Environmental disorders

Environmental disordersBraden Mcintosh

ObjectiveBurnsFreezing injuriesHypothermiaHyperthermiaBurns

Epidemiology500000 burns per year40000 admissions4000 deaths

Pathophys: disruption of cell membranesDisrupts sodium pumpsEfflux of KRelease of histamines, kinins, arachidonic acid, oxygen radicalsIncreased svr Met acidosisIncreased hct Local injury

Rule of 9's

ManagementAirway- enclosed spacePain controlParkland formula- give lrWatch for rhabdoLocal wound care: bacitracin, silvadene, jelly gauzeEscharotomy if circumferential

DispoMinor burns- < 15% bsa partial or 2% full - dcModerate- 15-25% partial and 2-10% full- admitMajor- >25% partial or 10% full, hands, face, major joint, feet - burn center

Cold injuries

PathophysCapillary stasis and thrombosis (hunting response)Ice crystal formationReperfusion injury- txa, pge, endothelial damage, clumping, sludging, tissue loss

TrenchfootNon-freezing injury Prolonged cooling accelerated by wet conditionsNerve damageNumbness. TinglingTx: supportive- keep feet clean, warm, dry, elevated

ChillblainsNon freezing dry injuryErythematous, pruritic and burning paresthesias Tx- supportive: rewarming, loose dressings, topical steroidsFrost bite: presentationSuperficial (skin soft) - vesicles> black and hard skin> sloughingDeep (hard)- hemorrhagic vesicles> mummification and sloughingCan't tell degree until reperfusion

Frost bite managementRapid rewarming circulating water 40-42 degTetanusWound care- debride clear vesicles, leave hemorrhagic ones, dress wounds, aloeIbuprofenPen G

Hyperthermia

PathopyhsNormal body regulation failsExcess heat > protein desaturation > cell death and endothelial damagedehydration > cardiovascular and metabolic derangementsHeat cramps, exhaustion, stroke

Heat crampsPainful involuntary contractions2/2 def of sodium and potassiumTx- fluids and salt replacement

Heatexhaustion2/2 hyponatremia or hypovolemia Presents as ha, n, vom.No cns impairmentTemp not > 40Tx: cool environment and fluids

Heat strokeHeat exhaustion plus temp > 40 and/ or ams Classic vs. exertionalMortality- 30-80%Tx: cooling- evaporative is best, can do immersion, benzos for inappropriate shivering, avoid pressorsStop once you get to core of 39Watch for renal failure. Hematologic disorders, respiratory distress and seizures

Hypothermia

Predisposing factorsDrunkHypoglycemiamalnutritionaddison'sInfectionmyxedema

PathophysDefined as core temp < 35Excitation and slowing phasesCardio- inc bp, hr, co > 32 degrees then all downhill, j waves, brady> afib > vfib> asystole Pulm- left shift of oxy hgb curve, abg looks better than it really isGI- pancreatitis and hepatic dysfxn Heme- enzyme malfxn> dic Renal- atn and volume depletionNervous- cns depression

Management: rewarmingpassive external- warm env, remove clothesactive external- forced air, warming blanket, warm water immersionactive internal- heated iv fluids, gastric, peritoneal, bladder lavage, bypass, chest tubesShock onceDon't give insulinCan't pronounce until 35 degrees Question #130 y/o m p/w eythematous tingly lesion on tips of toes after dry cold not < freezing.Dx? Frostnip, frost bite, trench foot, chillblains

Questions?

BilboiographyTintinalli, et al. Tintinalli's emergency medicine: a comprehensive study guide. Environmental disorders.

Marx, hockberger. Rosen's emergency medicine- concepts and clinical practice. Environmental disorders.

Rivers. Preparing for the written board exam in emergency medicine. Environmental disorders.

Hippo EM