frostbite
Introduction
Introduction to frostbite Frostbite is a localized inflammatory dermatosis caused by cold. It is a common disease in winter, which is exposed to the exposed parts. It is now characterized by congestive edema and erythema. It is characterized by itching in case of high temperature. In severe cases, it may appear. The skin of the affected area is erosive and ulcerated. The disease has a long course and will recur in winter and is not easy to cure. For some young ladies, it not only affects the aesthetics of the hands, but also brings great inconvenience to life. In terms of treatment, although there are many methods, they are rarely cured, so they are often tricky. basic knowledge The proportion of illness: 0.005% Susceptible people: no specific people Mode of infection: non-infectious Complications: bradycardia, frostbite, hypotension, shock
Cause
Cause of frostbite
Causes:
Climate factors (35%):
Cold weather, including air humidity, flow rate, and sudden changes in weather. Both moisture and wind speed accelerate the body's heat dissipation. The body is exposed to low temperature and humidity for a long time, causing frostbite.
Local factor (20%):
If the shoes and socks are too tight, standing for a long time and immersed in water for a long time, the blood vessels of the body surface will be paralyzed, and the blood flow will be reduced, resulting in tissue ischemia and hypoxia, and the cells will be damaged, especially the limbs. The part with poor blood circulation leads to frostbite.
Systemic factors (15%):
Such as fatigue, weakness, nervousness, hunger, blood loss and trauma can weaken the body's ability to regulate and adapt to changes in external temperature, so that local heat reduction leads to frostbite.
Pathogenesis:
After local skin is stimulated by the environment, the strong contraction of blood vessels leads to tissue ischemia, the temperature continues to decrease, the tissue freezes, and the cells freeze rapidly to form intracellular ice crystals, which slowly freeze to form intercellular ice crystals. Due to the formation of ice crystals, the microenvironment inside and outside the cells changes, and the cells are dehydrated. Intracellular electrolyte enzymes, sugar and other concentrations increase, detached from freezing, during the rewarming process, the blood vessels dilate, the blood enters the dilated microvessels and accumulates quickly, the exudate increases, forms edema, plasma extravasation, blood concentration, leading to thrombosis Formation and microcirculation disorders, making tissue more ischemic, and even lead to tissue necrosis. At the same time, due to increased tissue metabolism, increased oxygen demand, more likely to cause degeneration and necrosis of tissue cells, therefore, the extent and extent of frostbite needs to be observed for several days. Can be behind.
Make accurate judgments. In addition, different tissues have different tolerance to cold. It is generally believed that nerves, blood vessels and muscles are the most sensitive, skin, sarcolemma and connective tissue are second, and bones and tendons have the strongest cold tolerance.
Prevention
Frostbite prevention
1. Pay attention to exercise and improve the skin's adaptability to cold.
2, pay attention to keep warm, protect the easy frozen parts, such as hands, feet, ears, etc., should pay attention to wearing gloves, wearing thick socks, cotton shoes and so on. After the shoes are wet, they should be replaced in time. Wear earmuffs when you go out, pay attention to keep your ears warm. These parts are often licked to strengthen blood circulation.
3. Do not use soap that is too alkaline when washing your hands or washing your face to avoid irritating the skin. After washing, you can wipe some oily skin care products such as moisturizer, cream, glycerin to protect the skin.
4, often carry out cold-resistant exercise, wash your face with cold water, wash your hands to enhance cold resistance.
5, people with chronic diseases, such as anemia, malnutrition, etc., in addition to active treatment of the corresponding diseases, to increase nutrition, to ensure adequate heat supply to the body, enhance resistance.
Complication
Frostbite complications Complications, bradycardia, frostbite, hypotension, shock
When the body temperature drops below 26 ° C, ventricular fibrillation can occur, and finally the heartbeat, breathing stops.
Symptom
Symptoms of frostbite Common symptoms Skin frostbite "frozen" phenomenon Foot frostbite Septicemia Cold reaction Slow ear frostbite Frostbite expression Indifferent earlobe defect
It occurs mostly in areas with poor peripheral blood circulation and exposed parts, such as hands, feet, nose, auricles, cheeks, etc. The affected part is pale, cold, painful and numb. After rewarming, the local performance and burn are similar, but local swelling is generally not Obviously, it can be divided into four degrees according to its depth and severity of damage.
Once frostbite: shallow skin frostbite, local skin is pale at first, gradually turned blue-violet, followed by redness, itching, tingling and paresthesia, no blister formation, about 1 week later, the symptoms disappeared, the epidermis gradually Shedding, leaving scars after the healing.
Second degree frostbite: full-thickness skin frostbite, local skin redness, itching, burning pain, blistering within 24 to 48 hours, if there is no secondary infection, after 2 to 3 weeks, the blister is dry, forming a black dry sputum, shedding The posterior wound has a keratinized neonatal epithelial covering, which may have persistent stiffness and pain, but does not leave scars and convulsions.
Third degree frostbite: the whole skin and subcutaneous tissue were frostbitten, the skin gradually changed from pale to blue, then turned black, the skin felt disappeared, and the surrounding tissues of the frostbite showed edema and blisters, accompanied by severe pain and itching, necrosis. After the tissue is detached, there is a wound, which is easy to be infected, slow healing, scars left behind, and can affect the function.
Four degrees of frostbite: skin, subcutaneous tissue, muscles and even bones are frostbitten, the sensory and motor function of the wound completely disappears, the affected area is dark gray, edema and blisters may appear at the junction with healthy tissue, and there is obvious necrosis within 2 to 3 weeks. Demarcation lines appear, usually dry gangrene, but sometimes due to venous thrombosis, surrounding tissue edema and secondary infection, the formation of wet gangrene often leaves disability and dysfunction.
Some patients with frostbite may have complications, the most common are secondary infections of local wound necrotic tissue, such as acute lymphangitis and lymphadenitis, acute cellulitis, erysipelas, etc., more severe, tetanus, gas gangrene And sepsis, in addition, there are a small number of concurrent hepatitis, pericarditis, pyelonephritis and arthritis.
When the human body stays excessively in extremely low temperature environment, it can cause systemic frostbite. This condition is called freezing stiffness, rare, early mental excitement, peripheral vasoconstriction, blood pressure rises, pale skin and cold, heart rate is accelerated, with chills, when body temperature drops When the temperature is below 35 °C, various physiological functions are changed from excitement to inhibition; when the body temperature drops below 32 °C, the patient's expression is indifferent, mental disorder, breathing, heart rate are slowed down, muscle rigidity; when the body temperature drops below 29 °C, the reaction Slow and even coma, blood pressure drops; when the body temperature drops below 26 ° C, ventricular fibrillation can occur, and finally the heartbeat, breathing stops.
Examine
Frostbite inspection
Histopathology: epidermal and dermal edema, vascular congestion, red thrombosis, followed by intimal hyperplasia, narrowing of the lumen, atrophy or degeneration of the skin attachment, adipose tissue crystallization and necrosis, sometimes free and intracellular The fat droplets (unique characteristics of frostbite), with the severity of frostbite, the degree of degeneration and necrosis of tissue cells is also more serious, which can be expressed as tissue pathological changes of dry and wet gangrene.
Diagnosis
Frostbite diagnosis and identification
diagnosis:
1. Have a history of freezing, especially in a humid and windy environment.
2. Early numbness of the frozen part, burning, itching or tingling after rewarming, if there is necrosis, there is no feeling.
3. The clinical manifestations after frostbite rewarming are divided into four degrees:
I degree: superficial frostbite of the skin, erythema of the skin, mild edema.
II degree: shallow skin and part of deep frostbite, early congestion and edema, followed by blister formation.
III degree: frostbite of skin and subcutaneous tissue, full skin necrosis occurs, and the skin changes from pale to purple brown to black.
IV degree: frostbite involving deep tissue, dry necrosis of deep tissue, loss of function.
Generally not confused with other diseases.
