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Environmental emergencies
 

Environmental emergencies

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Environmental Emergencies Board Review Mary Welch 2013

Environmental Emergencies Board Review Mary Welch 2013

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    Environmental emergencies Environmental emergencies Presentation Transcript

    • Environmental Emergencies Mary Welch, DO
    • Electrical injuries Types of Current Direct:Electrons flow in one direction Ex. Batteries Alternating: Electrons flow back and forth (60 Hz) Used in household outlets Generally more dangerous
    • Electrical injuries Mechanism of Injury Thermal Injury: Damage caused by heat due to resistance to current resulting in internal burns and edema Bone and fat have the highest resistance Mechanical Injury: Fractures and dislocations caused by muscle contractions or associated trauma Disruption of Depolarization May cause Seizures or arrhythmias Degree of injury related to voltage and duration of exposure
    • Cutaneous Injury Skin burns Exit and entry wounds “Kissing Burns”- burns in skin creases due to opposition of skin during tetanic contractions
    • Musculoskeletal injury Direct Current Powerful Muscle spasm results in fractures More like to to cause traumatic fractures Alternating Current Causes sustained contractions Flexor muscles more powerful than extensors resulting in patient being brought closer to the source More powerful internal rotators may result in posterior shoulder dislocation
    • Vascular injury Venous Thrombosis More common due to slower flow and less ability to dissipate heat Delayed Arterial Thrombosis May appear similar to compartment syndrome Mesenteric artery thrombosis
    • CNS injury Seizure Loss of consciousness and amnesia Median nerve injury Autonomic dysfunction Pupils may be fixed and dilated you cannot rely on pupillary exam to cease resuscitation
    • cardiac DC injury can cause asystole AC injury may cause Vfib
    • complications Compartment syndrome Cataracts Rhabdo Labial artery bleeding Depression Delayed neurologic symptoms Similar to ALS and transverse myelitis Delayed Lower extremity weakness
    • Work up ECG Labs: CE, CHEM, Total CK UA for myoglobinuria Imaging PRN Compartment checks and pressures PRN
    • Management Cardiac monitoring Fluid management Be aware of possible fluid losses keep UOP to 1cc/kg/hr Fasciotomy or carpal tunnel release PRN
    • Admission Criteria ECG Changes Loss of conciousness Path of current possibly passed through the heart High voltage (>500V) injury Transfer significant electrical injuries to burn centers
    • Discharge Low voltage injuries No changes after 6 hours of monitoring NO loss of conciousness
    • Lightening injuries Massive unidirectional current 30% Mortality rate 70% Significant morbidity rate
    • Lightening injuries Flashover burns are common Ferning or Lichtenberg sign Patient may be thrown significant distances resulting in traumatic injuries Tympanic membrane rupture (>50%) Cataract formation is common Deep tissue damage uncommon
    • Lightening injuries Most common complications are related to depolarization abnormalities: Loss of consciousness Seizures Cardiac arrhythmias Death caused by Vfib or asystole
    • management Good prognosis if no respiratory or cardiac arrest Massive fluid boluses not required due to little tissue necrosis If mass casualty highest priority are those in respiratory or cardiac arrest Continue resuscitation even if victims appear dead as they be unresponsive with fixed and dilated pupils Defibrillate to restore rhythm
    • High Altitude illness acute mountain sickness acute mountain sickness Caused by hypoxia Decreased oxygen pressure increases cerebral blood flow resulting in cerebral edema
    • acute mountain sickness Signs and symptoms Signs and symptoms Headache Nausea and vomiting Insomnia Decreased urination Peripheral or facial edema Retinal hemorrhage
    • acute mountain sickness Treatment Treatment Halt ascent Acetazolamide carbonic anhydrase inhibitor which aids in acclimatization Take 12-24 hours before ascent for prophylaxis Bicarbonate diuresis stimulates respiratory compensation Contraindicated in SSD and sulfa allergies Steroids for cerebral edema Descent for refractory cases
    • management Descent Supplemental oxygen Acetazolamide Steroids Portable hyperbaric chamber if descent not possible
    • High Altitude illness High altitude cerebral edema High altitude cerebral edema Altered mental status Ataxia, confusion Retinal hemorrhages Death due to brain-stem herniation All patients with altered mental status should be observed for ataxia
    • High altitude pulmonary edema Most common cause of death from high altitude illness Due to hypoxia induced pulmonary vasoconstriction
    • edema Occurs a few days after ascent Symptoms worse at night Cough Decreased exercise tolerance Low grade fever Tachycardia, Tachypnea Rales and ronchi
    • edema Immediate descent Oxygen Calcium channel blockers Acetazolamide for prophylaxis Portable hyperbaric chamber if descent not possible
    • Diving Dysbarism Pathology related to increases and decreases of external pressure on the human body Pressure and volume changes as a function of depth Boyle’s Law: pressure X volume = k (constant) At a set temperature pressure and volume are inversely related Governs all gases under pressure Atmospheric pressure doubles every 33ft under water
    • Affects on HEENT system HEENT system Middle Ear Most commonly affected due to eustacian tube dysfunction Eustacian tube equalizes pressure in middle ear Patients with eustacian tube dysfunction may have: pain, hematoma, TM rupture, vertigo Inner Ear Rapid ascent may cause rupture of the round window resulting in sudden hearing loss, vertigo and tinnitus Requires ENT consultation and surgical repair
    • Affects on HEENT system HEENT system Sinus Squeeze Frontal sinus most commonly affected Inflammation or blockage of sinus ostia and decreased sinus drainage may result in difficulties On descent the air in sinuses contracts resulting in negative pressure on sinus mucosa causing: edema, hemorrhage and pain On ascent expanding gas results in increased pressure in the fixed space of the sinuses Treat with decongestions, steroids and ABX if necessary Dental Pain due to air trapped in fillings
    • Affects on pulmonary system pulmonary system Lung volume equalized by appropriate inspiration and expiration Complications due to rapid descent Hemoptysis Complications due to rapid ascent Due to inadequate exhalation: Lung volume doubles every 33 feet, exhalation required to prevent injury Inexperienced divers may hold their breath
    • Complications from ascent Pneumothorax May develop hypotension due to tension PTX Pneumomediastinum Arterial gas embolism Management Treat PTX Hyperbaric treatment
    • Air embolism Due to rupture of air or nitrogen into pulmonary vein May present similar to pulmonary embolism Suspect in any diver who comes up unconscious Air embolism into coronary artery may cause MI Air embolism into brain presents similarly to CVA Requires immediate hyperbaric treatment and supportive care
    • Decompression sickness Dysbarism due to reformation of dissolved nitrogen into gas bubbles in tissues During descent oxygen and nitrogen is compressed Oxygen continues to be consumed by the body as nitrogen accumulates During ascent nitrogen bubbles form in tissues and joints resulting in vessel obstruction
    • Decompression sickness risk factors risk factors Increased depth of dive and speed of ascent Multiple dives in the same day Nitrogen lasts for 12 hours Air flight soon after dive Obesity Nitrogen is fat soluble Poor physical conditioning and strenuous exercise while under water
    • Decompression sickness Symptoms and signs Symptoms and signs Onset within 6 hours MSK: Joint pain (“The bends”) Pulm: Chest pain, cough, dyspnea (“The chokes”) Inner Ear: Vertigo, hearing loss, and nausea (“The staggers”) Spinal Cord: pins and needles sensation CNS: visual disturbances and HA Derm: pruritis and burning of skin, mottling and erysipelas-like rash over fatty areas
    • Decompression sickness Diagnosis Diagnosis Clinical diagnosis Severe illness and arterial gas embolism may be difficult to differentiate AGE presents suddenly with 10-20 min of ascent AGE only affects brain (NO spinal cord involvement) AGE can occur with short and shallow dives
    • Decompression sickness management management Administer 100% oxygen IV hydration Aspirin if not bleeding Hyperbaric treatment Prevention Slow ascent Limit depth or dive time No flying for 12-24 hours
    • Breathing gas under high pressure high pressure Breathing oxygen or nitrogen at high partial pressure is neurotoxic Oxygen toxicity Risk begins at 200ft Tingling Focal seizures Vertigo Nausea and vomiting
    • Breathing gas under high pressure high pressure Nitrogen Narcosis Risk begins at 100ft Incapacitating at 300ft Resembles alcohol intoxication Prevention Deep divers use mixtures lower in oxygen mixed with helium or hydrogen Management Rabidly reversible with ascent
    • Radiation Injuries Radiation: energy emitted when change from higher energy state to lower energy state in the form of atomic particles or waves
    • Radiation Injuries ionizing radiation ionizing radiation Energy released from unstable atoms as they decay to more stable state Able to break chemical bonds and form ion pairs May be electromagnetic or particulate Causes cellular injury by cleaving DNA strands and producing free radicles Induces genetic mutations and cancer
    • Radiation Injuries non-ionizing Radiation non-ionizing Radiation All forms of electromagnetic radiation except: High energy UV, Xray, gamma ray Includes radio wave, microwave infrared visible light and low energy UV
    • Radiation Injuries electromagnetic radiation electromagnetic radiation Self-propagating waves of energeny with electric and magnetic components Ionizing or non-ionizing Ionizing electromagnetic radiation includes: high energy UV, Xray, Gamma ray UV radiation
    • Alpha Radiation Injuries Particulate radiation Particulate radiation Consists of 2 neutrons and 2 protons Cannot penetrate skin Dangerous if internalized (ingested or inhaled), id decays when inside the body Beta High energy electrons Can penetrate skin and cause burns Penetration may be prevented by heavy clothing Internalization is dangerous Neutrons Generally from nuclear explosion Penetrates tissue causing radioactivity and damaging tissue
    • Radiation Injuries signs and symptoms signs and symptoms Early vomiting correlates with radiation exposure c LD 50/30: Dose causing 50% mortality in 30 days is 4.5 Gy No documented survival with >10 Gy Dermatologic Cutaneous burns from localized exposure Delayed blistering and desquamation weeks later
    • Radiation Injuries signs and symptoms signs and symptoms Hematopoietic Syndrome: Destruction of bone marrow Pancytopenia resulting in anemia, bleeding and infections Gastrointestinal Syndrome: Prodrome of N/V/D Symptoms worsen after 1 wk with dehydration, bloody diarrhea and sepsis Death within 3-10 days CNS Syndrome: Nausea, vomiting, ataxia Seizures, AMS Death within hours to days
    • Radiation Injuries Diagnosis Diagnosis CBC Lymphocyte count at 48 hours is prognostic Good prognosis >1500 Poor prognosis <1500
    • Radiation Injuries signs and symptoms signs and symptoms Decontamination Removal of clothing, showers, and water Blocking agents to reduce amount of absorbed radiation Potassium iodine prevents absorption by the thyroid Close wounds early to decrease infection risk Supportive care IVF Anti-emetics Leukocyte reduced blood transfusion if necessary Antibiotics and antivirals if neutropenic
    • Animal bites Human Human Direct bite or “Fight Bite” Look for lacerations of the knuckle due to contact with teeth Xray For closed fist injuries to rule out fractures which may require inpatient antibiotics Rule out foreign body
    • Human Bites Management Management Fight Bites Irrigation and wound exploration in full range of motion Admit all infected bites Consider admitting uninfected fight bites to ensure close follow up Antibiotics for all wounds with or without infection
    • Human Bites treatment of infection treatment of infection Cover skin flora and oral flora Eikenella corrodens Augmentin is recommended Other options: Clinda or erythromycin + doxy, keflex or cefuroxime Wounds on extremities should not undergo primary repair Consider prophylaxis for communicable
    • cat and dog bites Dogs and large animals cause crush injuries Look for underlying tissue damage and fractures Cats and smaller animals cause puncture injuries Wounds appear benign but have higher risk of infection
    • cat and dog bites causes of infection causes of infection Dogs: Staph>Strep>Eikenella>Pasteurella Cats: Pasteurella>Actinomyces>Bacteroides>F usobacterium Infection rate of 50-80%
    • cat and dog bites management management Thorough neurovascular and tissue exam Treat underlying injury If bite to the head in young children consider penetrating injury to the skull Neurosurgery consultation and admission if suspected Update Td Assess risk for rabies
    • cat and dog bites Antibiotics Antibiotics Most cat bites should be treated Dog bites should be decided on a case-bycase basis Regimens Augmentin Clinda + Cipro Clinda + Bactrim
    • Snake envenomations 25 poisonous species of 2 major families native to North America Viperidae Elapidae
    • Viperidae Subfamily: crotalids or pit vipers Subfamily: crotalids or pit vipers Includes: rattlers, cottonmouths, copperheads, and the western diamondbacks 98% of all US envenomations Identified by: Triangular-shaped head Nostril pits anteroinferior to eye Elliptical pupils Single row of plates at distal tail
    • viperidae
    • Viperidae envenomation signs and symptoms signs and symptoms Most bites are “dry” Systemic Effects Weakness, paresthesias Metallic taste Chest pain and dyspnea Local Effects Pain, erythema, edema, bullae Compartment syndrome and rhabdo Hematologic consequences Coagulopathy, thrombocytopenia, bleeding
    • Viperidae envenomation diagnosis diagnosis CBC Coags UA Total CK Check compartment pressures XRay to rule out foreign bodies
    • Viperidae envenomation management management Antivenin CroFab (Crotalidae polyvalent immune Fab) Sheep product with few allergic manifestations Administer to most patients Antivenin (Crotalidae) polyvalent Horse serum with higher risk of anaphylaxis and serum sickness Only for moderate to severe envenomations Consider fasciotomy for compartment syndrome Observe “dry bites” for 8 hours Admit all true envenomations
    • Elapidae Family Includes: Coral snakes, cobras and mambas Identified by: Round pupils Double row of plates at distal tail Brightly colored “Black on yellow kill a fellow, red on black venom lack”
    • Elapidae
    • Elapidae envenomation signs and symptoms signs and symptoms Delayed for up to 13 hours Patients may look deceptively well Local Symptoms Pain and edema may be limited Neurotoxicity causes predominate symptoms Blurred vision, ophthalmoplegia, ptosis, fasiculations, paresthesias and hypersalivation Late symptoms: paralysis of face, palate, jaws and vocal cords Respiratory failure from neuromuscular blockade
    • Elapidae envenomation management management Do not underestimate degree of envenomation due to lack of initial symptoms All Eastern and Texas coral snake bites should be treated with antivenin Micrurus fulvius antivenin Symptoms completely reversible Admit all coral snake bites
    • Spider Bites Black Widow Black Widow Identification: red hourglass shape on ventral abdomen Symptoms and signs Systemic Autonomic instability Hypertension and tachycardia Nausea and vomiting Neurologic Muscle cramps, Headache Severe abdominal pain Fasiculations and ptosis
    • Black Widow Bite Management Management Supportive Care Analgesia Treat cramps with benzos IV calcium is discouraged Antivenin only for severe symptoms Horse serum derived, may cause anaphylaxis and serum sickness
    • Spider Bites Brown Recluse Brown Recluse Identification: violin-shaped markings on back Symptoms and signs May cause fever, chills, malaise, and hemolysis “Bull’s eye” lesion: red and white, with a necrotic center May become so severe it requires plastic surgery Rarely hemolysis and renal failure result in mortality
    • Brown Recluse Diagnosis Check labs for hemolysis, renal failure and DIC Management Consider anthrax in the differential Local wound care Some evidence for dapsone (remember side effects) Supportive care
    • Scorpion Stings The “Bark scorpion” is the only potentially letal scorpion species in the US Found in: AZ, NM, CO Signs and Symptoms Localized pain and inflammation (most common) Neurotoxic Roving eye movements Opisthotonic posturing Paresthesias
    • Scorpion Stings treatment treatment Antivenin available for severe symptoms Supportive care
    • Lethal jellyfish stings Box jellyfish Box jellyfish Carry the most lethal marine toxin Over 5000 deaths worldwide Severe pain and spasms Parasympathetic overstimulation leads to cardiac arrest Paralysis, respiratory weakness and drowning
    • Lethal jellyfish stings Portugese man-of-war Portugese man-of-war Severe pain as if being struck by lightening Rarely deadly
    • Lethal jellyfish stings management management Remove and prevent unfired nematocysts Wash with seawater or sterile saline Fix nematocyst with household vinegar Remove tentacles with gloves and forceps Coalesce nematocyst with talcum powder or shaving cream then scrape off skin with knife Antivenin exists for box jellyfish from Australia but ineffective after symptom onset Supportive and local wound care Apply topical anesthetic, antihistamine or steroid Update TD