Environmental Flashcards
general principles of non-freezing cold injuries and 2 examples
non-freezing = occur from wetness at above freezing temps (eg trench foot, chilbains)
presentation of trench foot
feet are initially pale, anesthetic, can be pulseless. after re-warming they change slowly (ie takes 2-3 days), then they become hyperemic with severe burning pain
mgmt of trench foot
supportive, rewarming, keep the dry and bandaged, watch for infection
two meds you can try in chilblains? one topical and one oral
nifedipine PO or topical corticosteroids
in addition to good supportive mgmt
what is pannaliculitis
necrosis of subcutaneous tissue from prolonged exposure to temps just above freezing.
no effective tx, resolves on its own
pathophys of frostbite
arachidonic acid cascade leads to vasoconstriction, platelet aggregation, erythrocyte sludging which leads to thrombosis –> ischemia, necrosis, dry gangrene
when to assess frostbite grade?
after 60 mins of rewarming
frostbite grading
how to re-warm frostbite
water immersion at 37-39 degrees, ideally circulating. try and use heater. do this for 30-60 mins, until extremity is erythematous and pliable
can use warm cloths for face/ears
expect ++ pain and pre-treat
management of frostbite: core treatments and post re-warming pulse deficits
note iloprost and TPA
WMS guideline = aspirate clear blister, leave hemorrhagic blisters alone
which protocol to use for frostbite mgmt in deep frostbite?
yukon protocol (can be googled)
temp that defines hypothermia
core temp under 35
primary vs secondary hypothermia
primary is from cold environment
secondary is from loss of thermoregulation from some other process (eg burns, sepsis, trauma, metabolic etc)
core temp, symptoms, mgmt of hypothermia: stage 1
core temp, symptoms, mgmt of hypothermia: stage 2
core temp, symptoms, mgmt of hypothermia: stage 3
core temp, symptoms, mgmt of hypothermia: stage 4
what is afterdrop in hypothermia?
where core temp continues to drop even after re-warming has begun. pts might cont to get worse, but just need to stick with it.
ECG changes in hypothermia
bradycardia, afib/flutter, long PR, QRS widening, long QTc (kind of hyperK like)
++ osborn J waves (can be misdiagnosed as STEMI)
are afib/flutter pathologic in hypothermia?
not really, they are expected rhythms. myocardium is +++ irritable though, especially below 32 risk of malignant arrhythmia increase .. lower temp = higher risk
where to measure core temp?
if intubated –> esophageal
if not rectal or bladder –> often lag behind true temp
what temp do you need to get up to before terminating a hypothermic code?
core temp > 32
pts in cardiac arrest often have hypothermia, if accurate core temp is > than _____, then cause of arrest was not hypothermia initially
32
rewarming techniques mostly used in stage 2-3 hypothermia
minimally invasive (aka passive external) and active external
can consider active internal in more severe HT, practically only use bladder lavage, but know others for exam
rewarming types/techniques
for active internal:
IV fluid should be used if hypotension/hypovolemia, otherwise hold off
-only really ever use bladder lavage, unless in cardiac arrest, can consider thoracic lavage
things to consider before starting CPR in hypothermia
it can be +++ hard to check for a pulse, if any signs of life (breathing, movement, or pulse), just wait. consider using POCUS
defibrillation/epi in hypothermic cardiac arrest
up to 3 shocks and 3 doses of epi, then only use once core temp increased (? up to 30)
algorithm for termination of resuscitation in hypothermia (mostly just for reference)
late ditch effort, with pretty good evidence, in stage 3 and 4 hypothermia
ECMO! transfer if can get there within 6 hours.
3 types of minor heat illness
heat edema, prickly heat, heat cramps,
could put heat stress in here too
what is heat edema?
mgmt?
mild swelling of feet, ankle and hands (usually non-pitting), that doesn’t interfere with function in anyway
mgmt = supportive, elevation etc. no role for diuretics
what is prickly heat? aka heat rash, aka miliaria rubra
itchy, red maculopapular rash from blocked sweat ducts. ITCH is main feature
what are heat cramps?
mgmt?
painful muscle spasms (most commonly calves), when prolonged exposure/exertion in heat, especially when replacing fluid loss with free water.
mgmt: self limited, PO or IV electrolyte replacement, cooling
what is heat stress( aka heat exhaustion)?
mgmt of same
normal or elevated core temp (but usually <40), n/v, dizziness, HA, malaise
heat stress (aka heat exhaustion) vs heat stroke
heat stroke: temp >40, NEURO ABN (AMS, confusion, delirium, seizure, ataxia etc)
heat stress mgmt
fluid/electrolyte (PO or IV), removal from environment,
only need to actively cool if they don’t respond to treatment after 30 mins, cool to temp <39 as can progress to heat stroke even after removal from environment.
2 cardinal features of heat stroke
hyperthermia (>40), AMS/neuro ABN
what core temp do you target in heat stroke when cooling.
target approx 39, then stop cooling to avoid overshoot hypothermia
cooling methods (3 common and 2 extreme)
common:
1. evaporative: spray pt with water, then blow cool air over them
- immersion cooling: body bag or bathfub with with ice
- ice packs in groin and axilla and neck
extreme: ECMO, body cavity lavage
monitor core temp whole time, target 39, avoid overshoot hypothermia
mgmt of bee/wasp stings
remove stinger, wash with soap and water, NSAIDs for pain, anti-histamines for itching
topical steroids can be tried, but limited no evidence
natural course of large local reactions for bee/wasp stings?
increase for 1-2 days, then go away after about 10 days. often develop lymphangitis.
superimposed infection is rare.
black widow spider bite symptoms and mgmt
pain –> can be local or whole limb
muscle cramps/spasms
hypertension and tachycardia are common
generally supportive with analgesics, benzos, call poison control if not responding to those and can consider anti-venom
%age of dry rattlesnake bites
25%
diagnosis of rattlesanke bite envenomation vs dry bite
envenomation=
snake bite PLUS:
- local injury (ecchymosis, swelling
-hematologic abn (prolonged INR/PTT, thrombocytopenia)
-systemic symptoms (hypotension, tachycardia, paresthesias)
first aid for rattlesnake bites
-dont do anything crazy/weird (incision, cupping, sucking etc)
-don’t tourniquet, can do constriction banding (if prolonged time to antivenom) = rope or penrose drain above bite to obstruct venous/lymphatic return, but maintain pulses distally!
-immoblize limb below level of heart
-remain calm/restrict activity
-get out of reach of snake so dont get bit again
hospital treatment for rattlesnake bite
supportive
CroFab – > call poison control
how long to observe al patients with a snake bite with potential for envenomation?
6-8 hours before calling it a dry bite
What is drowning
Submersion in liquid leading to resp difficulty or resp arrest.
Don’t need to die to call it drowning
Drowning event algorithm (mostly for reference)
Drowning victims with cardiac arrest who are normothermic. How long to resuscitate?
Consider stopping upon arrival to Ed. Recovery without profound neuro deficit is rare
2 broad categories of dive related illness?
barotrauma of descent
barotrauma of ascent (includes decompression sickness and AGE)
3 types of barotrauma of descent, their symptoms and mgmt
2 types of barotrauma of ascent, their symptoms and mgmt
(name two that aren’t decompression sickness, its a diff slide)
best way to prevent decompression sickness?
follow dive tables
pathophys of decompression sickness?
inert gas in tissues and vessels form bubbles when pressures decrease (ie why it happens on ascent)
one absolute contraindication to hyperbaric therapy?
untreated pneumothorax
mgmt of decompression sickness and arterial gas embolism?
HBO, consult hyperbaric centre even if type 1 DCS
types decompression sickness and their symptoms
What is “the bends”
Decompression sickness type 1
Cutoff between moderate, high and extreme altitude
Moderate: 2500-3000m
High: 3000-5000m
Extreme > 5000 m
3 distinct entities of high altitude illness
Acute mountain sickness
High altitude pulmonary edema (HAPE)
High altitude cerebral edema (HACE)
What is the definitive tx for all high altitude illnesses?
Descent!
How to prevent high altitude illness?
Ascend slowly
Acclimatize at each altitude
Avoid etoh and other sedatives
Avoid overexertion
Role of acetazolamide in acute mountain sickness
Prevents and treats symptoms
Symptoms and treatment of acute mountain sickness
Viral/hangover like symptoms.
Usually self limited and resolves with acclimatization. No further ascent until symptoms resolve, deceive, severe or unrelenting symptoms. Can’t treat with acetamide to speed up acclimatization or use it prophylactically
Symptoms of high altitude, pulmonary edema. Management of same.
Presents like acute mountain sickness, symptoms plus dry or productive cough. Onset 2-4 days after arriving at altitude. Pulmonary oedema on chest x-ray. Treatment is decent plus supplemental oxygen diuretics not routinely recommended
Symptoms and treatment of high altitude cerebral edema
Acute mountain sickness symptoms plus ataxia.
Onset 2 to 4 days after arrival at altitude.
Treatment is immediate descent/evacuation. Can give dexamethasone to increase face edema.
What voltage is cutoff for high voltage? Above what value is risk of serious injury/death increased?
> 1000 V is high voltage
600 V is cutoff for serious injury
What is electrical arch injury
It is a blast or burn injury caused by the arch of current going from one conductor to another. Can produce enough to heat to kill someone up to 10 feet away from the arch
Do asymptomatic pts, with normal ECGs in hospital, develop artythmia later on after a low voltage (<1000 V ) injury?
Nope!
High voltage injury pts should be treated with what mindset?
Trauma!! Can cause a huge range in injury. Compartment syndrome, fracture, any degree of neurological injury both centrally and peripherally, burns etc
What are two serious complications that can occur with low voltage injury?
VF
Compartment syndrome
Spectrum of injury in electrical injury
When to work up pts with low voltage electrical injury
If there are any symptoms or abnormal exam findings they need work up. Everyone should have an ECG regardless of symptoms
Electrical vs lightening injuries (table)- mostly for reference
But know current types and pathway
What is flashover in lightning injury?
Phenomenon where lightning travels over the surface of the body and makes it less likely to cause internal cardiac injury or muscle necrosis compared to human generated electrical energy
How is mass casualty from lightning/electrocution triaging different than other mechanisms?
Patient with respiratory or cardiac arrest should be treated first in electrical/lightning injury
What is the relative prognosis of cardiac arrest victims from lightning strike?
Pretty good compared to most other causes of cardiac arrest. Prolonged CPR/resuscitation should be attempted.
What is the Lacey red/firming pattern on the skin called and lightning strike?
Lichtenburg figures
What is keraunopatalysis
Transient paralysis with blue modelled pulseless extremities. Results from sympathetic activation and extreme basal restriction. Usually results over several hours. A.k.a. stunning from lightning injury.
Complication of lip burns in pediatrics?
Labral artery injury, which can occur up to two weeks after an injury when eschar falls off
Need to re warm cardiac arrest patients to ___ before calling code
32 degree core temp
How long do you need to observe non-fatal drowning patients?
Should be observed for 4 to 6 hours as respiratory can occur in a delayed fashion. If asymptomatic at six hours can send home.
To protect protective reflexes and drowning victims that can improve outcomes?
Diving reflex, mostly in young infants.
Laryngospasm
Pathophysiology of submersion injury/drowning
Aspiration causes loss of surfactant and alveolar collapse leads to hypoxia leads to brain cell death after three minutes
2 plants that cause anticholinergic toxicity?
Jimsomweed
Deadly nightshade
What plants contains ricin?
Castor bean
How to divide mushroom poisoning based on timing of symptoms and severity
Early onset GI symptoms (0-4 hrs) likely benign
Late onset GI symptoms (6-24 hrs) has potential to be quite serious
Seizures from mushroom toxicity consider giving what?
Pyridoxine (false morel mushroom has similar toxicity to isoniazid)
General tx of mushroom toxicity
-Mainly supportive
-Monitor for early symptoms (0-4hrs indicated probs benign)
-Counsel re delayed onset symptoms
-Monitor glucose as hypoglycaemia common
-atropine if anticholinergic tox
-consider pyridoxine for refractory seizures (false morel mushroom)
- probs contact poison control for any symptomatic ingestion
