inflammatory arthritis — normal in fibromyalgia); ANA and anti-dsDNA (lupus); RF and anti-CCP (rheumatoid arthritis); thyroid function (hypothyroidism mimics fibromyalgia); creatine kinase (CK — myopathy); vitamin D and B12; serum calcium; and sleep study (sleep apnea is a major cause of non-restorative sleep and fatigue). Normal investigations in the context of typical fibromyalgia symptoms confirm the diagnosis and avoid unnecessary further testing. Neuroimaging is not routinely required but can be considered to exclude central pathology.

Fibromyalgia requires a multimodal treatment approach — no single intervention is sufficient, and the combination of pharmacological and non-pharmacological treatments produces the best outcomes. Non-pharmacological (first-line and most important): Aerobic exercise (the single most evidence-based treatment for fibromyalgia — Cochrane reviews demonstrate moderate-quality evidence of benefit; 30 minutes of moderate-intensity aerobic exercise 3x/week — walking, cycling, swimming, aquatic therapy — reduces pain, fatigue, and improves function; begin low and increase very gradually to avoid post-exertional flare); graded exercise therapy (GET — gradually increasing physical activity in a structured programme); cognitive behavioural therapy (CBT — the most effective psychological treatment — addresses catastrophising, fear-avoidance beliefs, sleep hygiene, pacing, and activity planning; strong evidence for pain, disability, and mood improvement); mindfulness-based stress reduction (MBSR — significant benefit for pain and quality of life); pain education (explaining the central sensitisation model empowers patients and reduces catastrophising — 'understanding pain' therapeutic neuroscience education); multidisciplinary pain management programmes (most effective combination — pain physician, physiotherapist, psychologist, occupational therapist); pacing (activity management to avoid boom-bust cycles); and sleep hygiene. Pharmacological: Duloxetine (60-120mg daily — SNRI — FDA approved for fibromyalgia — reduces pain, fatigue, and improves function; pooled studies show 30-50% pain reduction in responders); milnacipran (SNRI — approved in US for fibromyalgia); pregabalin (150-450mg daily — alpha-2-delta calcium channel ligand — FDA approved — reduces pain and sleep disturbance; gabapentin similar but not specifically approved); amitriptyline (10-75mg at bedtime — low-dose tricyclic — improves sleep quality and reduces pain; most effective for sleep-predominant fibromyalgia); cyclobenzaprine (muscle relaxant at low dose — particularly for sleep). Medications to avoid or use cautiously: NSAIDs and opioids are generally ineffective in fibromyalgia (central sensitisation does not respond well to peripheral anti-inflammatory or opioid receptor mechanisms); long-term strong opioids can worsen central sensitisation (opioid-induced hyperalgesia). Tramadol (weak opioid/SNRI) may have modest benefit. Acupuncture: some evidence of modest short-term benefit.

While fibromyalgia does not cause organ damage or structural destruction, it generates significant complications that profoundly impair quality of life. Severe functional disability: 30-40% of fibromyalgia patients are unable to maintain full-time employment; the condition accounts for substantial medical costs — estimated 5,000-10,000 USD annually per patient in the United States. Progressive deconditioning: activity avoidance from pain fear leads to muscle wasting and reduced cardiovascular fitness, which paradoxically worsens pain sensitivity and fatigue — the 'vicious cycle' of deconditioning. Mental health complications: depression is present in 30-50% and anxiety in 40-60% of fibromyalgia patients — pain and mood disorders mutually amplify each other through shared neurobiological pathways. Sleep disorder comorbidities: non-restorative sleep and restless leg syndrome (prevalent in 30% of fibromyalgia) worsen cognitive function, immune regulation, and pain thresholds. Medication-related complications: opioid-induced hyperalgesia from inappropriate opioid prescribing paradoxically worsens central sensitisation. Comorbid irritable bowel syndrome (50-60%), interstitial cystitis, and temporomandibular disorder add to the total burden of illness. Social isolation and relationship difficulties from unpredictable flares and functional limitation are also common.

While fibromyalgia cannot be entirely prevented, its severity and impact can be mitigated. Early recognition and treatment of chronic pain conditions, depression, and sleep disorders reduces the risk of central sensitisation developing into full fibromyalgia syndrome. Psychological resilience and trauma-informed care for individuals with adverse childhood experiences or PTSD. Sleep hygiene: consistent sleep and wake times; limit caffeine after noon; dark, quiet, cool sleep environment; avoid screen exposure within 1 hour of bed; limit alcohol (disrupts sleep architecture). Regular paced physical activity — consistent aerobic exercise reduces fibromyalgia severity over time; abrupt inactivity worsens central sensitisation. Stress management: mindfulness, relaxation techniques, social support, and pacing help prevent flares triggered by psychological stress. Flare management: identify triggers (overexertion, stress, poor sleep, infection); use heat therapy (warm baths, heat pads) for muscle pain relief; short-term analgesic use for severe flares; continue gentle movement rather than complete rest; and seek early GP or specialist review if flares are prolonged.

See your GP for assessment if: you have widespread muscle and joint pain in multiple body regions persisting for more than 3 months; fatigue that is non-restorative and disproportionate to activity level; cognitive complaints ('fibro fog') combined with chronic pain; or symptoms that match the fibromyalgia pattern and significantly affect your daily function and quality of life. Seek urgent medical attention for: new severe joint swelling, redness, or warmth (may indicate inflammatory arthritis requiring urgent rheumatology assessment — not fibromyalgia); fever combined with joint or muscle pain (infection or inflammatory disease); significant unexplained weight loss combined with pain and fatigue (possible malignancy); and any focal neurological symptoms (weakness, sensory loss, vision changes). Request a rheumatology or pain specialist referral if: your GP is uncertain whether the diagnosis is fibromyalgia or inflammatory arthritis; if treatment in primary care has not controlled symptoms; or if you need access to a multidisciplinary pain management programme. Patient organisations (UK FibroAction, US National Fibromyalgia Association) provide valuable education and peer support alongside medical care.