Myalgia

Introduction Fibromyalgia syndrome (FS) is a non-articular rheumatism with clinical manifestations of multiple pains and stiffness in the musculoskeletal system and tender points in specific areas. Fibromyalgia syndrome is more common in women, the most common age of onset is 25-45 years old. Its clinical manifestations are diverse. The main symptoms: extensive pain in the whole body is a symptom of all patients with fibromyalgia syndrome. Although some patients only complain of one or several pains, 1/4 of the patients have more than 24 pain points.

Cause

The mechanism of the disease is still unclear. Literature reports are associated with sleep disorders, abnormal neurotransmitter secretion, and immune disorders.

1. Sleep disorders. Sleep disorders involve 60-90% of patients. It is characterized by sleep-easy wake-up, multiple dreams, lack of energy in the morning, fatigue, generalized pain and morning stiffness. Nighttime EEG recording revealed that alpha waves were involved in the IV sleep wave. The above-mentioned EEG pattern and clinical symptoms can also be induced by ringing the volunteers with non rapid eye movement. Other factors affecting sleep such as mental stress and environmental noise can aggravate the symptoms of fibromyalgia syndrome. Therefore, it is speculated that this type IV sleep abnormality plays an important role in the development of fibromyalgia syndrome.

2. Abnormal secretion of neurotransmitters. The literature reports that neurotransmitters such as serotonin (5-HT) and substance P (substance P) play an important role in the pathogenesis of this disease. The precursor of serotonin is tryptophan. The tryptophan in the food protein is mostly absorbed by the plasma protein in the intestinal tract, and a small part is in a free state. Free tryptophan can be carried by the carrier through the blood-brain barrier into the brain tissue. Then, 5-HT is formed by hydroxylation and decarboxylation in 5-HTergic neurons. 5-HT released into the synaptic cleft is partially reabsorbed by presynaptic nerve endings, and partially mitochondrial monoamine oxidase produces inactive 5-hydroxyindole acetic acid. 5-HT is also present in the digestive tract mucosa, platelets, and breast cells. Because it is difficult to pass the blood-brain barrier, the 5-HT in the central nervous system and peripheral blood belong to two systems. The study found that:

1 In patients with fibromyalgia syndrome, plasma free tryptophan and its transport rate (trannsport ratio) decreased. The degree of reduction is related to musculoskeletal pain, that is, the lower the plasma concentration and the rotation ratio, the more obvious the pain.

2 High-affinity 5-HT receptor on platelet membrane, imipramine can compete with 5-HT for binding to platelet receptor, and 5-HT receptor on platelet membrane is determined by -labeled imipramine Body density, found that fibromyalgia syndrome is affected by normal people.

3 fibrofrontalis syndrome 5-HT is significantly reduced in human brain tissue compared with normal people. Experiments have shown that 5-HT can regulate non-rapid eye movement sleep, reduce sensitivity to pain, improve depression, and enhance the analgesic effect of anesthesia. Amitriptyline and cyclobenzaprine can convert 5-HT to 5-hydroxyindolease, increasing 5-HT concentration, so it has a certain effect on fibromyalgia syndrome. In contrast, fibromyalgia syndrome-like pain occurs when the tryptophan hydroxylase inhibitor, parachlorophenylalamine, is administered, and the pain disappears after the drug is stopped.

Another neurotransmitter associated with fibromyalgia syndrome is substance P. Littlejohn found that physical or chemical stimuli can induce significant cutaneous hyperemia in patients with fibromyalgia syndrome, which may be associated with persistent peripheral damage. Due to these stimuli, the polymodal cutaneous nociceptor reflexively releases a pathological amount of substance P from the nerve endings, which in turn causes local vasodilation, enhanced vascular permeability and a neurogenic inflammation (neurogenic). Inflammmation). After the release of substance P at the nerve endings, the primary sensory neurons of the dorsal root ganglia will synthesize more substance P in order to maintain a constant level. The synthesized substance P is simultaneously transmitted to both the distal end and the central axis, and therefore, the substance P content of the central nervous system is increased. Due to its slow but long-lasting and intense excitatory effects, the central nervous system is bound to be affected.

It has also been found that substance P has a depressing effect on the release of sensory nerve impulses in the presence of normal or high levels of 5-HT. Lack of 5-HT, it will lose this control, leading to hyperalgesia.

3. Immune disorders. Some authors report the deposition of immunoreactants at the dermal-epidermal junction of patients with fibromyalgia syndrome. Electron microscopy revealed swelling of muscle capillary endothelial cells in patients with fibromyalgia, suggesting acute vascular injury; tissue hypoxia and Increased permeability. Unexplained weight gain, diffuse swelling of the hands, and nocturia may be associated with increased permeability.

In addition, preliminary studies have found that interleukin-2 (IL-2) levels are elevated in fibromyalgia syndrome. Tumor patients who receive IL-2 therapy will develop fibromyalgia syndrome-like symptoms, including extensive pain, sleep disturbances, morning stiffness, and tenderness. It has also been found that alpha interferon can cause fatigue. The above phenomenon suggests an immune regulation disorder. Abnormal cytokine levels in the body may be related to the onset of fibromyalgia syndrome.

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Fibromyalgia syndrome is more common in women, the most common age of onset is 25-45 years old. Its clinical manifestations are diverse, but mainly have the following four sets of symptoms:

1. The main symptoms: extensive pain in the whole body is a symptom of all patients with fibromyalgia syndrome. Although some patients only complain of one or several pains, 1/4 of the patients have more than 24 pain points. The disease is spread all over the body, especially in the mid-axis bones (neck, thoracic vertebrae, lower back) and shoulder straps, pelvic belts, etc. Other common parts are knee, head, elbow, ankle, foot, upper back, middle back, wrist, buttocks, thighs and calves. Most patients describe the pain as stinging and the pain is distracting.

In all other patients, there are symptoms of widespread tenderness. These tender points are present in tendons, muscles, and other tissues and tend to be symmetrically distributed. At the point of tenderness, the patient and the normal person respond differently to "pressing", but there is no difference in other parts.

2. Characteristic diseases: This group of symptoms includes sleep disorders, fatigue and morning stiffness. About 90% of patients have sleep disorders, which are characterized by insomnia, easy to wake up, multiple dreams, and lack of energy. The nighttime EEG showed that alpha waves were involved in the non-fast eye rhythm, suggesting a lack of sleep. 50-90% of patients have fatigue, and about half of the patients have severe fatigue symptoms, so that they feel "too tired to work." Morning stiffness is seen in 76-91% of patients, whose severity is related to sleep and disease activity.

3. Common symptoms: The most common of this group of symptoms is numbness and swelling. The patient often complained of swelling around the joints and joints, but no objective signs. Followed by headache, irritable bowel syndrome. A headache can be divided into a migraine or a non-migraine headache, which is a type of oppressive dull pain in the occipital region or the entire head. Psychological abnormalities, including depression and anxiety, are also common. In addition, the patient's labor capacity is reduced, about one-third of the patients need to change jobs, and a small number of people can not insist on daily work. The above symptoms are often aggravated by cold weather, nervousness, and overwork. Local fever, mental relaxation, good sleep, and moderate activity can alleviate symptoms.

4. Mixed symptoms: Primary fibromyalgia syndrome is rare, most patients with fibromyalgia syndrome also have some kind of rheumatism. At this time, the clinical symptoms are the interweaving and overlapping of the two symptoms. Fibromyalgia syndrome often causes symptoms of rheumatism to coexist with it, and failure to recognize this often leads to overtreatment and examination of the latter.

Differential diagnosis

Symptoms of fibromyalgia syndrome such as fatigue and pain are clinically common symptoms. It requires the identification of several diseases.

1. Mental rheumatic pain: Fibromyalgia is easily confused with mental rheumatism, but there are significant differences between the two. Mental rheumatism has emotional symptoms. For example, the pain is described as severe pain in the scalpel, or as numbness, tightness, needle-like or oppressive pain. These symptoms are often blurred. It is highly variable, has no anatomical basis, and is not affected by weather or activity. Patients often have mental or emotional disorders such as psychosis, depression, schizophrenia or other mental illnesses. It is important to distinguish between the two, because the former is more difficult to handle and often requires psychiatrists to treat.

2. Chronic fatigue syndrome: Chronic fatigue syndrome includes chronic active EB virus infection and idiopathic chronic fatigue syndrome. It is characterized by fatigue and fatigue, but lacks the underlying cause. Check the patient for low fever, pharyngitis, neck or axillary lymphadenopathy, and determine the anti-EB virus envelope antigen antibody IgM to help identify the two.

3. Rheumatic polymyalgia: Rheumatoid polymyalgia manifests as extensive neck, scapular, back and pelvic pain. However, according to the rapid blood sedimentation, more common in the elderly over 60 years old, synovial biopsy showed inflammatory changes, sensitivity to hormones, etc., can be differentiated from fibromyalgia syndrome.

4. Rheumatoid arthritis: Patients with RA and fibromyalgia syndrome have generalized generalized pain, stiffness and swelling of the joints. However, there is no objective evidence of swelling of the joints of fibromuscular syndrome. Its morning stiffness is shorter than RA. Laboratory tests including rheumatoid factor, erythrocyte sedimentation rate, and joint X-ray films are also political. Fibromyalgia syndrome has a wide range of pain, less confined to the joints, mostly in the lower back, thighs, abdomen, head and hip, while RA pain is mostly distributed in the wrist, fingers and toes.

5. Myofascial pain syndrome: Myofascial pain syndrome, also known as localized fibrosis, also has a learning tenderness point, which is easily confused with the fibrosis of the fiber. But the two have differences in diagnosis, treatment and prognosis. The tender point of myofascial pain syndrome is usually called the point of stimulation. When you press this point, the pain will radiate to other parts. Although the patient feels pain, they may not know where to activate the point. Myofascial syndrome usually has only one or several localized excitation points. The point of excitation originates from the muscles, and the affected muscles are restricted in activity. Passive or active contraction of the muscles can cause pain. Partial closure of the point of challenge with 1% procaine temporarily relieves pain. Unlike fibrosis, it does not have extensive symptoms of pain, stiffness or fatigue. However, if persistent pain causes stage IV sleep disorders, myofascial syndrome may evolve into fibromyalgia syndrome. Myofascial syndrome is usually caused by trauma or overwork. The general prognosis is good.

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