Emergency Medicine Flashcards
Dx
- IgE-mediated, immediate onset reaction to protein antigen
- prior sensitizing exposure to antigen required
Anaphylaxis
Dx
- occurs on initial exposure to antigen
- not IgE mediated but clinically identical to anaphylaxis
Anaphylactoid reaction
When does biphasic anaphylactic reaction occur?
4-32h after initial episode
- due to release of secondary mediators, causing late-phase response
- > IL4, IL5, TNF-alpha
What is protracted anaphylaxis?
- refractory resp distress or hypotension despite appropriate medical rx
Type of hypersensitivity reaction
- immediate hypersensitivity - IgE mediated (e.g. urticaria)
Type I
Type of hypersensitivity reaction
- cytotoxic reaction - IgM and IgG mediated (e.g. Goodpasture syndrome)
Type II
Type of hypersensitivity reaction
- immune complex reaction - soluble immune complexes and complement mediated (e.g. serum sickness)
Type III
Type of hypersensitivity reaction
- delayed-type reaction - lymphocyte mediated (e.g. contact sensitivity)
Type IV
What cells degranulate in anaphylaxis?
Mast cells and basophils
- release of preformed primary mediators (histamines, proteases, eosinophil and neutrophil chemotactic factors, and heparin)
- due to membrane bound IgE on cells
Common causes of urticaria?
- IgE mediated
- direct mast cell release
- complement mediated
- arachidonic acid metabolism
- physical (cold, sun, etc)
- mastocytosis
Management of anaphylaxis?
ABCs
- d/c antigen exposure
- 2 large bore IV
- cardiac and O2 monitoring
EPI
- 0.3-0.5 mg IM adults
- 0.01 mg/kg IM kids (max dose 0.3mg)
- repeat 5-15min x1 if no response
- epi drip if no response and pt in extremis
0. 1mL of 1:1,000 epi diluted in 10cc NS at 1-2cc/min IV
methylprednisolone 1-2mg/kg IV (leukotriene production in delayed phase response)
diphenhydramine 1mg/kg IV (block H1 receptors)
ranitidine 1mg/kg IV (block H2 receptors)
- observe 6-8h
Standard management in bites?
- irrigate!!!
- tetanus, rabies vaccine, prophylactic abx prn
- check FB in wound
What do you administer to hypotensive pt not responding to bolus treated for anaphylaxis, if pt on b-blocker?
refractory hypotension = glucagon IV
What us Skeeter syndrome?
- local immune reaction to mosquito bites
What are mosquito vectors?
- malaria
- West Nile virus
- yellow fever
- dengue
- filariasis
What are tick vectors?
- Rocky Mountain spotted fever
- Lyme disease
What is potential pathogen in human bites that is resistant to Piperacillin and Ticarcillin?
- Eikenella corrodens
Treatment for human/dog/cat bite with established infection or prophylaxis for high risk bite?
Amoxicillin/Clavulante or Doxycycline (kid>9 yr), Ceftriaxone
Treatment mod-severe infection from human/dog/cat bite?
Ceftriaxone IM/IV +/- metronidazole
or Ticaricillin/clavulante or Pip-Tazo
if Pen allergy in adult
Ciprofloxacin +/- clindamycin
Pen allergy in kid
TMP/SMX +/- clindamycin
3 distinct zones of tissue in full thickness burns?
- zone of coagulation - white, charred central portion, necrotic tissue
- zone of stasis - red, may blanch with pressure initially but fragile blood supply may give way to AVN
- zone of hyperaemia - red, blanches with pressure, intact blood supply
Classification of burns
- thermal
- electric
- chemical
- radiation
Sequelae of electric burns?
- cardiac arrhythmia
- MSK injury to muscle/ligament/bone (high resistance of tissues) - compartment syndrome +/- rhabdo
- renal ATN due to CK
- CNS LOC, paralysis, resp depression, amnesia
- eye cataracts and keraunoparalysis from lightening (fixed dilated pupils)
Do you neutralize acid/alkali burns?
NO - exothermic reaction can worsen burn
-> irrigate with WATER
Do alkali burns cause coagulation or liquefaction more commonly?
- Liquefaction
alkali dissolves protein and collagen (liquefaction) penetrating deeper than acid burns
What systems more commonly affected by radiation burns? Best prognostic factor?
GI and hematologic (rapidly dividing cells)
- best prognostic indicator is absolute lymphocyte count within 48h of whole body exposure
How do you estimate TBSA?
Rule of 9s
- hand 1%
- head 9% (4.5% each front/back)
- trunk 18% front, 18% back
- arms 9% (4.5% front/back)
- legs 18% (9% front, 9% back)
- groin 1%
Indications of transfer to burn centre?
- partial thickness >10% BSA
- burns involving face, hands, feet, genetalia, perineum, major joints
- any third degree burn
- electrical (incl lightening) or chemical burns
- preexisting medical condition with potential impact on recovery
- concomitant trauma where burn = worst thing
- kids in hospital without peds
- special emotional/social/rehab required
Dx degree of burn
- red
- epidermis involved
- ++painful, tender to touch, intact 2 point discrim
- complete healing ins several days
Superficial (first degree)
Dx degree of burn
- red/blanched white, fluid-filled blisters
- epidermis, superficial (papillary) +/- deep (reticular) dermis involved
- ++ painful, tender to touch, 2 point discrimination intact or diminished
+/- scarring, may be hypertrophic with contractors across joints, healing 2wk
Superficial-Partial thickness (superficial second degree)
Dx degree of burn
- white and leathery or black and charred
- epidermis and both layers of dermis involved
- numb with loss of 2 point discrimination
- extensive time to heal (3-4wk) but may require wound excision and skin grafting
Deep partial thickness (deep second degree)
Dx degree of burn
- white and leathery or black and charred
- epidermis, dermis and subcutaneous tissues (fascia/ muscle/ bone) involved
- numb with loss of 2 point discrim
- extensive debridement, reconstruction of specialized tissues, skin grafting
Full thickness (third degree)
Management burns
- Td immunization prn
- neomycin/ polymyxin B or Bacitracin creams -> ensure good antimicrobial coverage without risk of allergic reaction and able to be removed easily to view wound bed
+/- blister debridement
Foley to monitor ins and outs
Analgesia
Fluids - Parkland formula
How do you decrease half life of CO-Hbg in blood?
100% O2
When do you use gastric tube for burn pt?
> 20% BSA can develop ileus lasting 4-5d
- increased metabolic rate requires nutritional support too
Parkland formula
fluid requirement = 4x body wt x % TBSA (partial and full thickness only)
- half in first 8h and the other half over next 16h
- electrical and full thickness require more fluids
- adjust based on urine output (adult = 0.5 mL/kg/h; child = 1mL/kg/h; infant = 2 mL/kg/h) and vitals
Investigations for burn pt?
- CBCD, lytes, BUN, Cr, glucose, INR, PTT, ABG with CO-Hgb, b-hCG
- ECG, CK-MB, trop, UA for urine Mgb
- type and screen if anticipate OR debridement
- CXR, CT head if altered LOC, bronchoscopy if serious inh injury
Key Q on facial injury pt?
- is your bite normal (malocclusion)
- any numbness (trigeminal nerve injury)
- seeing double (orbital #/ impaired EOMs)
Hyperthermia - is it pathologic or adaptive?
- hyperthermia is pathologic thermoregulatory failure
- fever is adaptive, cytokine-mediate response
Define hyperthermia
- core body temp >38 not due to fever
- rise in body temp above hypothalamic set point when heat-dissipating mechanisms are impaired (drugs/ disease) or overwhelmed by extern or internal heat
Where are peripheral thermoreceptors?
Skin
Where are central thermoreceptors?
Anterior hypothalamus
Where is the central integrative area?
Posterior hypothalamus
Dx temp >37.5
- cramping of most worked muscle groups
- caused by replacement with isotonic fluid after ++ perspiration
Heat cramps
Dx temp >37.5
- ventilation -> orthostatic pooling -> increased ADH/ aldosterone
- commonly seen in non acclimatized or elderly pt
Heat edema
r/o other causes of edema
Dx temp >37.5
- similar mechanism as heat edema
- commonly in elderly
- transient LOC
Heat syncope
r/o other causes syncope
Dx temp >37.5
- superficial pruritic vesicles on erythematous base
- generally confined to clothed areas
Prickly heat rash/ malaria rubra/ lichen tropicus/ sweat rash
Dx
- temp 37.5 - 40.5
- mental function intact
- malaise, fatigue, headache
- increased HR, orthostatic hypotension, clinically dehydrated
Heat exhaustion
Dx
- temp >40.5
- CNS dysfunction (ataxia, coma, sz)
- liver dysfunction (delayed 24-48h - leaking of transaminases from centrilobular necrosis)
- up to 80% mortality if untreated
Heat stroke
- ataxia often first CNS sign because cerebellum most sensitive to heat
- 20% will have persistent neurologic dysfunction
Management rhabdomyolysis (in setting hyperthermia)?
- +++ fluids
- mannitol
- HCO3
Management MH, possibly NMS (setting hyperthermia)?
- dantrolene (lowers myoplasmic Ca++ by blocking Ca channels in sarcoplasmic reticulum of muscle fibres)
Cooling techniques
first line
- evaporation
- ice water submersion
adjuncts
- ice packs to axilla/ groin
- cooling blankets
- cardiopulmonary bypass (ECHMO)
not recommended
- cool fluid lavage
- cold IV fluid (worsen preexisting edema)
Rule of resuscitation re: minimum pt body temp?
At least 35 degrees
Define hypothermia
Core temp <35
- disruption in balance between heat production and heat dissipation
mild 32.2 - 35
moderate 28 - 32.2
severe <28
ECG moderate hypothermia?
- junctional bradycardia and afib; Osborn waves
Management hypothermia?
- external rewarming
- warm crystalloids
- invasive active rewarming
Toxidrome category of
- antihistamine
- TCAs
- phenothiazine
- atropine
Anticholinergic
Toxidrome category of
- insecticides
- nerve agents
- nicotine
- pilocarpine
- urecholine
Serotonergic
Toxidrome category of
- heroin
- morphine
- benzos
- barbiturates
- meprobamate
- EtOH
Cholinergic
Toxidrome category of
- MAOIs
- SSRIs
- meperidine
- TCA
- benzos
- L-tryptophan
Opioid/ sedative/ hypnotic
Toxidrome category of
- cocaine
- amphetamines
- MDMA
- ephedrine
- theophylline
Sympathomimetics
Causes elevated osmolar gap?
- EtOH
- isopropyl alcohol
- ethylene glycol
- methanol
- ethanol
Causes of elevated anion gap acidosis?
MUDPILES
- methanol
- uremia
- diabetic/ alcoholic ketoacidosis
- paraldehyde
- isoniazid/ iron
- lactate
- ethylene glycol
- salicylate
Causes of narrow AG?
HARDUPS
- hyperventilation
- acetazolamide, acids, Addision disease
- renal tubular acidosis
- diarrhea
- ureterosigmoidostomy
- pancreatic fistula
- saline
Increase in OG or AG first noticed in toxic alcohol ingestion?
OG
AG calculation
AG = [Na] - [Cl] - [HCO3] normal = 8-14
Osmolar gap calculation
OG = difference between measured serum osmolality and calculated serum osmolarity
normal <10 mOsm/L
Osm(calc) = 2 (Na) + BUN + Glucose
Dx
- increased BP, HR, temp +/- RR
- delirium
- increased pupils
- reduced bowel sounds
- dry, red skin
Anticholinergic
- hot as a hare, dry as a bone, red as a beet, blind as a bat, mad as a hatter
Dx
- increased RR +/- BP/HR, normal temp
- n/depressed LOC
- +/- pupils (nicotinic dilates; muscarinic constricts)
- increased bowel sounds
- wet skin
Cholinergic
- sludge (muscarinic sx - salivation, lacrimation, urination, diarrhea, GI distress, emesis)
- the Killer Bs (bronchospasm, bronchorrhea)
- fasciculations/ muscle cramps (nicotinic sx)
Dx
- decreased vitals
- depressed LOC
- reduced bowel sounds
- normal skin
- reduced reflexes, ataxia
Opioids and sedative/hypnotics
Dx
- labile BP; increased HR, RR, temp
- tremor, agitation, hallucination
- increased bowel sounds
- wet skin
- increased reflexes, vomiting
Serotonergic
Dx
- increased vitals
- agitated, increased psychomotor activity
- increased pupils
- increased bowel sounds
- wet skin
- tremors, seizures
Sympathomimetics
Dx
- increased vitas
- agitated, hallucinations
- increased pupils
- increased bowel sounds
- wet skin
- tremors, seizures
Withdrawal of sedatives/ EtOH
Dx
- vitals usually increased, temp can be normal
- anxious
- increased pupils
- increased bowel sounds
- wet skin
- GI upset, yawning, rhinorrhea, piloerection
Withdrawal of opioids
Methods of decontamination
- orogastric lavage
- whole bowel irrigation
- activated charcoal/ multi-dose activated charcoal
Antidote of acetaminophen
N-Acetylcysteine (NAC)
Antidote of opioid OD
Naloxone
Antidote of Warfarin
Vit K and/or prothrombin complex
Antidote of ethylene glycol/ methadone
Fomepizole or ethanol
Antidote of flumazenil
Benzo
Antidote of carbon monoxide
O2
Antidote of TCAs
sodium bicarbonate
Antidote of CCB
IV calcium
Antidote of b-blocker
glucagon
Antidote of organophosphates/ insecticides
atropine
Dx
- reduced LOC, ataxia, lethargy, coma
- blurry vision, reduced VA, snowstorm vision
- Parkinsonism in late stage
- delated presentation common
Tx?
Methanol
- hepatic metabolism by alcohol dehydrogenase to formic acid and depletion of folate stores
Rx - fomepizole or EtOH drip
- hemodialysis if severe
- folate
Salicylate toxic ingestion - pathophys, toxic dose and rx?
- resp alkalosis due to CNS chemoreceptors
- metabolic acidosis late
- toxic dose = 150mg/kg
rx - fluids +++
+/- K, dextrose
- urinary alkalization
- hemodialysis if severe
Acetaminophen toxicity - pathophys, 4 phases and rx?
- toxic metabolites conjugated in liver using glutathione
- glutathione depleted in OD -> metabolites = hepatotoxicity
toxic dose >150mg/kg or >7.5g
4 phases
- 24-48h - GI upset and diaphoresis
- d2-3 - GI improves, mild abdo pain, transaminases climb
- d3-4 - GI upset, jaundice, metabolic acidosis
- d>5 - multi organ failure with improvement or death
rx
- 4h post ingestion levels -> Rumack-Matthew nomogram
- NAC protective within 8h
TCAs - pathophys, dx, rx?
- block Na channels and serotonin reuptake
- anticholinergic and antihistaminic effects
- sx within 6h
- clinical dx (no labs) - nonspecific presentation with dizziness, agitation, confusion +/- anticholinergic effects
- ECG - long QRS, QT or PR +/- RAD of terminal 40ms of QRS
rx
- supportive
- charcoal if <2h
- NaHCO3 if ECG changes
- benzo for seizure
Wounds through what skin layer scar?
Through dermis
Timing to close wounds?
Within 12h, 24h if on face
Can you put chlorhexidine in wound to clean?
No - causes tissue damage
Maximum dose of lidocaine? + epi?
5 mg/kg
+ epi = 7 mg/kg
Maximum dose of bupivacaine? + epi?
2 mg/kg
+ epi = 3 mg/kg
Size of suture: back/trunk scalp arms/legs hands/feet face
back/trunk: 3.0- 4.0 scalp: 4.0 arms/legs: 4.0 - 5.0 hands/feet: 5.0 face: 6.0
- smaller suture = bigger number
Type of closure
- immediate skin closure in wounds with low infection risk
- within 12h (24h if face)
CI?
Primary closure
CI
- punctures
- bites
- extensive crush or debridement
Type of closure
- would left open to heal by granulation and contraction
- for contaminated infected wounds
- wounds presenting outside acceptable time for primary closure
CI?
Secondary closure
CI
- cosmetics significant concern
- unable to control bleeding
Type of closure
- wound initially left open, kept covered with antimicrobial mesh dressing, then closed 3-5d later if no signs of infection
- for high risk of infection but significant cosmetic concern
- wounds with significant tension
CI?
Delayed primary closure
CI n/a
When do administer Td or Tdap? Tig?
Td or Tdap:
- uncertain or <3doses
- last booster >10yr (>3doses initially received)
- last booster >5yr for wounds not clean/minor
Tig
- uncertain or <3 doses in wounds not clean/minor
What is result when person’s airway goes below surface of liquid?
Submersion -> resp impairment
What electrolytes can increase in dead sea submersions?
- increased Mg++ and Ca++ from absorption of sea water
What is the diving reflex?
cold water to face -> apnea + bradycardia -> shunting blood to brain and heart
- can be protective in infants and children
Systemic effects of submersion injuries?
CNS
- hypoxia and acidosis -> cerebral edema
CVS
- hypoxia, acidosis and hypothermia -> arrhythmia (CPR until core body temp >32)
Resp
- aspiration washes out surfactant -> pulmonary edema -> ARDS
+/- laryngospasm
Metabolic
- mixed resp/metabolic acidosis
- dead sea: lyte abnormalities
Renal
- hypoxia + acidosis -> myoglobinuria + ATN
Define shock
tissue hypoxia and end-organ dysfunction secondary to tissue hypo perfusion
Dx shock
- increased CO (HR/contractility)
- increased SVR (vasoconstriction)
- BP = narrow pulse pressure
- skin cold
Hypovolemic
Dx shock
- reduced CP (reduced preload)
- reduced SVR (vasodilation)
- BP = wide pulse pressure
- skin warm
Distributive
Dx shock
- reduced CO (reduced contractility)
- increased/normal SVR
- BP reduced
- skin cold
Cardiogenic
Dx shock
- reduced CO
- increased SVR (veno congestion)
- reduced BP
- cold skin
Obstructive
Is lactate increased or decreased in shock?
mitochondrial dysfunction -> anaerobic metabolism -> increased lactate
Is glucose increased or decreased in shock?
stress hormone release (catecholamines, glucocorticoids, glucagon) -> glyconeogenesis, lipolysis, insulin resistance -> increased glucose
Result of inflammatory events in shock?
inflammatory events -> activated neutrophils bind vascular endothelium -> release free radicals and proteolytic enzymes -> damage to cell membrane and DNA
Causes of multi-system organ failure in shock?
increased lactate, increased glucose, damage to cell membrane and DNA ->
ion pump malfunction -> cellular edema -> cellular dysfunction with dysregulation of intracellular pH -> cellular necrosis and death ->
multi system organ failure ->
death
Dx
- appears unwell
- tachycardia, tachypnea, hypotensive, hypoxemic
- increased serum lactate
- reduced u/o
hypovolemic shock
Can positive pressure ventilation affect pneumothorax?
Yes - can turn into tension pneumothorax
Areas where significant bleeding can occur?
- chest
- abdo
- pelvis (3L)
- thigh (1L each)
- retroperitoneal space
Investigations for trauma pt?
- CBC, type and screen, INR/PTT, lytes, BUN, Cr, b-hCG, lactate
+/- ABG/VBG, lipase, LFTs, toxicology workup
CXR, pelvic XR, spine films (re: C-spine rules)
XR suspected injuries
CT chest, abdo, pelvis, spines prn
Management of unstable pt with peritonitis?
Direct to OR for laparotomy
-> NO imaging
