TOXICOLOGY Flashcards
What is harder to treat – one time single large dose of Tylenol? Or: I took half a bottle today, yesterday, and the day after?
It’s worse if it’s over a time period
What should we remember about drugs with a narrow therapeutic windows?
Can become toxic with normal regimen
What are some key things we must ask about toxicology?
TIMING of ingestion if key
Talk to EVERYONE (you have to piece it together)
Ask about ALL OTC meds
Count pills
Remember patients may not appear toxic… INITIALLY
What entity is your friend/expectation with toxicology and you must consult them every time?
Poison control!
What blood test is most likely to change first with poisoning?
INR (will elongate out) then LFT’s
What 3 EKG changes are you looking for with poisonings?
High grade blocks, prolonged OT, terminal R wave (lead AVR), and wide QRS
What are the toxidromes?
pneumonic that help with syndromes
Why should we have a high suspicion for chronic OD in the elderly?
Polypharmacy; or docs not knowing what else they are taking
What does MUDPILES stand for?
Methanol, Uremia, DKA, Propylene glycol, Infection/isonized, Lactic acidosis, Ethylene glycol/ethanol, and Salicylates (aspirin)
What is MUDPILES used for?
The elevated anion gap DDx list! Often the bicarb stinks
How do you calculate an anion gap?
Sodium, bicarb, and chloride (all in a Chem 8)
Na – (Bicarb + Cl)
What’s a normal Anion Gap?
less than 12
If a patient presents with delirium, hallucinations, and anxiety are associated with what toxicology?
Chronic Aspirin
If a patient presents with hyperventilation (Kussmal), pulmonary edema, tinnitus – what overdose would this be associated with?
Aspirin
What do you have Kussmal breathing (bit deep fast respirations)?
They’re trying to correct their metabolic acidosis
What is a UDPRO?
Urine drug screen – it’s a yes or no test
Can you order an aspirin level?
Yes, serum, and it’s quantitative
At what point does aspirin cause serious toxicity?
300-500mg/kg
How often are you checking salicylate levels?
Repeat every 2 hours (for 6 hours)– to see when it peaks or declines
What other workup do you do for toxicology?
Chemistries, creatinine, calcium, magnesium
ABG
Monitor urine pH
Coag & liver studies
EKG & CXR
What do we need to keep their urine levels at?
pH 7.5-8 (via bicarb)
Should you see EKG changes with an aspirin overdose?
No
Why would we do a chest xr for aspirin OD?
To see if there’s a big clump of pills in their stomach
Be careful with serum levels less than 6 hours post ingestion, why?
Because they won’t be absorbing anymore after 6 hours
What blood test will change first with aspirin ingestion?
LFT’s
What’s the best treatment for aspirin?
BICARB (alkalinize the urine)
Dialysis is the TOC (enhanced elimination, acid-base and electrolyte correction)
Gastric lavage (60 mins post ingestion)
If you give charcoal (within 30 mins) → there’s a risk of aspiration & green-apple poos
What are the take home points for aspirin OD?
Consider in the acute altered patient
Look for acidosis
Alkalize urine
Dialysis TOC
What’s the max daily dose of Tylenol for an adult?
4 grams!!
Why do children do better with Tylenol?
They have more glutathylenol (they can metabolize it better)
What other common co-ingestion significantly worsens Tylenol OD? Why?
Alcohol
It uses the same enzyme to metabolize Tylenol & alcohol!!!
What’s the most common cause of acute liver failure in the US?
Tylenol
What are the 4 phases of Tylenol od?
1 = Asymptomatic
2 = RUQ pain (18-72 hours)
3 = jaundiced, coagulopathy, fatality (72-96) → AKA toxicity is DELAYED
What toasts your liver after glutathione is gone?
NAPQl
What’s the first sign of Tylenol OD
LFt’s
How often do we draw labs for Tylenol od, what do we use with it?
initial + every 4 hours
Rumack-Matthew nomogram (4 hours out)
When does the Rumack fail you?
When there is a multiple ingestion over multiple days!
What other labs should you test for Tylenol od?
AST/ALT; coag, and glucose
BUN/Cr (to r/o renal failure)
Lactate level (mortality)
ABG (acidosis → shouldn’t be present in a Tylenol od)
Type & Crossmatch
How do you treat a tylenol od?
Iv, oxygen, cardiac monitor
NAC (N-acetylcystine) within 8 hours or anytime if pregnant
Consult poison control!
Charcoal within 30 mins
At what point do you need a transplant (to the make the list)?
pH 100; serum creatinine >3.4
So, what are the take home points with Tylenol od?
use rumack nomogram
Get help if multiple/chronic ingestion
NAC = TOC
Will get sick DAY later
What types of meds often have a narrow therapeutic window, and will often become toxic without intentional overdose?
Psych meds = lithium & amitriptyline
Agitation, confusion, tremor or rigidity, sweating, hyper-reflexia, anxiety, and ataxia are symptoms associated with what?
Serotonin syndrome (sxs remembered with anticholinergic toxidrome)
What labs should you do for serotonin syndrome?
Look for rhabdo (CK)
How do you treat serotonin syndrome?
Benzos, BP control, and cooling
What’s the biggest complication with opiates?
Respiratory!!!
What if you see arrhythmias with opiate od?
They would have to have been down a LONG time (there’s significant neuro damage)
*You don’t see heart problems with opiate od
How do we reverse opiates?
narcan (naloxone)
What are the extended release opiates?
Dilaudid & Methadone
What’s critical about narcan?
IT’s half life is shorter than the opiate half life → Keep them in front of you!!! (otherwise they go into respiratory distress)
What is the time to peak effect for opiates?
IV = 10 min
IM = 30
Oral = 90
Transdermal = 2-4 hours (minutes if it touches mucous membranes – they lick it. They will die if ingested)
What type of labs should we do for opiate od?
ABC’s, tox screen (but not that helpful), FSBS (finger stick blood sugar), EKG, ABG, CXR
How does a person wake up after narcan is administered?
ANGRY
If you’ve given narcan and the person is still altered – what do you need to think?
Other ingestion
Methadone will need multiple narcan doses
What are the rapidly fatal drugs?
TCA’s, ethylene glycol, Verapamil
What’s the most common tricyclic antidepressant?
Amitryptyline
What is a classic diagnostic finding of a tricyclic-antidepressants?
EKG = Wide QRS and terminal R wave in aVR
What toxidrome is used for TCA OD?
SALT
Shock, AMS, wide (long) QRS, terminal R wave in aVR
It’s bad if they’re in shock, tachy, AMS
What is a toxic dose of a TCA, how long dose it take to absorb?
Absorbs in 1 hour
Toxic dose = 10-20mg
So, how do we treat TCA OD?
Bicarb!!
Serial EKG’s
Seizure precautions
What is ethylene glycol?
Antifreeze
How do you OD on ethylene glycol?
Drink it because it tastes sweet
What’s the metabolism of ethylene glycol?
EG → Alcohol dehydrogenase → glycolic acid (cause of severe acidosis)
If you see kussmal breathing, tachy, AMS (or obtunded), and no other gross abnormalities – is what diagnosis?
Ethylene glycol OD
What is the workup for ethylene glycol od?
ABG, ETOH levels, FSBS
You order an AG, chem 8, and a serum osmolarity – what do you do next?
Calculated osmolarity
SERUM & CALCULATED OSMOL SHOULD BE THE SAME
How do you calculate osmolarity?
2(Na) + BUN level/3 + glucose/18
If your serum osmol & calculated osmols don’t match what should you do?
Plug in the conversion factors → if they now match, you have made your diagnosis
So how do you treat ethylene glycol?
Fluids, bicarb, FOMEPIZOLE = TOC (expensive, so you give them alcohol or dialysis)
So dialysis is for what?
EG & Aspirin
What will verapamil cause?
Vasodilation + bradycardia/hypotensive! B/C they are taking a CCB to control their BP!
How much verapamil to get an od?
> 1gram
What is the workup for verapamil?
AG, tox screen, EKG for high grade blocks!
How do you treat a verapamil od?
Pacing, CaCL = TOC (reversal agent), also pressor or atropine
SO what are the take home points for verapamil od?
Look for bradycardia with severe hypotension
Extended release formulations are the WORST
EKG looking for high grade blocks
Pressor support, 10% CaCL
