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FROSTBITE

Introduction

Frostbite is localized damage to the extremities from exposure to cold temperatures for a prolonged period without proper protection.1 Frostbite severity depends on the temperature, wind, humidity, duration of exposure, and other risk factors that compromise blood flow. Subcutaneous tissue damage may differ significantly from skin damage and can be difficult to evaluate clinically. Treatment guidelines recommend rapid warming of the affected tissue provided there is no risk of refreezing, and analgesics/anti-inflammatory medications. Surgical treatment is recommended after the demarcation between damaged and intact tissue is clear. Prognosis ranges from complete recovery to amputation of the limbs with systemic involvement depending on the extent of initial lesion.2

Pathophysiology1,3

  • Owing to the natural response of human body in cold temperature to prioritize maintaining core temperature, blood supply to the extremities is restricted.
  • The risk of frostbite increases at temperatures below −3 °C or 26.6 degrees fahrenheit.
  • Tissue damage in frostbite occurs via:
    • Direct cell damage: formation of extracellular and/or intracellular ice crystals eventually leads to mechanical destruction of cells
    • Progressive dermal ischemia: blood flow to the dermis is reduced due to inflammatory edema and endothelial injury
  • Rewarming the tissue can lead to reperfusion injury due to capillary emboli and previous endothelial injury leading to hypoxia and thrombosis
  • A simple two-tier classification is favored:
    • Superficial: superficial injury with no risk of amputation
    • Deep: injury that extends to the subcutaneous tissue (muscle, nerves and perhaps bones) with high risk of amputation

Related Anatomy

  • Grade 1: only superficial skin
  • Grade 2: distal phalanx
  • Grade 3: metacarpal/metatarsal
  • Grade 4: proximal to the metacarpal joints

Incidence and Related Conditions

  • Military personnel employed in cold regions and extreme winter sport enthusiasts are at an increased risk of frostbite
  • Several studies measured the annual incidence of frostbite in populations at higher risk and reported an annual incidence of:
    • 13% and 1% of mild and severe frostbite in general Finnish population4  
    • 2% and lifetime occurrence of 44% among Finnish military personnel5
    • 22% and lifetime occurrence of 65% in reindeer herdsmen5
    • 75.4 per 100,000 person years for women and 50.3 per 100,000 person years for men among active service members in the US army6
    • 366/1000 among mountaineers5
    • A previous history of frostbite is associated with a significantly higher risk of another frostbite.
    • Frostbite is more common among individuals aged 30–49 years due to higher levels of risk-taking behaviors

Differential Diagnosis

  • Frostnip
  • Trench foot
ICD-10 Codes

  • FROSTBITE

    Diagnostic Guide Name

    FROSTBITE

    ICD 10 Diagnosis, Single Code, Left Code, Right Code and Bilateral Code

    DIAGNOSISSINGLE CODE ONLYLEFTRIGHTBILATERAL (If Available)
    FROSTBITE, SUPERFICIAL    
    - ARM T33.42X_T33.41X_ 
    - WRIST T33.512_T33.511_ 
    - HAND T33.522_T33.521_ 
    - FINGER(S) T33.532_T33.531_ 
    FROSTBITE WITH TISSUE NECROSIS    
    - ARM T34.42X_T34.41X_ 
    - WRIST T34.512_T34.511_ 
    - HAND T34.522_T34.521_ 
    - FINGER(S) T34.532_T34.531_ 

    Instructions (ICD 10 CM 2020, U.S. Version)

    THE APPROPRIATE SEVENTH CHARACTER IS TO BE ADDED TO EACH CODE FROM CATEGORY T33 AND T34
    A - Initial Encounter
    D - Subsequent Routine Healing
    S - Sequela

    ICD-10 Reference

    Reproduced from the International statistical classification of diseases and related health problems, 10th revision, Fifth edition, 2016. Geneva, World Health Organization, 2016 https://apps.who.int/iris/handle/10665/246208

Clinical Presentation Photos and Related Diagrams
Frostbite
  • Right thumb and finger necrosis after severe frostbite injury
    Right thumb and finger necrosis after severe frostbite injury
  • Distal foot and toe necrosis after severe frostbite injury
    Distal foot and toe necrosis after severe frostbite injury
Symptoms
Pain after exposure to excessive cold i.e. history of hypothermia
Bluish/purplish discoloration or yellowish-white hardness of the skin
Finger numbness
Typical History

A 28-year-old-female mountaineer experienced severe unexpected weather during her mountaineering expedition. On day 1, she slept on snow in a bivy sac, and her gloves were soaked while digging a snow cave the following morning. Later she experienced trouble tying her shoelaces. On day 3, she was able to rewarm the fingers and took care to avoid refreezing. Her team was rescued on day 4 when she presented with 3 dark fingers with eschar on the tips and the rest of the fingers were grey/white.8

Positive Tests, Exams or Signs
Work-up Options
Treatment Options
Treatment Goals
  • Minimize tissue loss and amputations
  • Maintain Function
Conservative

Initial treatment options depend on whether the patient is treated in the field or in a hospital setting.2,7 Hypothermia should be treated prior to frostbite warming

Pre-hospital care

  • Replace wet gloves with dry ones
  • Provide warm fluids
  • Provide aspirin (75 mg/d) and ibuprofen (1200–2400 mg/d)
  • Rewarm the frozen tissue only if there is no risk of refreezing
  • Do not rub the affected parts
  • Dressing of blisters
  • Debridement of blisters is not recommended in the field
  • Systemic antibiotics in case of severe frostbites
  • Hyperbaric oxygen

Hospital Management

  • Rehydration (oral or IV)
  • Rewarming
    • Immersion in 37–39 °C water bath, with added antiseptic, until red/purple color of the skin appears and the skin is pliable (30–60 min)
    • NSAIDs for pain and inflammation
    • May require narcotic medication
    • Systemic antibiotics in case of infection, trauma, or cellulitis
  • Blisters and dressings
    • Blisters should only be drained in a hospital setting
    • Superficial frostbite that shows clear/cloudy blisters can be selectively drained if they restrict movement
    • Deep frostbite results in hemorrhagic blisters; the current recommendation is to leave them alone, but some believe debriding blisters under general anesthesia will help wound healing
    • Topical aloe vera cream or silver sulfadiazine before dressing is recommended
    • Splinting and elevation is recommended
    • Loose dressing with padding between affected digits is recommended
  • Hyperbaric oxygen therapy8
    • Can be considered in patients at high altitude
  • Thrombolytics for deep frostbites9
    • Targeted to halt progressive dermal ischemia due to thrombosis
    • Administered within 24 hours of cold exposure or rewarming and when angiography with intra-arterial vasodilators do not show perfusion of affected tissue
    • Tissue plasminogen activator (tPA) used with concurrent heparin
  • Intra-arterial administration preferred over IV for tPA
  • Administered by trained medical professionals in a hospital setting
  • Stopped after perfusion restored to distal vessels as monitored by repeat angiograms performed every 12–24 hours or after 48 hours if no improvement is observed
  • Contraindicated in patients with existing trauma, recent surgery, neurological impairment, or bleeding diathesis
  • Prostacyclin for deep frostbite10,11
    • Ioloprost is a synthetic vasodilator (prostacyclin analogue)
  •  Ioloprostis available as an inhalant; not available as IV form in many countries including US
    • Efficacious when administered within 48 hours of cold exposure or post-thaw
    • Recent evidence demonstrated IV ioloprost to be effective and safer than tPA therapy in preventing amputations in severe frostbite
    • Unlike tPA, ioloprost:
      • Does not require invasive radiologic monitoring
      • Can be used in patients with existing trauma
      • Can be managed in general or vascular wards
      • Efficacy extends up to 48 hours post-thaw
Operative
  • Surgery for deep frostbite
    • Performed after demarcation between healthy and damaged tissue is clear
    • 6–12 weeks post injury
    • Tc99 triple-phase bone scans or magnetic resonance angiography imaging is recommended before surgery
    • Immediate amputation is only recommended in cases of wet gangrene, sepsis, liquefaction, or severe infection
    • Fasciotomy is recommended post-thaw if reperfusion is compromised by compartment syndrome
    • Orthotics and custom footwear recommended after surgery
Complications
  • Chronic pain
  • Localized osteoporosis
  • Sub-chondral bone loss
  • Chronic ulceration with risk of malignant transformation
Outcomes
  • Superficial frostbite usually recovers without tissue loss.
  • Deep frostbite usually requires amputations with or without systemic involvements.
Key Educational Points

Symptoms to check after rewarming

  • Throbbing pain with blisters in the affected tissue after rewarming (grade 2 or higher)
    • Grade 1: Absence of blisters
    • Grade 2: Clear blisters
    • Grade 3: hemorrhagic blisters on the digit
    • Grade 4: hemorrhagic blisters over carpal/tarsal region
  • Cyanosis after rewarming7
    • Grade 1: No visible cyanosis (bluish/purplish discoloration of the skin)
    • Grade 2: Cyanosis on the distal phalanx
    • Grade 3: Cyanosis up to the metacarpal joint
    • Grade 4: Cyanosis proximal to the metacarpal joints
References

Cited

  1. Lange K, Boyd LJ, Loewe L. The functional pathology of frostbite and the prevention of gangrene in experimental animals and humans. Science 1945;102(2641):151–2. PMID: 17802430
  2. Handford C, Buxton P, Russell K, et al. Frostbite: a practical approach to hospital management. Extreme Physiol Med 2014;3:7. PMID: 24764516
  3. Hutchison RL. Frostbite of the hand. J Hand Surg 2014;39(9):1863–8. PMID: 25154574
  4. Mäkinen TM, Jokelainen J, Näyhä S, et al.  Occurrence of frostbite in the general population--work-related and individual factors. Scand J Work Environ Health 2009;35(5):384–93. PMID: 19730758
  5. Heil K, Thomas R, Robertson G, et al. Freezing and non-freezing cold weather injuries: a systematic review. Br Med Bull 2016;117(1):79–93. PMID: 26872856
  6. O’Donnell FL, Taubman SB. Update: Cold weather injuries, active and reserve components, U.S. Armed Forces, July 2011-June 2016. MSMR 2016;23(10):12–20. PMID: 27792353
  7. Cauchy E, Davis CB, Pasquier M, et al. A New Proposal for Management of Severe Frostbite in the Austere Environment. Wilderness Environ Med 2016;27(1):92–9. PMID: 26948558
  8. Folio LR, Arkin K, Butler WP. Frostbite in a mountain climber treated with hyperbaric oxygen: case report. Mil Med 2007;172(5):560–3. PMID: 17521112
  9. Tavri S, Ganguli S, Bryan RG Jr, et al. Catheter-Directed Intraarterial Thrombolysis as Part of a Multidisciplinary Management Protocol of Frostbite Injury. J Vasc Interv Radiol 2016;27(8):1228–35. PMID: 27363299
  10. 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):189–90. PMID: 21226604
  11. Poole A, Gauthier J. Treatment of severe frostbite with iloprost in northern Canada. Can Med Assoc J 2016;188(17–18):1255–8. PMID: 27044477

New articles

  1. O’Donnell FL, Taubman SB. Update: Cold weather injuries, active and reserve components, U.S. Armed Forces, July 2011-June 2016. MSMR 2016;23(10):12–20. PMID: 27792353
  2. Cauchy E, Davis CB, Pasquier M, et al. A New Proposal for Management of Severe Frostbite in the Austere Environment. Wilderness Environ Med 2016;27(1):92–9. PMID: 26948558
  3. Tavri S, Ganguli S, Bryan RG Jr, et al. Catheter-Directed Intraarterial Thrombolysis as Part of a Multidisciplinary Management Protocol of Frostbite Injury. J Vasc Interv Radiol 2016;27(8):1228–35. PMID: 27363299
  4. Poole A, Gauthier J. Treatment of severe frostbite with iloprost in northern Canada. Can Med Assoc J 2016;188(17–18):1255–8. PMID: 27044477

Reviews

  1. Heil K, Thomas R, Robertson G, Porter A, Milner R, Wood A. Freezing and non-freezing cold weather injuries: a systematic review. Br Med Bull 2016;117(1):79–93. PMID: 26872856
  2. Hutchison RL. Frostbite of the hand. J Hand Surg Am 2014;39(9):1863–8. PMID: 25154574
  3. Handford C, Buxton P, Russell K, et al. Frostbite: a practical approach to hospital management. Extreme Physiol Med 2014;3:7. PMID: 24764516

Classic

  1. Lange K, Boyd LJ, Loewe L. The functional pathology of frostbite and the prevention of gangrene in experimental animals and humans. Science 1945;102(2641):151–2. PMID: 17802430
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