Fibromyalgia syndrome (FS) is a non-articular rheumatic disease that manifests clinically as pain and stiffness in multiple areas of the musculoskeletal system with pressure points in specific areas. Fibromyalgia syndrome can be secondary to trauma, various rheumatic diseases such as osteoarthritis (OA), rheumatoid arthritis (RA) and various non-rheumatic diseases (e.g. hypothyroidism, malignancy). This type of fibromyalgia syndrome is called secondary fibromyalgia syndromen, or primary fibromyagia syndrome if no other disorders are associated with it. Pathogenesis The mechanism of this disease is not clear. The literature reports that it is related to sleep disorders, abnormal neurotransmitter secretion and immune disorders. 1.Sleep disorder Sleep disorder involves 60-90% of patients. It is characterized by easy awakening, excessive dreaming, morning mental fatigue, generalized pain and morning stiffness. Nocturnal EEG recordings revealed alpha waves intervening in stage IV delta sleep waves. The above EEG patterns and clinical symptoms can also be induced by disturbing non-rapid eye movement in volunteers with a bell. Other factors affecting sleep, such as stress and environmental noise, can aggravate the symptoms of fibromyalgia syndrome. Therefore, it is speculated that this stage IV sleep abnormality plays an important role in the development of fibromyalgia syndrome. 2, abnormal neurotransmitter secretion The literature reports that neurotransmitters such as serotonin (serotonin, 5-HT) and substance P (substance P) play an important role in the development of this disease. The precursor of serotonin is tryptophan, a food protein that is absorbed in the intestine and is mostly bound to plasma proteins, with a small percentage being free. The free tryptophan can be carried by carriers across the blood-brain barrier into brain tissue. 5-HT is then hydroxylated and decarboxylated in 5-HTergic neurons to produce 5-HT. 5-HT released into the synaptic gap is partially reuptaken by presynaptic nerve endings and partially produced by mitochondrial monoamine oxidase to produce inactive 5-hydroxyindole acetic acid. 5-HT is also present in the mucosa of the digestive tract, platelets and mammary gland cells. 5-HT is also found in the mucosa of the digestive tract, platelets and mammary gland cells. Since it is difficult to cross the blood-brain barrier, 5-HT in the central nervous system and in peripheral blood belong to two separate systems. Another neurotransmitter associated with fibromyalgia syndrome is substance P. Littlejohn found that physical or chemical stimuli induce a marked cutaneous congestion response in patients with fibromyalgia syndrome and that this overreaction may be related to the presence of a persistent terminal injury stimulus. As a result of these stimuli, cutaneous polymodal cutaneous nociceptors reflexively release pathological amounts of substance P from nerve endings, which in turn can cause local vasodilation, increased vascular permeability, and a form of neurogenic inflammmation. After the release of substance P from nerve terminals, primary sensory neurons in the dorsal root ganglion synthesize more substance P in order to maintain a constant level. The synthesized substance P is simultaneously transmitted in both directions to the terminals and to the center, thus increasing the amount of substance P in the central nervous system. Due to its slow but long-lasting and strong excitatory effect, the central nervous system must be affected to some extent. It has also been found that in the presence of normal or high levels of 5-HT, substance P has a blocking effect on the release of sensory nerve impulses. In the absence of 5-HT, it will lose this control role, resulting in nociceptive hypersensitivity. 3. Immune disorders Some authors have reported deposits of immunoreactive substances at the dermal-epidermal junction in patients with fibromyalgia syndrome, and electron microscopic observation revealed swelling of muscle capillary endothelial cells in patients with fibromyalgia syndrome, suggesting acute vascular injury; tissue hypoxia and increased permeability. The unexplained weight gain, diffuse swelling of the hands and increased nocturia often reported by patients may be related to increased permeability. In addition, preliminary studies have found that interleukin-2 (IL-2) levels are elevated in fibromyalgia syndrome. Patients with tumors treated with IL-2 are born with fibromyalgia syndrome-like symptoms, including widespread pain, sleep disturbances, morning stiffness, and the appearance of pressure points. Alpha interferon has also been found to cause fatigue. The above phenomena suggest immune regulation disorders. Abnormal levels of cytokines in the body may be associated with the onset of fibromyalgia syndrome. Epidemiology The epidemiology of fibromyalgia anterior syndrome has not been reported in China, and there is no precise statistical data from abroad, but from some preliminary data, it seems that the disease is not uncommon. A survey in the United Kingdom shows that 10 or 9% of the people who are unable to work because of illness are caused by rheumatic diseases, of which fibromyalgia syndrome accounts for about half. The American Rheumatism Association points out that primary fibromyalgia syndrome is one of the most common rheumatic diseases, occupying the third place after RA and OA. Yunus et al. treated 285 patients with skeletal muscle system diseases in 1 year, 29% of which were OA, 20% were primary fibromyalgia syndrome, and 16% were RA. Among Asian countries, a report from Japan illustrates that they treated 182 patients in 2 years in the connective tissue A total of 182 patients with rheumatic diseases were treated in the outpatient clinics, of which 11 cases were fibromyalgia syndrome, accounting for 6% of the total. It ranked seventh after rheumatoid arthritis (27,5%), systemic lupus erythematosus (16%), systemic sclerosis (10,4%), and dry syndrome (7,7%). Clinical manifestations Fibromyalgia syndrome is mostly seen in women, and the most common age of onset is 25-45 years. The clinical manifestations are diverse, but there are four main groups of symptoms as follows: 1. Although some patients complain of pain in only one or a few places, 1/4 of them have more than 24 pain sites. The disease is widespread throughout the body, especially in the medial skeleton (neck, thoracic spine, lower back) and in the scapular and pelvic girdles. Other common sites are, in order, the knee, head, elbow, ankle, foot, upper back, mid-back, wrist, hip, thigh and calf. Most patients describe this pain as stabbing and distressing. Another symptom that all patients have is the widespread presence of pressure points that are present in tendons, muscles, and other tissues, often in a symmetrical distribution. The patient’s response to “pressure” is different from that of a normal person at the site of the pressure point, but there is no difference in other areas. This group of symptoms includes sleep disturbance, fatigue and morning stiffness. About 90% of the patients have sleep disorder, which is characterized by insomnia, easy to wake up, dreaminess, and mental fatigue. The nocturnal EEG shows alpha waves intervening in the non-fast branching eye rhythm, suggesting a lack of sleepiness. 50-90% of patients have fatigue, and about half have fatigue symptoms so severe that they feel “too tired to work”. Morning stiffness is seen in 76-91% of patients, and its severity is related to sleep and disease activity. 3. Common symptoms: The most common symptoms in this group are numbness and swelling. Patients often complain of joint and peri-articular swelling, but there are no objective signs. This is followed by headache and irritable bowel syndrome. Headaches can be classified as migraine or non-migrainous headache, the latter being a dull, compressive pain in the occipital region or throughout the head. Psychological abnormalities including depression and anxiety are also more common. In addition, the patient’s ability to work is reduced, with about 1/3 of patients needing to change jobs and a small number unable to hold down a daily job. The above symptoms are often aggravated by cold and humid weather, mental tension and overexertion. Local heat, mental relaxation, good sleep and moderate activity can reduce the symptoms. 4.Mixed symptoms: Primary fibromyalgia syndrome is rare, and most patients with fibromyalgia syndrome are suffering from some kind of rheumatic disease at the same time. This clinical symptoms are the intertwining and overlapping of the two symptoms. Fibromyalgia syndrome often makes the coexistence of rheumatic disease symptoms appear more serious, such as failure to recognize this situation often leads to excessive treatment and examination of the latter.