S16C202 - frostbite and other localized cold injuries

Question 1

What is trench foot?

Answer 1

• prolonged cooling resulting in STI, worsened by wet conditions
• pale mottled foot, pulseless, immobile
• hyperemic phase with rewarming, severe burning pain and reappearance of proximal sensation
• 2-3d into re-warming, tissue edema a bullae form
• tissue sloughing and gangrene may occur
• tx: warm, consider vasodilators (prostaglandins)

Question 2

What are chilblains?

Answer 2

• aka pernio
• inflammatory lesions from cold exposure (non-freezing temps), usually hands, ears, legs, feet
• early sx: n/t,
• 12h: edema, erythema, cyanosis, plaques, nodules, and rarely: ulcerations, vesicles, bullae
• pt c/o of pruritius, burning
• rewarming may cause blue nodules
• possible treatments: rewarm, bandage, elevate, consider nifedipine or limaprost or topical steroids

Question 3

Degrees of frostbite:

Answer 3

• 1st: (frostnip), erythema, edema, occassional desquamation, stinging/burning/throbbing,NO blisters, excellent prognosis
• 2nd: full thickness, edema, erythema, clear blisters (at 6-24h) which then form black eschars, numbness followed by aching, good prognosis
• 3rd: into subdermal layer, hemorrhagic blisters, blue discoloured skin, as rewarming occurs pt gets pain, burning, poor prognosis
• 4th: extension into subcutaneous tissue/bone/muscle/tendon, little edema, skin is mottled with non-blanching cyanosis, forms deep dry black eschars, vesicles may present, deep pain, extremely poor prognsosis

Question 4

Frostbite Tx

Answer 4

• no rewarming until risk of refreezing is eliminated
• rapid rewarming, place in 40deg water for 20-30min
• aloe vera topically to blisters
• elevate
• tetanus
• consider Abx prophylaxis
• do not debride blisters