What is Raynaud’s syndrome? Raynaud’s syndrome is a symmetrical, paroxysmal pallor, cyanosis and flushing of the skin of the distal extremity due to paroxysmal spasmodic constriction or occlusion of the small arteries in the distal extremity in response to factors such as cold or mental stimulation. The disease may be characterized solely by changes in the distal extremity, or it may be associated with arterial occlusive disease or connective tissue disease, manifesting a series of changes such as ischemia in the distal extremity.
The pallor of the distal extremity in Raynaud’s syndrome is mainly due to the complete closure of the small peripheral arteries and micro-arteries and the cessation of perfusion of the capillary network under the stimulation of cold and nervousness; with the accumulation of metabolites in the local capillary network, especially in a warm environment, the capillaries and micro-venules of the patient reactively dilate, while the spasm of the pre-capillary micro-arteries is relieved, allowing a large amount of arterial blood to enter the dilated arteries. This allows a large amount of arterial blood to enter the dilated capillary bed. Later, as the spasm of the peripheral arteries is completely relieved, the perfusion of the capillary bed is restored and a large amount of arterial blood enters the capillary network, which is clinically manifested as flushing of the distal limbs.
As the disease progresses, on the one hand, the primary disease itself will cause occlusion of small arteries, and on the other hand, the repeated attacks of Raynaud’s syndrome will lead to intimal hyperplasia and luminal narrowing of small arteries, and eventually complete occlusion, which will manifest as ulceration or even gangrene of the extremity.
What are the causes and pathogenesis of Raynaud’s syndrome?
Raynaud’s syndrome is more common in women than in men, with a male to female ratio of about 1:10, and the age of onset is mostly between 20-30 years old.
1. cold stimulation Typical Raynaud’s syndrome attacks are often after cold stimulation, the frequency and degree of attacks are also related to the cold degree of the climate.
The majority of patients with Raynaud’s syndrome are sympathetically excited, and some patients may also have attacks under high stress, probably because the patient’s vasomotor nerve center is in a disturbed state, making the terminal arterial smooth muscle tone higher and increasing sensitivity to stimuli.
3. Endocrine factors Raynaud’s syndrome is mostly seen in women, and the patient’s symptoms are aggravated during menstruation and reduced during pregnancy, which may be related to the secretion level of sex hormones.
4. Occupational factors The incidence of Raynaud’s syndrome can be as high as 50% among workers who are engaged in long-term vibratory work (such as steam drill, chainsaw), and studies have shown that when the vibration frequency is 125Hz, the impact tension on the terminal finger arteries is quite large, and the pathology can show the manifestation of subendothelial fibrosis. In addition, the incidence of Raynaud’s syndrome is significantly higher among those working in the frozen food industry.
Regarding the cause of complete closure of the terminal artery, current studies suggest that the two main causes are: first, arterial occlusion. The second is arterial spasm (of course, these two pathological processes are not completely independent and may be two stages of the same disease). There are many types of lesions that cause arterial occlusion, but the main ones are atherosclerosis, vasculitis and chronic arteritis caused by autoimmune reactions and local thrombosis. As for the specific mechanism of arterial spasm is currently unknown and may be related to neurological, endocrine, and immune system hyperfunction factors.
What are the clinical manifestations of Raynaud’s syndrome?
Raynaud’s syndrome is mostly seen in cold regions, prone to occur in cold climates, and is mostly seen in women. In fact, in a significant proportion of patients, Raynaud’s syndrome is an early manifestation of autoimmune connective tissue disease and arterial occlusive lesions.
A typical Raynaud’s syndrome attack is characterized by a paroxysmal change from pale to cyanotic to flushed skin on the patient’s fingers and even toes (but mostly fingers), accompanied by mild tingling, numbness and dullness of sensation under the effect of cold stimuli and mental stress, and each attack usually lasts 10-30 minutes. Most patients require the elimination of triggers such as cold stimuli before the attack will end. Of course there are many patients who do not exhibit the typical three-step changes, but only one or two changes in skin color. During an attack, both limbs are often involved at the same time, with the little finger and ring finger being the most common and the thumb less commonly involved, although there are a few patients who have sequential attacks on both limbs.
As the disease progresses, including a few patients in the early stages of the disease, chronic ischemia of the extremities may be manifested due to the presence of occlusion of the terminal arteries, i.e., persistent limb pain, nutritional impairment, and even ulceration or gangrene.
Treatment of Raynaud’s syndrome?
(A) Keep warm, sedation, quit smoking
For patients with Raynaud’s syndrome (especially those with mild symptoms), first of all, attention should be paid to the warmth of the affected hands and feet; those who are nervous should be given certain sedative treatment, such as oral Valium tablets, Synthroid, Glivec and Librium. A considerable number of patients after warmth and sedation treatment, the symptoms have been significantly improved. Since the nicotine component of cigarettes can cause vasospasm constriction, patients who smoke should strictly quit smoking and avoid being in a smoking environment. In addition, those with Raynaud’s syndrome due to occupational factors should change their jobs.
(ii) Drug treatment
Due to the lack of objective indicators to evaluate the drugs to improve the peripheral microcirculation, some of the drugs have obvious side effects, so the exact efficacy of drug therapy for Raynaud’s syndrome needs to be further evaluated.
The main drugs commonly used are adrenergic nerve blockers (to inhibit sympathetic hyperactivity), calcium channel blockers (to relax vascular smooth muscle and dilate blood vessels) and drugs to improve microcirculation (to dilate peripheral blood vessels).
(iii) Plasma replacement therapy
Because of the changes in blood viscosity and platelet function in some patients with Raynaud’s syndrome, plasma exchange has been used for treatment. The mechanism of action is firstly to reduce the fibrin level in the blood, and it also helps to dissolve fibrin deposits, regulate platelet function and remove harmful circulating immune complexes. It should be noted, of course, that plasma exchange therapy is mainly indicated for patients with severe Raynaud’s syndrome who have abnormal blood viscosity indicators, but for the majority of patients, the effect is not significant. Therefore, plasma exchange therapy is not indicated for most patients.
(iv) Surgical treatment
The vast majority of patients with Raynaud’s syndrome can obtain symptomatic relief with the above-mentioned conservative medical treatment. Surgical treatment is considered only when medical treatment is ineffective or when there is occlusion of the finger and toe arteries.
(1) Sympathectomy of the sympathetic nerve endings of the finger and toe arteries: good short-term results, with some recurrence rate in the long term.
(2) Microanastomosis of the finger and metacarpal arteries: improves blood supply to the terminal limb by bridging the vessels, but most patients with Raynaud’s disease have extensive involvement of the terminal arteries and are unable to bridge the vessels, and are not suitable for this procedure.
(3) For patients with ulcers, active cleaning of the wounds, drug exchange and anti-infection treatment should be carried out, and for the fingers and toes that have become necrotic, amputation should be performed.
(E) Treatment of concomitant diseases
As a considerable part of Raynaud’s syndrome is accompanied by systemic systemic diseases (such as arterial occlusive disease or connective tissue disease), the early manifestation is only arterial spasm, and then gradually manifest the original disease. Therefore, patients with Raynaud’s syndrome should be closely followed up in order to manage the primary disease in a timely manner. Arterial revascularization (balloon dilation, stenting, or bypass bypass) should be performed in the presence of occlusive arterial disease, and related immunotherapy should be performed in patients with connective tissue disease.