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Environmental Emergencies Part 1 Wilderness Emergencies Emergency Medicine Clerkship Series Author: Todd A. Parker, M.D. Co-author: Tom Bottoni, M.D.

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Presentation on theme: "Environmental Emergencies Part 1 Wilderness Emergencies Emergency Medicine Clerkship Series Author: Todd A. Parker, M.D. Co-author: Tom Bottoni, M.D."— Presentation transcript:

1 Environmental Emergencies Part 1 Wilderness Emergencies Emergency Medicine Clerkship Series Author: Todd A. Parker, M.D. Co-author: Tom Bottoni, M.D.

2 Vacation! You get that much needed time off Your significant other wants to go to St. Tropez –But you really want to climb Mt. McKinley (Denali) Highest peak in North America-20,320 ft! –She decides to give it a try, and youre off! 4 days into the climb, you are at camp 4000 ft from the summit, and she complains of a headache and is confused…..

3 High Altitude Sickness Definitions:- Moderate altitude ft - High Altitude Extreme High Altitude >18000 Can occur at altitudes greater than 5000 ft –Although most occur above 11,500 feet Influenced by: - Rate of ascent- Final altitude - Sleeping altitude- Duration at altitude

4 Who is at risk? Hard to predict who will get it! Higher risk –Younger > Older –Males > Females Except during water retaining phase of cycle (premenses) –Persons with previous high altitude illness Can occur in previously unaffected Those with previous illness can be unaffected –Persons who overexert themselves –Physical fitness not necessarily protective –Smoking, Alcohol, Sedatives

5 Physiology Hypoxia due to in barometric pressure Hypoxemia due to PO 2 of inspired air Impact on cell variable Ability to acclimatize/compensate Pre-existing medical conditions

6 Acclimatization Ventilation – increases almost immediately Cardiovascular –Increased Cardiac Output (CO) –Increased pulmonary perfusion Improves V/Q mismatches Increase in cerebral blood flow Hematologic –Relative increase in Hg due to diureses –Erythropoietin – stimulates bone marrow Effect takes weeks

7 Types of illness Altitude-exacerbated conditions –NOT the focus of this talk, but be aware! Congenital Heart Disease Pulmonary Hypertension Coronary Heart Disease CHF Sickle Cell Disease / Trait Obstructive Sleep Apnea Pregnancy Radial Keratotomy (Corrective Eye Surgery)

8 High Altitude Illnesses Acute Mountain Sickness High Altitude Cerebral Edema High Altitude Pulmonary Edema

9 Acute Mountain Sickness Defined as headache and one or more of: - Anorexia- Fatigue/weakness - Nausea/Vomiting- Difficulty Sleeping - Dizziness- Lightheadedness Develop 6-10 hours after ascent –May be <1 hr Usually Self Limiting

10 AMS - Treatment Rarely need to descend – slow / halt ascent Analgesics/antiemetics prn Consider acetazolamide ( mg BID) –Speeds acclimatization Descend if sx do not improve –Dexamethasone 4mg PO/IM if unable to descend Graded ascent is best preventive measure (600m/day)

11 High Altitude Cerebral Edema (HACE) AMS – Sx progress to global cerebellar dysfunction –Ataxia or altered mental status –Vertigo, Diplopia, rarely seizures Usually > ft (have occurred as low as 9K) Begin 12 hrs or greater after onset of AMS Sx usually global –Isolated focal sx – concern for CVA/TIA

12 HACE - Treatment HACE - Treatment Immediate descent definitive tx Supplemental O2 (highest flow or sats >90%) Dexamethasone 8mg PO/IM then 4mg Q6h If cannot descend, hyperbaric therapy (more later)

13 High Altitude Pulmonary Edema (HAPE) Non-cardiogenic pulmonary edema Accounts for most high altitude deaths Occurs 1-3 days after arrival at altitude –Rarely occurs after 4 days – consider alternative dx 1-2% of high altitude climbers –15% of those with rapid ascent

14 HAPE Pathophysiology Hypoxia leads to pulmonary artery HTN –Increased pulmonary vascular resistance –However, occurs in everyone – not just HAPE Pulmonary capillary pressure increases –Leads to overperfusion Capillary leakage –Fluid as well as proteins leak out Exudative fluid With descent, pressure decreases –Capillaries reseal, leakage stops Recovery Inflammatory mediators likely not primary process, but secondary to leaked proteins

15 HAPE Treatment Descent! Supplemental O2 Decreases pulmonary artery pressure up to 50% B-agonists: –Increase fluid clearance from alveolar spaces No role for dexamethasone Limited role for acetazolamide (may dyspnea)

16 HAPE Treatment - Nifedipine Controversial Reduces pulmonary artery pressure –Does NOT improve oxygenation Use only if –Descent impossible –Supplemental O2 unavailable Downside: Lowers systemic BP also –CPP = MAP – ICP –If risk for/concomitant HACE, lower MAP lowers CPP

17 Hyperbaric therapy Greatest benefit in HACE –Use highest PSI available HAPE – likely beneficial –Cost – benefit vs. Supplemental O2 generally precludes AMS – little additional benefit

18 HAI - Summary HAI - Summary Medications: –Acetazolamide – best for acclimatization Little benefit in acute tx (no use in HAPE) –Dexamethasone AMS and HACE No role in HAPE –B-agonists useful in HAPE –Nifedipine – likely beneficial in HAPE Use with extreme caution if concomitant concern for HACE Stop ascent – attempt acclimatization –Supplemental O2 immediately if available –If no improvement or worsening, descend

19 Recovery! With rest and oxygen, your significant other has recovered at base camp Now armed with more knowledge –Begin ascent again –Youre at camp 4000 ft from the summit again, and a storm hits – youre stuck! That night, she says that she cant feel her fingers…

20 Frostbite!

21 Frostbite Skin blood flow when skin temp < 14 0 C ( F) Skin blood flow when skin temp < 14 0 C ( F) Hunting Response – alternating cycles of vasodilation and vasoconstriction at < 10 0 C (50 0 F) Vasodilation brings cooled blood to core As core body temp drops, cycles end and blood flow completely cut to extremities Tissue freezes – ice crystals form when temp 0 0 C –Creates osmotic gradient pulling fluid from intracellular spaces –Intracellular NaCl rises, proteins denature, membranes fail Reperfusion injuries – hours to days

22 Frostbite Classification 1 0 : Non-sensate white area/surrounding erythema 2 0 : Vesicles with surrounding erythema 3 0 : Hemorrhagic blisters with eschar formation 4 0 : Necrotic tissue, involves muscle/tendon/bone Reclassification – Superficial (First/Second) and Deep (Third/Fourth) –Classified according to treatment/outcome vice tissue involved

23 Frostbite Treatment Thawing stage –Consider delay if: Adequate analgesia not available Delayed evacuation (i.e. ambulation required) –Remove wet/constrictive clothing –Rapid rewarming Use C water for minutes with motion Avoid hot untested tap water - risk of thermal burns! Avoid massaging and dry heat –Parenteral analgesics

24 Frostbite Treatment Post-Thawing Treatment –Debride CLEAR blisters –Apply aloe skin cream (Dermaide) Do NOT debride hemorrhagic blisters –Elevate affected parts –Tetanus prophylaxis –Scheduled ibuprofen / prn narcotics –Pen G 600,000 units q6h –Daily Hydrotherapy at 40 0 C for mins No Smoking!

25 Foiled! She recovers from her mild frostbite Since your flight home isnt for 10 days, you propose another summit attempt, and get this look…

26 Plan B On second thought, you propose camping in beautiful Denali National Park to view the Northern Lights… You fall asleep, under the lights, after sharing a couple bottles of wine together You wake up a few hours later and you notice she is shivering violently and you have a hard time waking her…

27 Accidental Hypothermia Definition: Core Temp < 35 0 C (95 0 F) Mild: 32 0 C – 35 0 C ( F – 95 0 F) Moderate: 28 0 C – 32 0 C ( F F) Severe: <28 0 C ( F)

28 Mild Hypothermia 32 0 C – 35 0 C ( F – 95 0 F) Signs / Symptoms: –Shivering –Tachypnea / Tachycardia / Hypertension –Ataxia / Dysarthria –Loss of fine motor coordination –Confusion / lethargy

29 Moderate Hypothermia 28 0 C – 32 0 C ( F F) Signs / Symptoms: –Shivering Stops –Bradycardia –Osborn (J) waves on EKG –Altered Mental Status –Slowed Reflexes –Cold Diuresis –Pupil Dilation

30 Severe Hypothermia <28 0 C ( F) Signs / Symptoms: –Unresponsive / Coma –Hypotensive –V Fib / Asystole –Acidemia –Loss of reflexes

31 Lab Tests (if able) BMP – pay attention to electrolytes (esp K+) CBC – Hct increases 2% for each 1 0 C drop –Trauma – normal Hct may mean blood loss ABG – interpret as is (blood rewarmed in lab) Coags: May be normal - blood is rewarmed –Do not necessarily reflect physiology in patient Other labs as indicated if another underlying cause o hypothermia suspected –EtOH/UDS –Cardiac Enzymes, etc

32 Hypothermia Treatment Large Bore IV(s) – Bolus with warm fluids Intubate if indicated Immediate Actions – ACLS! –Check Vital Signs and ECG Check seconds for pulse – difficult to detect Rectal thermometer – must be low temp capable –Standard thermometers only to C (94 0 F) –If no pulse, begin CPR Controversial in severe hypothermia, however likely beneficial

33 Hypothermia Treatment Most dysrhythmias convert on rewarming –A. Fib/Flutter –Sinus bradycardia –Transient ventricular dysrhythmias V. Fib / V. Tach – defibrillate at 1-2J/kg –One shock only –May be ineffective at temps < 30 0 C –If fails, reattempt after each degree rise

34 Hypothermia Treatment Intravenous drugs –May be ineffective below 30 0 C –Give at longer intervals above 30 0 C Amiodarone drug of choice for V. Fib Avoid procainamide – may worsen If EtOH – Replete glucose and thiamine –Hypoglycemia and Wernickes may help precipitate hypothermia

35 Rewarming Cornerstone of treatment – REWARM! Rapid rewarming to 30 degrees –Minimize risk of dysrhythmias –Once above 30 deg, can slow rewarming rate Cardiovascular status is most important

36 Passive Rewarming Ideal method: Slow, physiologic Must have intact thermoregulation –Shivering intact –Caution in underlying diseases Likely only effective in mild hypothermia Methods: –Remove from environment –Remove wet clothes –Blankets

37 Active External Rewarming Use for moderate hypothermia –Monitor closely! Rapid peripheral vasodilation May return cooled blood to core Likely not clinically significant –Consider rewarming trunk alone –Warm water immersion – ensure monitoring –Heating blankets –Forced air (BAIR Hugger) –Radiant heat

38 Active Core Rewarming ALL Patients –Warmed IV Fluids –Warmed humidified Oxygen Small heat gain – mostly prevents further heat loss

39 Active Core Rewarming Severe hypothermia/cardiac instability –Lavage with warm fluids - Nasogastric/rectal - Pleural (via thoracostomy) - Bladder (via Foley) - Peritoneal (via DPL catheter) –Mediastinal Lavage via open thoracotomy –If available Cardiopulmonary Bypass Hemodialysis Set up difficult, but most effective!

40 Thats it! Although she recovers uneventfully, shes had it with this cold weather vacation! Youre on the next flight for Hawaii That afternoon, after landing, she decides to unwind by going for a run –2 hours later she hasnt returned, you drive out to find her and shes sitting on the side of road…

41 Heat Emergencies Predominant forms of heat loss –Radiation (65%): loss via electromagnetic waves Only occurs if temperature differential (stops at 95 0 F) –Evaporation (30%): transfer of heat via sweat and saliva evaporation Minimal if humidity > 80% Causes: –Increased internal heat production –Increased external heat exposure –Impaired heat dispersion

42 Increased Internal Heat Physical Activity –Exercise –Seizures –Combative behavior Pharmacological agents –Amphetamines, cocaine, LSD, PCP Endogenous Fever –NOT the same as environmental hyperthermia –Should not be exogenously cooled

43 Increased External Heat High Ambient Temps –Minimizes radiation heat loss High Humidity –Minimizes evaporative heat loss Direct exposure to sunlight

44 Impaired Heat Dispersion CV disease –Impaired circulation –Impaired compensation Obesity –Adipose - decreased vascularity –Insulates the body Skin alterations ClothingMedications –Anticholinergics –Cardiovascular drugs –Diuretics –Sympathomimetics –Phenothiazines –Alcohol/Drugs Extremes of Age Dehydration

45 Acclimatization Increases ability to provide peripheral blood flow, protect kidneys, and increase sweating Improved physical condition = improved cardiac response to vasodilation Increased efficiency at shunting blood from non-critical areas Increased activation of renin-angiotensin-aldosterone system –Enables increased sodium retention Expansion of plasma volume Sweat glands increase sweat production

46 Heat Emergencies Minor heat illnesses –Head Edema –Heat Rash –Heat Syncope –Heat Cramps Heat Exhaustion Heat Stroke

47 Heat Edema Cutaneous vasodilation and orthostatic pooling Resolves spontaneously If treatment instituted Removal from heat Elevation of legs with support hose Do not use diuretics –Dehydration more risky –May cause electrolyte disturbances

48 Heat Rash Heat Rash Pruritic maculopapular rash Stratum corneum blocks sweat ducts –Ducts rupture –Localized inflammation –Pruritic Avoidance –Light, loose fitting clothes –Minimize sweating Treatment: Antihistamines and avoidance

49 Heat Syncope Secondary to –Peripheral vasodilation –Decreased vasomotor tone –Volume Depletion Treatment –Remove from heat source –Oral or IV fluids –Rest

50 Heat Cramps Usually secondary to electrolyte disturbances from sweating –Dehydration or water-only rehydration –Hyponatremia –Hyperkalemia Treatment –Remove from heat –Oral hydration with electrolyte containing fluids –IV fluids

51 Heat Exhaustion Signs and Symptoms: Non-specific! –Temp usually elevated but < 41 0 C –Fatigue/weakness/dizziness /syncope –Nausea/vomiting –Headaches –Myalgias and muscle cramps –Tachycardia –Piloerection –Profuse sweating usually present

52 Heat Exhaustion - Treatment Remove from heat and minimize activity Cool with fans/ice packs to neck, groin, axillae Oral rehydration w/electrolyte containing fluids IV Fluids if not alert or nausea/vomiting –Replace fluids over several hours Monitor vital signs –Urine output –Orthostatics

53 Heat Stroke Signs and Symptoms –Elevated Temp – usually > 41 0 C (106 0 F) –Hyperdynamic cardiac parameters Tachycardia/Tachypnea Increased systolic / increased pulse pressure –CNS Dysfunction - Seizure - Delirium- Cerebellar dysfunction - Coma- Hallucinations- Pupil dysfunction –Oliguria –Anhydrosis – often present but not required!

54 Heat Stroke - Treatment Initial resuscitation –ABCs, IV access, cardiac/pulse ox monitoring Rectal thermometer for continuous monitoring Intubation if indicated –Begin IV fluid boluses (Normal saline or LR) Place foley and NG Tube Rapid Cooling is key

55 Cooling Techniques Goal is C to avoid overshoot Evaporative cooling preferred –Remove clothing, spray with lukewarm water –Use large fans to blow air across skin Immersion – rapid cooling in ice water –Difficult to monitor patient –May cause shivering –Very uncomfortable if awake Internal cooling (lavages – i.e. bladder, gastric) –Effective, but probably unnecessary –CP bypass – likely not worth risks

56 Adjunct Therapies Antipyretics – NO ROLE! –May interfere with endogenous thermoregulation Benzodiazepines –Help reduce agitation / shivering / seizures –EtOH / Drug withdrawal Avoid large volumes of IV fluid –May lead to pulmonary edema (even healthy pts) –Except in rhabdomyolysis Renal failure –Hemodialysis if unresponsive to fluids / acid-base correction

57 Fortunately… She just has a mild case of heat exhaustion. You get her water and into your air conditioned vehicle Back at the hotel, after shes rested for a couple hours, she decides to go for a swim in the ocean You tell her youll meet her out there in a minute You lose track of time watching a great ER rerun, and 30 minutes later you arrive to find several lifeguards carrying her in Apparently a rip tide pulled her under, and it took the lifeguards several minutes to pull her out…

58 Submersion Injuries Drowning – Death within 24 hours of submersion Near Drowning – survival after submersion injury Third leading cause of accidental death –Freshwater > Saltwater –EtOH/Drugs commonly involved –Most victims children/ adolescents

59 Submersion Injuries Sequence: –Submersion –Breath holding –Panic –Swallowing water / emesis –Breathing water Dry drowning – laryngospasm/glottic closure Final common pathway - hypoxemia

60 Pulmonary Injuries Fresh Water –Inactivates surfactant –Atalectasis and loss of pulmonary compliance Salt Water –Osmotic gradient pulls fluid into alveoli –Intrapulmonary shunting / VQ mismatch If survive initial aspiration – ARDS or pneumonia

61 Signs/Symptoms 4 categories –Asymptomatic –Symptomatic Altered mental status / anxiety Hypothermia/Tachycardia/Bradycardia Any dyspnea, no matter how slight –Cardiopulmonary Arrest –Obviously Dead NormothermicAsystole No neurologic response

62 Submersion – Labs/Studies ABG essential CBC, BMP, Lactate, Coags –Follow creatinine – renal failure delayed EtOH / UDS Chest X-ray CT Spine / Head CT if at risk for injury –C-Collar until cleared by mechanism or studies

63 Submersion Treatment Pre-hospital –Unless certain, assume spinal injury C-Collar and backboard Maintain precautions when moving –Rescue breathing and supplemental O2 –CPR – start on almost all patients In water chest compressions generally worthless –Begin rewarming

64 Submersion Treatment -ED Unless obviously dead, assume survivability –Especially children Intubate if unable to oxygenate/ventilate –PEEP - Improves ventilation and volume Shifts fluid into capillaries –Consider BIPAP if awake –If intubated, perform bronchoscopy ACLS algorithms if indicated Rewarm patient (as per hypothermia protocols)

65 Complications ARDS –Supportive care Pneumonia –Direct water aspiration –Aspiration of gastric contents –Contaminants / organisms in water Bacteria and fungi common, esp warmer waters Disposition/Treatment –Most need admission, ICU if warranted –Prophylactic antibx / antifungals not necessary, unless sx Extended spectrum PCN / B-lactamase + aminoglycoside –If asymptomatic and no injuries, observe and discharge

66 Turns out shes OK You decide that youll go back in the water, together, but this time with scuba tanks to check out a nearby reef After enjoying a beautiful dive, you begin your ascent to the surface Suddenly, a large jellyfish stings her, she panics and races for the surface You remember your dive tables, and ascend as rapidly as you can, safely 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 and right shoulder pain….

67 Diving Injuries / Dysbarism Sea level – ambient air pressure = 1 atm –Ascending - ambient pressure halves at ft –Diving – ambient pressure increases by 1 atm every 33 feet! Boyles Law – pressure/volume inversely proportional –As pressure increases, volume decreases (diving) –Vice versa (ascending) Henrys Law – gas enters liquid in proportion to partial pressure –As descend, partial pressure increases – gases more soluble –During ascent, gases come out of solution –Oxygen metabolized, nitrogen does not Coalesces into bubbles if ascent too quick

68 Types of Injuries Barotrauma of descent Barotrauma of ascent –Direct barotrauma –Arterial gas emboli (AGE) / Dysbaric air embolism (DAE) Indirect effects of ascent –Nitrogen Narcosis –Decompression Sickness

69 Descent Barotrauma (Squeeze) Ear Squeeze –External (Barotitis Externa) Air trapped in ext canal compresses –TM bulges out –Trauma to TM and surrounding external canal –Middle (Barotitis Media) – most common! Cannot equalize air in middle ear TM bulges inward – may rupture May cause trauma to ossicles/ round window –Inner (Barotitis interna) Trauma to round window –Air enters inner ear Classic triad – tinnitus, hearing loss, vertigo –Also nausea/vomiting, ataxia, nystagmus

70 Descent Barotrauma (Squeeze) Sinus Squeeze –Air trapped in sinuses –Causes pain / hemorrhage into sinuses epistaxis Treatment of ear and sinus squeeze –Decongestants (oral and nasal spray) –Antibiotics if TM rupture –Analgesia –Avoidance of diving Mask Squeeze –Must equalize pressure behind mask during descent –Can cause localized petechiae /conjunctival hemorrhage

71 Ascent Barotrauma Reverse process of squeeze Occurs from gas expansion Normally gas escapes into atmosphere If escape blocked, barotrauma

72 Ascent Barotrauma (cont) Ears and sinuses – usually not affected –If air got in on descent, can get out Barodontalgia (Tooth Squeeze) –Descent - compressed air gets in fillings/decay –Ascent – expands Cannot escape Pain GI Barotrauma (Aerogastralgia) - air trapped in GI tract –Swallowing air (improper valsalva) –Drinking carbonated beverages or heavy meal prior –Generally self-limiting pain/discomfort – rupture rare If pneumoperitoneum, also consider GU source (esp females)

73 Pulmonary Barotrauma Most severe barotrauma of ascent Air normally breathed out –equalizes pressure If air not breathed out, expands –Ruptures into surrounding tissue Pneumomediastinum and SubQ emphysema common –Usually self-limiting Pneumothorax and Arterial Gas Embolism –Require intervention Pneumothorax – needle decompression / thoracostomy

74 Arterial Gas Embolism Rupture of alveolar air into pulmonary veins Air embolism left heart systemic circulation Symptoms of thromboembolic disease –CVA type symptoms or myocardial infarction –Any sudden, severe symptoms of thromboembolism on ascent should be treated as AGE Immediate recompression/hyperbaric treatment Resuscitate per ACLS Position right lateral decubitis or supine –Do not place head down – cerebral edema

75 Nitrogen Narcosis Nitrogen – increased solubility at increased partial pressures (remember Henry?) Intoxication effect at high partial pressure –Most feel effect by feet –Impaired >200 ft, unconscious >300ft Effects reverse with ascent Can precipitate other errors Impairs recollection of dive / ascent – impairs history

76 Decompression Sickness (DCS) Dissolved nitrogen forms bubbles if ascent too rapid Direct effect of bubbles Indirect effect of inflammatory response to bubbles –Causes activation of clotting/inflammatory cascades Net effect –Decreased tissue perfusion –Ischemic injury

77 Type 1 DCS Niggles – mild pains, begin to resolve ~ 10 mins Pruritis (Skin Bends) Skin rash Lymphatic involvement –Peripheral edema Pain (The bends) –Aching pain –Usually in joint, tendon, occasionally muscle –Shoulder most commonly affected

78 Type 2 DCS Pain uncommon (30%) Neurologic system –Nitrogen very soluble in fat – myelin sheath –Spinal cord most commonly affected (esp lower) –Bladder dysfunction Pulmonary DCS (The Chokes) –Venous nitrogen emboli –Chest pain, cough, dyspnea, pulmonary edema –Can progress to hemoptysis

79 Physical Exam In addition to vital organs, pay close attention to –Sclera / retina –Tympanic membranes –Thorough neurologic exam –Urinary retention Differentiating AGE from DCS –Length of dive (must be longer dive to develop DCS) –Time of onset (AGE rapid / DCS delayed) –AGE – only CNS effects are on the brain

80 DCS Treatment Prehospital –Extricate from water / immobilize if trauma –Supplemental O2 May result in resolution of mild DCS –ASA for anti-platelet activity –Consider in-water recompression only if in remote location –CPR if indicated –Needle decompression of tension ptx –Avoid trendelenburg

81 DCS Treatment ED care –All of the prehospital measures apply –100% O2 – intubate if warranted –Aggressive fluid resuscitation Goal UOP is 1-2ml/kg/hr –Treat nausea and headaches –Arrange transfer to HBO facility Consider even if improvement in symptoms Relapses / worsening occur Ensure air transport can maintain pressurization!

82 She recovers (again) Supplemental oxygen and about 30 minutes of rest, and shes feeling better But what about that jellyfish sting?

83 Marine Envenomations ~1200 species of venomous or poisonous marine animals worldwide Few cause major medical issues Broad array of species –Various neurotoxic and proteolytic venoms –Used for paralyzing / killing prey Humans are often accidental victims or hosts

84 Marine Envenomations InvertebratesCoelenterates –Anemones and Jellyfish Mollusks –Octopus/Squid –Cone Snails Echinoderms –Sea Urchins Poriferae –Fire Sponge VertebratesStingrays Scorpion fish Catfish Sea snakes (Hydrophidae)

85 Jellyfish / Man O War

86 Fire Coral

87 Sea Urchins Blue Ringed Octopus

88 Scorpion Fish Stingrays

89 Marine Envenomation - Treatment Cornerstones – ABCs First! –Detoxify venom – rinse with normal saline Freshwater may activate venom –Pain and symptom relief – narcotics, antihistamines –Local wound care –FB removal Deactivation and removal of attached nematocysts –5% acetic acid / isopropanol (further deactivate) –Apply baking soda slurry or shaving cream Allow nematocysts to coalesce and scrape off –May remove with adhesive tape Marine wounds prone to infection –Aeromonas, Vibrio, Pseudomonas, Erysipelothrix spp –Prophylactic antibiotics for serious wounds

90 Shes had it with the ocean! You make one last attempt to salvage your vacation, and let her pick the spot She wants as far away from the ocean as possible Off to the Grand Canyon!

91 First night of camping Your significant screams, and you wake up to see this guy in tent!

92 Land 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…

93 Snake Envenomations Poisonous or Not? Exception: Coral Snakes (Elapidae)

94 Epidemiology 14 Families of snakes 3 main poisonous snake families –Viperidae Vipers and Pit Vipers Rattlesnakes –Elapidae Cobras and Mambas Coral Snakes Hydrophidae – Sea snakes –Colubridae – Asps and Mole Vipers ~4000 snake bites annually reported in USA <20 deaths / year

95 Poisonous snakes Rattle SnakesCoral SnakesCopperhead Snakes

96 Components of Poisonous Venom Fibrinogenases, phospolipases Platelet aggregation inhibitors Enzymes with hemorrhagic activity Numerous other uncharacterized proteinases Neurotoxins (for coral snake venom)

97 Crotalid Envenomations None (dry bites) - ~15-20% Mild - local swelling and pain –No systemic features Moderate – progression of swelling –Local tissue destruction –Hematologic abnormalities –Systemic sx Severe – marked swelling –Bullae and tissue necrosis –Shock –Coagulopathy

98 Crotalid Envenomations – Initial Management Immobilize injured part at or below heart level Provide local wound care –Cleansing –Debridement –Prophylactic ABX –Tetanus Lab eval –CBC, CMP, CPK –Coags and DIC panel Observe for 24h or admit, for sx of progression Consider antivenin early, for mod / severe envenomations

99 Role 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

100 Crotalid 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

101 Complications 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

102 Scorpions Natural 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!

103 Scorpion Venom Components Numerous digestive enzymes –Hyaluronidase –Phospholipases Neurotoxins –Stabilizes Na+ channels in open position –Causes overfiring of N-M junction and autonomic nervous system

104 Clinical Presentations Most encounters –Local, immediate pain and inflammation –Subsequent paresthesias Sx often resolve in several hours with local wound and sx care Other symptoms (children at much higher risk) –Diplopia and nystagmus –Muscle fasciculations, seizures, and paralysis –Rarely, cardiovascular collapse and resp failure –Even rarer, pancreatitis

105 Scorpion Sting Management Local wound care & irrigation Tetanus prophylaxis Benzos for sedation/muscle spasm control Severe envenomation –Support ABCs and hemodynamics –Consider antivenin in consult with Poison Center

106 Spider Bites 50,000 spp of spiders in USA –Most possess paired poison glands attached to jaw like fangs Few poisonous spiders capable of penetrating human skin Predominant Poisonous Spiders in USA –Latrodectus (black widow) –Loxosceles (brown recluse) –Tarantulas (none in US are poisonous) Localized wound effects – systemic effects very rare If indigenous area, may not be just an abscess!

107 Poisonous Spiders Black Widow Spider (Latrodectus) Brown Recluse (Loxosceles)

108 Spider Venom Components Latrodectus Digestive enzymes Alpha latrotoxin –Binds to synaptic receptors –Ca+ channel dysfunction –Release of Ach with motor end plate stimulation Loxosceles Digestive enzymes Collagenases, proteases & phospholipases Sphingomyelinase D –Cytotoxic & hemolytic agent –Local tissue necrosis

109 Black Widow – Clinical Presentation Local puncture wound –Central clearing and outer ring of erythema –Painful within 30 min Painful muscle cramps –Fasciculations follow in 3-4h –Board like rigid abdomen Resembles an acute surgical abdomen Complications (rare) –Diaphoresis, nausea/vomiting –Severe HTN –Cardiorespiratory collapse

110 BWS Bite - Management Local wound care Tetanus 6-8h observation – supportive interim care IV calcium and benzos to treat muscle cramping Narcotic pain control Consider Latrodectus antivenin

111 Latrodectus (Black Widow) Antivenin Equine derived antivenin Small risk of anaphylaxis Indications –Severe envenomations –Elderly –Cardiac pts not responding to supportive care –Pregnant patients- prevent preterm labor

112 Loxosceles (Brown Recluse) Envenomations Immediate painful burning sensation at site Hemorrhagic central vesicle/bulla with surrounding –Gives way to a necrotic ulcer over next 48-72h –Slow to heal (can last a >month) Rare complications –Intravascular hemolysis –DIC –Secondary infections Difficult Dx – resembles many other disorders

113 Brown Recluse - Management Local wound care Tetanus Dapsone – attenuation of necrotic ulcer formation –Not clinically born out Hyperbaric Oxygen Goat derived antivenin, but not FDA approved for use Avoid surgery if possible –Most heal without surgical intervention

114 Solenosis (Fire Ants) 5 native spp of Solenosis in USA 2 spp imported via Mobile, AL –Have spread throughout gulf basin / west to AZ,/CA One nest can produce 200,000 ants! Swarm and attack en masse when provoked Cross reactivity of fire ant venom with Hymenoptera venoms –Systemic sx in susceptible individuals

115 Fire 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

116 Clinical Presentation Numerous papules at site of bites Local urticaria, pruritus & angioedema Systemic anaphylaxis in susceptible persons

117 Fire Ant Bite Management Local wound care Tetanus Removal of stingers & attached venom sacs Topical papain (meat tenderizer) to inactivate venom proteins H1 & H2 blockers, steroids, analgesics Tx of Anaphylaxis, airway management and hemodynamic support, where indicated.

118 Its A Dangerous World Out There! Now youre better equipped to handle it Prevention is the most important step in treatment And your significant other? She leaves you to be with someone much safer –Like a stuntman or explosives handling expert

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