Environmental EmergenciesEnvironmental EmergenciesPart 1Part 1

Wilderness EmergenciesWilderness Emergencies

Emergency Medicine Clerkship SeriesEmergency Medicine Clerkship SeriesAuthor: Todd A. Parker, M.D.Author: Todd A. Parker, M.D.Co-author: Tom Bottoni, M.D.Co-author: Tom Bottoni, M.D.

Vacation!Vacation!You get that much needed time offYou get that much needed time offYour significant other wants to go to St. TropezYour significant other wants to go to St. Tropez– But you really want to climb Mt. McKinley (Denali)But you really want to climb Mt. McKinley (Denali)

Highest peak in North America-20,320 ft!Highest peak in North America-20,320 ft!– She decides to give it a try, and you’re off!She decides to give it a try, and you’re off!

4 days into the climb, 4 days into the climb, you are at camp 4000 ftyou are at camp 4000 ftfrom the summit, andfrom the summit, andshe complainsshe complainsof a headache and is of a headache and is confused…..confused…..

High Altitude SicknessHigh Altitude Sickness

Definitions:Definitions: - - Moderate altitude 8000-10000ftModerate altitude 8000-10000ft

- - High Altitude 10000-18000High Altitude 10000-18000

- - Extreme High Altitude >18000Extreme High Altitude >18000

Can occur at altitudes greater than 5000 ftCan occur at altitudes greater than 5000 ft– Although most occur above 11,500 feetAlthough most occur above 11,500 feet

Influenced by:Influenced by:- Rate of ascent- Rate of ascent - Final altitude- Final altitude- Sleeping altitude- Sleeping altitude - Duration at altitude- Duration at altitude

Who is at risk?Who is at risk?

Hard to predict who will get it!Hard to predict who will get it!

Higher riskHigher risk– Younger > OlderYounger > Older– Males > FemalesMales > Females

Except during water retaining phase of cycle (premenses)Except during water retaining phase of cycle (premenses)

– Persons with previous high altitude illnessPersons with previous high altitude illnessCan occur in previously unaffectedCan occur in previously unaffectedThose with previous illness can be unaffectedThose with previous illness can be unaffected

– Persons who overexert themselvesPersons who overexert themselves– Physical fitness not necessarily protectivePhysical fitness not necessarily protective– Smoking, Alcohol, SedativesSmoking, Alcohol, Sedatives

PhysiologyPhysiology

Hypoxia due to ↓ in barometric pressureHypoxia due to ↓ in barometric pressure

Hypoxemia due to ↓ POHypoxemia due to ↓ PO22 of inspired air of inspired air

Impact on cell variableImpact on cell variableAbility to acclimatize/compensateAbility to acclimatize/compensate

Pre-existing medical conditionsPre-existing medical conditions

AcclimatizationAcclimatizationVentilation – increases almost immediatelyVentilation – increases almost immediately

CardiovascularCardiovascular– Increased Cardiac Output (CO)Increased Cardiac Output (CO)– Increased pulmonary perfusionIncreased pulmonary perfusion

Improves V/Q mismatchesImproves V/Q mismatches

Increase in cerebral blood flowIncrease in cerebral blood flow

HematologicHematologic– Relative increase in Hg due to diuresesRelative increase in Hg due to diureses– Erythropoietin – stimulates bone marrowErythropoietin – stimulates bone marrow

Effect takes weeksEffect takes weeks

Types of illnessTypes of illness

Altitude-exacerbated conditionsAltitude-exacerbated conditions– NOT the focus of this talk, but be aware!NOT the focus of this talk, but be aware!

Congenital Heart DiseaseCongenital Heart Disease

Pulmonary HypertensionPulmonary Hypertension

Coronary Heart DiseaseCoronary Heart Disease

CHFCHF

Sickle Cell Disease / TraitSickle Cell Disease / Trait

Obstructive Sleep ApneaObstructive Sleep Apnea

PregnancyPregnancy

Radial Keratotomy (Corrective Eye Surgery)Radial Keratotomy (Corrective Eye Surgery)

High Altitude IllnessesHigh Altitude Illnesses

Acute Mountain SicknessAcute Mountain Sickness

High Altitude Cerebral EdemaHigh Altitude Cerebral Edema

High Altitude Pulmonary EdemaHigh Altitude Pulmonary Edema

Acute Mountain SicknessAcute Mountain Sickness

Defined as headache and one or more of:Defined as headache and one or more of:- Anorexia- Anorexia - Fatigue/weakness- Fatigue/weakness

- Nausea/Vomiting- Nausea/Vomiting - Difficulty Sleeping- Difficulty Sleeping

- Dizziness- Dizziness - Lightheadedness- Lightheadedness

Develop 6-10 hours after ascent Develop 6-10 hours after ascent – May be <1 hrMay be <1 hr

Usually Self LimitingUsually Self Limiting

AMS - TreatmentAMS - Treatment

Rarely need to descend – slow / halt ascentRarely need to descend – slow / halt ascent

Analgesics/antiemetics prnAnalgesics/antiemetics prn

Consider acetazolamide (125-250mg BID)Consider acetazolamide (125-250mg BID)– Speeds acclimatizationSpeeds acclimatization

Descend if sx do not improveDescend if sx do not improve– Dexamethasone 4mg PO/IM if unable to descendDexamethasone 4mg PO/IM if unable to descend

Graded ascent is best preventive measure Graded ascent is best preventive measure (600m/day)(600m/day)

High Altitude Cerebral Edema High Altitude Cerebral Edema (HACE)(HACE)

AMS – Sx progress to global cerebellar dysfunctionAMS – Sx progress to global cerebellar dysfunction– Ataxia or altered mental statusAtaxia or altered mental status– Vertigo, Diplopia, rarely seizuresVertigo, Diplopia, rarely seizures

Usually > 12000 ft (have occurred as low as 9K)Usually > 12000 ft (have occurred as low as 9K)

Begin 12 hrs or greater after onset of AMSBegin 12 hrs or greater after onset of AMS

Sx usually globalSx usually global– Isolated focal sx – concern Isolated focal sx – concern

for CVA/TIAfor CVA/TIA

HACE - TreatmentHACE - Treatment

Immediate descent definitive txImmediate descent definitive tx

Supplemental O2 (highest flow or sats >90%)Supplemental O2 (highest flow or sats >90%)

Dexamethasone 8mg PO/IM Dexamethasone 8mg PO/IM then 4mg Q6hthen 4mg Q6h

If cannot descend, hyperbaric therapy (more If cannot descend, hyperbaric therapy (more later)later)

High Altitude Pulmonary Edema High Altitude Pulmonary Edema (HAPE)(HAPE)

Non-cardiogenic pulmonary edemaNon-cardiogenic pulmonary edema

Accounts for most high altitude deathsAccounts for most high altitude deaths

Occurs 1-3 days after arrival at altitudeOccurs 1-3 days after arrival at altitude– Rarely occurs after 4 days – consider Rarely occurs after 4 days – consider

alternative dxalternative dx

1-2% of high altitude climbers1-2% of high altitude climbers– 15% of those with rapid ascent15% of those with rapid ascent

HAPE PathophysiologyHAPE Pathophysiology

Hypoxia leads to pulmonary artery HTNHypoxia leads to pulmonary artery HTN– Increased pulmonary vascular resistanceIncreased pulmonary vascular resistance– However, occurs in everyone – not just HAPEHowever, occurs in everyone – not just HAPE

Pulmonary capillary pressure increasesPulmonary capillary pressure increases– Leads to overperfusion Leads to overperfusion Capillary leakage Capillary leakage– Fluid as well as proteins leak out Fluid as well as proteins leak out Exudative fluid Exudative fluid

With descent, pressure decreasesWith descent, pressure decreases– Capillaries “reseal”, leakage stops Capillaries “reseal”, leakage stops Recovery Recovery

Inflammatory mediators likely not primary process, Inflammatory mediators likely not primary process, but secondary to leaked proteinsbut secondary to leaked proteins

HAPE TreatmentHAPE Treatment

Descent!Descent!

Supplemental O2Supplemental O2Decreases pulmonary artery pressure Decreases pulmonary artery pressure up to 50%up to 50%

B-agonists:B-agonists:– Increase fluid clearance from alveolar spacesIncrease fluid clearance from alveolar spaces

No role for dexamethasoneNo role for dexamethasone

Limited role for acetazolamide (may dyspnea)Limited role for acetazolamide (may dyspnea)

HAPE Treatment - NifedipineHAPE Treatment - Nifedipine

ControversialControversial

Reduces pulmonary artery pressureReduces pulmonary artery pressure– Does NOT improve oxygenationDoes NOT improve oxygenation

Use only ifUse only if– Descent impossibleDescent impossible– Supplemental O2 unavailableSupplemental O2 unavailable

Downside: Lowers systemic BP alsoDownside: Lowers systemic BP also– CPP = MAP – ICPCPP = MAP – ICP– If risk for/concomitant HACE, lower MAP lowers CPPIf risk for/concomitant HACE, lower MAP lowers CPP

Hyperbaric therapyHyperbaric therapy

Greatest benefit in HACEGreatest benefit in HACE– Use highest PSI availableUse highest PSI available

HAPE – likely beneficialHAPE – likely beneficial– Cost – benefit vs. Supplemental O2 generally Cost – benefit vs. Supplemental O2 generally

precludesprecludes

AMS – little additional benefitAMS – little additional benefit

HAI - SummaryHAI - Summary

Medications:Medications:– Acetazolamide – best for acclimatizationAcetazolamide – best for acclimatization

Little benefit in acute tx (no use in HAPE)Little benefit in acute tx (no use in HAPE)– DexamethasoneDexamethasone

AMS and HACEAMS and HACENo role in HAPENo role in HAPE

– B-agonists useful in HAPEB-agonists useful in HAPE– Nifedipine – likely beneficial in HAPENifedipine – likely beneficial in HAPE

Use with extreme caution if concomitant concern for HACEUse with extreme caution if concomitant concern for HACE

Stop ascent – attempt acclimatizationStop ascent – attempt acclimatization– Supplemental O2 immediately if availableSupplemental O2 immediately if available– If no improvement or worsening, descendIf no improvement or worsening, descend

Recovery!Recovery!

With rest and oxygen, your significant other With rest and oxygen, your significant other has recovered at base camphas recovered at base camp

Now armed with more knowledgeNow armed with more knowledge– Begin ascent againBegin ascent again– You’re at camp 4000 ft from the summit again, You’re at camp 4000 ft from the summit again,

and a storm hits – you’re stuck!and a storm hits – you’re stuck!

That night, she says that she can’t feel her That night, she says that she can’t feel her fingers…fingers…

Frostbite!Frostbite!

FrostbiteFrostbite

Skin blood flow ↓ when skin temp < 14Skin blood flow ↓ when skin temp < 1400 C (57.2 C (57.200 F) F) ““Hunting Response” – alternating cycles of vasodilation and Hunting Response” – alternating cycles of vasodilation and vasoconstriction at < 10vasoconstriction at < 1000 C (50 C (5000 F) F)

Vasodilation brings cooled blood to coreVasodilation brings cooled blood to core

As core body temp drops, cycles end and blood flow completely As core body temp drops, cycles end and blood flow completely cut to extremities cut to extremities

Tissue freezes – ice crystals form when temp 0Tissue freezes – ice crystals form when temp 000 C C– Creates osmotic gradient pulling fluid from intracellular spacesCreates osmotic gradient pulling fluid from intracellular spaces– Intracellular NaCl rises, proteins denature, membranes failIntracellular NaCl rises, proteins denature, membranes fail

Reperfusion injuries – hours to daysReperfusion injuries – hours to days

Frostbite ClassificationFrostbite Classification

1100: Non-sensate white area/surrounding erythema: Non-sensate white area/surrounding erythema

2200: Vesicles with surrounding : Vesicles with surrounding erythemaerythema

3300: Hemorrhagic blisters with : Hemorrhagic blisters with eschar formationeschar formation

4400: Necrotic tissue, involves muscle/tendon/bone: Necrotic tissue, involves muscle/tendon/bone

Reclassification – Superficial (First/Second) and Deep Reclassification – Superficial (First/Second) and Deep (Third/Fourth)(Third/Fourth)– Classified according to treatment/outcome vice tissue Classified according to treatment/outcome vice tissue

involvedinvolved

Frostbite TreatmentFrostbite Treatment

Thawing stageThawing stage– Consider delay if:Consider delay if:

Adequate analgesia not availableAdequate analgesia not availableDelayed evacuation (i.e. ambulation required)Delayed evacuation (i.e. ambulation required)

– Remove wet/constrictive clothingRemove wet/constrictive clothing– Rapid rewarmingRapid rewarming

Use 40-42Use 40-4200 C water for 10-30 minutes with motion C water for 10-30 minutes with motionAvoid hot untested tap water - risk of thermal Avoid hot untested tap water - risk of thermal burns!burns!Avoid massaging and dry heatAvoid massaging and dry heat

– Parenteral analgesicsParenteral analgesics

Frostbite TreatmentFrostbite Treatment

Post-Thawing TreatmentPost-Thawing Treatment– Debride CLEAR blistersDebride CLEAR blisters– Apply aloe skin cream (Dermaide)Apply aloe skin cream (Dermaide)

Do NOT debride hemorrhagic blistersDo NOT debride hemorrhagic blisters

– Elevate affected partsElevate affected parts– Tetanus prophylaxisTetanus prophylaxis– Scheduled ibuprofen / prn narcoticsScheduled ibuprofen / prn narcotics– Pen G 600,000 units q6hPen G 600,000 units q6h– Daily Hydrotherapy at 40Daily Hydrotherapy at 4000 C for C for

30-45 mins30-45 mins

No Smoking!

Foiled!Foiled!

She recovers from her mild frostbiteShe recovers from her mild frostbite

Since your flight home isn’t for 10 Since your flight home isn’t for 10 days, you propose another summit days, you propose another summit attempt, and get this look…attempt, and get this look…

Plan BPlan B

On second thought, you propose camping in On second thought, you propose camping in beautiful Denali National Park beautiful Denali National Park to view the Northern Lights…to view the Northern Lights…

You fall asleep, under the lights,You fall asleep, under the lights,after sharing a couple bottlesafter sharing a couple bottlesof wine togetherof wine together

You wake up a few hours later and you notice You wake up a few hours later and you notice she is shivering violently and you have a hard she is shivering violently and you have a hard time waking her…time waking her…

Accidental HypothermiaAccidental Hypothermia

Definition: Core Temp < 35Definition: Core Temp < 3500 C C (95(9500 F) F)

Mild: 32Mild: 3200 C – 35 C – 3500 C (89.6 C (89.600 F – F – 959500 F) F)

Moderate: 28Moderate: 2800 C – 32 C – 3200 C (82.4 C (82.400 F - 89.6F - 89.600 F) F)

Severe: <28Severe: <2800 C (82.4 C (82.400 F) F)

Mild HypothermiaMild Hypothermia

323200 C – 35 C – 3500 C (89.6 C (89.600 F – 95 F – 9500 F) F)

Signs / Symptoms:Signs / Symptoms:– ShiveringShivering– Tachypnea / Tachycardia / HypertensionTachypnea / Tachycardia / Hypertension– Ataxia / DysarthriaAtaxia / Dysarthria– Loss of fine motor coordinationLoss of fine motor coordination– Confusion / lethargyConfusion / lethargy

Moderate HypothermiaModerate Hypothermia

282800 C – 32 C – 3200 C (82.4 C (82.400 F - 89.6 F - 89.600 F) F)

Signs / Symptoms:Signs / Symptoms:– Shivering StopsShivering Stops– BradycardiaBradycardia– Osborn (J) waves on EKG Osborn (J) waves on EKG – Altered Mental StatusAltered Mental Status– Slowed ReflexesSlowed Reflexes– Cold DiuresisCold Diuresis– Pupil DilationPupil Dilation

Severe HypothermiaSevere Hypothermia

<28<2800 C (82.4 C (82.400 F) F)

Signs / Symptoms:Signs / Symptoms:– Unresponsive / ComaUnresponsive / Coma– HypotensiveHypotensive– V Fib / AsystoleV Fib / Asystole– AcidemiaAcidemia– Loss of reflexesLoss of reflexes

Lab Tests (if able)Lab Tests (if able)

BMP – pay attention to electrolytes (esp K+)BMP – pay attention to electrolytes (esp K+)

CBC – Hct increases 2% for each 1CBC – Hct increases 2% for each 100 C drop C drop– Trauma – normal Hct may mean blood lossTrauma – normal Hct may mean blood loss

ABG – interpret as is (blood rewarmed in lab)ABG – interpret as is (blood rewarmed in lab)

Coags: May be normal - blood is rewarmedCoags: May be normal - blood is rewarmed– Do not necessarily reflect physiology in patientDo not necessarily reflect physiology in patient

Other labs as indicated if another underlying Other labs as indicated if another underlying cause o hypothermia suspectedcause o hypothermia suspected– EtOH/UDSEtOH/UDS– Cardiac Enzymes, etcCardiac Enzymes, etc

Hypothermia TreatmentHypothermia Treatment

Large Bore IV(s) – Bolus with warm fluidsLarge Bore IV(s) – Bolus with warm fluidsIntubate if indicatedIntubate if indicated

Immediate Actions – ACLS!Immediate Actions – ACLS!– Check Vital Signs and ECGCheck Vital Signs and ECG

Check 30-60 seconds for pulse – difficult to detectCheck 30-60 seconds for pulse – difficult to detectRectal thermometer – must be low temp capableRectal thermometer – must be low temp capable

– Standard thermometers only to 34.4Standard thermometers only to 34.400 C (94 C (9400 F) F)

– If no pulse, begin CPRIf no pulse, begin CPRControversial in severe hypothermia, however Controversial in severe hypothermia, however likely beneficiallikely beneficial

Hypothermia TreatmentHypothermia Treatment

Most dysrhythmias convert on rewarmingMost dysrhythmias convert on rewarming– A. Fib/FlutterA. Fib/Flutter– Sinus bradycardiaSinus bradycardia– Transient ventricular dysrhythmiasTransient ventricular dysrhythmias

V. Fib / V. Tach – defibrillate at 1-2J/kgV. Fib / V. Tach – defibrillate at 1-2J/kg– One shock onlyOne shock only– May be ineffective at temps < 30May be ineffective at temps < 3000 C C– If fails, reattempt after each degree riseIf fails, reattempt after each degree rise

Hypothermia TreatmentHypothermia Treatment

Intravenous drugsIntravenous drugs– May be ineffective below 30May be ineffective below 3000 C C– Give at longer intervals above 30Give at longer intervals above 3000 C C

Amiodarone drug of choice for V. FibAmiodarone drug of choice for V. Fib

Avoid procainamide – may worsenAvoid procainamide – may worsen

If EtOH – Replete glucose and thiamineIf EtOH – Replete glucose and thiamine– Hypoglycemia and Wernicke’s may help Hypoglycemia and Wernicke’s may help

precipitate hypothermiaprecipitate hypothermia

RewarmingRewarming

Cornerstone of treatment – REWARM!Cornerstone of treatment – REWARM!

Rapid rewarming to 30 degreesRapid rewarming to 30 degrees– Minimize risk of dysrhythmiasMinimize risk of dysrhythmias– Once above 30 deg, can slow rewarming rateOnce above 30 deg, can slow rewarming rate

Cardiovascular status is most importantCardiovascular status is most important

Passive RewarmingPassive Rewarming

Ideal method: Slow, physiologicIdeal method: Slow, physiologic

Must have intact thermoregulationMust have intact thermoregulation– Shivering intactShivering intact– Caution in underlying diseasesCaution in underlying diseases

Likely only effective in mild hypothermiaLikely only effective in mild hypothermia

Methods:Methods:– Remove from environmentRemove from environment– Remove wet clothesRemove wet clothes– BlanketsBlankets

Active External RewarmingActive External Rewarming

Use for moderate hypothermiaUse for moderate hypothermia– Monitor closely!Monitor closely!

Rapid peripheral vasodilationRapid peripheral vasodilation

May return cooled blood to coreMay return cooled blood to core

Likely not clinically significantLikely not clinically significant– Consider rewarming trunk aloneConsider rewarming trunk alone

– Warm water immersion – ensure monitoringWarm water immersion – ensure monitoring– Heating blanketsHeating blankets– Forced air (BAIR Hugger)Forced air (BAIR Hugger)– Radiant heatRadiant heat

Active Core RewarmingActive Core Rewarming

ALL PatientsALL Patients– Warmed IV FluidsWarmed IV Fluids– Warmed humidified OxygenWarmed humidified Oxygen

Small heat gain – mostly prevents further heat lossSmall heat gain – mostly prevents further heat loss

Active Core RewarmingActive Core Rewarming

Severe hypothermia/cardiac instabilitySevere hypothermia/cardiac instability– Lavage with warm fluidsLavage with warm fluids

- - Nasogastric/rectal - Pleural (via thoracostomy)Nasogastric/rectal - Pleural (via thoracostomy)

Bladder (via Foley) - Peritoneal (via DPL catheter)Bladder (via Foley) - Peritoneal (via DPL catheter)

– Mediastinal Lavage via open thoracotomyMediastinal Lavage via open thoracotomy

– If availableIf availableCardiopulmonary BypassCardiopulmonary BypassHemodialysisHemodialysisSet up difficult, but most effective!Set up difficult, but most effective!

That’s it!That’s it!

Although she recovers uneventfully, she’s Although she recovers uneventfully, she’s had it with this cold weather vacation!had it with this cold weather vacation!

You’re on the next flight for HawaiiYou’re on the next flight for Hawaii

That afternoon, after landing, she decides to That afternoon, after landing, she decides to unwind by going for a rununwind by going for a run– 2 hours later she hasn’t returned, you drive out to 2 hours later she hasn’t returned, you drive out to

find her and she’s sitting on the side of road…find her and she’s sitting on the side of road…

Heat EmergenciesHeat Emergencies

Predominant forms of heat lossPredominant forms of heat loss– Radiation (65%): loss via electromagnetic wavesRadiation (65%): loss via electromagnetic waves

Only occurs if temperature differential (stops at 95Only occurs if temperature differential (stops at 9500 F) F)– Evaporation (30%): transfer of heat via sweat and Evaporation (30%): transfer of heat via sweat and

saliva evaporationsaliva evaporationMinimal if humidity > 80%Minimal if humidity > 80%

Causes:Causes:– Increased internal heat Increased internal heat

productionproduction– Increased external heat Increased external heat

exposureexposure– Impaired heat dispersionImpaired heat dispersion

Increased Internal HeatIncreased Internal Heat

Physical ActivityPhysical Activity– ExerciseExercise– SeizuresSeizures– Combative behaviorCombative behavior

Pharmacological agentsPharmacological agents– Amphetamines, cocaine, LSD, PCPAmphetamines, cocaine, LSD, PCP

Endogenous FeverEndogenous Fever– NOT the same as environmental hyperthermiaNOT the same as environmental hyperthermia– Should not be exogenously cooledShould not be exogenously cooled

Increased External HeatIncreased External Heat

High Ambient TempsHigh Ambient Temps– Minimizes radiation Minimizes radiation

heat lossheat loss

High HumidityHigh Humidity– Minimizes evaporative heat lossMinimizes evaporative heat loss

Direct exposure to sunlightDirect exposure to sunlight

Impaired Heat DispersionImpaired Heat Dispersion

CV diseaseCV disease– Impaired circulationImpaired circulation– Impaired compensationImpaired compensation

ObesityObesity– Adipose - decreased Adipose - decreased

vascularityvascularity– Insulates the bodyInsulates the body

Skin alterationsSkin alterations

ClothingClothing

MedicationsMedications– AnticholinergicsAnticholinergics– Cardiovascular drugsCardiovascular drugs– DiureticsDiuretics– SympathomimeticsSympathomimetics– PhenothiazinesPhenothiazines– Alcohol/DrugsAlcohol/Drugs

Extremes of AgeExtremes of Age

DehydrationDehydration

AcclimatizationAcclimatization

Increases ability to provide peripheral blood flow, protect Increases ability to provide peripheral blood flow, protect kidneys, and increase sweatingkidneys, and increase sweating

Improved physical condition = improved cardiac response to Improved physical condition = improved cardiac response to vasodilationvasodilation

Increased efficiency at shunting blood from non-critical areasIncreased efficiency at shunting blood from non-critical areas

Increased activation of renin-angiotensin-aldosterone systemIncreased activation of renin-angiotensin-aldosterone system– Enables increased sodium retentionEnables increased sodium retention

Expansion of plasma volumeExpansion of plasma volume

Sweat glands increase sweat productionSweat glands increase sweat production

Heat EmergenciesHeat Emergencies

Minor heat illnessesMinor heat illnesses– Head EdemaHead Edema– Heat RashHeat Rash– Heat SyncopeHeat Syncope– Heat CrampsHeat Cramps

Heat ExhaustionHeat Exhaustion

Heat StrokeHeat Stroke

Heat EdemaHeat Edema

Cutaneous vasodilation and orthostatic Cutaneous vasodilation and orthostatic poolingpooling

Resolves spontaneouslyResolves spontaneously

If treatment institutedIf treatment institutedRemoval from heatRemoval from heatElevation of legs with support hoseElevation of legs with support hoseDo not use diureticsDo not use diuretics

– Dehydration more riskyDehydration more risky– May cause electrolyte disturbancesMay cause electrolyte disturbances

Heat RashHeat Rash

Pruritic maculopapular rashPruritic maculopapular rash

Stratum corneum blocks Stratum corneum blocks sweat ductssweat ducts– Ducts ruptureDucts rupture– Localized inflammationLocalized inflammation– PruriticPruritic

AvoidanceAvoidance– Light, loose fitting clothesLight, loose fitting clothes– Minimize sweatingMinimize sweating

Treatment: Antihistamines and avoidanceTreatment: Antihistamines and avoidance

Heat SyncopeHeat Syncope

Secondary toSecondary to– Peripheral vasodilationPeripheral vasodilation– Decreased vasomotor toneDecreased vasomotor tone– Volume DepletionVolume Depletion

TreatmentTreatment– Remove from heat sourceRemove from heat source– Oral or IV fluidsOral or IV fluids– RestRest

Heat CrampsHeat Cramps

Usually secondary to electrolyte disturbances Usually secondary to electrolyte disturbances from sweatingfrom sweating– Dehydration or water-only Dehydration or water-only

rehydrationrehydration– HyponatremiaHyponatremia– HyperkalemiaHyperkalemia

TreatmentTreatment– Remove from heatRemove from heat– Oral hydration with electrolyte containing fluidsOral hydration with electrolyte containing fluids– IV fluidsIV fluids

Heat ExhaustionHeat Exhaustion

Signs and Symptoms: Non-specific!Signs and Symptoms: Non-specific!– Temp usually elevated but < 41Temp usually elevated but < 4100 C C– Fatigue/weakness/dizziness /syncopeFatigue/weakness/dizziness /syncope– Nausea/vomitingNausea/vomiting– HeadachesHeadaches– Myalgias and muscle crampsMyalgias and muscle cramps– TachycardiaTachycardia– PiloerectionPiloerection– Profuse sweating usually presentProfuse sweating usually present

Heat Exhaustion - TreatmentHeat Exhaustion - Treatment

Remove from heat and minimize activityRemove from heat and minimize activity

Cool with fans/ice packs to neck, groin, axillaeCool with fans/ice packs to neck, groin, axillae

Oral rehydration w/electrolyte containing fluidsOral rehydration w/electrolyte containing fluids

IV Fluids if not alert or IV Fluids if not alert or nausea/vomitingnausea/vomiting– Replace fluids over several Replace fluids over several

hourshours

Monitor vital signsMonitor vital signs– Urine outputUrine output– OrthostaticsOrthostatics

Heat StrokeHeat Stroke

Signs and SymptomsSigns and Symptoms– Elevated Temp – usually > 41Elevated Temp – usually > 4100 C (106 C (10600 F) F)

– Hyperdynamic cardiac parametersHyperdynamic cardiac parametersTachycardia/TachypneaTachycardia/TachypneaIncreased systolic / increased pulse pressureIncreased systolic / increased pulse pressure

– CNS DysfunctionCNS Dysfunction- Seizure - Seizure - Delirium- Delirium - Cerebellar dysfunction- Cerebellar dysfunction- Coma- Coma - Hallucinations- Hallucinations - Pupil - Pupil

dysfunctiondysfunction

– OliguriaOliguria

– Anhydrosis – often present but not required!Anhydrosis – often present but not required!

Heat Stroke - TreatmentHeat Stroke - Treatment

Initial resuscitationInitial resuscitation– ABC’s, IV access, cardiac/pulse ox monitoringABC’s, IV access, cardiac/pulse ox monitoring

Rectal thermometer for continuous monitoringRectal thermometer for continuous monitoringIntubation if indicatedIntubation if indicated

– Begin IV fluid boluses (Normal saline or LR)Begin IV fluid boluses (Normal saline or LR)

Place foley and NG TubePlace foley and NG Tube

Rapid Cooling is keyRapid Cooling is key

Cooling TechniquesCooling TechniquesGoal is 38-39Goal is 38-3900 C to avoid overshoot C to avoid overshoot

Evaporative cooling preferredEvaporative cooling preferred– Remove clothing, spray with lukewarm waterRemove clothing, spray with lukewarm water– Use large fans to blow air across skinUse large fans to blow air across skin

Immersion – rapid cooling in ice waterImmersion – rapid cooling in ice water– Difficult to monitor patientDifficult to monitor patient– May cause shiveringMay cause shivering– Very uncomfortable if awakeVery uncomfortable if awake

Internal cooling (lavages – i.e. bladder, gastric)Internal cooling (lavages – i.e. bladder, gastric)– Effective, but probably unnecessaryEffective, but probably unnecessary– CP bypass – likely not worth risksCP bypass – likely not worth risks

Adjunct TherapiesAdjunct Therapies

Antipyretics – NO ROLE!Antipyretics – NO ROLE!– May interfere with endogenous thermoregulationMay interfere with endogenous thermoregulation

BenzodiazepinesBenzodiazepines– Help reduce agitation / shivering / seizuresHelp reduce agitation / shivering / seizures– EtOH / Drug withdrawalEtOH / Drug withdrawal

Avoid large volumes of IV fluidAvoid large volumes of IV fluid– May lead to pulmonary edema (even healthy pts)May lead to pulmonary edema (even healthy pts)– Except in rhabdomyolysisExcept in rhabdomyolysis

Renal failureRenal failure– Hemodialysis if unresponsive to fluids / acid-base Hemodialysis if unresponsive to fluids / acid-base

correctioncorrection

Fortunately…Fortunately…

She just has a mild case of heat exhaustion. You get her water and She just has a mild case of heat exhaustion. You get her water and into your air conditioned vehicle into your air conditioned vehicle

Back at the hotel, after she’s rested for a couple hours, she decides Back at the hotel, after she’s rested for a couple hours, she decides to go for a swim in the oceanto go for a swim in the ocean

You tell her you’ll meet her out there You tell her you’ll meet her out there in a minutein a minute

You lose track of time watching a great ERYou lose track of time watching a great ERrerun, and 30 minutes later you arrive to rerun, and 30 minutes later you arrive to find several lifeguards carrying her infind several lifeguards carrying her in

Apparently a rip tide pulled her under, Apparently a rip tide pulled her under, and it took the lifeguards several minutes and it took the lifeguards several minutes to pull her out…to pull her out…

Submersion InjuriesSubmersion Injuries

Drowning – Death within 24 hours of submersionDrowning – Death within 24 hours of submersion

Near Drowning – survival after submersion injuryNear Drowning – survival after submersion injury

Third leading cause of Third leading cause of accidental deathaccidental death– Freshwater > SaltwaterFreshwater > Saltwater– EtOH/Drugs commonly EtOH/Drugs commonly

involvedinvolved– Most victims children/Most victims children/

adolescentsadolescents

Submersion InjuriesSubmersion Injuries

Sequence:Sequence:– SubmersionSubmersion– Breath holdingBreath holding– PanicPanic– Swallowing water / emesisSwallowing water / emesis– Breathing waterBreathing water

““Dry drowning” – laryngospasm/glottic closureDry drowning” – laryngospasm/glottic closure

Final common pathway - hypoxemiaFinal common pathway - hypoxemia

Pulmonary InjuriesPulmonary Injuries

Fresh WaterFresh Water– Inactivates surfactantInactivates surfactant– Atalectasis and loss of pulmonary complianceAtalectasis and loss of pulmonary compliance

Salt WaterSalt Water– Osmotic gradient pulls fluid into alveoliOsmotic gradient pulls fluid into alveoli– Intrapulmonary shunting / VQ mismatchIntrapulmonary shunting / VQ mismatch

If survive initial aspiration – ARDS or If survive initial aspiration – ARDS or pneumoniapneumonia

Signs/SymptomsSigns/Symptoms

4 categories4 categories– AsymptomaticAsymptomatic– SymptomaticSymptomatic

Altered mental status / anxietyAltered mental status / anxietyHypothermia/Tachycardia/BradycardiaHypothermia/Tachycardia/BradycardiaAny dyspnea, no matter how slightAny dyspnea, no matter how slight

– Cardiopulmonary ArrestCardiopulmonary Arrest– Obviously DeadObviously Dead

NormothermicNormothermicAsystoleAsystoleNo neurologic responseNo neurologic response

Submersion – Labs/StudiesSubmersion – Labs/Studies

ABG essentialABG essential

CBC, BMP, Lactate, CoagsCBC, BMP, Lactate, Coags– Follow creatinine – renal failure delayedFollow creatinine – renal failure delayed

EtOH / UDSEtOH / UDS

Chest X-rayChest X-ray

CT Spine / Head CT if at risk for injuryCT Spine / Head CT if at risk for injury– C-Collar until cleared by mechanism or studiesC-Collar until cleared by mechanism or studies

Submersion TreatmentSubmersion Treatment

Pre-hospitalPre-hospital– Unless certain, assume spinal injuryUnless certain, assume spinal injury

C-Collar and backboardC-Collar and backboard

Maintain precautions when movingMaintain precautions when moving

– Rescue breathing and supplemental O2Rescue breathing and supplemental O2– CPR – start on almost all patientsCPR – start on almost all patients

In water chest compressions generally worthlessIn water chest compressions generally worthless

– Begin rewarmingBegin rewarming

Submersion Treatment -EDSubmersion Treatment -ED

Unless obviously dead, assume survivabilityUnless obviously dead, assume survivability– Especially childrenEspecially children

Intubate if unable to oxygenate/ventilateIntubate if unable to oxygenate/ventilate– PEEP - Improves ventilation and volumePEEP - Improves ventilation and volume

Shifts fluid into capillariesShifts fluid into capillaries

– Consider BIPAP if awakeConsider BIPAP if awake– If intubated, perform bronchoscopyIf intubated, perform bronchoscopy

ACLS algorithms if indicatedACLS algorithms if indicated

Rewarm patient (as per hypothermia protocols)Rewarm patient (as per hypothermia protocols)

ComplicationsComplications

ARDSARDS– Supportive careSupportive care

PneumoniaPneumonia– Direct water aspirationDirect water aspiration– Aspiration of gastric contentsAspiration of gastric contents– Contaminants / organisms in waterContaminants / organisms in water

Bacteria and fungi common, esp warmer watersBacteria and fungi common, esp warmer waters

Disposition/TreatmentDisposition/Treatment– Most need admission, ICU if warrantedMost need admission, ICU if warranted– Prophylactic antibx / antifungals not necessary, unless sxProphylactic antibx / antifungals not necessary, unless sx

Extended spectrum PCN / B-lactamase Extended spectrum PCN / B-lactamase ++ aminoglycoside aminoglycoside– If asymptomatic and no injuries, observe and dischargeIf asymptomatic and no injuries, observe and discharge

Turns out she’s OKTurns out she’s OK

You decide that you’ll go back in the water, together, but this You decide that you’ll go back in the water, together, but this time with scuba tanks to check out a nearby reeftime with scuba tanks to check out a nearby reef

After enjoying a beautiful dive, you begin your ascent to the After enjoying a beautiful dive, you begin your ascent to the surfacesurface

Suddenly, a large jellyfish stings her, Suddenly, a large jellyfish stings her, she panics and races for the surfaceshe panics and races for the surface

You remember your dive tables, and You remember your dive tables, and ascend as rapidly as you can, safelyascend as rapidly as you can, safely

At the surface, she seems to be doing OK but is complaining At the surface, she seems to be doing OK but is complaining of severe leg pain (where she was stung) as well as itchy skin of severe leg pain (where she was stung) as well as itchy skin and right shoulder pain….and right shoulder pain….

Diving Injuries / DysbarismDiving Injuries / Dysbarism

Sea level – ambient air pressure = 1 atmSea level – ambient air pressure = 1 atm– Ascending - ambient pressure halves at 18000 ftAscending - ambient pressure halves at 18000 ft– Diving – ambient pressure Diving – ambient pressure increases by 1 atm every increases by 1 atm every 33 feet!33 feet!

Boyle’s Law – pressure/volume inversely proportionalBoyle’s Law – pressure/volume inversely proportional– As pressure increases, volume decreases (diving)As pressure increases, volume decreases (diving)– Vice versa (ascending)Vice versa (ascending)

Henry’s Law – gas enters liquid in proportion to partial Henry’s Law – gas enters liquid in proportion to partial pressure pressure – As descend, partial pressure increases – gases more As descend, partial pressure increases – gases more

solublesoluble– During ascent, gases come out of solutionDuring ascent, gases come out of solution– Oxygen metabolized, nitrogen does notOxygen metabolized, nitrogen does not

Coalesces into bubbles if ascent too quickCoalesces into bubbles if ascent too quick

Types of InjuriesTypes of Injuries

Barotrauma of descentBarotrauma of descent

Barotrauma of ascentBarotrauma of ascent– Direct barotraumaDirect barotrauma– Arterial gas emboli (AGE) / Dysbaric air embolism Arterial gas emboli (AGE) / Dysbaric air embolism

(DAE)(DAE)

Indirect effects of ascentIndirect effects of ascent– Nitrogen NarcosisNitrogen Narcosis– Decompression SicknessDecompression Sickness

Descent Barotrauma (“Squeeze”)Descent Barotrauma (“Squeeze”)

Ear SqueezeEar Squeeze– External (Barotitis Externa)External (Barotitis Externa)

Air trapped in ext canal compressesAir trapped in ext canal compresses– TM bulges outTM bulges out– Trauma to TM and surrounding external canalTrauma to TM and surrounding external canal

– Middle (Barotitis Media) – most common!Middle (Barotitis Media) – most common!Cannot equalize air in middle ear Cannot equalize air in middle ear TM bulges inward – may ruptureTM bulges inward – may ruptureMay cause trauma to ossicles/May cause trauma to ossicles/round windowround window

– Inner (Barotitis interna)Inner (Barotitis interna)Trauma to round windowTrauma to round window

– Air enters inner earAir enters inner ear

Classic triad – tinnitus, hearing loss, vertigoClassic triad – tinnitus, hearing loss, vertigo– Also nausea/vomiting, ataxia, nystagmusAlso nausea/vomiting, ataxia, nystagmus

Descent Barotrauma (“Squeeze”)Descent Barotrauma (“Squeeze”)Sinus SqueezeSinus Squeeze– Air trapped in sinusesAir trapped in sinuses– Causes pain / hemorrhage into sinuses Causes pain / hemorrhage into sinuses epistaxis epistaxis

Treatment of ear and sinus squeezeTreatment of ear and sinus squeeze– Decongestants (oral and nasal spray)Decongestants (oral and nasal spray)– Antibiotics if TM ruptureAntibiotics if TM rupture– AnalgesiaAnalgesia– Avoidance of divingAvoidance of diving

Mask SqueezeMask Squeeze– Must equalize pressure behind mask during descentMust equalize pressure behind mask during descent– Can cause localized petechiae /conjunctival Can cause localized petechiae /conjunctival

hemorrhagehemorrhage

Ascent BarotraumaAscent Barotrauma

Reverse process of squeezeReverse process of squeeze

Occurs from gas expansionOccurs from gas expansion

Normally gas escapes into atmosphereNormally gas escapes into atmosphere

If escape blocked, barotraumaIf escape blocked, barotrauma

Ascent Barotrauma (cont)Ascent Barotrauma (cont)

Ears and sinuses – usually not affectedEars and sinuses – usually not affected– If air got in on descent, can get outIf air got in on descent, can get out

Barodontalgia (“Tooth Squeeze”)Barodontalgia (“Tooth Squeeze”)– Descent - compressed air gets in Descent - compressed air gets in

fillings/decayfillings/decay– Ascent – expandsAscent – expands

Cannot escape Cannot escape Pain Pain

GI Barotrauma (Aerogastralgia) - air trapped in GI tractGI Barotrauma (Aerogastralgia) - air trapped in GI tract– Swallowing air (improper valsalva)Swallowing air (improper valsalva)– Drinking carbonated beverages or heavy meal priorDrinking carbonated beverages or heavy meal prior– Generally self-limiting pain/discomfort – rupture rareGenerally self-limiting pain/discomfort – rupture rare

If pneumoperitoneum, also consider GU source (esp females)If pneumoperitoneum, also consider GU source (esp females)

Pulmonary BarotraumaPulmonary Barotrauma

Most severe barotrauma of ascentMost severe barotrauma of ascent

Air normally breathed outAir normally breathed out– equalizes pressureequalizes pressure

If air not breathed out, expandsIf air not breathed out, expands– Ruptures into surrounding tissueRuptures into surrounding tissue

Pneumomediastinum and Pneumomediastinum and SubQ emphysema commonSubQ emphysema common– Usually self-limitingUsually self-limiting

Pneumothorax and Arterial Gas EmbolismPneumothorax and Arterial Gas Embolism– Require interventionRequire intervention

Pneumothorax – needle decompression / thoracostomyPneumothorax – needle decompression / thoracostomy

Arterial Gas EmbolismArterial Gas Embolism

Rupture of alveolar air into pulmonary veinsRupture of alveolar air into pulmonary veins

Air embolism Air embolism left heart left heart systemic circulation systemic circulation

Symptoms of thromboembolic diseaseSymptoms of thromboembolic disease– CVA type symptoms or myocardial infarctionCVA type symptoms or myocardial infarction– Any sudden, severe symptoms of thromboembolism Any sudden, severe symptoms of thromboembolism

on ascent should be treated as AGEon ascent should be treated as AGEImmediate recompression/hyperbaric treatmentImmediate recompression/hyperbaric treatmentResuscitate per ACLSResuscitate per ACLSPosition right lateral decubitis or supinePosition right lateral decubitis or supine

– Do not place head down – cerebral edemaDo not place head down – cerebral edema

Nitrogen NarcosisNitrogen Narcosis

Nitrogen – increased solubility at increased partial Nitrogen – increased solubility at increased partial pressures (remember Henry?)pressures (remember Henry?)

Intoxication effect at high partial pressureIntoxication effect at high partial pressure– Most feel effect by 90-100 feetMost feel effect by 90-100 feet– Impaired >200 ft, unconscious >300ftImpaired >200 ft, unconscious >300ft

Effects reverse with ascentEffects reverse with ascent

Can precipitate other errorsCan precipitate other errors

Impairs recollection of dive / ascent – impairs historyImpairs recollection of dive / ascent – impairs history

Decompression Sickness Decompression Sickness (DCS)(DCS)

Dissolved nitrogen forms bubbles if ascent too Dissolved nitrogen forms bubbles if ascent too rapidrapid

Direct effect of bubblesDirect effect of bubbles

Indirect effect of inflammatory response to bubblesIndirect effect of inflammatory response to bubbles– Causes activation of clotting/inflammatory cascadesCauses activation of clotting/inflammatory cascades

Net effect Net effect – Decreased tissue perfusionDecreased tissue perfusion– Ischemic injuryIschemic injury

Type 1 DCSType 1 DCS““Niggles” – mild pains, begin to resolve ~ 10 mins Niggles” – mild pains, begin to resolve ~ 10 mins

Pruritis (“Skin Bends”)Pruritis (“Skin Bends”)

Skin rashSkin rash

Lymphatic involvement Lymphatic involvement – Peripheral edemaPeripheral edema

Pain (“The bends”)Pain (“The bends”)– Aching painAching pain– Usually in joint, tendon, occasionally muscleUsually in joint, tendon, occasionally muscle– Shoulder most commonly affectedShoulder most commonly affected

Type 2 DCSType 2 DCS

Pain uncommon (30%)Pain uncommon (30%)

Neurologic systemNeurologic system– Nitrogen very soluble in fat – myelin sheathNitrogen very soluble in fat – myelin sheath– Spinal cord most commonly affected (esp lower)Spinal cord most commonly affected (esp lower)– Bladder dysfunctionBladder dysfunction

Pulmonary DCS (The “Chokes”)Pulmonary DCS (The “Chokes”)– Venous nitrogen emboliVenous nitrogen emboli– Chest pain, cough, dyspnea, pulmonary edemaChest pain, cough, dyspnea, pulmonary edema– Can progress to hemoptysisCan progress to hemoptysis

Physical ExamPhysical Exam

In addition to vital organs, pay close attention toIn addition to vital organs, pay close attention to– Sclera / retinaSclera / retina– Tympanic membranesTympanic membranes– Thorough neurologic examThorough neurologic exam– Urinary retentionUrinary retention

Differentiating AGE from DCSDifferentiating AGE from DCS– Length of dive (must be longer dive to develop Length of dive (must be longer dive to develop

DCS)DCS)– Time of onset (AGE rapid / DCS delayed)Time of onset (AGE rapid / DCS delayed)– AGE – only CNS effects are on the brainAGE – only CNS effects are on the brain

DCS TreatmentDCS Treatment

PrehospitalPrehospital– Extricate from water / immobilize if traumaExtricate from water / immobilize if trauma– Supplemental O2Supplemental O2

May result in resolution of mild DCSMay result in resolution of mild DCS

– ASA for anti-platelet activityASA for anti-platelet activity– Consider in-water recompression only if in Consider in-water recompression only if in

remote locationremote location– CPR if indicatedCPR if indicated– Needle decompression of tension ptxNeedle decompression of tension ptx– Avoid trendelenburgAvoid trendelenburg

DCS TreatmentDCS Treatment

ED careED care– All of the prehospital measures applyAll of the prehospital measures apply– 100% O2 – intubate if warranted100% O2 – intubate if warranted– Aggressive fluid resuscitationAggressive fluid resuscitation

Goal UOP is 1-2ml/kg/hrGoal UOP is 1-2ml/kg/hr

– Treat nausea and headachesTreat nausea and headaches– Arrange transfer to HBO facilityArrange transfer to HBO facility

Consider even if improvement in symptomsConsider even if improvement in symptoms

Relapses / worsening occurRelapses / worsening occur

Ensure air transport can maintain pressurization!Ensure air transport can maintain pressurization!

She recovers (again)She recovers (again)

Supplemental oxygen and about 30 minutes of Supplemental oxygen and about 30 minutes of rest, and she’s feeling betterrest, and she’s feeling better

But what about that jellyfish sting?But what about that jellyfish sting?

Marine EnvenomationsMarine Envenomations

~1200 species of venomous or poisonous ~1200 species of venomous or poisonous marine animals worldwidemarine animals worldwide

Few cause major medical issuesFew cause major medical issues

Broad array of speciesBroad array of species– Various neurotoxic and proteolytic venomsVarious neurotoxic and proteolytic venoms– Used for paralyzing / killing preyUsed for paralyzing / killing prey

Humans are often accidental victims or Humans are often accidental victims or hostshosts

Marine EnvenomationsMarine Envenomations

InvertebratesInvertebrates

CoelenteratesCoelenterates– Anemones and JellyfishAnemones and Jellyfish

MollusksMollusks– Octopus/SquidOctopus/Squid– Cone SnailsCone Snails

EchinodermsEchinoderms– Sea UrchinsSea Urchins

PoriferaePoriferae– Fire SpongeFire Sponge

VertebratesVertebrates

StingraysStingrays

Scorpion fishScorpion fish

CatfishCatfish

Sea snakes Sea snakes (Hydrophidae(Hydrophidae))

Jellyfish / Man O’ WarJellyfish / Man O’ War

Fire CoralFire Coral

Sea UrchinsSea Urchins

Blue Ringed OctopusBlue Ringed Octopus

Scorpion FishScorpion Fish StingraysStingrays

Marine Envenomation -Marine Envenomation -TreatmentTreatment

Cornerstones – ABC’s First!Cornerstones – ABC’s First!– Detoxify venom – rinse with normal salineDetoxify venom – rinse with normal saline

Freshwater may activate venomFreshwater may activate venom– Pain and symptom relief – narcotics, antihistaminesPain and symptom relief – narcotics, antihistamines– Local wound careLocal wound care– FB removalFB removal

Deactivation and removal of attached nematocystsDeactivation and removal of attached nematocysts– 5% acetic acid / isopropanol (further deactivate)5% acetic acid / isopropanol (further deactivate)– Apply baking soda slurry or shaving creamApply baking soda slurry or shaving cream

Allow nematocysts to coalesce and scrape offAllow nematocysts to coalesce and scrape off– May remove with adhesive tapeMay remove with adhesive tape

Marine wounds prone to infectionMarine wounds prone to infection– Aeromonas, Vibrio, Pseudomonas, ErysipelothrixAeromonas, Vibrio, Pseudomonas, Erysipelothrix spp spp– Prophylactic antibiotics for serious woundsProphylactic antibiotics for serious wounds

She’s had it with the ocean!She’s had it with the ocean!

You make one last attempt to salvage your You make one last attempt to salvage your vacation, and let her pick the spotvacation, and let her pick the spot

She wants as far She wants as far away from the away from the ocean as possibleocean as possible

Off to the Grand Off to the Grand Canyon!Canyon!

First night of campingFirst night of camping

Your significant screams, and you wake up to Your significant screams, and you wake up to see this guy in tent!see this guy in tent!

Land EnvenomationsLand Envenomations

Meanwhile, her hand begins to swell

rapidly and goes numb as the wound site oozes blood, and she starts to get nauseated and dizzy…

Snake EnvenomationsSnake Envenomations

Poisonous or Not?Poisonous or Not?

Exception: Coral Snakes (Elapidae)

EpidemiologyEpidemiology

14 Families of snakes 14 Families of snakes

3 main poisonous snake families3 main poisonous snake families– ViperidaeViperidae

Vipers and Pit VipersVipers and Pit VipersRattlesnakesRattlesnakes

– ElapidaeElapidaeCobras and MambasCobras and MambasCoral SnakesCoral SnakesHydrophidae – Sea snakesHydrophidae – Sea snakes

– Colubridae – Asps and Mole VipersColubridae – Asps and Mole Vipers

~4000 snake bites annually reported in USA~4000 snake bites annually reported in USA

<20 deaths / year<20 deaths / year

Poisonous snakesPoisonous snakes

Rattle Snakes Coral Snakes Copperhead Snakes

Components of Poisonous VenomComponents of Poisonous Venom

• Fibrinogenases, phospolipases

• Platelet aggregation inhibitors

• Enzymes with hemorrhagic activity

• Numerous other uncharacterized proteinases

• Neurotoxins (for coral snake venom)

Crotalid EnvenomationsCrotalid Envenomations

None (dry bites) - ~15-20%None (dry bites) - ~15-20%

Mild - local swelling and painMild - local swelling and pain– No systemic featuresNo systemic features

Moderate – progression of swellingModerate – progression of swelling– Local tissue destructionLocal tissue destruction– Hematologic abnormalitiesHematologic abnormalities– Systemic sxSystemic sx

Severe – marked swellingSevere – marked swelling– Bullae and tissue necrosisBullae and tissue necrosis– ShockShock– CoagulopathyCoagulopathy

Crotalid Envenomations – Crotalid Envenomations – Initial ManagementInitial Management

Immobilize injured part at or below heart levelImmobilize injured part at or below heart level

Provide local wound careProvide local wound care– CleansingCleansing– DebridementDebridement– Prophylactic ABXProphylactic ABX– TetanusTetanus

Lab eval Lab eval – CBC, CMP, CPKCBC, CMP, CPK– Coags and DIC panelCoags and DIC panel

Observe for 24h or admit, for sx of progressionObserve for 24h or admit, for sx of progression

Consider antivenin early, for mod / severe Consider antivenin early, for mod / severe envenomationsenvenomations

Role of AntiveninsRole of Antivenins

Neutralizes circulating venom toxins when given early (<6H)– Can mitigate local tissue destruction– Slows/prevents coagulopathy and systemic sx

Active against:– US rattlesnakes– Copperheads, and cottonmouths – Some sea snakes– Separate antivenin for coral snakes

No dose adjustment for children– Dose is based on venom load, not subject weight!

Call local poison control center

Crotalid AntiveninCrotalid Antivenin

Indications for Antivenin

Rapid progression of sxs

Significant coagulopathy

Profound thrombocytopenia

Hemodynamic compromise

Neuromuscular toxicity

• Contraindications for Antivenin

• Hypersensitivity to horse or sheep serum

• Hypersensitivity to papain or papaya

• Poorly controlled atopy• Concurrent beta blocker use

• May worsen anaphylaxis

Complications of EnvenomationsComplications of Envenomations

Immediate (<24H)

– Local tissue necrosis

– Systemic shock– Coagulopathy– Rhabdomyolysis– Compartment

Syndrome– Neurotoxicity

• Delayed (24-96H)

- Renal Failure- Compartment

syndrome- Antivenin Rebounds- Serum Sickness

ScorpionsScorpionsNatural Light

UV Light

• Numerous venomous species worldwide

• Several species native to US southwest• Only Centruroides bark

scorpions have a poisonous venom

• Centruroides spp are indigenous to AZ and CA

Desert Scorpion – in attack posture!

Scorpion Venom ComponentsScorpion Venom Components

Numerous digestive enzymesNumerous digestive enzymes– HyaluronidaseHyaluronidase– PhospholipasesPhospholipases

NeurotoxinsNeurotoxins– Stabilizes Na+ channels in open positionStabilizes Na+ channels in open position– Causes overfiring of N-M junction and Causes overfiring of N-M junction and

autonomic nervous systemautonomic nervous system

Clinical PresentationsClinical Presentations

Most encountersMost encounters– Local, immediate pain and inflammationLocal, immediate pain and inflammation– Subsequent paresthesiasSubsequent paresthesias

Sx often resolve in several hours with local Sx often resolve in several hours with local wound and sx carewound and sx care

Other symptoms (children at much higher risk)Other symptoms (children at much higher risk)– Diplopia and nystagmusDiplopia and nystagmus– Muscle fasciculations, seizures, and paralysisMuscle fasciculations, seizures, and paralysis– Rarely, cardiovascular collapse and resp failureRarely, cardiovascular collapse and resp failure– Even rarer, pancreatitisEven rarer, pancreatitis

Scorpion Sting ManagementScorpion Sting Management

Local wound care & irrigationLocal wound care & irrigation

Tetanus prophylaxisTetanus prophylaxis

Benzos for sedation/muscle spasm controlBenzos for sedation/muscle spasm control

Severe envenomationSevere envenomation– Support ABC’s and hemodynamicsSupport ABC’s and hemodynamics

– Consider antivenin in consult with Poison CenterConsider antivenin in consult with Poison Center

Spider BitesSpider Bites

50,000 spp of spiders in USA50,000 spp of spiders in USA– MostMost possess paired poison glands attached to jaw possess paired poison glands attached to jaw

like fangslike fangs

Few poisonous spiders capable of penetrating Few poisonous spiders capable of penetrating human skinhuman skin

Predominant Poisonous Spiders in USAPredominant Poisonous Spiders in USA– Latrodectus Latrodectus (black widow)(black widow)– LoxoscelesLoxosceles (brown recluse) (brown recluse)– Tarantulas Tarantulas (none in US are poisonous)(none in US are poisonous)

Localized wound effects – systemic effects very rareLocalized wound effects – systemic effects very rare

If indigenous area, may not be just an abscess!If indigenous area, may not be just an abscess!

Poisonous SpidersPoisonous Spiders

Black Widow Spider (Latrodectus)

Brown Recluse (Loxosceles)

Spider Venom ComponentsSpider Venom Components

Latrodectus Latrodectus

Digestive enzymesDigestive enzymes

Alpha latrotoxinAlpha latrotoxin– Binds to synaptic receptorsBinds to synaptic receptors– Ca+ channel dysfunctionCa+ channel dysfunction– Release of Ach with motor Release of Ach with motor

end plate stimulationend plate stimulation

LoxoscelesLoxosceles

Digestive enzymesDigestive enzymes

Collagenases, proteases Collagenases, proteases & phospholipases& phospholipases

Sphingomyelinase DSphingomyelinase D– Cytotoxic & hemolytic Cytotoxic & hemolytic

agentagent– Local tissue necrosisLocal tissue necrosis

Black Widow – Clinical Black Widow – Clinical PresentationPresentation

Local puncture woundLocal puncture wound– Central clearing and outer ring of erythemaCentral clearing and outer ring of erythema– Painful within 30 minPainful within 30 min

Painful muscle crampsPainful muscle cramps– Fasciculations follow in 3-4hFasciculations follow in 3-4h– Board like rigid abdomenBoard like rigid abdomen

Resembles an acute surgical abdomenResembles an acute surgical abdomen

Complications (rare)Complications (rare)– Diaphoresis, nausea/vomitingDiaphoresis, nausea/vomiting– Severe HTNSevere HTN– Cardiorespiratory collapseCardiorespiratory collapse

BWS Bite - ManagementBWS Bite - Management

Local wound careLocal wound care

TetanusTetanus

6-8h observation – supportive interim care6-8h observation – supportive interim care

IV calcium and benzos to treat muscle IV calcium and benzos to treat muscle crampingcramping

Narcotic pain controlNarcotic pain control

Consider Latrodectus antiveninConsider Latrodectus antivenin

LatrodectusLatrodectus (Black Widow) (Black Widow) AntiveninAntivenin

Equine derived antiveninEquine derived antivenin

Small risk of anaphylaxisSmall risk of anaphylaxis

IndicationsIndications– Severe envenomationsSevere envenomations– ElderlyElderly– Cardiac pts not responding to supportive careCardiac pts not responding to supportive care– Pregnant patients- prevent preterm laborPregnant patients- prevent preterm labor

Loxosceles (Brown Recluse) Loxosceles (Brown Recluse) EnvenomationsEnvenomations

Immediate painful burning sensation at siteImmediate painful burning sensation at site

Hemorrhagic central vesicle/bulla with surroundingHemorrhagic central vesicle/bulla with surrounding– Gives way to a necrotic ulcer over next 48-72hGives way to a necrotic ulcer over next 48-72h– Slow to heal (can last a >month)Slow to heal (can last a >month)

Rare complicationsRare complications– Intravascular hemolysisIntravascular hemolysis– DICDIC– Secondary infectionsSecondary infections

Difficult Dx – resembles many other disordersDifficult Dx – resembles many other disorders

Brown Recluse - ManagementBrown Recluse - Management

Local wound careLocal wound care

TetanusTetanus

Dapsone – attenuation of necrotic ulcer formationDapsone – attenuation of necrotic ulcer formation– Not clinically born outNot clinically born out

Hyperbaric OxygenHyperbaric Oxygen

Goat derived antivenin, but not FDA approved for useGoat derived antivenin, but not FDA approved for use

Avoid surgery if possibleAvoid surgery if possible– Most heal without surgical interventionMost heal without surgical intervention

Solenosis (Fire Ants)Solenosis (Fire Ants)

5 native spp of 5 native spp of SolenosisSolenosis in USA in USA

2 spp imported via Mobile, AL 2 spp imported via Mobile, AL – Have spread throughout gulf basin /Have spread throughout gulf basin /

west to AZ,/CAwest to AZ,/CA

One nest can produce 200,000 ants!One nest can produce 200,000 ants!

Swarm and attack en masse when provoked Swarm and attack en masse when provoked

Cross reactivity of fire ant venom Cross reactivity of fire ant venom with Hymenoptera venomswith Hymenoptera venoms– Systemic sx in susceptible Systemic sx in susceptible

individualsindividuals

Fire Ant VenomFire Ant Venom• Similar to Hymenoptera venoms of

bees, wasps, hornets and yellow jackets

• Biogenic amines• Ach, histamine, dopamine, serotonin)

• Proteases and alkaloids• Hyaluronidase, phospholipase)

Fire Ant Nest

Clinical PresentationClinical Presentation

Numerous papules at Numerous papules at site of bitessite of bites

Local urticaria, pruritus Local urticaria, pruritus & angioedema& angioedema

Systemic anaphylaxis Systemic anaphylaxis in susceptible personsin susceptible persons

Fire Ant Bite ManagementFire Ant Bite Management

Local wound careLocal wound care

TetanusTetanus

Removal of stingers & attached venom sacsRemoval of stingers & attached venom sacs

Topical papain (meat tenderizer) to inactivate Topical papain (meat tenderizer) to inactivate venom proteinsvenom proteins

H1 & H2 blockers, steroids, analgesicsH1 & H2 blockers, steroids, analgesics

Tx of Anaphylaxis, airway management and Tx of Anaphylaxis, airway management and hemodynamic support, where indicated.hemodynamic support, where indicated.

It’s A Dangerous World Out It’s A Dangerous World Out There!There!

Now you’re better equipped to handle itNow you’re better equipped to handle it

Prevention is the most important step in Prevention is the most important step in treatmenttreatment

And your significant other?And your significant other?

She leaves you to be with someone much She leaves you to be with someone much safersafer– Like a stuntman or explosives handling expertLike a stuntman or explosives handling expert