Emergency Medicine/Toxicology Flashcards
What is the most important step for an acute change in mental status of unclear etiology (e.g. after suicide attempt)?
- antidotes (e.g. naloxone, dextrose, thiamine)
- On a CCS case, also give O2 and saline while checking tox screen (all at same time)
When do I answer “gastric emptying?”
the answer is almost ALWAYS wrong, only useful in 1st hour after OD (removes ~50% of pills); you can NEVER do this when caustics (acids and alkalis) have been ingested
Is ipecac ever the right answer?
It seems like likely not (and especially not in pt w/ AMS and kids)
When can intubation and lavage be performed?
rarely; only done if pt has ingested the substance w/i last 1-2 hours and there is NO response to naloxone, thiamine, and dextrose
When do I give charcoal?
just give it, no harm; will help in most OD cases
What is the “overdose case menu” in CCS OD cases?
- specific antidote if etiology clear
- tox screen
- charcoal
- CBC, BMP, U/A
- psych consult if OD result of suicide attempt
- O2 for CO poisoning or any dyspneic patient
What is the antidote for acetaminophen?
N-acetyl cysteine
What is the antidote for ASA?
bicarbonate to alkalinize the urine
What is the antidote for benzodiazepines?
do NOT give flumazenil; may precipitate a SZ
What is the antidote for carbon monoxide?
100% O2; hyperbaric in some cases
What is the antidote for digoxin?
digoxin-binding antibodies (in severe disease i.e. CNS and cardiac abnormalities)
What is the antidote for ethylene glycol?
fomepizole or ethanol
What is the antidote for methanol?
fomepizole or ethanol
What is the antidote for methemoglobinemia?
methylene blue
What is the antidote for neuroleptic malignant syndrome?
bromocriptine, dantrolene
What is the antidote for opiates?
naloxone
What is the antidote for organophosphates?
atropine, pralidoxime
What is the antidote for tricyclic antidepressants?
bicarbonate protects the heart
What is the clinical course of acetaminophen OD?
- 1st 24 hours: N/V, which resolve
- 48-72 hrs: hepatic failure
For how long is N-acetyl cystine useful to prevent liver toxicity from acetaminophen OD?
24 hours; after that, it is useless and there is no specific tx to prevent/reverse toxicity
How can you give NAC in acetaminophen OD pt who is vomiting?
NAC IV
What blood level of acetaminophen is toxic? Fatal?
10 g; 15 g (lower if underlying liver disease or alcohol abuse)
What physical exam findings are present in ASA/salicylate overdose?
hyperventilation but NO DYSPNEA (stimulant to brainstem), tinnitus, +/- confusion, fever, seizures, coma
What lab findings do you see in ASA/salicylate OD?
metabolic acidosis w/ elevated anion gap, respiratory alkalosis (precedes metabolic acidosis), renal insufficiency (ASA directly toxic to kidneys), elevated PT (ASA interferes with Vit K-dependent clotting factors)
What do you order in ASA/salicylate OD pt?
- CBC
- BMP
- ABG
- PT/INR/PTT
- salicylate (ASA) level
Tx for ASA/salicylate OD?
- alkalinize the urine with D5W w/ 3 amps of bicarbonate
- charcoal
- dialysis in severe cases
What substances does alkalinization of the urine help facilitate excretion of?
- salicylates (ASA)
- TCAs
- phenobarbital
- chlorpropamide (sulfonylurea used to treat T2DM)
Tx for benzodiazepine OD?
Let the patient sleep! Benzos by themselves are not fatal. The OD will pass. Do not administer flumazenil in the ED - you do not know who has chronic dependency and you do not want to precipiate a withdrawal and SZs.
What are the presenting sxs of CO poisoning?
SOB, lightheadedness/HA, disorientation, metabolic acidosis from tissue hypoxia
How does digoxin poisoning most commonly present?
GI disturbance (N/V, diarrhea, pain), +/- pt seeing “yellow halos” around objects, blurred vision, arrhythmias, encephalopathy
What lab abnormality is seen in digoxin poisoning?
hyperkalemia (poisoning of Na+/K+ ATPase)
What lab abnormality is common to both ethylene glycol and methanol OD?
metabolic acidosis with increased anion gap
What organ system does ethylene glycol OD particularly affect?
kidney (renal insufficiency from direct toxicity, hypocalcemia from precipitation of oxalic acid w/ Ca2+, kidney stones)
Also causes rapid and deep breathing (Kussmaul’s respirations), N/V, slurred speech, ataxia, nystagmus, lethargy
What organ system does methanol OD particularly affect?
eyes (visual disturbance, retinal hyperemia from toxicity of formic acid)
How are ethylene glycol and methanol OD treated?
- fomepizole (antidote of choice; inhibitor of ADH)
- dialysis to remove them from the body before they are metabolized into the toxic metabolite
Physiologically, what happens in methemoglobinemia?
hemoglobin is locked in an oxidized state that will not allow it to pick up oxygen
How does methemoglobinemia present?
cyanosis, SOB, dizziness, HA, confusion, SZs
What drugs can precipitate methemoglobinemia?
nitrates, anesthetics, dapsone, other oxidants, any of the drugs ending in -caine (lidocaine, benzocaine, bupivacaine), nitroglycerin
Dx of methemoglobinemia?
- normal pO2 on ABG with chocolate-brownish blood (oxidized blood)
- methemoglobin level
Tx of methemoglobinemia?
100% O2, methylene blue restores the hemoglobin to its normal state
What will usually be in the history of a patient with neuroleptic malignant syndrome?
ingestion of neuroleptic meds (e.g phenothiazines)
Lab abnormalities in NMS?
CPK and K+ can be elevated
Physical exam findings in NMS?
muscle rigidity
What is usually in history of pt with malignant hyperthermia?
h/o anesthetic use
Tx of malignant hyperthermia?
dantrolene
Tx of heat stroke?
physical removal of heat from body (spray patient with water and fan patient in air conditioned room or use ice baths/packs); do NOT infuse iced saline into body - this can stop the heart
Why do people die in opiate OD?
death from respiratory depression
Mechanism in organophosphate poisoning?
inhibition of acetylcholinesterase
What should you look for in hx with organophosphate poisoning?
- crop duster exposed to insecticides
- nerve-gas attack
What are presenting sxs in organophosphate poisoning?
salivation, lacrimation, urination, diarrhea, wheezing from bronchospasm, bradycardia, skin flushing, miosis, garlic-like odor on clothes
Tx of organophosphate poisoning?
- best initial tx: atropine
- most effective tx: pralidoxime
- remove the clothes and wash the rest off the patient
Death from TCA overdose occurs from what?
seizures, arrhythmias
If you suspect TCA OD in a patient, what is the first step?
EKG –> if widened QRS, give bicarbonate (otherwise, don’t)
What are the physical exam findings in TCA OD?
dilated pupils, dry mouth, dry skin, constipation, urinary retention (anticholinergic effects)
Presenting sxs of black widow spider bite?
abdominal pain, rigidity, hypocalcemia, pain WITHOUT tenderness
Tx of black widow spider bite?
antivenin
Presenting sxs of brown recluse spider?
local necrosis, bullae, dark lesions
Tx of brown recluse spider bite?
debride the wound
What is the 1st step in a burn patient?
100% O2! (most common cause of death is CO poisoning)
After 100% O2 administration, what do you do next for a burn pt?
look for hoarseness, wheezing, stridor, burns inside the nose or mouth - if none, give fluids (4 mL LR or NS for each % w/ a 2nd or 3rd degree burn for each kilogram)
What is the most common cause of death later on for a burn patient?
infection
How does hypothermia kill?
arrhythmias (J waves of Osborn, look like ST elevation, on EKG)
How does acute angle closure glaucoma present?
red eye, fixed midpoint pupil
Tx of acute angle closure glaucoma?
pilocarpine drops (to constrict pupil) -other therapies = acetazolimide (decreases production of aqueous humor), prostaglandin analogues (latanoprost, travoprost), beta blockers topically (timolol), alpha agonists (apraclonidine)
How does retinal detachment present?
sudden loss of vision “like a curtain coming down”
Tx of retinal detachment?
- consult ophthalmology, perform dilated retinal exam
- reattach by: tilting head back, reattach w/ surgery, cryotherapy, by injecting expansile gas into eye
Presentation of conjunctivitis?
- viral: bilateral watery discharge, itchy eyes
- bacterial: unilateral purulent discharge, eyelids stuck together
Dx of conjunctivitis?
clinical
Tx of conjunctivitis?
topical Abx (if bacterial) - Erythromycin ointment
Presentation of uveitis?
photophobia
Dx of uveitis?
slit lamp exam (leukocytes in anterior chamber)
Tx of uveitis?
antimicrobial for viral or bacterial; steroids for non-infectious
Presentation of corneal abration?
h/o trauma, most commonly from contact lenses
Dx of corneal abrasion?
fluorescein stain picks up on damaged cornea
Tx of corneal abrasion?
NO specific tx; do NOT patch abrasions caused by contact lenses
How do calculate an anion gap?
Na - [HCO3 + Cl-] (normal = 12, range 8-16)
Dx of CO poisoning?
CO-oximetry
Dx of organophosphate poisoning?
RBC cholinesterase (but hard to perform)
Sxs of PCP intoxication?
disorientation, restlessness, tachycardia, hypertension, b/l vertical nystagmus
Tx of PCP intoxication?
- low-stim environment, metabolic and hemodynamic control
- if agitation or SZ –> benzos
- if aggression –> Haloperidol
Sxs of lead poisoning?
anorexia, decreased activity, irritability, vague abd pain, insomnia, neurocognitive defects
Dx of lead poisoning?
CBC, serum iron and ferritin, retic ct, blood lead level
Tx of dry chemical burns with powder?
Brush off first, then rinse with low-pressure water x 15-30 min
Tx of hypothermia?
- if hypoventilation –> intubation
- if hypotension –> fluids
- then, active rewarming with warm IV fluids
Cause of scombroid?
improperly stored seafood (histidine –> histamine!)
Sxs of scombroid?
flushing, throbbing HA, palpitations, abd cramps, diarrhea, skin erythema, oral burning
