Environmental Emergencies Flashcards
Exertional heat illness
- 4 conditions
- heat cramps
- Heat syncope
- Heat exhaustion
- Heat stroke
Heat Cramps
- overview
- Heat does not trigger cramping
- Usually involves exercise to high intensity or to exhaustion
- Occurs more often in heat, can occur in cooler temps
Heat Cramps
- tx
- Hydration, sodium (oral just as good as IV)
- Stretching: especially young athletes
- Prevention - sodium load before activity
- “salt losers” more at risk
Heat syncope
- overview
- Heat does not cause syncopal events, should be called exercise associated collapse
- Pt cannot stand/walk dt lightheadedness or syncope
Usually after endurance event
Heat syncope
- mechanism
- abrupt decrease in venous return after activity is complete.
- High systemic vascular resistance during exertion
- Stop exertion and get vasodilation from loss of skeletal muscle pressure –> precipitous decline in venous return
- results in collapse
Heat syncope
- presentation and treatment
- Core temp normal or only slightly elevated
- Tx: hydration, rest
- Mental status changes quickly resolve (<15 min)
- Failure to improve within 20 min should prompt a syncope workup (sent to hospital)
Heat Exhaustion
- overview
- Inability to maintain adequate CO dt strenuous physical exercise and environmental heat stress
- during exercise, free water loss exceeds electrolyte loss (including Na)
Heat Exhaustion
- presentation
- Can manifest as collapse, person cannot continue with activity
- Core temp usually elevated, 101-104
- No sig CNS dysfn, no AMS, Sz, delirium (one way to differentiate from heat stroke which does have CNS alterations)
- Tachycardia +/- hypotension, dehydration
- Weak, lightheaded, lack of coordination
HA, abd cramps, nv/d
Heat Exhaustion
- treatment
- Place supine with feet elevated
- Move to cool area
- Cool until body temp 101
- Cool by immersion, spray with cool water
- Rehydrate orally if no vomiting, IV with normal saline if necessary
- No rapid improvement - send to ER
Heat stroke
- characteristic sx
CNS dysfunction, some form of AMS
- disorientated, HA, irrational, irritable, emotional unstable, confusion, AMS, coma, seizure
Heat stroke
- core body temp
elevated
Heat stroke
- effect on organs and tissue
rhabdo, kidney, liver injury
Heat stroke
- clinical
- tachycardia
- hypotension
- nvd
- weak
- profuse sweating**
- thirst
- cramps
- ataxia
- dehydration
- loss of muscle function.
- *Not true that when you stop sweating it is a problem!!! Many people think this
Heat stroke
- treatment
- Rapid cooling!! Get a core temp
- Cold water immersion - ideal, with ice
- Ice/wet towel rotation
- High flow cold water dousing, use fans
- Cool first, transport second!! (try to cool to 102.2F), if no thermometer, cool until they shiver or immersion for 15-20 minutes
Heat stroke
- workup
general stuff:
CBC, CMP, CK, coag, serum lactate, ABG, CXR, CT head, ongoing monitoring
Heat stroke
- Treatment
- Cooling
- IV fluids
- Electrolyte abnl correct (Na, K)
- Treat complications: rhabdo, kidney injury, DIC, cardiac dysfunction, liver failure
Heat stroke
- points to remember
- Severity of heat illness might not be apparent initially
- Body temp can continue to increase!
Morbidity and mortality related to duration of elevated temp
Hypothermia
- define temps
- how to measure temps
- core temp <95
- Mild 90-95
- Moderate 82-90
- Severe <82
- **Not super important to know the difference…
Hypothermia
- how to measure temps
- Core temp: rectal temp normal 99.6F/37C, 95-99.6 is normal
- How to measure: usually a rectal temp? But most thermometers don’t’ measure less than 93 temps (made to measure elevations, not lows)
Hypothermia
- causes
- Increased heat loss or decreased heat production
- Environmental exposure (usually alcohol is involved)
- Metabolic: Hypopituitary, hypoadrenal, hypothyroid (not common)
- Insufficent fule: Hypoglycemia, malnutrition
- Neuromsk: Extremes of age, Impaired shivering, Inactivity
- Other: Sepsis, esp at extremes of age, be very concerned when have cold baby or old person!
Hypothermia
- risk factors
- Alcohol use, homeless, psych, elderly
- When get cold, body tells you to react, if impaired or psych illness, you don’t do it…
Hypothermia
- Symptoms key
follow mental status
Hypothermia
- mild sx
- Mental status is normal
- Tachypnea, tachycardia, ataxia, dysarthria, impaired judgement
- Shivering
- Cold diuresis - vasoconstrict peripherally, all fluid centrally, including to kidney = increased urine output
Hypothermia
- moderate sx
- Altered mental status
- Bradycardia, CNS depression, hyporeflexia,
- Loss of shivering, paradoxical undressing
Hypothermia
- severe sx
- Basically unconscious
- Hypotension, bradycardia, ventricular arrhythmias
- Areflexia, coma
Hypothermia
- PE
- Heart is very sensitive to movement, be careful moving them, try not to jostle
- Measure core temp best you can
- Don’t forget to exam the entire patient, look for trauma, infection source
Hypothermia
- Labs
- Routine: cbc, cmp, drug screan, ck, fsbs, etc. etc. TSH, T4, cortisol if old person from nursing home
- Main takeaway: know the hgb! Will be artificially increased due to volume reduction. If have a LOW hgb, something else is going on
Hypothermia
- EKG findings
- Slow impulse conduction
- All intervals are prolonged!
- Afib is common, esp during re-warming
- **Osborn wave or J wave classic finding. Taller the wave, usually the colder the patient, best seen V2-V5. Also seen in SAH, brain injury, etc.
Hypothermia
- tx
- ABCs
- CPR
- Treat underlying condition!!!
- A lot of drugs don’t’ work at these temps (insulin, epinephrine, etc.)
Rewarm as soon as possible
Hypothermia
- rewarming techniques
- Passive’ blanket, warm room
- Active external: Bair hugger (blows warm air), warm blanket. Wrap head
- Active core: warm IV fluids (hard to get them THAT warm), heated humidified air (surface area of lungs is huge, this works well), peritoneal irrigation, thorax irrigation
- Extracorporeal (severe cases): hemodialysis, cardiopulmonary bypass, ECMO (being used more often, the heart lung machine)
- can take a long time! Hours and hours
Hypothermia
- complications related to rewarming
- Hypotension from cold diuresis, dehydration and fluid shifts (isotonic fluid, pressors?)
- Electrolyte changes
- Rhabdo is common
- Arrhythmias: usually brady (don’t’ treat) same with afib and a flutter. Ventricular arrhythmias: need to warm the patient!!
Nobody is dead until…
they are WARM and dead
Chilblains/pernio
- description
- Cold induced erythocyanotic skin lesion
- Abnl vascular response to cold, vasoconstriction/vasospasm, inflammatory response. Not sure why it happens in some people. Exaggerated response to cold.
Chilblains/pernio
- presentation
- tx
- MC fingers and toes, common on kids (esp on cheeks)
- Confused for bite or infection often!
- Pruritis, pain, burning with rash
- 12-24 hours after cold exposure, takes weeks to resolve
- No treatment - just don’t get cold, stay warm :)
Frostbite
- overview
- Freezing of tissue, exposure to subfreezing temps - ice formation extracellularly or inside cells if rapid
- Inflammatory response and ischemia and ultimately necrosis
Frostbite
- two classification schemes
- based on level at which skin lesions are noted after rapid rewarming, how far along the skin there is cyanosis
- Traditional system, based on how deep the tissue is injured, similar to burn classifications
- more details in press
Frostbite
- Treatment
- If pt has possibility of getting cold again, don’t rewarm!! Think about helicopter transport (not very warm)
- Do not rub, use fire or stove to rewarm
- Skin will be insensate before, might develop bullae after thawing
- Rewarm
- Wound care - long term. Possible amputation
Frostbite
- how to rewarm
- Immerse in heated water, gentle motion of the water
- Complete when tissue is red/purple and soft to touch (15-30 min)
- Will be painful, will need pain control (IV narcotics??)
Trenchfoot/Immersion foot
- WWI trench warfare
- Nothing to do with temp, more due to exposure to dampness
- Tight boots exacerbate
- Feet: red, edematous, numb, painful
- Can develop hemorrhagic bullae, loose tissue
- MC with homeless population
Drowning
- epidemiology
- Leading cause of death in children <5 in states with beaches and pools (CA, FL, AZ)
- Highest incidence among males, AA, low socioeconomic state (don’t know how to swim).
- Second highest males 15-25
Drowning
- definition
- “process of experiencing respiratory impairment from submersion or immersion in liquid
- Bunch of terms but just call it drowning
Drowning
- risk factors
- lack of supervision
- can’t swim or over estimate ability
- risk taking
- drug and alcohol use
- concomitant trauma, stroke, MI
- hyperventilate prior to shallow dive: reduce PaCO2, while hold breath, PaO2 falls before PaCO2 rises enough to trigger urge to breath, producing hypoxia and LOC
Drowning
- pathophysiology overview
- Initial breath holding and panic lead to reflex inspiratory effort leads to aspiration or laryngospasm (water in lungs) leads to hypoxia leads to acidosis and cardiac arrest.
- Degree of hypoxia, how long under, how much aspirate = how bad
- Doesn’t take much water to affect O2 exchange
Drowning
- pulmonary pathophysiology
- Washes out surfactant - can’t echange gases
- Causes pulmonary edema, inflammatory response in lungs - no exchange and ARDS
- SOB, crackles, wheezing. Can happen rapidly or insidously.
- Work of breathing is important to observe
- Clinical dx, CXR can vary (and lag behind clinical presentation and improvement)
Drowning
- Neuro pathophysiology
Hypoxia and ischemia - neuron damage and cerebral edema
Drowning
- cardiac pathophysiology
- Arryhtmias usually dt hypoxemia
- Acidosis = tachypnea which leads to bradycardia to PEA to asystole
Drowning
- management
- Ventilation is MOST important initial treatment
- Rescue breaths ASAP
- C-spine injury: routine c-spine immobility is not recommended without sx of injury (breath is most important unless you are pretty sure c-spine injury)
- Airway management:
• Intubation for neuro deterioration, inability to protect airway
• Bi-PAP: inspiratory and expiratory setting, VERY helpful - Trauma eval: look for 2ndary injuries
- Salt vs. fresh: doesn’t matter
- CXR: findings lag
Species of insect that cause problems
hymenoptera
bees, wasps, yellow jackets, hornets, fire ants
Sting
- local reaction
- Redness to sting site, mild, transient
- Painful swelling
- 1-2 days, treat with cold compress
- Fire ants: sterile pustule
Sting
- large local reaction
- Tx
- 10% of individuals
- Gradual enlargemetn over 1-2 days
- Cold compress
- Low does, short course prednisone
- NSAIDs
- Antihistamine
Sting
- tx
- remove the stinger, flick it off
- no need for tetanus
- secondary infection: 3-5 days after sting, worsening redness, swelling, pain, fever (MC in yellow jackets and fire ants)
- Anaphylaxis is very uncommon
Black widow spider
- bite situation
- lactrodectism
- Usually with outdoor activities
- Initial bite: usually LE is asx or mild pain
Black widow spider
- presentation
- Systemic sx 30-120 min after bite
- Muscle pain most prominent feature. Pain in extremities, back, abdomen, agonizing
- Acute/surgical abd picture (peritoneal signs)
- Self limited, usually resolves 24-72 hours
- Diaphroesis corresponding to affected muscle group in 60%
- Presenting 24 hours after bite, can have burning in sole of feet, pain below knees, sweating of lower legs
Black widow spider
- bite characteristics
Skin with central clearing area with surrounding red perimeter, infection rare
***no necrosis
Black widow spider
- tx
- Wound care
- Pain care
- Oral benzo?
- Severe
• IV drugs
• No calcium
• Antivenom but in short supply and has own problems (can induce anaphylaxis), only for very severe situations
Brown recluse spider
- venom enzyme to know
phospholipase D
Brown recluse spider
- bite
- red plaque or papule, develop central pallor
- Occasionally vesiclation around site
- Can develop dark, depressed center, dry eschar 24-48 hours after.
- Can expand rapidly
- **Necrosis!!
Brown recluse spider
- stages of bite progression
Papule develops dusky red or blue –> dry depressed center, may be anesthesia in center –> eschar and then breaks down to form ulcer, may enlarge in gravitational manner
Brown recluse spider
- systemic sx
- malaise
- n/v
- fever
- myalgia
Brown recluse spider
- mnemonic to differentiate from other skin lesions
- Numerous - usually just one
- Occurrence - secluded areas in home like attic, garage, closet
- Timing - Nov - March not usually recluse
- Red center - recluse usually pale
- Elevated - recluse is usually flat
- Chronic – lesions >several weeks unlikely to be recluse
- Large - usually smaller than 10 cm
- Ulcerates too early - recluse not until >7 days
- Swollen: recluse usually not very swollen
- Exudative: recluse usually not moist or exudative or have frank pus
Three snakes to worry about in OK
- copperhead
- cottonmouth
- rattlesnake
25% of snake bites are
dry - no venom
Envenomation syndrome from snake bite
- Local tissue damage
- n/v/d, weakness, diaphoresis, affects coags, can cause rhabdo
- Tachycardia, hypotension
- Oral paresthesia, usually taste, fasciculations
Snake bite
- comparison of bites from diff snakes
- Rattlesnake - more severe s/sx vs. cottonmouth
- Copperhead usu cause limited local sx
How to consider pt identification of snake
Pt ID of snake is often wrong or not available… treat based on s/sx
overview of snake bite w/u
- Assess pt
- initial labs
- treat pain, etc.
- Look for signs of severe envenomation
Snake bite tx
- Remove jewelry
- Immobilize
- Clean wound
- Transport supine
- Crofab: Purified Fab fragments of sheep IgG, binds venom, might need multiple doses, cleared by kidney
