Decreased skin temperature

Introduction Clinical manifestations of arterial embolization when skin temperature is lowered. Arterial embolization refers to a pathological process in which the embolus is detached from the heart or the proximal arterial wall, or enters the artery from the outside, pushed to the distal side by the blood flow, and blocks the blood flow of the artery, resulting in ischemia or even necrosis of the limb or internal organs. When the peripheral arteries are embolized, the affected limbs are painful, pale, distant arterial pulsations disappear, cold, numbness, and movement disorders. The onset of the disease is rapid, and the limbs and even the life are threatened after the onset of the disease. It is important to diagnose and count the appropriate treatments every second. The main symptoms are severe pain, numbness, movement disorder, pale waxy skin, cold skin, skin temperature can be reduced by 3 ~ 5 ° C, arterial pulse disappeared or weakened.

Cause

(1) Causes of the disease

The source has two categories of cardiogenic and non-cardiac:

Cardiogenic

80% to 90% of peripheral arterial acute embolism is from heart disease, and 2/3 is complicated by atrial fibrillation. Common heart diseases include rheumatic heart disease, coronary heart disease, acute myocardial infarction, cardiomyopathy, congestive heart failure, and postoperative cardiac valve replacement, subacute bacterial endocarditis, and cardiac tumor (atrial myxoma).

(1) Rheumatic heart disease and coronary heart disease are the most common in organic heart disease. The former patients are younger, the ratio of male to female is 1:2; the latter is mostly elderly patients, and the incidence rate of men and women is similar. According to statistics, before the 1960s, rheumatic heart disease was the most common cause of arterial embolism; after the 1960s, coronary heart disease was the main cause, currently coronary heart disease accounted for more than 70%, and rheumatic heart disease was less than 20%. Atrial fibrillation was a high risk factor for peripheral arterial embolization, and approximately 77% of patients with peripheral arterial embolism had atrial fibrillation. According to statistics, chronic atrial fibrillation complicated with acute arterial embolism is 3% to 6% per year, and the incidence of paroxysmal atrial fibrillation and arterial embolism is much lower. Old myocardial infarction is also a risk factor for arterial embolism. Studies have shown that long-term anticoagulant therapy [mainly oral warfarin and/or aspirin] can not only effectively reduce the incidence of stroke, but also significantly reduce the rate of peripheral arterial embolization, regardless of whether or not atrial fibrillation is combined.

(2) Acute myocardial infarction is also a common cause of arterial embolism, most of which occurs within 6 weeks of myocardial infarction. The mortality rate of arterial embolism after myocardial infarction is as high as 50%. Heparin anticoagulation can reduce the incidence of arterial embolism. After myocardial infarction combined with ventricular aneurysm, is another source of arterial embolism, about half of the ventricular aneurysm has a wall thrombosis, 5% with arterial embolism.

(3) In arrhythmia type: heart disease, sick sinus syndrome (SSS) is about 16%, complete atrioventricular block is about 1.3% with arterial embolism. Other rare heart diseases that can be complicated by arterial embolization include bacterial endocarditis and prosthetic heart valve replacement. The embolus of bacterial endocarditis (SBE) often embolizes peripheral arterioles, such as the palm, ankle, and toe arteries. In addition to causing arterial embolism and tissue ischemia, it also spreads inflammation, which is bacterial endocarditis. Severe complications, the incidence rate is 15% to 35%; after prosthetic heart valve replacement, 25% of patients will have more than one arterial embolism, and 80% embolization in the brain, 10% of which are fatal, more Seen in those who failed to adhere to lifelong anticoagulant therapy. Partial shedding of the left atrial myxoma can lead to peripheral arterial embolization, but it is very rare.

2. Non-cardiac: non-cardiac arterial embolism is less common. It mainly includes aneurysms, atherosclerosis with ulcers or stenosis, arterial grafts, vascular injuries, tumors and venous thrombosis.

(1) The wall thrombus of aneurysm is an important source of arterial embolism after heart disease: aneurysms with arterial embolization include abdominal aortic aneurysm, femoral aneurysm, aneurysm and subclavian aneurysm. Aneurysms (25%) and subclavian aneurysms (33%) were most common with arterial embolism.

(2) Atherosclerotic stenosis combined with thrombosis: often occurs in the aorta or iliac artery, the formation of thrombus is larger, the diameter of the embolized artery is also correspondingly larger. Atherosclerotic plaque surface ulcer, cholesterol crystals enter the blood circulation, can also lead to arterial embolization, embolization of the distal diameter of 200 ~ 900m artery, characterized by small embolus, a large number, not only block the peripheral blood vessels after embolization, but also cholesterol After the crystal dissolves into the wall of the tube, it also becomes an inflammatory granuloma, which induces perivascular inflammation and aggravates tissue ischemia. Atherosclerosis cholesterol crystal embolism, often occurs after angiography or endovascular treatment, involving the renal artery, retinal artery, lower extremity peripheral artery. There are no effective treatments for persistent hypertension, renal insufficiency, and "blue toe" or limb blemish. Drug thrombolysis may be effective.

(3) vascular injury: especially the iatrogenic injury factors have a tendency to increase. More common in invasive examination and treatment, thrombosis on the surface of the catheter, and even broken guidewires, catheters, etc., can cause arterial embolism. Other extravascular extravascular injuries, such as the thoracic outlet syndrome, and abnormal neck ribs or first thoracic rib compression of the subclavian artery often produce a wall thrombus that becomes the source of embolism for upper extremity arterial embolism. Long-term walking can also contus the brachial artery and cause wall thrombosis.

(4) Tumor: more common in primary or metastatic lung cancer, the prognosis is very poor.

(5) Venous thrombosis: less common, also known as "paradoxical embolus", is the venous thrombosis that enters the arterial system through the patent foramen ovale or ventricular septal defect. More often associated with pulmonary embolism and pulmonary hypertension.

(two) pathogenesis

Pathological changes caused by acute arterial embolism include local changes (changes in embolized arteries and affected limbs) and systemic changes (hemodynamic changes and tissue ischemia, metabolic changes due to hypoxia).

1. Embolization site: Limb arterial embolization accounted for 70% to 80% of all cases, and lower extremity arterial embolization was 5 times higher than upper extremity arterial embolization. About 20% of cases of arterial embolization involve the cerebral blood vessels, and about 10% involve the visceral artery. Acute arterial embolism is easy to occur in the bifurcation of the arteries. The femoral artery bifurcation is the most common, accounting for 35% to 50%. The pulmonary artery bifurcation is second. The femoral artery and pulmonary embolism is twice as high as that of the aorta and radial artery.

However, arteriosclerotic disease changes the traditional embolization site. Arteriosclerotic multi-segment, multi-planar stenotic lesions, so that the thrombus is not limited to the vascular bifurcation, can also be embolized in the stenosis of the artery.

2. Local changes of arterial embolization: The prognosis of arterial embolization depends largely on the establishment of collateral circulation of the embolization artery. The embolus stays in the bifurcation of the artery, blocks the arterial blood flow and completely blocks the collateral circulation, causing serious limb damage. Ischemia. The following three mechanisms are more important for limb ischemia:

(1) Arterial thrombus spread, blocking the blood supply of the main trunk and collateral circulation, is the main secondary factor for aggravating ischemia. Early anticoagulant therapy should be actively prevented to prevent the spread of thrombus and protect the collateral circulation of the limb.

(2) local metabolite aggregation, tissue edema, causing compartment syndrome.

(3) Cellular edema, causing severe stenosis and occlusion of small arteries, venules and capillary lumens, aggravating tissue ischemia and venous return disorders (Fig. 1).

Ischemic time, degree of ischemia, ischemia and reperfusion injury affect capillary wall integrity. Ischemia-reperfusion injury causes the tissue to release a large amount of oxygen free radicals, which greatly exceeds the processing capacity of the intracellular free radical oxidation system, damages the cell phospholipid membrane, and the fluid flows to the interstitial space and tissue edema. Severe edema reduces local tissue blood flow, aggravates capillary edema of capillary endothelial cells, and forms a compartment syndrome. It is called "no reflow phenomenon". Although the blood supply to the main artery is established by measures such as thrombectomy, the peripheral tissues are still insufficiently supplied with blood. Arteries that have been unclogged at this time may soon form a thrombus. Fascia incision decompression can alleviate compartment syndrome, but it is difficult to relieve small vessel obstruction.

3. Systemic changes in arterial embolism

(1) Renal dysfunction: Arterial embolism cases are often accompanied by systemic diseases. After Haimovici reported that blood supply was established, 1/3 of the cases died of metabolic related complications. Reperfusion injury "triple syndrome": peripheral muscle necrosis, myoglobinemia and myoglobinuria, causing acute renal failure. The site of renal injury occurs in the proximal tubule and may be endothelin-mediated tubular damage. Oxygen free radical scavengers and alkalized urine have been considered as the recommended treatments, and it is currently considered that proper expansion is one of the most important treatments.

(2) Metabolites aggregate, causing systemic changes such as high K, hyperlactemia, myoglobinemia, and elevated cellular enzymes such as SCOT, suggesting that the striated muscle is ischemic. When the blood supply to the affected limb is established, these metabolites accumulated in the ischemic limb can be suddenly released into the systemic blood circulation, causing severe acidosis, high K and myoglobinuria.

an examination

Related inspection

Doppler echocardiography

Limbs with arterial embolism often have characteristic so-called "5P" signs: pain, numbness, no pulse, paleness, and dyskinesia.

(A) Pain: The main symptoms of most patients are severe pain. Some patients may only feel soreness, and individual patients may have no pain.

(B) numbness, movement disorders: the distal part of the affected limb is a sore-type sensory loss zone, caused by peripheral nerve ischemia. The proximal end has a hyposensitivity zone, and the sensed depression plane is lower than the embolization site.

(C) pale, cold: due to tissue ischemia, blood flow in the subcutaneous venous plexus of the skin is empty, the skin is waxy pale. If a small amount of blood accumulates in the blood vessels, scattered bruising plaques may appear between the pale skin. The circumference of the limb is reduced and the superficial vein is wilting. Fine blue lines appear under the skin, the skin is cold, especially at the distal end of the limb, and the skin temperature can be lowered by 3 to 5 °C.

(4) The arterial pulse disappears or weakens: the arteries at the embolization site have tenderness, and the arterial pulsation disappears or weakens after embolization.

In the case of sudden onset of limb pain with acute arterial ischemia, and corresponding arterial pulsation disappeared, the diagnosis is generally established.

Acute arterial embolization in the absence of collateral circulation compensation will result in signs of acute limb ischemia: Pulselessness, Pain, Pallor, Paresthesia, and Paralysis. , that is, the "5P" sign. The occurrence of these phenomena and their extent are related to the degree of ischemia.

1. Arterial pulsation diminished or disappeared: occurs in the distal arteries of the embolized arterial segment. Sometimes due to the impact of blood flow, embolization of the distal artery may touch the conductive pulsation. If the embolization is incomplete, the weakened distal arterial pulsation can be reached. In addition, arterial embolization will also cause tenderness of the affected arteries, which generally occurs at the proximal end of limb ischemia. The use of ultrasound Doppler stethoscopes or blood flow recorders, which do not smell normal arterial sounds, or the absence of arterial waveforms, is a more reliable method of examination.

2. Pain: After arterial embolization, most patients have severe limb pain. The pain site begins at the embolization and later extends to the distal limb of the embolization. The pain site can be displaced, and when the detached embolus rides across the bifurcation of the abdominal aorta, it shows severe abdominal pain; if the embolus is rushed to the femoral artery by blood flow, it becomes a pain in the thigh. The affected limb is tender, and the active or passive activity of the limb can cause pain and is therefore in a state of braking.

3. Pale, skin temperature decreased: due to the blood supply barrier at the distal end of the embolization artery, the skin was pale and waxy. If there is still a small amount of blood in the subcutaneous venous plexus, there are cyanosis spots of different sizes on the pale skin color. As a result of reduced blood flow, the superficial veins are collapsed.

The change of skin temperature is related to the site of arterial embolization. When the abdominal aortic bifurcation is embolized, the skin temperature of the buttocks and the lower limbs is decreased. When the radial artery is embolized, the temperature of the ipsilateral thigh is decreased, and the femoral artery is embolized in the middle of the thigh. The following skin temperature was reduced; the arterial embolization, the lower leg and its distal skin temperature decreased. Subclavian artery, radial artery embolization, symptoms involving the entire upper limb; radial artery embolism, symptoms involving the forearm; embolization of the ulnar artery or anterior and posterior iliac artery, due to a rich collateral circulation, symptoms are limited and light. The skin temperature can be changed by the following methods: 1 The examiner touches the affected limb with the middle side of the middle middle finger of the middle finger, and moves from the proximal end to the distal end, and the plane where the skin temperature of the affected limb is lowered can be perceived. 2 Using the same method to compare the skin temperature of the same plane of the bilateral limbs, it can be found that the skin temperature of the affected limb is lower than that of the non-embolized limb. 3 Using a skin thermometer to measure the bilateral limbs, the degree and plane of the skin temperature reduction can be measured.

4. Feeling and movement disorders

When the peripheral nerve has ischemic damage, a skin sensory loss zone may occur at the distal end of the limb, and the proximal end has a sensory loss zone and a skin sensory sensitive zone. Long embolization time, when there is peripheral nerve damage and ischemic necrosis of muscle tissue, it can cause finger and toe dyskinesia, hand and foot drooping and other symptoms. The examiner can measure the skin sensation of the affected limb by touching the skin of the affected limb with a hand or by a simple method of acupuncture. The finger or toe of the passively affected limb can be clearly defined as having a deep sensory loss.

5. Tissue necrosis

Once the course of arterial embolization is longer, the skin appears blisters, containing bloody exudate; the tissue thickens and hardens. At this time, there are obvious systemic symptoms: scorpion, high fever, chills, heart rate, and even blood pressure.

1. Qualitative diagnosis

Sudden onset of severe limb ischemia, the corresponding arterial pulsation disappeared, that is, there are "5P" signs, accompanied by organic heart disease, arteriosclerosis, especially with atrial fibrillation, recent myocardial infarction or abdominal aorta The patient with the tumor can be diagnosed clearly.

2. Positioning diagnosis

The position of the embolus can be blocked by: 1 the location of the initial pain; 2 the plane of normal pulse disappearance, the plane of skin temperature and other changes; 3 non-invasive examination (such as Doppler ultrasound); 4 range of limb circulation disorders 5 emboli are easy to stay at the arterial bifurcation and other characteristics to determine (Table 1).

3. Degree diagnosis

According to clinical signs and examination results, acute arterial embolization can be divided into three categories:

(1) mild ischemia: such patients have severe intermittent claudication, and the resting pain is mild. There are often several days from onset to treatment. The signs are free of movement and sensory disturbances except for pale limbs and decreased skin temperature. . There is no secondary thrombus or a small extent at the distal end of the arterial occlusion, and the collateral circulation is abundant. Such patients may have more time to do the corresponding examination and preoperative preparation, according to the specific conditions, consider conservative treatment of anticoagulant thrombolysis.

(2) Moderate ischemia: Most of the clinical patients belong to this category. Resting pain is obvious but can be tolerated. There are mild sensory disturbances. For example, the sensitivity to light touch is reduced, but there is no movement disorder. It is necessary to actively prepare for the operation and timely take the thrombus.

(3) Severe ischemia: loss of sensory and motor function of the affected limb, stiffness of the gastrocnemius muscle, purple spots or blisters on the skin, often requiring amputation to save lives. Some scholars have pointed out that patients with severe ischemia, such as arterial thrombectomy, have a mortality rate of 50% to 75%. If the patient's general condition allows, no renal insufficiency, only limb sensation and motor dysfunction but no muscle stiffness, compartment syndrome and skin purpura, Fogarty catheter thrombectomy is safe and effective for most patients. However, most of the postoperative patients often have sequelae of nerve damage such as numbness and foot drop.

Differential diagnosis

To be differentiated from elevated local skin temperature.

Increased local skin temperature: The surface skin temperature of the arteriovenous fistula is increased to varying degrees compared with the same site of the contralateral limb. The skin temperature of the distal part of the fistula is normal or lower than normal.

The temperature of each part of the human body is different, the head is higher, and the foot is lower. Different skin temperatures are determined by the heat balance between the heat flow from the core of the body to the surface of the skin and the heat dissipation from the surface of the skin to the environment. The skin temperature of 14 parts of a group of people was measured in a comfortable environment. The average skin temperature of the human body was 33.5 ° C and the mean square error was 0.5 ° C.

Limbs with arterial embolism often have characteristic so-called "5P" signs: pain, numbness, no pulse, paleness, and dyskinesia.

(A) Pain: The main symptoms of most patients are severe pain. Some patients may only feel soreness, and individual patients may have no pain.

(B) numbness, movement disorders: the distal part of the affected limb is a sore-type sensory loss zone, caused by peripheral nerve ischemia. The proximal end has a hyposensitivity zone, and the sensed depression plane is lower than the embolization site.

(C) pale, cold: due to tissue ischemia, blood flow in the subcutaneous venous plexus of the skin is empty, the skin is waxy pale. If a small amount of blood accumulates in the blood vessels, scattered bruising plaques may appear between the pale skin. The circumference of the limb is reduced and the superficial vein is wilting. Fine blue lines appear under the skin, the skin is cold, especially at the distal end of the limb, and the skin temperature can be lowered by 3 to 5 °C.

(4) The arterial pulse disappears or weakens: the arteries at the embolization site have tenderness, and the arterial pulsation disappears or weakens after embolization.

In the case of sudden onset of limb pain with acute arterial ischemia, and corresponding arterial pulsation disappeared, the diagnosis is generally established.

Acute arterial embolization in the absence of collateral circulation compensation will result in signs of acute limb ischemia: Pulselessness, Pain, Pallor, Paresthesia, and Paralysis. , that is, the "5P" sign. The occurrence of these phenomena and their extent are related to the degree of ischemia.

1. Arterial pulsation diminished or disappeared: occurs in the distal arteries of the embolized arterial segment. Sometimes due to the impact of blood flow, embolization of the distal artery may touch the conductive pulsation. If the embolization is incomplete, the weakened distal arterial pulsation can be reached. In addition, arterial embolization will also cause tenderness of the affected arteries, which generally occurs at the proximal end of limb ischemia.

The use of ultrasound Doppler stethoscopes or blood flow recorders, which do not smell normal arterial sounds, or the absence of arterial waveforms, is a more reliable method of examination.

2. Pain: After arterial embolization, most patients have severe limb pain. The pain site begins at the embolization and later extends to the distal limb of the embolization. The pain site can be displaced, and when the detached embolus rides across the bifurcation of the abdominal aorta, it shows severe abdominal pain; if the embolus is rushed to the femoral artery by blood flow, it becomes a pain in the thigh. The affected limb is tender, and the active or passive activity of the limb can cause pain and is therefore in a state of braking.

3. Pale, skin temperature decreased: due to the blood supply barrier at the distal end of the embolization artery, the skin was pale and waxy. If there is still a small amount of blood in the subcutaneous venous plexus, there are cyanosis spots of different sizes on the pale skin color. As a result of reduced blood flow, the superficial veins are collapsed.

The change of skin temperature is related to the site of arterial embolization. When the abdominal aortic bifurcation is embolized, the skin temperature of the buttocks and the lower limbs is decreased. When the radial artery is embolized, the temperature of the ipsilateral thigh is decreased, and the femoral artery is embolized in the middle of the thigh. The following skin temperature was reduced; the arterial embolization, the lower leg and its distal skin temperature decreased. Subclavian artery, radial artery embolization, symptoms involving the entire upper limb; radial artery embolism, symptoms involving the forearm; embolization of the ulnar artery or anterior and posterior iliac artery, due to a rich collateral circulation, symptoms are limited and light.

The skin temperature can be changed by the following methods: 1 The examiner touches the affected limb with the middle side of the middle middle finger of the middle finger, and moves from the proximal end to the distal end, and the plane where the skin temperature of the affected limb is lowered can be perceived. 2 Using the same method to compare the skin temperature of the same plane of the bilateral limbs, it can be found that the skin temperature of the affected limb is lower than that of the non-embolized limb. 3 Using a skin thermometer to measure the bilateral limbs, the degree and plane of the skin temperature reduction can be measured.

4. Sensory and dyskinesia: When the peripheral nerve has ischemic damage, the skin sensory loss zone may appear at the distal end of the limb, and the proximal end has a hyposensitivity zone and a skin sensory sensitive zone. Long embolization time, when there is peripheral nerve damage and ischemic necrosis of muscle tissue, it can cause finger and toe dyskinesia, hand and foot drooping and other symptoms.

The examiner can measure the skin sensation of the affected limb by touching the skin of the affected limb with a hand or by a simple method of acupuncture. The finger or toe of the passively affected limb can be clearly defined as having a deep sensory loss.

5. Tissue necrosis: Once the course of arterial embolization is longer, the skin appears blisters, containing bloody exudate; the tissue is thickened and hardened. At this time, there are obvious systemic symptoms: scorpion, high fever, chills, heart rate, and even blood pressure.

1. Qualitative diagnosis: the patient suddenly has severe signs of limb ischemia, and the corresponding arterial pulsation disappears, that is, there are "5P" signs, accompanied by organic heart disease, arteriosclerosis, especially with atrial fibrillation, recent myocardial Patients with infarction or abdominal aortic aneurysm can be diagnosed.

2. Positioning diagnosis: The position of the occlusion can be passed: 1 the location of the initial pain; 2 the plane where the normal pulse disappears, the plane of the skin temperature, etc.; 3 non-invasive examination (such as Doppler ultrasound, etc.); The extent of limb circulation disorders; 5 emboli are easy to stay at the arterial bifurcation and other characteristics to determine.

3. Degree diagnosis: According to clinical signs and examination results, acute arterial embolization can be divided into three categories:

(1) mild ischemia: such patients have severe intermittent claudication, and the resting pain is mild. There are often several days from onset to treatment. The signs are free of movement and sensory disturbances except for pale limbs and decreased skin temperature. . There is no secondary thrombus or a small extent at the distal end of the arterial occlusion, and the collateral circulation is abundant. Such patients may have more time to do the corresponding examination and preoperative preparation, according to the specific conditions, consider conservative treatment of anticoagulant thrombolysis.

(2) Moderate ischemia: Most of the clinical patients belong to this category. Resting pain is obvious but can be tolerated. There are mild sensory disturbances. For example, the sensitivity to light touch is reduced, but there is no movement disorder. It is necessary to actively prepare for the operation and timely take the thrombus.

(3) Severe ischemia: loss of sensory and motor function of the affected limb, stiffness of the gastrocnemius muscle, purple spots or blisters on the skin, often requiring amputation to save lives. Some scholars have pointed out that patients with severe ischemia, such as arterial thrombectomy, have a mortality rate of 50% to 75%. If the patient's general condition allows, no renal insufficiency, only limb sensation and motor dysfunction but no muscle stiffness, compartment syndrome and skin purpura, Fogarty catheter thrombectomy is safe and effective for most patients. However, most of the postoperative patients often have sequelae of nerve damage such as numbness and foot drop.

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