Overview.
Sympathetic chain syndrome is pain that is relieved by blocking the sympathetic nerves that innervate the area of pain with a local anesthetic. Pain that does not respond to blockade of the sympathetic nerves is referred to as nonsympathetic interdependent pain (SIP). It is a clinical syndrome with multiple etiologies leading to a long-term insidious presence. Typical symptoms appear when ganglion damage is severe and compensatory capacity is weakened, and diagnosis and treatment are often delayed, with major clinical symptoms such as pain sensory deficits and vascular dysfunction. The disease can occur at any age and is not uncommon in both sexes.
Causes
Many factors can cause sympathetic chain syndrome. For example, various acute and chronic infections, systemic or local infections, various endogenous and exogenous poisoning, as well as trauma, degenerative spinal diseases, tumors, vascular diseases and chronic irritating lesions.
Symptoms
1. Mostly subacute or chronic onset, or acute onset. The basic characteristics of local sympathetic chain lesions are: segmental asymmetry, strong diffusion and cyclic aggravation, etc. Clinical manifestations vary according to the damaged sympathetic ganglia.
2. Pain and sensory impairment, pain is episodic or persistent, accompanied by episodic aggravation, heavier at night, emotional fluctuations, physical labor, weather changes and cold stimulation and other factors can make the pain worse. The range is more diffuse. Pressure pain may appear in the projection area of the damaged sympathetic ganglion, and if pressure points are found, it is often helpful to localize the diagnosis. A variety of sensory abnormalities may appear, such as numbness, ant-like sensation, etc. Objective sensory disorders are less severe than subjective symptoms, and most of them are abnormal pain sensation, abnormal temperature sensation, and less common are tactile and deep sensory disorders.
3. Skin and appendage changes, the skin can show irritating symptoms, such as increased sweating and hyperreflexia; it can also show functional deficits, such as reduced skin conductivity, reduced sweating and weakened reflexia. In addition, the skin can also appear nutritional disorders, dryness and atrophy, hair loss and finger (toe) nails become brittle and so on.
4. Vascular dysfunction is mainly manifested as spasm of small arteries and capillaries, and there is also vascular hypotonia or even paralysis, as well as somatic neurological dysfunction.
Examination
1. Laboratory examination
(1) Blood, urine and stool routine and biochemical tests are related to the original disease.
(2) Routine examination of cerebrospinal fluid is mostly nonspecific.
2. Other auxiliary examinations
(1) Cranial and limb imaging has the significance of differential diagnosis.
(2) Drugs and poisons test also has the significance of etiologic differential diagnosis.
3. Commonly used phycological nerve function examination methods
(1) Oculocardiac reflex: lie on your back with your eyes closed, use your fingers to gently press on both sides of one eyeball of the patient, and start counting the pulse after 3~4 seconds (with mild pain) (count for 15 seconds), and record the number of pulses per minute and compare it with the number of pulses before the examination. Normal people may decrease by 4 to 7 beats/minute after the examination. If the patient decreases by more than 12 beats/minute, it is positive, indicating increased vagal tone; if the decrease is more than 18 to 24 beats/minute, the vagal tone is significantly increased. Such patients are particularly susceptible to syncope, and there is a risk of cardiac arrest during treatment. In addition to a slowed heart rate, pulse force is often diminished, and clinically there may be blackness, dizziness, nausea, and even vomiting, often referred to as vagal tone. On the contrary, if the pulse increases after pressing the eyeballs, it is called inversion reaction, indicating that the patient has increased sympathetic tone.
(2) White scratching syndrome When a bamboo stick or fingernail is lightly and quickly scratched across the skin (the lower limbs are more obvious), white scratches appear within 8 to 20 seconds and last for 3 to 5 minutes. This is due to vasoconstriction caused by neurological reflexes, indicating increased sympathetic excitability.
(3) Red stripe syndrome: If a bamboo stick is used to scratch the skin with a little pressure, red stripes will appear in 3 to 5 seconds and last for 8 to 30 minutes. If the red lines are wider and last longer, they may be related to increased parasympathetic excitability. In severe cases, they may appear only 1 to 2 minutes after crossing the skin and last for 1 to 12 hours. The raised, edematous skin at the site of the scratch is caused by vasodilatation with blood exudation. Skin tattooing can also occur in normal people, and is clinically significant only when it lasts too long, or when a reaction occurs regardless of the severity of the tattoo.
(4) Prone and Stand Test The patient lies down and the pulse is counted for 1 minute; then the patient sits up and the pulse is counted for another minute. If the pulse increases 10-20 times/minute from lying to standing position, the sympathetic excitability will be increased; if it decreases 10-20 times/minute from standing to lying position, the parasympathetic excitability will be increased.
(5) Vertical hair reflex When ice cubes or other cold stimuli are placed on the skin of the back of the neck or armpits of the patient for a few seconds, contraction of the vertical hair muscles can be seen, and the follicles of the skin bulge with a chicken skin-like appearance. This reflex is innervated by the sympathetic segmental nerve, and according to the response of different parts, the sympathetic nerve dysfunction can be localized and diagnosed. For example, C8~T3 innervates the head, face and neck, T4~T7 innervates the upper limbs, T8~T9 innervates the trunk, and T10~L2 innervates the lower limbs.
(6) Trace sweating assay Skin humidity and the function of sweat glands are related. Thermal sweating is mainly related to the environmental temperature, which can regulate the body temperature. Neurogenic sweating is mainly controlled by vegetative nerve function. Sweat glands are innervated by the postganglionic fibers of the cholinergic sympathetic nerves. By monitoring the neurogenic microscopic sweat secretion of the skin, the sympathetic nerve tension can be determined in time.
(7) Tiny Nerve Electrode Method A silicon-carbon tiny nerve electrode with a tip diameter of 0.1μ can be inserted into a single nerve cell, and then amplified by an electronic instrument under the shielded environment of a copper mesh to directly draw out the impulses of the sympathetic nerve. This is one of the most direct methods to determine sympathetic nerve function.
(8) Diagnostic sympathetic nerve block is the most commonly used method in clinical practice. Selectively block the sympathetic nerves innervating the lesion site. If the pain is rapidly relieved after the block, and the affected area changes from cold and damp to a comfortable warm feeling, the temperature of the facial skin rises, and sweating decreases, it means that the occurrence of the pain is closely related to the sympathetic nerves.
(9) Others Electrocardiogram R2R interval method, measurement of hormone concentration in blood, etc.
Diagnosis
The disease may be considered on the basis of the presence of episodic or persistent pain within the sympathetic innervation area on a particular side, or significant pressure pain in the sympathetic ganglionic projection area. The disease must be differentiated from spinal cord cavernous disease, angina pectoris, and thromboembolic vasculitis. Attention should also be paid to the differentiation of the different etiologies.
Treatment
1. Sympathetic nerve block
Sympathetic nerve block is used to block the pain mediated by sympathetic nerves and to dilate the blood vessels in the innervated area to achieve the therapeutic effect.
(1) Stellate ganglion block (SGB): There are 3 sympathetic ganglia on each side of the cervical sympathetic trunk, called upper, middle and lower cervical ganglia, and the lower cervical ganglia often merge with the thoracic 1 sympathetic nerves to form a star, so it is called stellate ganglion. The stellate ganglion block inhibits cardiovascular motility, glandular secretion, muscle tension, and nociceptive transmission innervated by sympathetic fibers in the distribution area, and these peripheral effects are used to treat a number of disorders of the head, neck, shoulder, heart, and lungs.SGB block is generally marked by the appearance of Horner’s sign as a sign of success. It is important to note that SGB should be administered as a single agent, using only local anesthetics. Its efficacy may be slow and should be repeated for optimal results.
(2) Thoracic sympathetic nerve block is often used to treat hyperhidrosis of the head, neck and chest with laparoscopic thoracic sympathetic nerve block and good results have been reported abroad.
(3) Lumbar sympathetic nerve block often use local anesthesia or nerve destroying drugs or radiofrequency thermocoagulation on the lumbar sympathetic nerve block, for the lower extremity vascular disease and lumbar spinal stenosis caused by lower extremity pain in the short-term efficacy is remarkable, long-term efficacy is more than 50%, and can effectively reduce the occurrence of ulcers. Lumbar sympathetic nerve block is effective in improving the temperature of the lower limbs.
(4) Abdominal plexus block Abdominal plexus block can effectively relieve intractable epigastric pain, with an effective rate of 70% to 90%.
(5) Visceral nerve blockFujita2Y reported that the use of 15 ml of anhydrous alcohol for visceral nerve destruction in patients with epigastric cancer pain can effectively relieve pain and substantially reduce the amount of morphine.
(6) Inferior mesenteric plexus block is mainly used for lower abdominal pain in the area innervated by the inferior mesenteric artery.
(7) The inferior epigastric plexus block is located anterior to the lumbar 5 vertebrae and below the bifurcation of the common iliac artery. It is mainly used for pain caused by lesions from pelvic organs such as bladder, rectum, uterine adnexa, etc. It is effective for both benign and malignant pelvic pain.
(8) Chi ganglion block is mainly used for perianal and perineal pain.
(9) Epidural sympathetic nerve block for a wide range of SMP, the use of 0.5% lidocaine continuous epidural infusion, to interrupt the vicious cycle of pain, can achieve better results. Among them, thoracic epidural sympathetic nerve block is commonly used in the treatment of unstable angina.
2. Receptor antagonist therapy
Phentolamine is commonly used for intravenous administration, which has the effect of blocking the sympathetic nerves of the whole body, especially suitable for patients with SMP in many parts of the body.
3. Sympathectomy
Most people do not advocate its use, mainly because of the possibility of new pain in the days to weeks after the operation – post-sympathectomy pain, which occurs in the distal limb of the removed sympathetic innervation, with symptoms of sympathetic denervation, such as excessive sweating, deep muscle tenderness, and cutaneous nociceptive sensitization.
4. Spinal cord electrical stimulation (SCS)
It is mainly used for well-localized refractory SMP such as intractable angina, peripheral vascular disease, and CRPS. Spinal cord electrical stimulation, as a mature operation technique, has been more and more widely used in the world. Firstly, unipolar or multipolar stimulating electrodes are placed into the epidural cavity of the corresponding segment by percutaneous puncture technique, and the spinal cord segment is stimulated with evoked potentials to see whether it can cover the corresponding pain area, and then the test phase is carried out for about one week, and if the patient’s response is good, the stimulator will be permanently buried into the abdominal or gluteal subcutis to become the permanent stimulation device.