Fibromyalgia
Fibromyalgia is a long-term adverse health condition characterised by widespread chronic pain. Current diagnosis also requires an above-threshold severity score from among six other symptoms: fatigue, trouble thinking or remembering, waking up tired, pain or cramps in the lower abdomen, depression, or headache. Other symptoms may also be experienced. The causes of fibromyalgia are unknown, with several pathophysiologies proposed.
Fibromyalgia is estimated to affect 2 to 4% of the population. Women are affected at a higher rate than men. Rates appear similar across areas of the world and among varied cultures. Fibromyalgia was first recognised in the 1950s, and defined in 1990, with updated criteria in 2011, 2016, and 2019.
The treatment of fibromyalgia is symptomatic and multidisciplinary. Aerobic and strengthening exercise is recommended. Duloxetine, milnacipran, and pregabalin can give short-term pain relief to some people with FM. Symptoms of fibromyalgia persist long-term in most patients.
Fibromyalgia is associated with a significant economic and social burden, and it can cause substantial functional impairment among people with the condition. People with fibromyalgia can be subjected to significant stigma and doubt about the legitimacy of their symptoms, including in the healthcare system. FM is associated with relatively high suicide rates.
Terminology
The term "fibromyalgia" was derived from Neo-Latin fibro-, meaning 'fibrous tissues'; Greek μυο- ; and Greek άλγος ; thus, the term literally means 'muscle and fibrous connective tissue pain'. Thus, this term is inaccurate and misleading, as it only reflects a part of the symptom set.The term FM is increasingly used.
Classification
ICD-11
Fibromyalgia is not listed as a code in the ICD-11."Fibromyalgia syndrome" is listed as an inclusion in the ICD-11 code of "Chronic widespread pain" .
Other classifications
Research seeing FM as a subset of chronic widespread pain has estimated the population prevalence of chronic widespread pain as 11% and of fibromyalgia as 2–6%.FM has been seen as a functional somatic syndrome condition, although this term does not appear in the ICD-11.
Subgroups or clusters within FM
There may be clusters of symptom characteristics within fibromyalgia. A 2024 systematic review found that fibromyalgia could be clustered according to symptom severity, adjustment to the condition, thermal pain sensitivity, personality, and response to treatment. However it stated there was a need for more objective measures, and for more validation and replication of clusters. Clustering has also been undertaken based on psychological and coping characteristics of FM people.Signs and symptoms
The characteristic symptom of fibromyalgia is chronic widespread pain. The current prevalent diagnosis method also requires an above-threshold severity score from among six other symptoms: fatigue, trouble thinking or remembering, waking up tired, pain or cramps in the lower abdomen, depression, and headache. Many other symptoms can be present. The key symptoms of fibromyalgia often present concurrently, in varying severity, and are intertwined with and influence each other.Chronic pain
continues to be regarded as the core characteristic of fibromyalgia. According to the NHS, widespread pain is a major symptom, which could feel like an ache, a burning sensation, or a sharp, stabbing pain. Patients are also susceptible to pain, and the slightest touch can cause pain. Pain also tends to linger for a longer period when a patient experiences it. The pain associated with fibromyalgia is often a constant dull ache that has lasted for at least three months, occurring on both sides of the body and above and below the waist.Pain in fibromyalgia may include contributions from central pain, peripheral musculoskeletal pain generators, neuropathic pain, and other pathways.
Men may be affected by FM pain differently to women.
Fatigue
is a common symptom of fibromyalgia. Patients may experience physical or mental fatigue. Physical fatigue can present as a feeling of exhaustion after exercise or limitation in daily activities. Fibromyalgia fatigue can range from feeling mildly tired to flu-like exhaustion. Severe fatigue may come on suddenly and make it difficult to be active at all. The impact of fatigue can be severe and pose more of a problem than the pain. Fatigue is a complicated, multifactorial, and vexing symptom that is highly prevalent and stubbornly persistent, as evidenced by longitudinal studies over 5 years. Fatigue does not improve with sleep or rest. Medication seems to have little impact on FM fatigue.Sleep problems
Sleep problems are a common symptom of fibromyalgia. Waking up feeling unrefreshed is used in fibromyalgia diagnosis. People with FM may also experience difficulty falling or staying asleep.A meta-analysis compared quantitative and qualitative sleep metrics in people with fibromyalgia and healthy people. Individuals with fibromyalgia indicated lower sleep quality and efficiency, longer wake time after sleep start, shorter sleep duration, lighter sleep, and greater trouble initiating sleep when quantitatively assessed, and more difficulty initiating sleep when qualitatively assessed.
Improving sleep quality can help people with fibromyalgia manage pain.
Cognitive problems ("fibro fog")
Many people with fibromyalgia experience cognitive problems often known as "fibro fog". The CDC and the American Pain Society recognize these problems as a major feature of fibromyalgia.About 75% of people with fibromyalgia report significant problems with concentration, memory, and multitasking. A 2018 meta-analysis found that the largest differences between people with fibromyalgia and healthy subjects were in inhibitory control, memory, and processing speed. A 2023 scoping review grouped effects into subjective cognitive dysfunction, perceived variability, changes in functional activities and participation limitations.
A 2017 review found that the neuropsychological mechanisms underlying brain fog may be similar to those in isolated functional cognitive disorders. One hypothesis is that chronic pain in fibromyalgia compromises attention systems, resulting in cognitive problems.
Other signs and symptoms
People with fibromyalgia may experience hyperalgesia and allodynia. People with FM may be intolerant to bright lights, loud noises, perfumes, and cold.Other symptoms may be musculoskeletal stiffness, environmental sensitivity, hypervigilance, sexual dysfunction, and visual symptoms. Nocturnal myoclonus can be present in people with fibromyalgia. A 2021 review found that fibromyalgia can also cause ocular discomfort and visual disturbances.
Comorbidity
Fibromyalgia as a stand-alone diagnosis is uncommon, as most fibromyalgia patients often have other chronic overlapping pain problems, mental disorders or physical conditions.Comorbidities can give higher levels of pain and other symptoms.
Fibromyalgia is associated with mental health issues including anxiety, posttraumatic stress disorder, bipolar disorder, alexithymia, and depression. Approximately one third of patients presenting with an FM diagnosis also meet the criteria for PTSD, and are five times more likely to have major depression than the general population.
Experiencing pain and limited energy from having fibromyalgia leads to less activity, leading to social isolation and increased stress levels, which tends to cause anxiety and depression. Separation of symptoms due to depression or FM can be difficult.
Numerous chronic pain conditions are often comorbid with fibromyalgia. These include Chronic tension headaches, Myofascial pain syndrome, and Temporomandibular disorders.
Neurological disorders that have been linked to pain or fibromyalgia include, Multiple sclerosis, Post-polio syndrome, Neuropathic pain, Parkinson's disease.
Fibromyalgia largely overlaps with several syndromes that may share the same pathogenetic mechanisms. These include myalgic encephalomyelitis/chronic fatigue syndrome and irritable bowel syndrome.
Comorbid fibromyalgia has been reported to occur in 20–30% of individuals with rheumatic diseases, including rheumatoid arthritis. It has been reported in people with noninflammatory musculoskeletal diseases.
The prevalence of fibromyalgia in gastrointestinal disease has been described mostly for celiac disease and irritable bowel syndrome. IBS and fibromyalgia share similar pathogenic mechanisms, involving immune system mast cells, inflammatory biomarkers, hormones, and neurotransmitters such as serotonin. Changes in the gut biome alter serotonin levels, leading to autonomic nervous system hyperstimulation.
Other conditions that are associated with fibromyalgia include obesity, connective tissue disorders, cardiovascular autonomic abnormalities, obstructive sleep apnea-hypopnea syndrome, restless leg syndrome and an overactive bladder.
Causal and risk factors
The cause of fibromyalgia is unknown. However, several risk factors, genetic and environmental, have been identified.Fibromyalgia may have a variety of causal factors, including disease, trauma, psychological and social emotional factors. Thus more than one pathophysiological state may cause fibromyalgia.
Genetics
Genetics plays a major role in fibromyalgia and may explain up to 50% of the disease's susceptibility. Fibromyalgia is potentially associated with polymorphisms of genes in the serotonergic, dopaminergic and catecholaminergic systems. Several genes have been suggested as candidates for susceptibility to fibromyalgia. These include SLC6A4, TRPV2, MYT1L, NRXN3, and the 5-HT2A receptor 102T/C polymorphism. The heritability of fibromyalgia is estimated to be higher in patients younger than 50.Nearly all the genes suggested as potential risk factors for fibromyalgia are associated with neurotransmitters and their receptors. Neuropathic pain and major depressive disorder often co-occur with fibromyalgia — the reason for this comorbidity appears to be due to shared genetic abnormalities, which leads to impairments in monoaminergic, glutamatergic, neurotrophic, opioid and proinflammatory cytokine signaling. In these vulnerable individuals, psychological stress or illness can cause abnormalities in inflammatory and stress pathways that regulate mood and pain. Eventually, a sensitization and kindling effect occurs in certain neurons leading to the establishment of fibromyalgia and sometimes a mood disorder.