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Flashcards in Toxicology Deck (64):
1

Charcoal, optimal ratio of  charcoal: toxin
poorly bound (4)

 

10:1
small molecules (lithium, iron, cyanide), hydrocarbons, alcohol, acid/alkalai

2

Antidotes

BAL, DMS (3)

FFP / Vit K / PCCs

Calcium, glucagon, gluc/insulin, intralipids

Sodium nitrite, sodium thiosulfate, hydroxycobalamine

Arsenic, mercury, lead (add EDTA)
warfarin
calcium channel blocker

cyanide

3

Antidote 2

Alkaline diuresis, hemodialysis (2)

Bicarbonate, ethanol, dialysis, 4-MP (2)

Glucagon, intralipids

Protamine

Aspirin, barbiturates
ethylene glycol, methanol
beta blocker
heparin

4

Antidote 3

pyridoxine (a.k.a.)
sodium bicarbonate, intra-lipids
methylene blue (2)
calcium, magnesium

INH; vitamin B6
TCA
nitrates, met hemoglobin EMEA
hydrofluoric acid

5

Dereroxamine

atropine, 2-PAM

octreotide and two other things

Physostigmine

Iron
organophosphate (cholinergic and central nicotinic)
Oral hypoglycemic along with glucagon and glucose

anticholinergics if severe (but not for TCA)

6

Anion gap formula

MUDPILES pneumonic

(Na) - (Cl + CO2), normal < 12

MUDPILES pneumonic - causes of anion gap metabolic acidosis

M    Methanol, metformin, massive ingestions

U    Uremia

D    DKA

P    Paraldehyde

I    Iron, INH

L    Lactic acidosis (CO, CN)

E    Ethylene glycol

S    Salicylates

7

Increased osmolar gap (3)

false positives
amphetamines
TCAs
PCP

Alcohol toxic (acetone, isopropanol, methanol, ethylene glycol) or not, mannitol, ketoacidosis

 Osmolar gap = Actual - Calculated (nl 285-295) = 2 Na + BUN/18 + Glu/18 + EtOH/4.6

amphetamines: Sudafed
TCAs: cyclobenzaprine, carbamazepine, diphenhydramine, phenothiazines
PCP: ketamine, dextromethorphan

             

8

Drug levels helpful when predictive of subsequent toxicity or guides specific therapy (5)

Iron, lithium, acetaminophen, aspirin, digoxin

9

Anticholinergic toxidrome

classic examples (5)

key difference with similar toxidrome:

“Hot as hell, blind as a bat, dry as a bone, red as a beet, mad as a hatter”; Dry, flushed skin, dry mucus membranes, mydriasis, decreased bowel sounds, urinary retention

examples: atropine, antihistamine, Jimsonweed, Parkinson's medications (L dopa), , phenothiazines, TCAs

key difference: sympathomimetic has diaphoresis rather than dry skin

A image thumb
10

Anticholinergic treatments of

Classic toxidrome (Mad as hatter.....) normal and if severe

wide complex tachycardia
torsade de pointes

Benzodiazepines, Physostigmine if very severe and no TCA
bicarbonate
magnesium, overdrive pacing
 

11

Q image thumb

A image thumb
12

Sympathomimetic treatment

Mimic of opiod OD

Benzodiazepine

Clonidine

13

Cholinergic toxidrome

Key examples (2) and mechanism

muscarinic effects mnemonic

 

Organophosphate insecticides, chemical warfare agents, some mushrooms
inhibit cholinesterases -> increases acetylcholine

SLUDGEM- Bs

salivation, lacrimation, urination, diarrhea, GI distress, emesis, miosis

Bs: –Bradycardia, Bronchospasm, Bronchorrhea 

14

Cholinergic toxidrome

Nicotinic effects (3)

tx

Muscle weakness, fasciculations, respiratory failure

atropine, 2-PAM (Pralidoxime)

15

Withdrawal syndromes
common treatment for alcohol, barbiturates, benzodiazepines, cocaine, clonidine

Benzodiazepines, clonidine

16

Tylenol tox

mechanism

stages

Saturated normal metabolism shifts to minor pathway cytochrome P450 ->  when glutathione depletes, toxic free radical metabolits NAPQI accumulates and damages hepatocytes

 

A image thumb
17

Tylenol tox

toxic ingestion mg/kg; grams average adult

4 hour toxic level

Mech

Use > 24 hours presentation?

140 mg per kilo, 7 to 10 g
140 at four hours
provides necessary cofactor to metabolize NAPQI

>24 hours: yes

18

Wernicke’s encephalopathy sx (4)

Korsakoff’s psychosis sx (2) 

Wernicke’s encephalopathy: Oculomotor crisis

CN VI palsy (lateral rectus), nystagmus, ataxia, global confusion

Korsakoff’s psychosis: Retrograde amnesia, confabulation

19

Methanol
metabolic presentation

Pathogenesis
Key symptom

Other sx (3)

Anion gap metabolic acidosis with increased osmolar gap

alcohol dehydrogenase creates formaldehyde and formic acid

Visual changes/blindness

Seizures, resp failure, pancreatitis

 

20

Methanol

Antidote (2)

Adjuncts if refractory to above (2)

Fomepizole (4MP) -> prevents conversion leading to renal excretion

Ethanol (preferentially metabolized)

Dialysis, bicarbonate

21

Ethylene glycol
toxidrome key:
mechanism of toxicity

toxidrome key: altered mental status + elevated anion and osmolar gap acidosis
mechanism of toxicity: toxic metabolites oxalic acid and glycolic acid

other findings: renal failure, hematuria, hypocalcemia; calcium oxalate crystals in the urine

22

Ethylene glycol

treatment similar to other toxic alcohols
unique treatment (2)

supportive treatment

treatment similar to other toxic alcohols: fomepizole (4MP)
unique treatment: pyridoxine, thiamine

supportive treatment: bicarbonate four acidosis, dialysis for severe acidosis and/or high blood levels

23

Isopropyl alcohol

toxidrome compared to other toxic alcohols

symptoms (4)
treatment (2) and how differenent from other toxic alcohols

toxidrome compared to other toxic alcohols: ketosis /elevated osmolar gap WITHOUT anion gap or acidosis

symptoms: altered mental status plus hemorrhagic gastritis, pulmonary edema, hypotension
treatment: supportive care +/- hemodialysis

Tx difference: NO role for fomepizole or EtOH since metabolite less toxic than the toxin

24

Cocaine
similar toxidromes with key difference

Similar to anticholinergic toxidrome

cocaine: diaphoresis, dilated pupils

anticholinergic: skin dry instead of sweaty
cholinergic: pupils pinpoint instead of dilated

25

Toxicology pearls

bradycardia pneumonic (6)

tachycardia pneumonic (4)

Bradycardia

P   Propranolol (beta blockers), poppies (opioids)

A   Anticholinesterase drugs

C   Clonidine, calcium channel blockers

E   Ethanol, other alcohols

D   Digoxin

Tachycardia

F    Freebase (cocaine) 

A    Anticholinergics,                                antihistamines, amphetamines

S    Sympathomimetics, solvent abuse

T    Theophylline

26

Toxicology pearls

hyperthermia (4)

hypothermia (5)

Hyperthermia

N     NMS, nicotine

A     Antihistamines

S     Salicylates, sympathomimetics, Serotonin syndrome

A     Anticholinergics, antidepressants

Hypothermia

C   Carbon monoxide

O   Oral hypoglycemics, insulin

O   Opioids

L    Liquor

S    Sedatives, hypnotics

27

Toxicology pearls
hypotension (5)
hypertension (6)

hypotension 

C   Carbon monoxide

O   Oral hypoglycemics, insulin

O   Opioids

L    Liquor

S    Sedatives, hypnotics

hypertension

C    Clonidine, calcium channel blockers

R    Reserpine (antihypertensive agents)

A    Antidepressants, aminophylline

S    Sedatives, hypnotics

H    Heroin (opioids)

28

Toxicology pearls
hypoventilation (4)

hyperventilation (4)

Hypoventilation

S    Sedatives, hypnotics

L    Liquor

O   Opioids

W   Weed (marijuana)

Hyperventilation

P    PCP, pneumonitis (chemical)

A    ASA (salicylates)

N    Noncardiogenic pulmonary edema

T    Toxic metabolic acidosis

29

Toxicology paroles
Miosis (4)

Mydriasis

NMiosis

C    Cholinergics, clonidine

O    Opioids, organophosphates

P    Phenothiazines, pilocarpine, pontine bleed

S    Sedatives, hypnotics

30

Toxicology Pearls

Red Skin (2-3)

Blue Skin (2 + expand)

Red skin:  Anticholinergics, boric acid, carbon monoxide

Blue skin:  Cyanosis, methemoglobinemia, (nitrates, nitrites, aniline dyes, dapsone, phenazopyridine)

31

Toxicology Pearls - odors

Bitter almonds or “silver polish”

Mothballs

Garlic (3)

Wintergreen: Methyl salicylate

Carrots

Gasoline

Fruity (2)

Pears 

Bitter almonds or “silver polish”: Cyanide

Mothballs: Camphor

Garlic: Arsenic, organophosphate, DMSO

Rotten eggs: Sulfur dioxide, hydrogen sulfide

Wintergreen: Methyl salicylate

Peanuts: Vacor (rat poison)

Carrots: Water hemlock

Gasoline: Hydrocarbons

Fruity: DKA, isopropanol

Pears: Chloral hydrate

32

Toxicology Pearls

Radioopaque drugs (5)

COINS

C    Chloral hydrate, Cocaine packets

O    Opiate packets

I      Iron, (Heavy metal: Pb, As, Hg)

N    Neuroleptic agents

S    Sustained release products, enteric coated preparations

33

Toxicology pearls

noncardiogenic pulmonary edema

MOPS

M   Meprobamate, methadone

O   Opioids

P   Phenobarbital, propoxyphene

S   Salicylates

34

Toxicology pearls

multidose charcoal indications (4)
all bowel irrigation indications (2)

multidose charcoal indications: phenobarbital, sustained-release drugs, salicylates, theophylline
all bowel irrigation indications: sustained-release drugs not absorbed by charcoal, body packing

35

Toxicology pearls

appropriate for dialysis (7)

Toxic alcohols (methanol, isopropyl alcohol, ethylene glycol), lithium, salicylate, theophylline, phenobarbital

36

Delayed-release toxicity - many, review

Delayed toxicity

–  Acetaminophen

–  Digoxin

–  Ethylene glycol

–  Heavy metals

–  Methanol

–  Mushrooms

–  Narcotics

–  Iron

–  Salicylates

–  Slow release compounds

37

Anticholinergics/antihistamine

classic cause of severe symptoms and other 2 parts of this drugs toxidrome
EKG changes

TCA -> also causes sodium channel blockade. CNS depression
EKG: tachycardia, QRS wide, dominant R' in AVR

38

TCA overdose

treatment

decontamination?

Drug for EKG changes

Drug for ventricular dysrhythmia

decontamination: yes, multidose charcoal, whole bowel irrigation

Drug for EKG changes: bicarbonate

Drug for ventricular dysrhythmia: lidocaine

39

Barbiturates
toxidrome similar to
treatment (4)

toxidrome similar to opiates
treatment: charcoal, gastric lavage, dialysis, urinary alkalinization

40

Beta-blocker/CCB
treatment (3-4)
unexpected's systemic toxicity from this form

treatment: insulin/D5, glucagon, intralipids, calcium for CCB
unexpected's systemic toxicity from this form: timolol eye drops

41

Carbon monoxide poisoning

mechanism
lab abnormality to suspect associated toxidrome

SaO2 and PaO2 level

delayed sequela

CO has 250 times the affinity for 02 and inhibits the release of oxygen from hemoglobin (why there is not significant cyanosis; O2 present but bound)

severe metabolic acidosis should suggest associated cyanide

SaO2 and PaO2 level: often normal

delayed: neuropsychiatric syndrome, HBO may prevent

42

Caustic ingestion

acid necrosis type
alkali necrosis type
Which is worse and why?

Predictive value of oropharyngeal burns with alkali

Acid: coagulation
alkali: liquefaction
alkali since liquefaction necrosis facilitates progression whereas eschar stops progression of coagulation necrosis

predictive value: none

43

Caustic ingestions

dilute?

Hydrofluoric acid treatment
solid alkali treatment

dilute: generally not as this can induce vomiting

Hydrofluoric acid treatment: magnesium citrate and milk
solid alkali treatment: dilution with water or milk

consider endoscopy

44

Clonidine
mechanism
toxidrome (3)
mimics? Toxidrome
treatment (3+1?)

mechanism: alpha adrenergic agonist
toxidrome: hypotension, bradycardia, AMS
mimics? Opiate overdose
treatment: fluids, atropine, pressers, naloxone may be helpful

45

Cyanide
odor
signature lab abnormality

other sx (2+)
PaO2 and SaO2 levels

medication -induced cause

treatment principle and medication

Bitter almonds
large AG metabolic acidosis
altered mental status,CV collapse
normal 

nitroprusside

induce methemoglobinanemia with hydroxocobalamin (or amyl nitrate, sodium nitrate/thiosulfate etc)

46

Digoxin toxicity
electrolyte abnormality?

signature EKG abnormality and most common

Antidote, acute and chronic

contraindicated hyperkalemia treatment

Hyperkalemia, hyponatremia (from inhibition of the Na-K pump)

AV blocks, PVCs
Digibind 10 and 6 vials; 20 if severe 

calcium (increases toxicity)

47

Psychedelics - mechanism

hydrocarbons - often cause

gastric emptying?

Serotonin 5HT2 agonist
aspiration pneumonitis

no except when CHAMP

Camphor

Halogenated (carbon tet, PVC, vinyl chloride)

Aromatic (benzene, toluene, xylene)

Metals (leaded gas)

Pesticides

48

Hydrogen fluoride
mechanism
physical exam caveat
treatment

hydrogen sulfide treatment

Potent inorganic acid used in glass etching
May have deep injuries despite normal appearing skin
calcium gluconate gel, titrate to pain

hydrogen sulfide treatment: use methylene blue for MetHgb; simllar mech to CO

49

Intractable seizures classic tox cause and tx

Iron poisoning effects (3) and timing

diagnosis
treatment (2)

INH overdose, B6 - pyridoxine

G.I. bleed, inhibits aerobic metabolism, CV collpase/ARF

immediate and delayed phases

4 hour iron level; deferoxamine
 

50

Lead poisoning

timing, effective age
classic symptom (+ others)

Chronic, children
peripheral neuropathy leading to rest drop, also: ha, encephalopathy, belly pain

51

Lithium tox

diagnosis
treatment (3+)

Mercury from thermometer toxic?

Symptoms plus a positive level (actual # not reliable)

aggressive hydration, dialysis, lavage, kayexalate

Mercury from thermometer toxic? NO

52

MAOI inhibitors

mechanism
toxic complication types (2) and drugs for 2nd type

Inhibits breakdown of catecholamines (norepi, epi, serotonin)

hypertensive crisis: with amphetamines, wine, cheese, fava beans
serotonin syndrome/severe hypothermia: meperidine and dextromethorphan

53

Methhemoglobinemia

mechanism

signature finding and blood color
classic causes

PaO2 level?

Antidote

MetHgb unable to bind O2

hypoxia unresponsive to oxygen; chocolate brown

causes: nitrates, benzocaine, dapone, pyridium

PaO2: normal
methylene blue

54

Mushroom toxicity
timing Pearl

specific for pictured species

Q image thumb

Time from ingestion to symptom onset helps determine risk of significant toxicity

–Symptoms within 2 hours of ingestion indicate benign course if only one type of mushroom ingested

–Symptoms delayed more than 6 hours indicate a toxic ingestion with risk of hepatic and renal failure

Amanita Phalloides: initial G.I. symptoms in 12 hours, then latent, then liver and renal failure in 1 to 2 days

55

Neuroleptics

side effect categories (5)

treatment (3)

 

Dystonia, Tardive dyskinesia, Akathesia, anticholinergic,Quinidine like (prolonged QT)

benztropine/Cogentin, Benadryl, benzodiazepines

56

Neuroleptic malignant syndrome

timing
symptoms (3)

lab clue

treatment (3+)

Subacute onset
AMS, hyperthermia, leadpipe rigidity
elevated CK
fever control, benzodiazepines, dantrolene, bromocriptine, paralysis

57

Naloxone - duration of action

do non-sulfonylureas cause hypoglycemia?

Metformin complication

sulfonylureas antidote when severe

30 to 60 minutes

no
lactic acidosis
octreotide

58

Organophosphates mechanism of actions (2)

Toxidrome pneumonic

Inhibit cholinesterases; cholinergic toxidrome and nicotinic effects

cholinergic: SLUDGE + killers Bs

Nicotinic: weakness, fasciculations, respiratory failure

Killer “B”s – Bradycardia, Bronchospasm, Bronchorrhea

  S – Salivation

  L – Lacrimation

  U – Urination

  D – Diarrhea

  G – Gastrointestinal upset

  E – Emesis

59

Tox, Rotary nystagmus =

toxidrome for toxic plants

deadly nightshade, Henbane, jimsonweed

foxglove, Oleander, Lily of the Valley

tobacco/cigarettes

Q image thumb

PCP

anticholinergic
digitalis toxidrome

Pictures - side 1 Jimsonweed, side 2 Foxglove

cholinergic

A image thumb
60

Salicylates
classic dyad

other symptoms (3)

treatment (2)

product with high amount of salicylate

Anion gap metabolic acidosis, respiratory alkalosis

other symptoms: tinnitus, pulmonary edema, hypoglycemia

urinary alkalinization, dialysis
oil of Wintergreen

61

Serotonin syndrome
timing
symptoms (with underlying categories)

treatment (2)

Acute
hyperthermia, altered mental status, myoclonus
cooling, cyproheptadine

Easiest way to distinguish from NMS is the acuity 

–CNS (altered mental status, coma, seizures)

–Autonomic (hyperthermia, tachycardia, hypertension)

–Neuromuscular (myoclonus, hyperkinesia)

62

Strychnine mechanism/syndrome

Blocks inhibition of postsynaptic brainstem glycine receptors and spinal cord motor neurons

Results in CNS hyperstimulation

63

TCA overdose

symptom categories (3)

Anticholinergic, CNS, cardiovascular

Anticholinergic effects

–Flushed skin, dry mouth, mydriasis, decreased bowel sounds, urinary retention

CNS effects

–Drowsiness, confusion, ataxia, delirium, seizures, coma

Cardiovascular effects

–Hypotension, tachycardia, wide QRS, V-tach, torsades

–Right axis deviation (negative S in I, positive R in aVR)

64

-xabans; best test to assess activity

Pradaxa reversal

Thrombin time

praxabind