Environmental Emergencies

Mary Welch, DO

Electrical injuriesTypes of Current

Direct:Electrons flow in one directionEx. Batteries

Alternating: Electrons flow back and forth (60 Hz)

Used in household outlets

Generally more dangerous

Electrical injuriesMechanism 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 DepolarizationMay 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 CurrentPowerful Muscle spasm results in fractures

More like to to cause traumatic fractures

Alternating CurrentCauses 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 ThrombosisMore common due to slower flow and less ability to dissipate heat

Delayed Arterial ThrombosisMay appear similar to compartment syndrome

Mesenteric artery thrombosis

CNS injury

Seizure

Loss of consciousness and amnesia

Median nerve injury

Autonomic dysfunctionPupils 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 symptomsSimilar 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 managementBe 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 illnessacute mountain sickness

Caused by hypoxia

Decreased oxygen pressure increases cerebral blood flow resulting in cerebral edema

acute mountain sicknessSigns and symptoms

Headache

Nausea and vomiting

Insomnia

Decreased urination

Peripheral or facial edema

Retinal hemorrhage

acute mountain sicknessTreatment

Halt ascent

Acetazolamidecarbonic 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 illnessHigh 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

High altitude pulmonary edema

Occurs a few days after ascent

Symptoms worse at night

Cough

Decreased exercise tolerance

Low grade fever

Tachycardia, Tachypnea

Rales and ronchi

High altitude pulmonary 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

Middle EarMost 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 EarRapid 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

Sinus SqueezeFrontal 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

Lung volume equalized by appropriate inspiration and expiration

Complications due to rapid descentHemoptysis

Complications due to rapid ascentDue to inadequate exhalation:

Lung volume doubles every 33 feet, exhalation required to prevent injury

Inexperienced divers may hold their breath

Complications from ascent

PneumothoraxMay develop hypotension due to tension PTX

Pneumomediastinum

Arterial gas embolism

ManagementTreat 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 sicknessrisk factors

Increased depth of dive and speed of ascent

Multiple dives in the same dayNitrogen lasts for 12 hours

Air flight soon after dive

ObesityNitrogen is fat soluble

Poor physical conditioning and strenuous exercise while under water

Decompression sicknessSymptoms 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 sicknessDiagnosis

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 sicknessmanagement

Administer 100% oxygen

IV hydration

Aspirin if not bleeding

Hyperbaric treatment

PreventionSlow ascent

Limit depth or dive time

No flying for 12-24 hours

Breathing gas underhigh pressure

Breathing oxygen or nitrogen at high partial pressure is neurotoxic

Oxygen toxicityRisk begins at 200ft

Tingling

Focal seizures

Vertigo

Nausea and vomiting

Breathing gas underhigh pressure

Nitrogen NarcosisRisk begins at 100ft

Incapacitating at 300ft

Resembles alcohol intoxication

PreventionDeep divers use mixtures lower in oxygen mixed with helium or hydrogen

ManagementRabidly 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 Injuriesionizing 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 Injuriesnon-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 Injurieselectromagnetic radiation

Self-propagating waves of energeny with electric and magnetic components

Ionizing or non-ionizingIonizing electromagnetic radiation includes: high energy UV, Xray, Gamma ray

UV radiation

Radiation InjuriesParticulate radiation

AlphaConsists of 2 neutrons and 2 protons

Cannot penetrate skin

Dangerous if internalized (ingested or inhaled), id decays when inside the body

BetaHigh energy electrons

Can penetrate skin and cause burns

Penetration may be prevented by heavy clothing

Internalization is dangerous

NeutronsGenerally from nuclear explosion

Penetrates tissue causing radioactivity and damaging tissue

Penetration may be prevented by heavy clothing

Internalization is dangerous

Radiation Injuriessigns 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

DermatologicCutaneous burns from localized exposure

Delayed blistering and desquamation weeks later

Radiation Injuriessigns 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 InjuriesDiagnosis

CBCLymphocyte count at 48 hours is prognostic

Good prognosis >1500

Poor prognosis <1500

Radiation Injuriessigns and symptoms

DecontaminationRemoval 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 careIVF

Anti-emetics

Leukocyte reduced blood transfusion if necessary

Antibiotics and antivirals if neutropenic

Animal bitesHuman

Direct bite or “Fight Bite”

Look for lacerations of the knuckle due to contact with teeth

XrayFor closed fist injuries to rule out fractures which may require inpatient antibiotics

Rule out foreign body

Human BitesManagement

Fight BitesIrrigation 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 Bitestreatment of infection

Cover skin flora and oral floraEikenella 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 diseases

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 bitescauses of infection

Dogs: Staph>Strep>Eikenella>Pasteurella

Cats: Pasteurella>Actinomyces>Bacteroides>Fusobacterium

Infection rate of 50-80%

cat and dog bitesmanagement

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 bitesAntibiotics

Most cat bites should be treated

Dog bites should be decided on a case-by-case basis

RegimensAugmentin

Clinda + Cipro

Clinda + Bactrim

Snake envenomations

25 poisonous species of 2 major families native to North AmericaViperidaeElapidae

ViperidaeSubfamily: 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 envenomationsigns and symptoms

Most bites are “dry”

Systemic EffectsWeakness, paresthesias

Metallic taste

Chest pain and dyspnea

Local EffectsPain, erythema, edema, bullae

Compartment syndrome and rhabdo

Hematologic consequencesCoagulopathy, thrombocytopenia, bleeding

Viperidae envenomationdiagnosis

CBC

Coags

UA

Total CK

Check compartment pressures

XRay to rule out foreign bodies

Viperidae envenomationmanagement

AntiveninCroFab (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 envenomationsigns and symptoms

Delayed for up to 13 hoursPatients may look deceptively well

Local SymptomsPain and edema may be limited

Neurotoxicity causes predominate symptomsBlurred vision, ophthalmoplegia, ptosis, fasiculations, paresthesias and hypersalivation

Late symptoms: paralysis of face, palate, jaws and vocal cords

Respiratory failure from neuromuscular blockade

Elapidae envenomationmanagement

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 BitesBlack Widow

Identification: red hourglass shape on ventral abdomen

Symptoms and signsSystemic

Autonomic instability

Hypertension and tachycardia

Nausea and vomiting

NeurologicMuscle cramps, Headache

Severe abdominal pain

Fasiculations and ptosis

Black Widow BiteManagement

Supportive CareAnalgesia

Treat cramps with benzos

IV calcium is discouraged

Antivenin only for severe symptomsHorse serum derived, may cause anaphylaxis and serum sickness

Spider BitesBrown Recluse

Identification: violin-shaped markings on back

Symptoms and signsMay 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

DiagnosisCheck labs for hemolysis, renal failure and DIC

ManagementConsider 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 Stingstreatment

Antivenin available for severe symptoms

Supportive care

Lethal jellyfish stingsBox 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 stingsPortugese man-of-war

Severe pain as if being struck by lighteningRarely deadly

Lethal jellyfish stingsmanagement

Remove and prevent unfired nematocystsWash 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 careApply topical anesthetic, antihistamine or steroid

Update TD