Frostbite occurs when exposure to low temperatures leads to freezing of the skin or other tissues. Early symptoms are usually numb. This may be followed by irregularity with white or bluish skin. Swelling or blisters may occur after treatment. The hands, feet, and face are most commonly affected. Complications may include hypothermia or compartment syndrome.
People exposed to low temperatures for long periods, such as winter sports enthusiasts, military personnel, and homeless people, are at greatest risk. Other risk factors include drinking alcohol, smoking, mental health problems, certain medications, and previous injuries due to cold. The underlying mechanism involves injury from ice crystals and blood clots in small blood vessels after liquefaction. Diagnosis is based on symptoms. Severity can be divided into superficial (levels 1 and 2) or within (levels 3 and 4). Bone scan or MRI can help in determining the extent of injury.
Prevention is to wear proper clothes, maintain hydration and nutrition, avoid low temperatures, and stay active without getting tired. Treatment is by rewarming. This should be done only when refreezing is not a concern. Rubbing or applying snow to the affected part is not recommended. Use of ibuprofen and tetanus toxoid is usually recommended. For severe injuries iloprost or trombolytics may be used. Surgery is sometimes necessary. Amputation, however, should generally be delayed for several months to allow for the determination of injury rates.
The number of cases of frostbite is unknown. The price may be as high as 40% per year among those who climb the mountain. The most common age groups are those aged 30 to 50 years. Evidence of frostbite occurring in humans dates back to 5,000 years ago. Frostbite also played an important role in a number of military conflicts. The first formal description of the condition was in 1814 by Dominique Jean Larrey, a physician in the Napoleonic army.
Video Frostbite
Signs and symptoms
Areas normally exposed include the cheeks, ears, nose and fingers and toes. Frostbite is often preceded by frostnip. Symptoms of the development of frostbite with prolonged cold exposure. Historically, frostbite has been classified according to degrees according to skin changes and sensations, similar to burning classification. However, the degree does not match the amount of long-term damage. The simplification of this classification system is superficial (first or second level) or deep injury (third or fourth level).
First degree
- The first degree of frostbite is the surface, surface skin damage that is usually not permanent.
- From the beginning, the main symptom is the loss of feeling in the skin. In the affected area, the skin is numbed, and may be swollen, with a flushed border.
- In the weeks after the injury, the skin surface may peel.
Second degree
- In the second-degree frostbite, the skin develops clear blisters early on, and the skin surface hardens.
- In the weeks after the injury, the hardened and blistered skin is dry, blackened, and peeling.
- At this stage, the ongoing sensitivity and coldness can develop.
Third degree
- In fifth grade inflammation, the tissue lining beneath the skin freezes.
- Symptoms include blood abrasions and "grayish-blue changes in the skin".
- In the weeks after the injury, the pain continues and the black crust (eschar) develops.
- There can be long-term ulceration and damage to the growth plate.
Fourth degree
- In fourth degree frostbite, the structures under the skin are involved like muscles, tendons, and bones.
- Early symptoms include the appearance of skin colorless, hard texture, and painless warmth.
- Later, the skin becomes black and mummy. The amount of permanent damage can take a month or more to determine. Autoamputation can occur after two months.
Maps Frostbite
Cause
Risk factors
The main risk factor for frostbite is cold exposure through geography, work and/or recreation. Inadequate clothing and shelter are major risk factors. Frostbite is more likely when the body's ability to produce or retain heat is disrupted. Physical, behavioral, and environmental factors may contribute to the development of frostbite. Physical immobility and stress (such as malnutrition or dehydration) are also risk factors. Disturbances and substances that damage the circulation contribute, including diabetes, Raynaud's phenomenon, tobacco use and alcohol. Homeless people and individuals with some mental illness may be at higher risk.
Mechanism
Holds
In frostbite, cooling the body causes a constriction of blood vessels (vasoconstriction). Temperatures below -4 Â ° C are needed to form ice crystals in the tissues. The freezing process causes ice crystals to form in the tissues, which in turn causes damage to the cellular level. Ice crystals can damage the cell membrane directly. In addition, ice crystals can damage small blood vessels at the site of injury. Scar tissue is formed when fibroblasts replace dead cells.
Appreciate
Rewards cause tissue damage through reperfusion injury, which involves vasodilation, swelling (edema), and poor blood flow (stasis). Platelet aggregation is another possible mechanism of injury. Blisters and spasms of blood vessels (vasospasm) can develop after rewarming.
Non-freezing cold injury
The frostbite process is different from the non-coldzing cold injury (NFCI) process. At NFCI, the temperature in the network decreases gradually. This slower temperature reduction allows the body to try to compensate through the alternating cycle of closing and opening blood vessels (vasoconstriction and vasodilation). If this process continues, inflammatory mast cells act in the area. A small clot (mikrothrombi) forms and can cut blood to the affected area (known as ischemia) and damage the nerve fibers. Reclaiming causes a series of inflammatory chemicals such as prostaglandins to increase local clotting.
Pathophysiology
Pathological mechanisms where frostbite causes tissue injury can be characterized by four stages: Prefreeze, freeze-thaw, vascular stasis, and late ischemic stage.
- Prefreeze phase: involves cooling the tissue without the formation of ice crystals.
- The freeze-thaw phase: ice crystals are formed, resulting in cellular damage and death.
- The phase of vascular stasis: characterized by blood clots or leakage of blood from blood vessels.
- The final ischemic phase: characterized by inflammatory, ischemic, and tissue death events.
Diagnosis
Frostbite is diagnosed based on the signs and symptoms described above, and based on patient history. Other conditions that may have similar appearances or occur at the same time include:
- Frostnip is similar to frostbite, but without the formation of ice crystals in the skin. Skin bleaching and numbness retreat quickly after burning.
- Foot trenches are damage to the nerves and blood vessels that result in exposure to wet, cold (not frozen) conditions. This is reversible if treated early.
- Pernio or chillbains are skin inflammation from exposure to wet, cold (not frozen) conditions. They can appear as various types of boils and abrasions.
- Bullous pemphigoid is a condition that causes an itchy scab over the body that can resemble frostbite. No need to get cold to develop.
- The toxicity of Levamisole is a vasculitis that can appear similar to frostbite. This is due to the contamination of cocaine by levamisole. Skin lesions may look the same as frostbite, but do not require cold exposure to occur.
People with hypothermia often experience frostbite as well. Because hypothermia is life-threatening, it should be treated first. Technetium-99 or MR scan is not required for diagnosis, but may be useful for prognostic purposes.
Prevention
The Wilderness Medical Society recommends to cover the skin and scalp, take adequate nutrition, avoid rigid shoes and clothing, and remain active without causing fatigue. Additional oxygen may also be useful at high altitudes. Repeated exposure to cold water makes people more susceptible to frostbite. Additional actions to prevent frostbite include:
- Avoid temperatures below -15 ° C
- Avoids moisture, including in the form of sweat and/or emollient skin
- Avoid alcohol and drugs that damage circulation or natural-protection responses
- Coat clothing
- Using a chemical or electric heating device
- Recognize the early signs of frostnip and frostbite
Treatment
Individuals with frostbite or potential frostbite should go to a protected environment and get warm fluids. If there is no risk of re-freezing, the extremities may be exposed and warmed in the groin or under the armpits of the companion. If the area is left to freeze, there could be worse network damage. If the area can not be trusted to remain warm, the person should be taken to a medical facility without re-warming the area. Rubbing the affected area can also increase tissue damage. Aspirin and ibuprofen can be given in the field to prevent clotting and inflammation. Ibuprofen is often preferred over aspirin because aspirin can block a subset of prostaglandins that are important in repairing the injury.
The first priority in people with frostbite should be to assess for hypothermia and other life-threatening complications from cold exposure. Before treating frostbite, the core temperature should be raised above 35C. Oral or intravenous (IV) fluids should be administered.
Other considerations for standard hospital management include:
- wound care: blisters can be dried with needle aspiration, unless they are bleeding (haemorrhagic). Aloe vera gel may be applied before breathing, sanitary napkins or dressings are worn.
- antibiotics: if there is trauma, skin infection (cellulitis) or severe injury
- tetanus toxoid: should be given in accordance with local guidelines. Uncomplicated cold sore wounds are not known to induce tetanus.
- pain control: NSAIDs or opioids are recommended during a painful rewarming process.
Entertaining
If the area is still partially or completely frozen, it should be rejuvenated in the hospital with a warm bath with povidone iodine or chlorhexidine antiseptic. Active breathing attempts to warm the injured tissue as quickly as possible without burning. The faster the network is liquefied, the less tissue damage occurs. According to Handford and colleagues, "The Wilderness Medical Society and the State of Alaska Cold Injury Guidelines recommend a temperature of 37-39Ã, Â ° C, which reduces the pain experienced by patients while only slightly delaying rewarming time." Warming takes 15 minutes to 1 hour. Entertaining can be very painful, so pain management is important.
Drugs
People with large amputation potential and who come within 24 hours after injury can be given a landfill with heparin. These medications should be kept confidential if there is contraindication. Bone scan or CT angiography can be performed to assess the damage.
Blood vessels that use drugs such as iloprost can prevent the clogging of blood vessels. This treatment may be appropriate in grade 2-4 frostbite, when people get treatment within 48 hours. In addition to vasodilators, sympatholytic drugs can be used against the adverse peripheral vasoconstriction that occurs during frostbite.
Surgery
Different types of surgery may be indicated in frostbite injury, depending on the type and extent of damage. Necrotic tissue debridement or amputation is usually delayed unless there is gangrene or systemic infection (sepsis). This has led to the saying "Frozen in January, amputated in July". If symptoms of compartment syndrome develop, fasciotomy may be done to try to maintain blood flow.
Prognosis
Loss of tissue and autoamputation is a potential consequence of frostbite. Permanent nerve damage including loss of feeling can occur. It may take a few weeks to figure out what parts of the network will last. Cold exposure time is more predictive of a lasting injury than the temperature experienced by a person. Classroom classification systems, based on network responses to initial rewarming and other factors are designed to predict long-term recovery rates.
Value
Grade 1: if there is no initial lesion in the area, no amputation or lasting effect is expected
Grade 2: if there are lesions on the distal part of the body, tissue and nails can be destroyed
Grade 3: if there are lesions on the middle or near body parts, autoamputation and loss of function may occur
Grade 4: if there are lesions that are very close to the body (such as hand strokes), the limbs may disappear. Sepsis and/or other systemic problems are expected.
A number of long-term residual symptoms can occur after frostbite. These include temporary or permanent changes in sensation, paresthesia, increased perspiration, cancer, and bone/arthritis damage in the affected area.
Epidemiology
There is a lack of comprehensive statistics on the epidemiology of frostbite. In the United States, frostbite is more common in the northern states. In Finland, the annual incidence is 2.5 per 100,000 among the civilian population, compared to 3.2 per 100,000 in Montreal. Research shows that men aged 30-49 are at the highest risk, possibly due to occupational exposure or recreation for cold.
History
Frostbite has been described in military history for thousands of years. The Greeks encountered and discussed the problem of frostbite as early as 400 BC. Researchers have found evidence of frostbite in humans aged 5,000 years, in the Andean mummy. The Napoleonic Army was the first documented example of a massive cold injury in the early 1800s. According to Zafren, nearly 1 million fighters became victims of frostbite in World War One and Second, and the Korean War.
Society and culture
Notable cases of frostbite include Captain Lawrence Oates, a British army captain and Antarctic explorer, who died of a complication of frostbite in 1912. In 1982, American rock climber Hugh Herr lost both legs under his knee to frostbite after being stranded on Mount Washington in a snowstorm. In addition, many explorers of Mount Everest lose numbers and limbs due to frostbite. Beck Weathers, who survived the disaster of Mount Everest in 1996, lost his nose and hands for frostbite. In 1999, Scottish mountain climber Jamie Andrew had four amputated limbs due to sepsis from frostbite that constantly attacked the Mont Blanc massif.
Direction of research
Evidence is not enough to determine whether hyperbaric oxygen therapy as an adjuvant therapy can help in tissue rescue. Cases have been reported, but no randomized controlled trials are conducted in humans.
Medical sympathectomy using intravenous resuspin has also been tried with limited success. Studies have suggested that administration of tissue plasminogen activators (tPa) either intravenously or intra-arterially may decrease the probability of end-use for amputation.
References
External links
- Mayo Clinic
- Definitions
Source of the article : Wikipedia
0 Comments