FrostbiteFrostbite

LENG RUPULENG RUPU

Chapter OutlineChapter Outline

History, Physiology, Pathophysiology, Clinical preHistory, Physiology, Pathophysiology, Clinical presentation, Treatment, Sequelae, Preventionsentation, Treatment, Sequelae, Prevention

HISTORYHISTORY

Peripheral cold injuries are almost uniquely seen in Peripheral cold injuries are almost uniquely seen in humans. Unlike cold-adapted animals, our peripheral humans. Unlike cold-adapted animals, our peripheral tissue temperatures can drop below freezing. The tissue temperatures can drop below freezing. The highest homeostatic priority is to maintain the core highest homeostatic priority is to maintain the core temperature. This is accomplished through temperature. This is accomplished through vasoconstriction and shunting, which prevents vasoconstriction and shunting, which prevents adequate heat distribution to the extremities. As a adequate heat distribution to the extremities. As a result, failure to achieve adequate protection from result, failure to achieve adequate protection from the environment results in these preventable injuries.the environment results in these preventable injuries.

Peripheral cold injuries include both freezing and nPeripheral cold injuries include both freezing and nonfreezing syndromes. These may occur independentonfreezing syndromes. These may occur independently or in conjunction with systemic hypothermia. Frosly or in conjunction with systemic hypothermia. Frostbite is the most common freezing injury. Trench footbite is the most common freezing injury. Trench foot and immersion foot are nonfreezing injuries resultit and immersion foot are nonfreezing injuries resulting from exposure to wet cold. Nonfreezing injury folng from exposure to wet cold. Nonfreezing injury following exposure to dry cold is termed chilblains (perlowing exposure to dry cold is termed chilblains (pernio).nio). one unique aspect of peripheral cold injury is the pa one unique aspect of peripheral cold injury is the pathogenesis of the freezing injury cascade. thogenesis of the freezing injury cascade.

Most civilian frostbite results from routine exposure Most civilian frostbite results from routine exposure without consideration of risk factors. Iwithout consideration of risk factors. Increased ncreased participation in outdoor recreational activities will participation in outdoor recreational activities will continue to produce exposure to unanticipated drastic continue to produce exposure to unanticipated drastic climactic changes. The unsheltered and the homeless climactic changes. The unsheltered and the homeless are no longer the most likely group at risk.are no longer the most likely group at risk. Military history is replete with accounts of the effects Military history is replete with accounts of the effects of cold injury on combat troops. Trench foot was of cold injury on combat troops. Trench foot was particularly common among U. S. troops in the particularly common among U. S. troops in the Vietnam War. Vietnam War.

soldiers would acutely thaw frozen extremities directlsoldiers would acutely thaw frozen extremities directly over open fires. The subsequent refreeze further increy over open fires. The subsequent refreeze further increased tissue destruction.ased tissue destruction. Unfortunately, the resultant gangrene was misattribute Unfortunately, the resultant gangrene was misattributed to this rapid thawing of frostbite and trench foot injurid to this rapid thawing of frostbite and trench foot injuries. Therefore gradual thawing, often including friction es. Therefore gradual thawing, often including friction massage with snow, remained the standard treatment remassage with snow, remained the standard treatment regimen until the 1950s. In addition to dry radiant heat regimen until the 1950s. In addition to dry radiant heat rewarming and massage, another common rewarming mowarming and massage, another common rewarming modality was immersion thawing in icy water. dality was immersion thawing in icy water.

PHYSIOLOGYPHYSIOLOGY

Human cold stress should produce adaptive behavioral rHuman cold stress should produce adaptive behavioral reactions in addition to complex endocrinologic and cardeactions in addition to complex endocrinologic and cardiovascular physiologic responses. Peripheral cooling of iovascular physiologic responses. Peripheral cooling of the blood activates the preoptic anterior hypothalamus. the blood activates the preoptic anterior hypothalamus. This central thermostat orchestrates temperature regulatiThis central thermostat orchestrates temperature regulation. The dynamic process encompasses catecholamine reon. The dynamic process encompasses catecholamine release, thyroid stimulation, shivering thermogenesis, and lease, thyroid stimulation, shivering thermogenesis, and peripheral vasoconstriction. Consumption of stored fuelperipheral vasoconstriction. Consumption of stored fuels is accelerated. The elevated metabolic rate eventually fs is accelerated. The elevated metabolic rate eventually fatigues with a chronic cold insult.atigues with a chronic cold insult.

Acral skin structures (fingers, toes, ears, nose) contaiAcral skin structures (fingers, toes, ears, nose) contain a plethora of arteriovenous anastomoses . These faciln a plethora of arteriovenous anastomoses . These facilitate shunting and subsequent drastic reductions in bloitate shunting and subsequent drastic reductions in blood flow to these areas. During a cold stress peripheral od flow to these areas. During a cold stress peripheral vasoconstriction limits radiative heat loss. vasoconstriction limits radiative heat loss. This”life-vThis”life-versus-limb” mechanismersus-limb” mechanism reflects the hemeostatic attreflects the hemeostatic attempt to prevent systemic hypothermia.empt to prevent systemic hypothermia. In contrast to heat exposure, humans do not appear to In contrast to heat exposure, humans do not appear to display significant physiologic adaptation to the cold, display significant physiologic adaptation to the cold,

Exposing extremities to cold temperatures down to Exposing extremities to cold temperatures down to 1515℃℃ results in maximal peripheral vasoconstriction results in maximal peripheral vasoconstriction with minimal blood flow. with minimal blood flow. Continued exposure to Continued exposure to progressively colder temperatures down to 10progressively colder temperatures down to 10℃℃ produces the ``hunting response,'' which is termed produces the ``hunting response,'' which is termed cold-induced vasodilatation (CIVD).cold-induced vasodilatation (CIVD). These periods These periods of vasodilatation, recurring in 5-to-10-minute of vasodilatation, recurring in 5-to-10-minute cycles, interrupt vasoconstriction and serve to cycles, interrupt vasoconstriction and serve to protect the extremity.protect the extremity. Eskimos, as well as Lapps and Eskimos, as well as Lapps and others of Nordic extraction, are capable of stronger others of Nordic extraction, are capable of stronger CIVD responses than individuals from tropical CIVD responses than individuals from tropical regions.regions.

PATHOPHYSIOLOGYPATHOPHYSIOLOGY

The pathologic phases that occur with local cold injThe pathologic phases that occur with local cold injury often overlap and vary with the extent and rapiditury often overlap and vary with the extent and rapidity of the cold response (see box below). y of the cold response (see box below). Frostbite occFrostbite occurs when the tissue temperature drops to below 0urs when the tissue temperature drops to below 0℃℃. There are two putative mechanisms of tissue in. There are two putative mechanisms of tissue injury: architectural cellular damage from ice-crystjury: architectural cellular damage from ice-crystal formation and microvascular thrombosis and stal formation and microvascular thrombosis and stasis. asis.

Freezing Injury CascadeFreezing Injury CascadePrefreeze phasePrefreeze phase1.1.              Superficial tissue”cooling”Superficial tissue”cooling”2.2.              Increased viscosity of vascular contentsIncreased viscosity of vascular contents3.3.              Microvascular constrictionMicrovascular constriction4.4.              Endothelial plasma leakageEndothelial plasma leakage  Freeze-thaw phaseFreeze-thaw phase1.1.              Extracellular fluid ice-crystal formation*Extracellular fluid ice-crystal formation*2.2.              Water diapedesis across cell membraneWater diapedesis across cell membrane3.3.              Intracellular dehydration and hyperosmolalityIntracellular dehydration and hyperosmolality4.4.              Cell-membrane denaturation/disruptionCell-membrane denaturation/disruption5.5.              Cell shrindage and collapseCell shrindage and collapse  Vascular stasis and progressive ischemiaVascular stasis and progressive ischemia1.1.              Vasospasticity and stasis coagulationVasospasticity and stasis coagulation2.2.              Arteriovenous shuntingArteriovenous shunting3.3.              Vascular endothelial cell damage/prostanoid releaseVascular endothelial cell damage/prostanoid release4.4.              Interstitial leakage/tissue hypertensionInterstitial leakage/tissue hypertension5.5.              Necrosis/demarcation/mummification/sloughNecrosis/demarcation/mummification/slough  *Extremely rapid cooling produces more initial intracellular than extacellular ice crystallization.*Extremely rapid cooling produces more initial intracellular than extacellular ice crystallization.

Nerve and muscle tissues are more susceptible to Nerve and muscle tissues are more susceptible to cold injury than connective tissuecold injury than connective tissue. For example, no. For example, nonviable hands and feet can be moved after thawing if tnviable hands and feet can be moved after thawing if the tendons are intact.he tendons are intact. Edema progresses for 48 to 72 hours after tissue hEdema progresses for 48 to 72 hours after tissue has been thawed.as been thawed. Leukocyte infiltration, thrombosis, a Leukocyte infiltration, thrombosis, and early necrosis become apparent as this edema resolnd early necrosis become apparent as this edema resolves. The dry gangrene carapace of frostbite is superficves. The dry gangrene carapace of frostbite is superficial in comparison to arteriosclerotic induced full-thickial in comparison to arteriosclerotic induced full-thickness gangrene. Final demarcation between viable and ness gangrene. Final demarcation between viable and nonviable tissue often requires more than 60 to 90 daynonviable tissue often requires more than 60 to 90 days. Hence the surgical aphorism, ``s. Hence the surgical aphorism, ``Frostbite in JanuarFrostbite in January, amputate in Julyy, amputate in July”. ”.

Predisposing FactorsPredisposing Factors

Physiologic Physiologic PsychologicPsychologicGenetic Mental statusGenetic Mental statusCore Temperature Fear/panicCore Temperature Fear/panic

Prior cold injuryPrior cold injury Attitude Attitude±Acclimatization Peer pressure±Acclimatization Peer pressureDehydration FatigueDehydration FatigueOverexertion Intense concentration on tasksOverexertion Intense concentration on tasksTrauma:multisystem/extremity Hunger; malnutritionTrauma:multisystem/extremity Hunger; malnutritionDermatologic diseases IntoxicantsDermatologic diseases IntoxicantsPhysical conditioningPhysical conditioning

Diaphoresis/hyperhidrosisDiaphoresis/hyperhidrosis EnvironmentalEnvironmentalHypoxia Ambient temperature Hypoxia Ambient temperature Humidity Humidity Cardiovascular Duration of exposureCardiovascular Duration of exposureHypotension Wind chill factorHypotension Wind chill factorAtherosclerosis Altitude±associated conditionsAtherosclerosis Altitude±associated conditionsArteritis Orantity of exposed surface areaArteritis Orantity of exposed surface areaRaynaud’s syndrome Heat loss: conductive, evaporativeRaynaud’s syndrome Heat loss: conductive, evaporativeCIVDCIVD

Anemia Anemia Mechanical MechanicalSickle cell diseaseSickle cell disease Constricting/wet clothingConstricting/wet clothing

Diabetes Diabetes Tight bootsTight boots

Hypovolemia; shockHypovolemia; shock Vapor barrier/alveolite linersVapor barrier/alveolite liners

Vasoconstrictors/vasodilatorsVasoconstrictors/vasodilators Inadequate insulationInadequate insulation Immobility/cramped positioning Immobility/cramped positioning

CLINICAL PRESENTATIONCLINICAL PRESENTATION

SymptomsSymptoms The symptoms of frostbite usually reflect the severity The symptoms of frostbite usually reflect the severity of the exposure. All patients will have of the exposure. All patients will have some initial senssome initial sensory deficiency in light touch, pain, or temperature.ory deficiency in light touch, pain, or temperature. T The he most common presenting symptom is numbnessmost common presenting symptom is numbness, p, present in over 75% of patients. resent in over 75% of patients. AnesthesiaAnesthesia is produced b is produced by intense vasoconstrictive ischemia and neuropraxia. y intense vasoconstrictive ischemia and neuropraxia. Patients often complain of Patients often complain of clumsinessclumsiness and report a `` and report a ``cchunk of woodhunk of wood'' sensation in the extremity. '' sensation in the extremity. ````FrostnipFrostnip'' is '' is a superficial cold insult manifested by transient numbnesa superficial cold insult manifested by transient numbness and tingling that resolves after rewarming. This does ns and tingling that resolves after rewarming. This does not represent true frostbite because there is no tissue destrot represent true frostbite because there is no tissue destruction.uction.

Chilblains (pernio)Chilblains (pernio) is a mild form of dry-cold injur is a mild form of dry-cold injury often following repetitive exposure. These ``y often following repetitive exposure. These ``cold socold soresres'' usually affect facial areas and the dorsum of the '' usually affect facial areas and the dorsum of the hands and feet. Persistent vasospasm and vasculitis rehands and feet. Persistent vasospasm and vasculitis result in pruritus, erythema, and mild edema. Plaques, bsult in pruritus, erythema, and mild edema. Plaques, blue nodules, and ulcerations can develop. lue nodules, and ulcerations can develop. Trench fooTrench foot (immersion foot)t (immersion foot) is produced by prolonged exposu is produced by prolonged exposure to wet cold at temperatures above freezing. Initiallre to wet cold at temperatures above freezing. Initially the feet often appear cyanotic, cold, and edematous. y the feet often appear cyanotic, cold, and edematous. There is often numbness and leg cramping. After warThere is often numbness and leg cramping. After warming, the skin remains erythematous, dry, and very pming, the skin remains erythematous, dry, and very painful to touch. Vesiculation proceeds to ulceration anainful to touch. Vesiculation proceeds to ulceration and liquefaction gangrene in severe cases. d liquefaction gangrene in severe cases.

SignsSigns Classically, Classically, the initial presentation of frostbite is the initial presentation of frostbite is deceptively benign.deceptively benign. Frozen tissues will often appear Frozen tissues will often appear mottled or violaceouswhite, waxy, or pale yellow. Favmottled or violaceouswhite, waxy, or pale yellow. Favorable presenting signs include normal sensation, warorable presenting signs include normal sensation, warmth and color. Soft, pliable subcutaneoustiss.. suggestmth and color. Soft, pliable subcutaneoustiss.. suggests a superficial injury. A residual violaceous hue after rs a superficial injury. A residual violaceous hue after rewarming is ominous. ewarming is ominous. Lack of edema formation may Lack of edema formation may also suggest significant tissue damage. Postthaw edealso suggest significant tissue damage. Postthaw edema usually develops in less than 3 hours. In severe cama usually develops in less than 3 hours. In severe cases, frostbitten skin forms an early black, dry eschar uses, frostbitten skin forms an early black, dry eschar until mummification and apparent demarcation. ntil mummification and apparent demarcation.

ClassificationClassification Historically, frostbite has been classified into degrees Historically, frostbite has been classified into degrees of injury similar to burns. Anesthesia and erythema are of injury similar to burns. Anesthesia and erythema are characteristic of first-degree frostbite. Superficial vesiccharacteristic of first-degree frostbite. Superficial vesiculation surrounded by edema and erythema is considerulation surrounded by edema and erythema is considered second degree. Third-degree frostbite produces deeped second degree. Third-degree frostbite produces deeper hemorrhagic vesicles . Fourth-degree injuries extend er hemorrhagic vesicles . Fourth-degree injuries extend into subcuticular osseous and muscle tissues. into subcuticular osseous and muscle tissues. Classification by degrees is often prognostically incor Classification by degrees is often prognostically incorrect and thus therapeutically misleading. Mills suggests rect and thus therapeutically misleading. Mills suggests two simple classifications. Superficial or mild frostbtwo simple classifications. Superficial or mild frostbite does not entail tissue loss, whereas deep or severite does not entail tissue loss, whereas deep or severe doese does

TREATMENTTREATMENT

PrehospitalPrehospital The ultimate goal of The ultimate goal of prehospital treatment is preseprehospital treatment is preservation of lifervation of life. Since accidental hypothermia and fros. Since accidental hypothermia and frostbite often coexist, tbite often coexist, prevention of further systemic hprevention of further systemic heat loss is the highest priority.eat loss is the highest priority. Field rewarming of frozen tissue is rarely practical. Field rewarming of frozen tissue is rarely practical. If possible, remove constricting or wet clothing. GentlIf possible, remove constricting or wet clothing. Gently insulate and immobilize the affected areas. Friction y insulate and immobilize the affected areas. Friction massage is not efficacious, and will increase tissue losmassage is not efficacious, and will increase tissue loss. s. Frozen parts should be kept away from dry heat Frozen parts should be kept away from dry heat sources in the transport vehicle to prevent a gradusources in the transport vehicle to prevent a gradual partial thaw. al partial thaw.

Emerpency DepartmentEmerpency Department Prethaw:Prethaw: obtain pertinent history regarding the ambie obtain pertinent history regarding the ambient temperature, wind velocity, and duration of exposure.nt temperature, wind velocity, and duration of exposure. Determine the type of apparel and the circumstances su Determine the type of apparel and the circumstances surrounding rescue. Document preexistent cardiovascular rrounding rescue. Document preexistent cardiovascular or neurologic diseases that could affect tissue loss. or neurologic diseases that could affect tissue loss. AfteAfter stabilizing the core temperature and addressing asr stabilizing the core temperature and addressing associated conditions, prepare to initiate rapid thawinsociated conditions, prepare to initiate rapid thawing. g. Thaw:Thaw: Frozen or partially thawed tissue should be Frozen or partially thawed tissue should be rarapidly and actively rewarmed by immersion in gently pidly and actively rewarmed by immersion in gently circulating water.circulating water. Carefully maintain the temperature a Carefully maintain the temperature at t 40 to 43℃40 to 43℃ by thermometer measurement. by thermometer measurement.

They are invariably hypothermic and at risk for signThey are invariably hypothermic and at risk for significant fluid and electrolyte fluxes during rewarming. ificant fluid and electrolyte fluxes during rewarming. The acute thawing of large amounts of distal musculaThe acute thawing of large amounts of distal musculature extinguishes peripheral vasoconstriction. This reture extinguishes peripheral vasoconstriction. This results in the sudden return of cold, hyperkalemic, acidsults in the sudden return of cold, hyperkalemic, acidotic blood to the central circulation. This ``otic blood to the central circulation. This ``core tempcore temperature after-droperature after-drop'' is dysrhythmogenic. In the most '' is dysrhythmogenic. In the most severe cases, extracorporeal rewarming should be cosevere cases, extracorporeal rewarming should be considered to manage these massive metabolic and electnsidered to manage these massive metabolic and electrolyte derangements . rolyte derangements .

Emergency Department Rewarming ProtocolEmergency Department Rewarming ProtocolPrethawPrethaw•Protectpart•Protectpart•Stabilize core temperature•Stabilize core temperature•Address medical/surgical conditions•Address medical/surgical conditions•Hydration•Hydration•Nofriction massage•Nofriction massage  ThawThaw•Rapid rewarming in 38 -41 circulating water until distal flush (thermom℃ ℃•Rapid rewarming in 38 -41 circulating water until distal flush (thermom℃ ℃eter monitoring)eter monitoring)•Requires 10-30 min with active motion of part without friction massage•Requires 10-30 min with active motion of part without friction massage•Parenteral analgesia•Parenteral analgesiaPostthawPostthaw•Clear vesicles –aspirate (if intact) vs. debride•Clear vesicles –aspirate (if intact) vs. debride•Hemorrhagic vesicles – aspirate•Hemorrhagic vesicles – aspirate•Apply topical aloe vera (Dermaide) q6h•Apply topical aloe vera (Dermaide) q6h•Ibuprofen 400 mg q12h•Ibuprofen 400 mg q12h•Tetanus prophylaxis•Tetanus prophylaxis•Streptococcal prophylaxis for 48-72hr•Streptococcal prophylaxis for 48-72hr•Elevation •Elevation

SEQUELAESEQUELAE

SequelaeSequelaeNeuropathicNeuropathicPain StricturePain StricturePhantom Epiphyseal fusionPhantom Epiphyseal fusionCausalgia OsteoarthritisCausalgia Osteoarthritis“Tabes” burning Osteolytic lesions“Tabes” burning Osteolytic lesionsChronic NecrosisChronic Necrosis Amputation AmputationSensationSensationHypesthesia Hypesthesia DermatologicDermatologicDysesthesia EdemaDysesthesia EdemaParesthesia LymphedemaParesthesia LymphedemaAnesthesia Chronic/recurrent ulcersAnesthesia Chronic/recurrent ulcers Epidermoid/squamous carcinoma Epidermoid/squamous carcinomaThermal sensitivityThermal sensitivity Hair/nail deformities Hair/nail deformitiesHeatHeatCold Cold MiscellaneousMiscellaneous Core temperature afterdrop Core temperature afterdropAutonomic dysfunction Autonomic dysfunction Acute tubular necrosis Acute tubular necrosisHyperhidrosis Electrolyte fluxesHyperhidrosis Electrolyte fluxesRaynaud’s Psychic stressRaynaud’s Psychic stress Gangrene GangreneMusculoskeletal Musculoskeletal Sepsis SepsisAtrophyAtrophyCompartment syndromeCompartment syndromeRhabdomyolysisRhabdomyolysisTenosynovitisTenosynovitis

Electrical InjuresElectrical Injures

EPIDEMIOLOGYEPIDEMIOLOGY     The first report of electrical injury from man-made s The first report of electrical injury from man-made sources occurred in 1746 after the development of the ources occurred in 1746 after the development of the capacitor. capacitor. The first recorded death due to electrical current froThe first recorded death due to electrical current from a man-made source was reported in 1879, when a cm a man-made source was reported in 1879, when a carpenter in Lyons, France, inadvertently contacted a 2arpenter in Lyons, France, inadvertently contacted a 250- volt AC dynamo. The first U. S. fatality occured i50- volt AC dynamo. The first U. S. fatality occured in 1881, when a local inebriate, Samuel W. Smith, passn 1881, when a local inebriate, Samuel W. Smith, passed out on a generator in front of a crowd in Buffalo, Ned out on a generator in front of a crowd in Buffalo, New York. ew York.

The apparent painlessness of his death impressed the The apparent painlessness of his death impressed the crowd, and electrocution began to be thought of as a `crowd, and electrocution began to be thought of as a ``humane'' mode of execution. In 1890 William Kemm`humane'' mode of execution. In 1890 William Kemmeler became the first man to be put to death in New Yeler became the first man to be put to death in New York State's electric chair.ork State's electric chair. Electrical burns account for 4% to 6.5% of all admi Electrical burns account for 4% to 6.5% of all admissions to burn unitsssions to burn units

PATHOPHYSIOLOGYPATHOPHYSIOLOGY The exact pathophysiology of electrical injury is not The exact pathophysiology of electrical injury is not well understood because of the large number of variabwell understood because of the large number of variables that cannot be measured or controlled when an eleles that cannot be measured or controlled when an electrical current passes through tissue. Most of the injurctrical current passes through tissue. Most of the injury appears to be y appears to be thermalthermal, and most histologic studies r, and most histologic studies reveal coagulation necrosis consistent with thermal injeveal coagulation necrosis consistent with thermal injury. A magnetic field exists wherever an electric curreury. A magnetic field exists wherever an electric current passes, there may be magnetic effects. nt passes, there may be magnetic effects.

Factors Determining Electrical InjuryFactors Determining Electrical Injury

Type of circuitType of circuitResistance of tissuesResistance of tissuesAmperageAmperageVoltageVoltageCurrent pathwayCurrent pathwayDurationDurationEnvironmental factorsEnvironmental factors

Type of CircuitType of Circuit The type of circuit, alternating current (AC) vs. The type of circuit, alternating current (AC) vs. Direct current (DC), will help to determine the Direct current (DC), will help to determine the severity of the injury. High-voltage DC tends to severity of the injury. High-voltage DC tends to cause a single muscle spasm, often throwing the cause a single muscle spasm, often throwing the victim from the source. This results in a shorter victim from the source. This results in a shorter duration of exposure but increases the likelihood of duration of exposure but increases the likelihood of traumatic blunt injury. It is well-known that contact traumatic blunt injury. It is well-known that contact with a DC source can result in disturbances in with a DC source can result in disturbances in cardiac rhythm, depending on the phase of the cardiac rhythm, depending on the phase of the cardiac cycle affected, a phenomenon that is utilized cardiac cycle affected, a phenomenon that is utilized in the common defibrillator. in the common defibrillator.

AC tends to be three times more dangerous than dirAC tends to be three times more dangerous than direct current of the same voltage. ect current of the same voltage. The hand is frequently the site of entry as it grasps The hand is frequently the site of entry as it grasps a tool that comes into contact with an electric source. a tool that comes into contact with an electric source. Because the flexors of the hand and forearm are mucBecause the flexors of the hand and forearm are much stronger than the extensors, contraction of the flexh stronger than the extensors, contraction of the flexors at the wrist, elbow, and shoulder occur, causing tors at the wrist, elbow, and shoulder occur, causing the hand holding onto the current source to pull the sohe hand holding onto the current source to pull the source even closer to the body. At currents above the leurce even closer to the body. At currents above the let-go threshold (6 to 9 mA) this can result in the victit-go threshold (6 to 9 mA) this can result in the victim's being unable to voluntarily release the current som's being unable to voluntarily release the current source, prolonging the duration of exposure to the electurce, prolonging the duration of exposure to the electrical current.rical current.

ResistanceResistance The Row of electrical energy through a substance is The Row of electrical energy through a substance is described by Ohm‘s law:described by Ohm‘s law: R = V/I R = V/I

Resistence(R) of a tissue , electrical energy(I) to the Resistence(R) of a tissue , electrical energy(I) to thermal energy(P) at any given current as described by Jrmal energy(P) at any given current as described by Joule's Law:oule's Law: P=I P=I22××RR

DurationDuration In general the longer the duration of contact, the In general the longer the duration of contact, the greater the degree of tissue destruction.greater the degree of tissue destruction.CurrentCurrent Current, expressed in amperes, is a measure of the Current, expressed in amperes, is a measure of the amount of energy that flows through an object. amount of energy that flows through an object. Voltage Voltage Voltage is a measure of potential difference Voltage is a measure of potential difference between two points and is determined by the between two points and is determined by the electrical source. electrical source.

Effects of Amperage Levels in Milli-ampheres(mA)Effects of Amperage Levels in Milli-ampheres(mA)

Tingling sensation 1-4Tingling sensation 1-4Let-go currentLet-go current Children 4 Children 4 Women 7 Women 7 Men 9 Men 9Freezing to circuit 10-20Freezing to circuit 10-20Respiratory arrest from thoracic muscle tetany 20-50Respiratory arrest from thoracic muscle tetany 20-50Ventricular fibrillation 50-100Ventricular fibrillation 50-100

PathwayPathway The pathway that a current takes determines the tissue The pathway that a current takes determines the tissues at risk, the type of injury seen, and the degree of convs at risk, the type of injury seen, and the degree of conversion of electrical energy to heat. Current passing throersion of electrical energy to heat. Current passing through the heart or thorax can cause cardiac dysrhythmias ugh the heart or thorax can cause cardiac dysrhythmias and direct myocardial damage. Current passing througand direct myocardial damage. Current passing through the brain can result in respiratory arrest, seizures, and h the brain can result in respiratory arrest, seizures, and paralysis. Current passing close to the eyes can cause cparalysis. Current passing close to the eyes can cause cataracts. It has been suggested that current flowing throataracts. It has been suggested that current flowing through the left side of the body may be more dangerous thugh the left side of the body may be more dangerous than through the right side or one isolated to an extremity.an through the right side or one isolated to an extremity.

As the cross-sectional diameter of the tissue a given As the cross-sectional diameter of the tissue a given current passes through increases the less heat is current passes through increases the less heat is generated, and less damage occurs as the energy is generated, and less damage occurs as the energy is ``diluted‘’ by the tissue. ``diluted‘’ by the tissue. Because the current is often concentrated at the Because the current is often concentrated at the entrance and exit sites, the greatest degree of damage entrance and exit sites, the greatest degree of damage is often observed there, although deep destruction of is often observed there, although deep destruction of the tissues in between may often occur, leading some the tissues in between may often occur, leading some to describe the surface damage as only ``to describe the surface damage as only ``the tip of the tip of the iceberg.the iceberg.

MECHANISMS OF INJURYMECHANISMS OF INJURY The mechanisms of electrical injury are listed in the The mechanisms of electrical injury are listed in the box below. Obviously the victim who becomes part of box below. Obviously the victim who becomes part of an electrical circuit, particularly if it is of high an electrical circuit, particularly if it is of high voltage, may suffer significant injury. Nonconductive voltage, may suffer significant injury. Nonconductive thermal injury can occur by several mechanisms. thermal injury can occur by several mechanisms. The most destructive indirect injury occurs when a The most destructive indirect injury occurs when a victim victim becomes part of an electrical arc. it can becomes part of an electrical arc. it can cause very deep thermal burnscause very deep thermal burns . Sometimes the arc . Sometimes the arc may cause may cause clothing to ignite, resulting in secondary clothing to ignite, resulting in secondary thermal burnsthermal burns. The electrical . The electrical flash burnflash burn. a third . a third mechanism of nonconductive injury, usually results in mechanism of nonconductive injury, usually results in only superficial partial thickness. only superficial partial thickness.

Traumatic injuryTraumatic injury is frequently seen in patients susta is frequently seen in patients sustaining electrical injury because they may be thrown cleining electrical injury because they may be thrown clear of the source by intense contraction of their muscles ar of the source by intense contraction of their muscles or by falling from a height. or by falling from a height. The histologic changes seen in muscle injury are coa The histologic changes seen in muscle injury are coagulation necrosis with shortening of the sarcomere. gulation necrosis with shortening of the sarcomere. Vascular damage is greatest in the media, possibly be Vascular damage is greatest in the media, possibly because of the diffusion of heat away from the intima by cause of the diffusion of heat away from the intima by the flow of blood, but can lead to delayed hemorrhage the flow of blood, but can lead to delayed hemorrhage when the vessel eventually breaks down. Intimal damawhen the vessel eventually breaks down. Intimal damage may result in either immediate or delayed thrombosge may result in either immediate or delayed thrombosis and vascular occlusion is and vascular occlusion

Damage to neural tissue may occur from many mechanDamage to neural tissue may occur from many mechanisms. It may show an immediate drop in conductivity as isms. It may show an immediate drop in conductivity as it undergoes coagulation necrosis similar to that observeit undergoes coagulation necrosis similar to that observed in muscle tissue. In addition, it may suffer indirect dad in muscle tissue. In addition, it may suffer indirect damage as its vascular supply or myelin sheath is injured.mage as its vascular supply or myelin sheath is injured. The brain is frequently injured, focal petechial hemorrhThe brain is frequently injured, focal petechial hemorrhages in the brainstem, widespread chromatolysis, and cerages in the brainstem, widespread chromatolysis, and cerebral edema.ebral edema. Immediate death in electrical injury may be from Immediate death in electrical injury may be from asystasystole, ventricullar fibrillation, or respiratory paralysisole, ventricullar fibrillation, or respiratory paralysis , , depending on the voltage and pathway.depending on the voltage and pathway.

Mechanisms of InjuryMechanisms of Injury

Direct contactDirect contactArcArcFlashFlashThermalThermalBlunt traumaBlunt trauma

CLINICAL FINDINGSCLINICAL FINDINGS

Prehospital ConsiderationsPrehospital Considerations When first reaching the scene, paramedic personnel s When first reaching the scene, paramedic personnel should secure the area so that no other injuries can occuhould secure the area so that no other injuries can occur to bystanders or rescuers. It is essential that the power r to bystanders or rescuers. It is essential that the power source be turned off Although many approaches to this source be turned off Although many approaches to this have been touted, Use of electrical gloves by emergenchave been touted, Use of electrical gloves by emergency medical service (EMS) groups has been condemned, y medical service (EMS) groups has been condemned, A downed high-tension line may jump as it repowers A downed high-tension line may jump as it repowers periodically (similar to a water hose that jumps when tperiodically (similar to a water hose that jumps when turned off and on) and may land anywhere in its radius, urned off and on) and may land anywhere in its radius, causing more injuries. Therefore the rescue vehicle shocausing more injuries. Therefore the rescue vehicle should park at least one entire span away from the line. uld park at least one entire span away from the line.

The victim of an electrical incident should be approThe victim of an electrical incident should be approached like any other trauma patient because the persached like any other trauma patient because the person may have suffered injury as a result of violent muon may have suffered injury as a result of violent muscle contraction or a fall, in addition to having severe scle contraction or a fall, in addition to having severe burns that are often more extensive than they initiallburns that are often more extensive than they initially appear. y appear. Attention should be paid to the airway, bAttention should be paid to the airway, breathing, and circulationreathing, and circulation. High-flow oxygen and in. High-flow oxygen and intubation should be provided if necessary. Cardiac motubation should be provided if necessary. Cardiac monitoring is essential. If the victim has experienced canitoring is essential. If the victim has experienced cardiac arrest, standard advanced life support protocols rdiac arrest, standard advanced life support protocols should be instituted. should be instituted.

Emergency Department AssessmentEmergency Department Assessment

History. History. Specific injuries:Specific injuries: Cardiovascular System. Cardiovascular System. Cardiac arrest, either froCardiac arrest, either from asystole or ventricular fibrillation, is a common prm asystole or ventricular fibrillation, is a common presenting condition in electrical accidents.esenting condition in electrical accidents. Skin.Skin. Skin injury are burns. The most common site Skin injury are burns. The most common sites of entry for the current include the hands and the sks of entry for the current include the hands and the skull. The most common areas of exit are the heels. paiull. The most common areas of exit are the heels. painless, depressed, yellow-grey, punctate areas with cenless, depressed, yellow-grey, punctate areas with central necrosis. ntral necrosis.

ExtremitiesExtremities. Muscle necrosis. Muscle necrosis Massive release of myMassive release of myoglobin from the damaged muscle may lead to myoglooglobin from the damaged muscle may lead to myoglobinuric renal failure. binuric renal failure. Vascular damageVascular damage Damage to the vessel wall at the tiDamage to the vessel wall at the time of injury can result in delayed thrombosis and hemme of injury can result in delayed thrombosis and hemorrhage, especially in the small arteries to the muscle.orrhage, especially in the small arteries to the muscle. Progressive loss of muscle because of vascular ischemiProgressive loss of muscle because of vascular ischemia downstream from damaged vessels may lead to the na downstream from damaged vessels may lead to the need for repeated deep debridements.eed for repeated deep debridements.

`kissing burn," occurs at the flexor creases.`kissing burn," occurs at the flexor creases.

Nervous System.Nervous System. Loss of consciousness is common Loss of consciousness is common and usually transient, Patients may exhibit confusion and usually transient, Patients may exhibit confusion flat affect, and difficulty with short-term memory and flat affect, and difficulty with short-term memory and concentration. A seizure may occur after electrical concentration. A seizure may occur after electrical injury . Peripheral nerve damage in extremities injury . Peripheral nerve damage in extremities sustaining injury is common, and recovery is usually sustaining injury is common, and recovery is usually poor. poor.

Other Viscera.Other Viscera. Skeletal System.Skeletal System. Eyes. Eyes. Cataracts develop in approximately 6% of Cataracts develop in approximately 6% of cases cases Mouth.Mouth. Mouth burns secondary to sucking on Mouth burns secondary to sucking on household electrical extension cords are the most household electrical extension cords are the most common electrical injury seen in children under 4 common electrical injury seen in children under 4 years of age.years of age.

ComplicationsComplications

Primary Complications and Causes of DePrimary Complications and Causes of Death in order of Occurrenceath in order of Occurrence

Cardiopulmonary arrestCardiopulmonary arrestOverwhelming injuriesOverwhelming injuriesCardiac arrhythmiasCardiac arrhythmiasHypoxia and electrolytesHypoxia and electrolytesIntracranial injuriesIntracranial injuriesMyoglobinuric renal failureMyoglobinuric renal failureAbdominal injuriesAbdominal injuriesSepsisSepsisTetanusTetanusIatrogenicIatrogenicSuicideSuicide

  

TREATMENTTREATMENT

Resuscitation. Resuscitation. Once the accident scene is controlled. Once the accident scene is controlled. a quick initial assessment of the patient is indicated, a quick initial assessment of the patient is indicated, with attention to the airway, breathing, and with attention to the airway, breathing, and circulation. Cardiac monitoring is helpful and circulation. Cardiac monitoring is helpful and cardiopulmonary resuscitation (CPR) should be cardiopulmonary resuscitation (CPR) should be initiated, if indicated, with institution of advanced life initiated, if indicated, with institution of advanced life support. support. Cardiac monitoring is more controversial and is Cardiac monitoring is more controversial and is probably only necessary for the severely injured probably only necessary for the severely injured patient and for those who have the indications listed patient and for those who have the indications listed in the Box below. in the Box below.

Indication for Electrocardiographic MonitoringIndication for Electrocardiographic Monitoring

Cardiac arrestCardiac arrestDocumented loss of consiousnessDocumented loss of consiousnessAbnormal ECGAbnormal ECGDysrhythmia observed in prehospital or emergency departmeDysrhythmia observed in prehospital or emergency department settingnt settingHistory of cardiac diseaseHistory of cardiac diseasePresence of significant risk factors for cardiac diseasePresence of significant risk factors for cardiac diseaseConcommitant injury severe enough to warrant addmissionConcommitant injury severe enough to warrant addmissionSuspicion of conductive injurySuspicion of conductive injuryHypoxiaHypoxiaChest painChest pain

Rhabdomyolysis.Rhabdomyolysis. Patients with heme pigment in the Patients with heme pigment in the urine should be treated as though they have myoglobinurine should be treated as though they have myoglobinuria.uria. Burn Wound Care.Burn Wound Care. Extremity Injuries. Extremity Injuries. The current trend with regard to The current trend with regard to damaged extremities favors early and aggressive surgidamaged extremities favors early and aggressive surgical management, including early decompressive eschacal management, including early decompressive escharotomy, fasciotomy, carpal tunnel release, or even amprotomy, fasciotomy, carpal tunnel release, or even amputation of an obviously nonviable extremity. Extremitiutation of an obviously nonviable extremity. Extremities should be splinted in functional position to minimizes should be splinted in functional position to minimize edema and contracture formation. e edema and contracture formation.

DISPOSITIONDISPOSITION

All patients with significant electrical burns should All patients with significant electrical burns should be stabilized and transferred to a regional burn center be stabilized and transferred to a regional burn center if possible. if possible. Electrical injury during pregnancy from low voltage Electrical injury during pregnancy from low voltage sources has been reported to result in stillbirth. Obstesources has been reported to result in stillbirth. Obstetric consultation should probably be obtained in all prtric consultation should probably be obtained in all pregnant patients reporting electrical injury, egnant patients reporting electrical injury, Treatment of pediatric patients with oral burns is mo Treatment of pediatric patients with oral burns is more controversial. In general, these patients need surgicre controversial. In general, these patients need surgical and dental consultation for planning of debridemenal and dental consultation for planning of debridement, oral splinting and occasionally, reconstructive surget, oral splinting and occasionally, reconstructive surgery. ry.

Lightning InjuriesLightning Injuries

EPlDEMlOLOGYEPlDEMlOLOGY

As would be expected, lightning incidents are most As would be expected, lightning incidents are most common where there are more thunderstorms, common where there are more thunderstorms, They also occur more frequently during the times They also occur more frequently during the times that people tend to be outdoors, in the afternoon and that people tend to be outdoors, in the afternoon and early evening, and during the thunderstorm season, early evening, and during the thunderstorm season, May to September.May to September. Lightning incidents were once most frequently Lightning incidents were once most frequently reported among farmers.reported among farmers. With the population shift to the cities, where With the population shift to the cities, where lightning strikes are less frequent, those most lightning strikes are less frequent, those most commonly reported in lightning incidents are campers, commonly reported in lightning incidents are campers, joggers and other athletes, and construction workers.joggers and other athletes, and construction workers.

LIGHTNING PRODUCTIONLIGHTNING PRODUCTION

Lightning is produced from the static charges that Lightning is produced from the static charges that occur as a cold high-pressure front moves over a occur as a cold high-pressure front moves over a warm, moist, low-pressure area. The warm, moist air warm, moist, low-pressure area. The warm, moist air rises through the cold air, allowing the moisture to rises through the cold air, allowing the moisture to condense into a cloud. The friction of moving air condense into a cloud. The friction of moving air particles within the cloud causes ionization and particles within the cloud causes ionization and complicated energy changes . complicated energy changes . In most cases the lightning begins as a In most cases the lightning begins as a leader strokeleader stroke from a cloud and takes a slow, jagged, irregular path from a cloud and takes a slow, jagged, irregular path downward the oppositely charged earth below the downward the oppositely charged earth below the storm cloud. storm cloud.

A pilot strokeA pilot stroke rising from ground upward cloud rising from ground upward cloud cause the column of ionized air to flicker and cause the column of ionized air to flicker and brighten momentarily as massive amounts of energy brighten momentarily as massive amounts of energy are discharged. Although the majority of the are discharged. Although the majority of the lightning discharge occurs in an upward direction, lightning discharge occurs in an upward direction, lightning is perceived as a downward stroke because lightning is perceived as a downward stroke because of the irregular, weak, slower leader stroke.of the irregular, weak, slower leader stroke.

MYTHS AND MISTREATMENTSMYTHS AND MISTREATMENTS From ancient times lightning has played a prominent From ancient times lightning has played a prominent part in the religions and folklore of many cultures, part in the religions and folklore of many cultures, giving rise to many superstitions and myths. giving rise to many superstitions and myths. Unfortunately many of these myths persist today, Unfortunately many of these myths persist today, including some in the medical literature. They include:including some in the medical literature. They include:

1. Lightning is always fatal.1. Lightning is always fatal.2. Lightning burns can turn victims into “crispy critters”.2. Lightning burns can turn victims into “crispy critters”.3. Lightning never strikes in the same place twice.3. Lightning never strikes in the same place twice.4. Victims of lightning strikes remain electrified.4. Victims of lightning strikes remain electrified.5. The bodies of victims of lightning strikes can remain in 5. The bodies of victims of lightning strikes can remain in “suspended animation”. “suspended animation”. 6. Lightning injuries are like other high-voltage injuries.6. Lightning injuries are like other high-voltage injuries.

Because of the general lack of experience of most urBecause of the general lack of experience of most urban physicians with lightning injuries, a great deal of ban physicians with lightning injuries, a great deal of confusion exists between lightning injuries and other confusion exists between lightning injuries and other high-voltage electrical injuries. Usually much less enhigh-voltage electrical injuries. Usually much less energy is imparted to the lightning victim than to the viergy is imparted to the lightning victim than to the victim of regular high-voltage exposure, and consequenctim of regular high-voltage exposure, and consequently far less injury occurs. Although the body's electrictly far less injury occurs. Although the body's electrical systems may be short-circuited by lightning, resultial systems may be short-circuited by lightning, resulting in cardiac arrest, tinnitus, temporary blindness, anng in cardiac arrest, tinnitus, temporary blindness, and paralysis, injuries typical of man-made high-voltagd paralysis, injuries typical of man-made high-voltage electricity such as burns, myoglobinuria, and deep-e electricity such as burns, myoglobinuria, and deep-muscle damage are rare. muscle damage are rare.

PATHOPHYSIOLOGY OF PATHOPHYSIOLOGY OF LIGHTNING INJURYLIGHTNING INJURY

Mechanisms of Lightning InjuryMechanisms of Lightning Injury

Direct strikeDirect strikeContactContactSide flash, "splash"Side flash, "splash"Ground current or step voltageGround current or step voltageBlunt traumaBlunt trauma

A direct strike is self-evident. Injury from contact occuA direct strike is self-evident. Injury from contact occurs when the person is touching an object that is part of trs when the person is touching an object that is part of the pathway of lightning current. Side flash or splash oche pathway of lightning current. Side flash or splash occurs as lightning jumps from its pathway to a nearby pcurs as lightning jumps from its pathway to a nearby person.erson. Step voltage occurs as a result of lightning current sprStep voltage occurs as a result of lightning current spreading radially through the ground. A person who has eading radially through the ground. A person who has one foot closer than the other to the strike point will haone foot closer than the other to the strike point will have a potential difference between his or her feet so that ve a potential difference between his or her feet so that a current may be induced through the legs and body. Ta current may be induced through the legs and body. This is a frequent killer of large livestock such as cattle ahis is a frequent killer of large livestock such as cattle and horses because of the distance between their hindlend horses because of the distance between their hindlegs and forelegs.gs and forelegs.

Blunt injury can occur from two mechanisms. (1) the peBlunt injury can occur from two mechanisms. (1) the person may be thrown a considerable distance by the opisthrson may be thrown a considerable distance by the opisthotonic contraction caused by current passing through the otonic contraction caused by current passing through the body or (2) from the explosive/implosive force caused as body or (2) from the explosive/implosive force caused as the lightning pathway is instantaneously superheated and the lightning pathway is instantaneously superheated and then rapidly cooled after the passage of the lightning is othen rapidly cooled after the passage of the lightning is over. The heating is seldom long enough to cause severe bver. The heating is seldom long enough to cause severe burns but does cause rapid expansion of air followed by raurns but does cause rapid expansion of air followed by rapid implosion of the cooled air as it rushes back into the pid implosion of the cooled air as it rushes back into the void.void.

Factors Governing Electrical InjuriesFactors Governing Electrical Injuries

Type of circuit(AC or DC)Type of circuit(AC or DC)DurationDurationVoltageVoltageAmperageAmperageResistance of tissuesResistance of tissuesPathwayPathway

Not only is there an absolute energy difference, but Not only is there an absolute energy difference, but the duration of lightning is so incredibly short that the duration of lightning is so incredibly short that the energy seldom has time to break down the skin the energy seldom has time to break down the skin and cause any significant internal current flow or and cause any significant internal current flow or tissue damage. Thus the pathway is also different. As tissue damage. Thus the pathway is also different. As with metal conductors, the vast majority of the with metal conductors, the vast majority of the current travels around the outside of the conductor, current travels around the outside of the conductor, ``flashing over'' the outside ``flashing over'' the outside of the victim. of the victim.

Although a small amount of current may leak internaAlthough a small amount of current may leak internally, causing short-circuiting of electrical systems such lly, causing short-circuiting of electrical systems such as the heart, respiratory centers, and autonomic nervouas the heart, respiratory centers, and autonomic nervous system or causing spasm of arteries and muscles, ligs system or causing spasm of arteries and muscles, lightning seldom causes any significant burns or tissue dhtning seldom causes any significant burns or tissue destruction. Thus burns and myoglobinuric renal failure estruction. Thus burns and myoglobinuric renal failure play a small part in the injury pattern, whereas cardiac play a small part in the injury pattern, whereas cardiac and respiratory arrest, vascular spasm, and autonomic and respiratory arrest, vascular spasm, and autonomic instability play a much greater role. instability play a much greater role.

PREHOSPlTAL CONSIDERATPREHOSPlTAL CONSIDERATIONSIONS

The prehospital personnel must remember that lightThe prehospital personnel must remember that lightning can strike the same place twice and guard themsning can strike the same place twice and guard themselves against also becoming victims.elves against also becoming victims. The major cause of death in lightning injuries is car The major cause of death in lightning injuries is cardiorespiratory arrest. victims are unlikely to die of andiorespiratory arrest. victims are unlikely to die of any other cause. Thus triage of lightning victims shouly other cause. Thus triage of lightning victims should concentrate on those who appear to be in cardioresd concentrate on those who appear to be in cardiorespiratory arrest. Lightning acts as a massive DC countpiratory arrest. Lightning acts as a massive DC countershock, sending the heart into asystole. Although auershock, sending the heart into asystole. Although automaticity may lead to the heart restarting, the respirtomaticity may lead to the heart restarting, the respiratory arrest often lasts longer than the cardiac pause atory arrest often lasts longer than the cardiac pause and may lead to a secondary cardiac arrest with ventrand may lead to a secondary cardiac arrest with ventricular fibrillation from hypoxia. icular fibrillation from hypoxia.

CLINICAL FINDINGSCLINICAL FINDINGS

Patients may present with little evidence of injury oPatients may present with little evidence of injury or, alternately, cardiopulmonary arrest. After initial resr, alternately, cardiopulmonary arrest. After initial resuscitation, additional, rarely life-threatening, conditiouscitation, additional, rarely life-threatening, conditions may be identified.ns may be identified. Head and Neck.Head and Neck. including skull fractures, Over 50 including skull fractures, Over 50% of victims have at least 1 % of victims have at least 1 tympanic membrane rutympanic membrane rupturedptured. Although most recover without serious seque. Although most recover without serious sequelae, disruption of the ossicles and mastoid may occur, lae, disruption of the ossicles and mastoid may occur, as well as cerebrospinal fluid otorrhea, hemotympanuas well as cerebrospinal fluid otorrhea, hemotympanum, and permanent deafness.m, and permanent deafness. Cataracts may occur. Other injuries to the eyes may Cataracts may occur. Other injuries to the eyes may occur.Cervical spine injury may be caused by a fall or occur.Cervical spine injury may be caused by a fall or being thrown. being thrown.

Cardiopulmonary.Cardiopulmonary. Pulmonary contusion and hemorr Pulmonary contusion and hemorrhage have been reported. Cardiac damage or arrest caushage have been reported. Cardiac damage or arrest caused by either the electrical shock or induced vascular spaed by either the electrical shock or induced vascular spasm may occur. Numerous dysrhythmias have been reposm may occur. Numerous dysrhythmias have been reported in the absence of cardiac arrest. Nonspecific ST-T rted in the absence of cardiac arrest. Nonspecific ST-T wave-segment changes may occur, and serum levels of wave-segment changes may occur, and serum levels of cardiac enzymes are sometimes elevated. Hypertension cardiac enzymes are sometimes elevated. Hypertension is often present initially but usually resolves in an hour is often present initially but usually resolves in an hour or two so that treatment is not usually or two so that treatment is not usually

Abdominal.Abdominal. Blunt abdominal injuries have been report Blunt abdominal injuries have been reported but are rare. None of the other intraabdominal catastred but are rare. None of the other intraabdominal catastrophies associated with electrical injury (e.g. gall-bladder ophies associated with electrical injury (e.g. gall-bladder necrosis, mesenteric thrombosis) have been reported witnecrosis, mesenteric thrombosis) have been reported with lightning injury. h lightning injury. Extremities.Extremities. On initial presentation, two-thirds of the s On initial presentation, two-thirds of the seriously injured patients have keraunoparalysis with loweriously injured patients have keraunoparalysis with lower and sometimes upper extremities that are blue, mottleer and sometimes upper extremities that are blue, mottled, cold, and pulseless because of vascular spasm and syd, cold, and pulseless because of vascular spasm and sympathetic nervous system instability. Generally this cleampathetic nervous system instability. Generally this clears within a few hours, although some patients may be lefrs within a few hours, although some patients may be left with permanent paresis or paresthesias. t with permanent paresis or paresthesias.

Skin. Skin. The skin may show no signs of injury initially. The skin may show no signs of injury initially. Deep burns occur in less than 5% of the reported injurDeep burns occur in less than 5% of the reported injuries. As mentioned previously, burns are usually superfies. As mentioned previously, burns are usually superficial, if present at all. They consist of four types (see bicial, if present at all. They consist of four types (see box below and ox below and Fig. 1Fig. 1).).  Lightning BurnsLightning BurnsLinearLinearPunctatePunctateFeatheringFeatheringThermalThermal

COMPLICATIONSCOMPLICATIONS

Complications of lightning injury fall into two areas. Complications of lightning injury fall into two areas. (1) those which could be reasonably predicted from the (1) those which could be reasonably predicted from the presenting signs and which can be treated routinely (i. presenting signs and which can be treated routinely (i. e. ,hearing loss from tympanic membrane rupture, paree. ,hearing loss from tympanic membrane rupture, paresthesias and paresis from neurologic damage) and (2) tsthesias and paresis from neurologic damage) and (2) those complications which are iatrogenically caused by hose complications which are iatrogenically caused by over-aggressive management.over-aggressive management.

Lightning injuries tend to cause few external or internal Lightning injuries tend to cause few external or internal burns, rarely myoglobulinuria, and little tissue loss, althoburns, rarely myoglobulinuria, and little tissue loss, although there may certainly be permanent functional impairugh there may certainly be permanent functional impairment. As a result, treatment of lightning victims seldom rment. As a result, treatment of lightning victims seldom requires massive fluid resuscitation, fasciotomies for comequires massive fluid resuscitation, fasciotomies for compartment syndromes, mannitol and furosemide diuretics, partment syndromes, mannitol and furosemide diuretics, alkalinization of the urine, amputations, or large repeated alkalinization of the urine, amputations, or large repeated debridements. In fact, most lightning victims, particularldebridements. In fact, most lightning victims, particularly those with head injuries, should probably have their fluy those with head injuries, should probably have their fluids restricted to decrease the likelihood of cerebral edema.ids restricted to decrease the likelihood of cerebral edema.

DIFFERENTIAL DIAGNOSISDIFFERENTIAL DIAGNOSIS

Differential DiagnosisDifferential Diagnosis

Cardiac dysrhythmiasCardiac dysrhythmiasMyocardial infarctionMyocardial infarctionCerebrovascular accidentCerebrovascular accidentSubarachnoid hemorrhageSubarachnoid hemorrhageSeizuresSeizuresClosed-head injuryClosed-head injurySpinal cord traumaSpinal cord traumaTick-bite paralysisTick-bite paralysisHeavy-metal poisoningHeavy-metal poisoning

TREATMENTTREATMENT

Initial care must be given to the ABCs (airway, breatInitial care must be given to the ABCs (airway, breathing, and circulation), with primary attention going to hing, and circulation), with primary attention going to those in cardiac arrest or near arrest. those in cardiac arrest or near arrest. All victims should be transported to a hospital and reAll victims should be transported to a hospital and receive an ECG, cardiac isoenzyme level study, urinalysceive an ECG, cardiac isoenzyme level study, urinalysis for myoglobin, CBC, and other tests and x-ray studiis for myoglobin, CBC, and other tests and x-ray studies as appropriate for their injuries. Most should be moes as appropriate for their injuries. Most should be monitored for 24 hours and receive standard antidysrhythnitored for 24 hours and receive standard antidysrhythmia medications if they develop any signs of cardiac imia medications if they develop any signs of cardiac irritability.rritability.

The vast majority of lightning victims will behave as The vast majority of lightning victims will behave as though they have had electroconvulsive psychiatric ththough they have had electroconvulsive psychiatric therapy and will be confused and have an anterograde aerapy and will be confused and have an anterograde amnesia covering several days after the incident. If any mnesia covering several days after the incident. If any neurologic deterioration occurs, CT or MRI scanning neurologic deterioration occurs, CT or MRI scanning is indicated to rule out intracranial hemorrhage. is indicated to rule out intracranial hemorrhage. Long-term sequelae include insomnia and other slee Long-term sequelae include insomnia and other sleep disturbances, anxiety attacks, decrease in fine mentap disturbances, anxiety attacks, decrease in fine mental functions, fear of storms, and paresthesias and paresil functions, fear of storms, and paresthesias and paresis of affected extremities. s of affected extremities.

Arctic BearArctic Bear