
                         Peripheral Cold Injuries
                          Richard N. Nelson, M.D.

I.   Introduction

II.  Nonfreezing Injuries
     A.  Chilblains (alias erythrocyanosis, pernio, perniosis, perniones)
         1)  dusky, red itchy swellings on exposed skin in response to
             cold exposure
         2)  Pathophysiology
             a)   exaggeration of the physiologic response of
                  vasoconstriction
                  1)   high vascular tone
                  2)   delay in vasodilatation
             b)   ischemia, edema of papillary dermis
                  1)   sometimes separation of epidermis from dermis
             c)   endothelial proliferation and lymphocytic infiltration
                  of dermal vessels
             d)   vasculitis, perivasculitis of deeper dermal vessels
         3)  Predisposing factors
             a)   cold, damp climates (England, Northern Europe).
             b)   1 - 16oC (33 - 60oF)
             c)   youth, females
             d)   Raynaud's collagen vascular disorders
         4)  Presentation
             a)   early winter; often perennial
             b)   exposed areas
                  1)   fingers, toes, hands, feet, knees, pre-tibial
                       areas, cheeks
             c)   erythematous swellings, papules, plaques, blisters,
                  ulcers
                  1)   well demarcated
                  2)   intense pruritis
             d)   spontaneous recovery with warm weather
         5)  Laboratory
             a)   usually unnecessary
             b)   LE prep, ANA, skin biopsy
         6)  Differential diagnosis
             a)   Raynaud's, lupus, herpes, vasculitidis, erythema
                  induratum, erythema nodosum
         7)  Treatment
             a)   Ernest Angely
             b)   UV light
             c)   exercise
             d)   nicotinic acid
             e)   phenoxybenzamine
             f)   bland creams, ointments
         8)  Prevention
             a)   proper coverings
             b)   relocation
     B.  Trenchfoot and Immersion Foot
         1.  "The most serious menace confronting us today is not the
             German Army, which we have practically destroyed, but the
             weather which...may well destroy us through the incidence of
             trench foot."
                                               George S. Patton, 1944
         2.  Pathophysiology
             a)   minimum of 10 - 12 hours exposure to cold (33 - 50oF),
                  damp footgear or cold water
             b)   cold-induced vasoconstriction
                  1)   tissued hypoxia, ischemia
                  2)   increased capillary permeability
         3.  Presentation
             a)   Phase I:  Ischemia

             b)   Phase II:  Hyperemia

             c)   Phase III:  Recovery

         4.  Treatment
             a)   Prevention
             b)   In the field

             c)   In the hospital
III. Freezing Injuries
     A.  Frostbite
         1)  Definition

         2)  Pathophysiology
             a)   Mechanisms
                  1)   ice crystals in tissues
                  2)   vascular stasis

         3)  Predisposing factors
             a)   ambient temperature
             b)   wind-chill factor
             c)   alcohol and drugs
             d)   underlying medical conditions
             e)   high altitudes
             f)   conduction injury
             g)   fatigue
             h)   race and geographic origin
             i)   tobacco use
             j)   previous frostbite
         4)  Presentation
             a)   areas of involvement
             b)   early symptoms
             c)   frostnip
             d)   superficial frostbite
             e)   deep frostbite
                  1)   see gross slides

         5)  Possible laboratory adjuncts
             a)   angiography
             b)   doppler ultrasound
             c)   digital plethysmography
             d)   CPK
             e)   x-rays of extremities
             f)   miscellaneous lab studies

         6)  Diagnosis

         7)  a)   In the field

             b)   At the hospital
                  1)   treat life-threatening conditions first
                  2)   rapid thawing
                  3)   protection from further injury
                       a)   elevation, cradles
                       b)   leave blisters alone
                       c)   avoid early surgery
                  4)   Prevention of infection
                       a)   aseptic handling
                       b)   cleansing (whirlpool)
                       c)   antibiotics
                       d)   tetanus toxoid
                  5)   Enhancement of circulation
                       a)   anticoagulation?
                       b)   dextran?
                       c)   sympathectomy?
                       d)   vasodilators?
                       e)   avoidance of tobacco

                  6)   Rehabilitation

                  7)   Late sequelae

                  8)   Prognosis

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