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Frostbite
Donald Morando, DO
Lina N. Qazi, DO
Courtney Maiden, DO
image BASICS
DESCRIPTION
  • A localized complication of exposure to cold, causing tissue to freeze, resulting in diminished blood flow to the affected part (especially hands, face, or feet).
  • System(s) affected: endocrine/metabolic, skin/exocrine
  • Synonym(s): dermatitis congelationis; frostnip; environmental injuries
EPIDEMIOLOGY
  • Predominant age: all ages
  • Predominant sex: male = female
ETIOLOGY AND PATHOPHYSIOLOGY
  • Prolonged exposure to cold
  • Refreezing thawed extremities
  • Ice crystals form intracellularly, damaging capillaries
  • Vasoconstriction reduces blood flow and microclotting leads to ischemia.
  • Cellular dehydration, abnormal electrolyte concentrations due to the above and ultimately cell death
  • In severe cases, deep tissue freezing may occur with damage to underlying blood vessels, muscles, and nerve tissue.
  • With rewarming, the ice crystals melt and injured endothelium promotes edema resulting in the formation of epidermal blisters.
  • Inflammatory mediators, prostaglandins, and thromboxane A2 induce vasoconstriction and platelet aggregation, worsening ischemia.
RISK FACTORS
  • Environmental: lack of proper clothing or shelter resulting in prolonged exposure to below freezing temperatures
  • Substance abuse, especially alcohol
  • Age: infants and elderly
  • Previous cold-related injury
  • Decreased caloric intake (<1,500 calories/day)
  • Dehydration or hypovolemia
  • Underlying psychiatric disturbance
  • Smoker
  • Lean body mass
  • Raynaud phenomenon
  • Peripheral vascular disease
  • Diabetes
GENERAL PREVENTION
  • Dress in layers with appropriate cold weather gear, avoid clothing that is too constricting.
  • Cover exposed areas and extremities appropriately.
  • Prepare properly for trips to cold climates.
  • Minimize wind exposure.
  • Stay dry.
  • Avoid alcohol.
  • Ensure adequate hydration and caloric intake.
  • Supplemental oxygen at very high altitudes (>7,500 meters)
COMMONLY ASSOCIATED CONDITIONS
  • Alcohol and/or drug abuse
  • Hypothermia
image DIAGNOSIS
PHYSICAL EXAM
  • Feet, hands, and face are the most commonly affected.
  • Classified as superficial or deep injuries
  • Superficial: Only the skin and subcutaneous tissues are involved. Tissue is pliable. White mottled appearance with minimal capillary refill. Erythematous and edematous on rewarming, blisters are usually clear and neurovascular compromise is reversible.
  • Deep: Injury extends into the bone. Tissue remains mottled and pulseless after rewarming, loss of sensation persists. Infrequent hemorrhagic blister formation. Tissue loss is common. High risk of infection
DIFFERENTIAL DIAGNOSIS
  • Frostnip: a superficial cold injury that does not cause permanent damage
  • Chilblains (pernio): an inflammatory reaction to short-term cold, wet exposure without tissue freezing
  • Immersion syndrome (trench foot): inflammatory reaction to prolonged cold, wet exposure, typically socks or footwear
DIAGNOSTIC TESTS & INTERPRETATION
ECG in hypothermia may show bradycardia, atrial fibrillation, atrial flutter, ventricular fibrillation, diffuse T-wave inversion, Osborn waves (upward-going “hump” following S wave in the RST segment).
Initial Tests (lab, imaging)
  • Baseline labs: CBC, CMP, UA for myoglobinuria, culture wound if suspected infection
  • Triple-phase bone scan can identify tissue viability at early stage and facilitate early débridement.
  • Other imaging techniques sometimes used include MRI/MRA, infrared thermography, angiography, digital plethysmography, and laser Doppler studies.
Test Interpretation
  • Ice crystallization in the intravascular extracellular space
  • Atrophy
  • Fibroblastic proliferation
  • Skin necrosis
image TREATMENT
Geriatric Considerations
  • Associated disease states increase mortality.
  • Periarticular osteoporosis complicates
  • More prone to hypothermia
Pediatric Considerations
Loss of epithelial growth centers
GENERAL MEASURES
  • Admit patient to a burn center for deep injuries.
  • Increase patient's body temperature to 34°C.
  • Only warm areas of injury if possibility of refreezing can be excluded. Warm affected parts of body in 37-39°C water with antiseptics (iodine, polyhexanide) for 15 to 60 minutes or until skin color changes to red/violet (1)[C].
  • Apply topical aloe vera gel before dressing.
  • Débride open blisters only, débridement of tense, cloudy, or clear blisters at discretion of provider
  • Splint and elevate affected extremity.
  • Tetanus prophylaxis
  • Analgesia and hydration, oral hydration if patient is alert and has no GI symptoms, otherwise IV hydration with warm normal saline in small boluses.
  • Ibuprofen 400 mg BID
  • Daily bathing in warm water containing antiseptics with active and passive mobilization
  • Dry, loose bulky dressings, including in between fingers/toes (2)[C]
  • Prohibit smoking
  • Regular monitoring for reperfusion, consider experimental vasodilatation, thrombolytics, or sympathectomy for failed reperfusion (1)[C].
MEDICATION
First Line
  • tPA administered within 24 hours of injury may prevent damage from thrombosis and may reduce amputation rate (3),(4)[B].
  • Low-molecular-weight dextran to decrease blood viscosity should be considered in patients not given other systemic treatments (e.g., thrombolysis) (2)[C].
  • Aspirin 250 mg plus buflomedil 400 mg IV followed by 8 days of iloprost 0.5 to 2 mg/kg/min for 6 hr/day may prevent amputation in patients with frostbite extending to the proximal phalanx (5)[B].
  • Tetanus toxoid
  • Ibuprofen 400 mg q12h to inhibit prostaglandins (6)[C]
  • NSAIDs for mild to moderate pain; for severe pain, narcotic analgesia
  • Systemic antibiotics should be used for proven infection, trauma, or cellulitis. Prophylactic antibiotics are not recommended (7)[C].
  • Precautions: tPA should not be used with history of recent bleeding, stroke, ulcer, and so forth.
P.389

Second Line
Pentoxifylline has been tried with some success (6)[C].
ADDITIONAL THERAPIES
  • Heated oxygen
  • Warm IV fluids via central venous pressure line
  • Avoid rubbing the affected area, as this can lead to further tissue destruction and worse outcomes.
SURGERY/OTHER PROCEDURES
  • Urgent surgery is rarely needed, except fasciotomy for compartment syndrome.
  • Suspect compartment syndrome if tissue swollen and compartment pressures >37 to 40 mm Hg.
  • Fasciotomy is indicated if elevated compartment pressures (2)[B]
  • Surgical débridement, as needed, to remove necrotic tissue
  • Amputation should not be considered until tissues are definitively dead: may take ˜3 weeks to know whether the tissue is permanently injured.
  • Imaging with 99 mTc bone scan and/or MRA should be considered in severe cases to help determine extent of injury and assess viability of surrounding tissue. Imaging can help determine need for surgery (8).
INPATIENT CONSIDERATIONS
Admission Criteria/Initial Stabilization
Hospitalization is generally recommended unless no blisters are present after rewarming (4,8).
  • Institute emergency measures for hypothermic patient without pulse or respiration. Such measures may include CPR and internal warming with warm IV fluids and warm oxygen (see topic “Hypothermia”).
  • Prevent refreezing.
  • It may be necessary to keep the frostbitten part frozen until the patient can be transported to a care facility. Prolonged freezing is preferable to warming and refreezing (9)[C].
  • Remove nonadherent wet clothing and shoes.
  • Treat for hypothermia.
  • Treat for pain.
  • NSAIDs and/or narcotics, if needed.
  • Do not rub areas to warm them; increased tissue damage may occur (3)[C].
  • Avoid pressure on frostbitten body parts except when the life of the patient or rescuer is in danger (10)[C].
IV Fluids
If patient cannot tolerate oral fluids or has altered mental status, give warmed normal saline in small boluses (2)[C].
image ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Outpatient or inpatient, depending on severity
  • As tolerated; protect injured body parts.
  • Initiate physical therapy once healing progresses sufficiently.
  • Avoid nicotine.
  • Avoid recurrent cold exposure.
  • Properly fitting attire; consider custom footwear if feet were affected (7).
Patient Monitoring
  • Preferably, electronic probe for temperature monitoring (rectal or vascular)
  • Follow-up for physical therapy progress, infection, other complications
DIET
  • As tolerated
  • Warm oral fluids
PATIENT EDUCATION
  • Refer to local library for information.
  • Provide education on
    • Exposure protection
    • Risk factors for frostbite injuries
    • Early signs and symptoms of frostbite
PROGNOSIS
  • Anesthesia and bullae may occur.
  • The affected areas will heal or mummify without surgery; the process may take 6 to 12 months for healing.
  • Patient may be sensitive to cold and experience burning and tingling.
  • Cyanotic nonblanching skin and blisters with dark fluid suggest worse prognosis (9)[C].
  • Loss of sensation after rewarming indicates poor prognosis.
REFERENCES
1. Sachs C, Lehnhardt M, Daigeler A, et al. The triaging and treatment of cold-induced injuries. Dtsch Arztebl Int. 2015;112(44):741-747.
2. McIntosh SE, Hamonko M, Freer L, et al. Wilderness Medical Society practice guidelines for the prevention and treatment of frostbite. Wilderness Environ Med. 2011;22(2):156-166.
3. Bruen KJ, Ballard JR, Morris SE, et al. Reduction of the incidence of amputation in frostbite injury with thrombolytic therapy. Arch Surg. 2007;142(6):546-551.
4. Jurkovich GJ. Environmental cold-induced injury. Surg Clin North Am. 2007;87:247-267.
5. Cauchy E, Cheguillaume B, Chetaille E. A controlled trial of a prostacyclin and rt-PA in the treatment of severe frostbite. N Engl J Med. 2011;364(2):189-190.
6. Imray C, Grieve A, Dhillon S. Cold damage to the extremities: frostbite and non-freezing cold injuries. Postgrad Med J. 2009;85(1007):481-488.
7. Handford C, Buxton P, Russell K, et al. Frostbite: a practical approach to hospital management. Extrem Physiol Med. 2014;3:7.
8. Ingram BJ, Raymond TJ. Recognition and treatment of freezing and nonfreezing cold injuries. Curr Sports Med Rep. 2013;12(2):125-130.
9. Biem J, Koehncke N, Classen D, et al. Out of the cold: management of hypothermia and frostbite. CMAJ. 2003;168(3):305-311.
10. State of Alaska Department of Health and Social Services. Cold injuries guidelines: Alaska Multilevel 2003 version. http://www.hypothermia.org/Hypothermia_Ed_pdf/Alaska-Cold-Injuries.pdf.
Additional Reading
&NA;
  • Cappaert TA, Stone JA, Castellani JW, et al. National Athletic Trainers' Association position statement: environmental cold injuries. J Athl Train. 2008;43(6):640-658.
  • Murphy JV, Banwell PE, Roberts AH, et al. Frostbite: pathogenesis and treatment. J Trauma. 2000;48(1):171-178.
  • Twomey JA, Peltier GL, Zera RT. An open-label study to evaluate the safety and efficacy of tissue plasminogen activator in treatment of severe frostbite. J Trauma. 2005;59(6):1350-1354.
See Also
&NA;
  • Hypothermia
  • Algorithm: Hypothermia
Codes
&NA;
ICD10
  • T33.90XA Superficial frostbite of unspecified sites, init encntr
  • T34.90XA Frostbite with tissue necrosis of unsp sites, init encntr
  • T33.829A Superficial frostbite of unspecified foot, initial encounter
Clinical Pearls
&NA;
  • Frostbite is considered a tetanus-prone injury. Treat as any injury involving tissue destruction.
  • Avoid rewarming en route to the hospital if there is a chance of refreezing. Avoid burns to affected areas, which may be numb and insensitive to heat.
  • It is difficult to assess degree of tissue involvement early on. Delay surgery until definite tissue destruction is present.