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Frostbite, Emergency Medicine

Basics

Description

- Diagnosis is based on the clinical presentation. Wound description should include skin color and temperature, blister formation and color, and soft tissue consistency. - A neurologic and vascular exam should include pulses (by Doppler if necessary), cap refill, and 2-point discrimination. - Look for underlying factors contributing to cold exposure and comorbid conditions requiring emergency management: - Hypothermia - Trauma - Hypoglycemia - Cardiac or neurologic problems - Intoxication/overdose - Compartment syndrome

- None indicated in mild cases - For deep frostbite: - CBC - Electrolytes, BUN/creatinine, glucose - Urinalysis/CK for evidence for myoglobinuria

- Frostnip: - Superficial, reversible ice crystal formation without tissue destruction - Transient numbness and paresthesia resolve after dry rewarming.

- Trench (immersion) foot: - Exposure to wet cold for prolonged periods - Neurovascular damage without ice crystal formation - Pallor, mottling, paresthesias, pulselessness, paralysis, and numbness - May be difficult to distinguish from post-thaw phase of frostbite - Hyperemia with dry rewarming may last up to 6 wk.

- Chilblains: - Chronic repeated exposure to dry cold - Localized erythema, cyanosis, plaques, and vesicles - Recurrent episodes common in patients with underlying vasculitis - Symptomatic treatment, dry rewarming

- Analgesia: IV morphine - NSAIDs (e.g., ibuprofen) to combat the effects of prostaglandins on skin necrosis. - Aloe vera topical cream: - Recommended for all intact blisters - Combats the arachidonic acid cascade - Avoid preparations containing alcohol, scent, salicylates, all of which interfere with aloe effectiveness.

  • Tissue damage caused by cold temperature exposure
  • Mechanism:Tissue damage results from:Direct cell damage: Intracellular ice crystal formationIndirect cell damage: Extracellular ice crystal formation leads to intracellular dehydration and enzymatic disruption.Reperfusion injury: Occurs upon rewarming. Fluid rich in inflammatory mediators (prostaglandin and thromboxane) extravasates through damaged endothelium promoting vasoconstriction and platelet aggregation.Clear blisters form from extracellular exudation of fluid.Hemorrhagic blisters occur when deeper subdermal vessels are disrupted, indicating more severe tissue injury.The end result is arterial thrombosis, ischemia, and ultimately, necrosis.Devitalized tissue demarcates as the injury evolves over weeks to months, hence the phrase "frostbite in January, amputate in July."пїЅ

Etiology

  • Cold exposure: Duration of exposure, wind chill, humidity, and wet skin and clothing all increase the likelihood of frostbite.
  • Predisposing factors:Extremes of ageAltered mental status (intoxication or psychiatric illness)Poor circulatory status

Diagnosis

Signs and Symptoms

  • Extremities (fingers, toes) and head (ears, nose) most commonly affected.
  • After rewarming frostbite can be classified; however, initial classification often fails to provide an accurate prognosis and does not alter initial management.
  • Superficial frostbite:Only skin structures involved. Usually no tissue loss.1st degree: Erythema and edema with stinging, burning, and throbbing. No blisters or necrosis.2nd degree: Significant edema, clear blister formation. Numbness common.
  • Deep frostbite:Tissue loss inevitable.3rd degree: Involves subcutaneous tissue. Hemorrhagic blister formation due to subdermal venous plexus injury:Initially insensate, injuries develop severe pain/burning on rewarming.4th degree: Involves muscle, tendon, and bone. Initially mottled, deep red, or cyanotic.Unfavorable prognostic indicators include: Hemorrhagic blisters, persistent cyanosis, mottling, anesthesia, and reduced mobility after rewarming.Devitalized tissue demarcates as the injury evolves over weeks to months forming skin necrosis and dry black eschar.

Essential Workup

  • Diagnosis is based on the clinical presentation. Wound description should include skin color and temperature, blister formation and color, and soft tissue consistency.
  • A neurologic and vascular exam should include pulses (by Doppler if necessary), cap refill, and 2-point discrimination.
  • Look for underlying factors contributing to cold exposure and comorbid conditions requiring emergency management:HypothermiaTraumaHypoglycemiaCardiac or neurologic problemsIntoxication/overdoseCompartment syndrome

Diagnosis Tests & Interpretation

Lab

  • None indicated in mild cases
  • For deep frostbite:CBCElectrolytes, BUN/creatinine, glucoseUrinalysis/CK for evidence for myoglobinuria
  • Cultures and Gram stains from open areas when infection suspected

Imaging

Technetium-99 scintigraphy or MRA: пїЅ

  • May be helpful in early identification of salvageable vs. unsalvageable tissue
  • Permits earlier decision about amputation

Diagnostic Procedures/Surgery

Method to create a warm water bath in the ED: пїЅ

  • Whirlpool hydrotherapy ideal, however, most EDs do not have
  • Mix hot and cold tap water from a standard hospital sink in a large basin
  • Use a thermometer to keep temperature between 40 пїЅC and 42 пїЅC.
  • The water will cool quickly: Intermittently add warm water or replace the water to keep the temperature in the proper range.
  • Warmer temperatures can cause thermal injury while cooler temperatures delay thawing and decrease tissue survival.

Differential Diagnosis

  • Frostnip:Superficial, reversible ice crystal formation without tissue destructionTransient numbness and paresthesia resolve after dry rewarming.
  • Trench (immersion) foot:Exposure to wet cold for prolonged periodsNeurovascular damage without ice crystal formationPallor, mottling, paresthesias, pulselessness, paralysis, and numbnessMay be difficult to distinguish from post-thaw phase of frostbiteHyperemia with dry rewarming may last up to 6 wk.
  • Chilblains:Chronic repeated exposure to dry coldLocalized erythema, cyanosis, plaques, and vesiclesRecurrent episodes common in patients with underlying vasculitisSymptomatic treatment, dry rewarming

Treatment

Pre-Hospital

  • Protect and immobilize frostbitten area during transport
  • Remove restrictive or wet garments
  • Avoid dry rewarming of the frostbitten limb if there is a likelihood of refreezing injury during transport.
  • If evacuation will be delayed and suitable facilities are available, field rewarming in warm (40 пїЅC-42 пїЅC) water can be attempted.
  • Rubbing, manipulating the limb, or applying snow while it is still frozen is contraindicated.
  • Hypothermia:
  • Common in frostbite victims
  • In the severely hypothermic patient, avoid rough handling to minimize risk of cardiac dysrhythmias.

Initial Stabilization/Therapy

  • ABCs management
  • Identify and correct hypothermia.
  • IV fluid volume expansion with 0.9% NS for severe frostbite
  • Protect frostbitten areas from excessive handling during resuscitation.

Ed Treatment/Procedures

  • If the injury is <24 hr old and has not yet been rewarmed:Initiate rapid rewarming of the frostbitten extremity in a 40-42 пїЅC water bath for 15-30 min.Stop treatment when the limb is warm, red, and pliable.Monitor water temperature closely to prevent thermal injury.
  • Analgesia: IV morphine
  • NSAIDs (e.g., ibuprofen) to combat the effects of prostaglandins on skin necrosis.
  • Aloe vera topical cream:Recommended for all intact blistersCombats the arachidonic acid cascadeAvoid preparations containing alcohol, scent, salicylates, all of which interfere with aloe effectiveness.
  • Blister d пїЅbridement or aspiration:Indicated for clear blebs:Removes thromboxane and prostaglandinsContraindicated for hemorrhagic blebs:Exposes deeper structures to dehydration and infection
  • Tetanus prophylaxis
  • Antibacterial prophylaxis:Consider during the hyperemic recovery phase (at least 2-3 days) in severely frostbitten areasAgainst Streptococci, Staphylococci, and Pseudomonas species (cephalosporin, penicillinase-resistant penicillin, quinolone)Topical antibacterial agents interfere with the use of aloe vera cream and should be considered a 2nd-line approach.
  • Elevation and splinting of frostbitten area
  • Change dressing 2-4 times daily.
  • Avoid vasoconstrictive agents (including tobacco).
  • Adjunctive treatments include:Thrombolytic therapy (<24 hr of cold exposure):Both intra-arterial and systemic tPA may improve tissue salvage rates.Consult with plastic/burn surgeon before treatment.Vasodilator therapy:Pentoxifylline-limited dataIloprost-limited data and availability

Medication

  • Aloe vera: Topical cream (70% concentration) q6h
  • Cephalexin (cephalosporin): 500 mg (peds: 25-50 mg/kg/24h q6h) PO QID
  • Ciprofloxacin (quinolone): 500 mg PO BID
  • Dicloxacillin (penicillinase-resistant penicillin): 500 mg (peds: 12.5-25 mg/kg/24h q6h) PO QID
  • Ibuprofen (NSAID): 800 mg (peds: 40 mg/kg/24h q6-8h) PO TID
  • Morphine sulfate: 0.1-0.2 mg/kg (peds: 0.1 mg/kg) IV or IM PRN (titrate to patient response)

Follow-Up

Disposition

Admission Criteria

  • All but the most superficial cases should be admitted.
  • Lower admission threshold where risk of refreezing exists.
  • Immersion (trench) foot patients may be discharged only if an environment that allows for proper treatment can be provided.

Discharge Criteria

Minimal superficial injury, all others should be admitted. пїЅ

Issues for Referral

General, burn, plastic, or hand surgeon should be consulted in all but the most superficial of cases. пїЅ

Followup Recommendations

All discharged patients should be referred to a general, burn, plastic, or hand surgeon. пїЅ

Pearls and Pitfalls

Pitfalls: пїЅ

  • Allowing freeze, thaw, refreeze cycle to occur
  • Failure to keep warm water bath between 40 пїЅC and 42 пїЅC during rewarming
  • Failure to address hypothermia or other systemic illness
  • Failure to consider compartment syndrome in a pulseless frostbitten extremity

Additional Reading

  • Gross пїЅEA, Moore пїЅJC. Using thrombolytics in frostbite injury. J Emerg Trauma Shock. 2012;5(3):267-271.
  • McIntosh пїЅSE, Hamonko пїЅM, Freer пїЅL, et al. Wilderness Medical Society practice guidelines for the prevention and treatment of frostbite. Wilderness Environ Med. 2011;22(2):156-166.
  • Murphy пїЅJV, Banwell пїЅPE, Roberts пїЅAH, et al. Frostbite: Pathogenesis and treatment. J Trauma. 2000;48(1):171-178.
  • Wolfson пїЅAB, ed. Harwood-Nuss' Emergency Medicine. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2010:1599-1603.

See Also (Topic, Algorithm, Electronic Media Element)

Hypothermia пїЅ

Codes

ICD9

  • 991.0 Frostbite of face
  • 991.1 Frostbite of hand
  • 991.3 Frostbite of other and unspecified sites
  • 991.2 Frostbite of foot

ICD10

  • T33.09XA Superficial frostbite of other part of head, init encntr
  • T33.90XA Superficial frostbite of unspecified sites, init encntr
  • T33.539A Superficial frostbite of unspecified finger(s), init encntr
  • T33.839A Superficial frostbite of unspecified toe(s), init encntr
  • T33.019A Superficial frostbite of unspecified ear, initial encounter
  • T33.02XA Superficial frostbite of nose, initial encounter
  • T33.521A Superficial frostbite of right hand, initial encounter
  • T33.522A Superficial frostbite of left hand, initial encounter
  • T33.529A Superficial frostbite of unspecified hand, initial encounter
  • T33.531A Superficial frostbite of right finger(s), initial encounter
  • T33.532A Superficial frostbite of left finger(s), initial encounter
  • T33.821A Superficial frostbite of right foot, initial encounter
  • T33.822A Superficial frostbite of left foot, initial encounter
  • T33.829A Superficial frostbite of unspecified foot, initial encounter
  • T33.831A Superficial frostbite of right toe(s), initial encounter
  • T33.832A Superficial frostbite of left toe(s), initial encounter
  • T34.019A Frostbite with tissue necrosis of unsp ear, init encntr
  • T34.02XA Frostbite with tissue necrosis of nose, initial encounter
  • T34.09XA Frostbite w tissue necrosis of oth part of head, init encntr
  • T34.539A Frostbite w tissue necrosis of unsp finger(s), init encntr
  • T34.839A Frostbite with tissue necrosis of unsp toe(s), init encntr
  • T34.90XA Frostbite with tissue necrosis of unsp sites, init encntr

SNOMED

  • 370977006 frostbite (disorder)
  • 4763005 frostbite of hand (disorder)
  • 86018005 frostbite of face (disorder)
  • 35195001 frostbite of foot (disorder)
  • 212924009 Frostbite with tissue necrosis (disorder)
  • 410703004 superficial frostbite (disorder)