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Flashcards in Toxicology Deck (20):
1

Acetaminophen toxicity

nausea
hepatic failure
max therapeutic dose (4g in 24 hours for an adult)
toxicity at >10-12 g (adult)

Treat with PO or IV N-acetylcysteine (also used in renal protection and CF)

2

Stages of acetaminophen toxicity

Stage I: (30min-24hrs)- n/v, diaphoresis, pallor, lethargy, malaise

Stage II: (24-72hrs)- elevated LFT, PT, tbili, RUQ pain and tenderness

Stage III: (72-96hrs)- peak LFT elevation, jaundice, hepatic encephalopathy, bleeding, +/- acute renal failure, possible multisystem organ failure, leading to death

Stage 4:3 days- 2 weeks- recovery

3

Anticholinergic toxicity

Hot as a hare
dry as a bone
red as a beet
blind as a bat
mad as a hatter
bloated as a toad
tachycardia
decreased or absent bowel sounds
antidote: physostigmine

4

Benzodiazepine toxicity

sedation
respiratory depression

Treatment: flumazenil

5

Beta blocker toxicity, CCB toxicity

bradycardia
hypotension
hypoglycemia
pulmonary edema

Treatment: fluids, atropine, glucagon which activates adenylate cyclase there by increasing calcium

give calcium to increase HR and contractility
insulin and glucose (beta blockers interferes with myocyte metabolism and inhibits insulin release, so administering these gives energy to organs)

6

cocaine toxicity

tachycardia
agitation
mydriasis
HTN
cardiac arrest
hemorrhagic stroke

treatment:
supportive care, benzodiazepines, alpha- blockers

7

cyanide toxicity characteristics and treatment

tachycardia, htn, flushing, tachypnea leading to obtundation, coma, death

almond- scented breath (in 60% of the population)

late findings: bradycardia, hypotension, bradypnea, cyanosis, hepatic necrosis, renal failure

delayed- onset Parkinsonism in survivors of severe poisoning (basal ganglia is sensative to cyanide)

Tx: ABC, high-flow oxygen regardless of pulse-ox readings. mouth-to-mouth resuscitation is contraindicated here due to risk of provider exposure

if oral ingestion, one dose of activated charcoal

Sodium thiosulfate (sulfure donor that facilitates conversion of cyanide to thiocyanate, which is renally excreted)

Hydroxocobalamin (B12 precursor), directly binds cyanide to form cyanocobalamin, which is less toxic and excreted in the urine
Causes reddish discoloration of the skin, mucous membranes, and urine
Generally preferred over nitrate- induced methemoglobinemia, which can be lethal

Amyl nitrate and sodium nitrate
induce methemoglobin production, which binds cyanide to form cyanomethemoglobin. Goal methemoglobin level is 20-30%, but this is lethal in children and anemic patients. Contraindicated in patients with carboxyhemoglobinemia (usually from smoke inhalation)
Although methemoglobinemia can be reversed with methylene blue, this should be avoided in cyanide- poisoned patients because it will release free cyanide
Works well in conjunction with sodium thosulfate

8

Digoxin toxicity

Nonspecific symptoms: fatigue, blurred vision, change in color vision (eg yellow vision), anorexia, nausea, vomiting, diarrhea, abdominal pain, headache, dissiness, confusion, delirium

characteristic EKG changes:
-prolonged PR interval, "scooping" of ST segments- seen at therapeutic levels

-bradycardia- frequent vital sign abnormality
-PVCs are most common findings on EKG
-atrial tachycardia with AV block (4:1 or 6:1)- less common

Hyperkalemia indicates the severity of the digoxin toxicity (it inhibits the Na-K ATPase), look for elevated serum digoxin levels as well

9

What is the treatment for digoxin toxicity?

Activated charcoal in repeated doses
Digoxin Ab fragments if one of the following is present:
-hemodynamic instability
-life-threatening arrhythmia or severe bradycardia (even if responsive to atropice)
-plasma potassium level>5 mEq/L in an acute overdose
-plasma digoxin level>10ng/mL
-ingestion of >10mg of digoxin in adults or >4mg in children
-presence of a digoxin toxic rhythm in the setting of an elevated digoxin level

Treat hyperkalemia only if it is causing EKG disturbances and avoid calcium, which can worsen intracellular hyperkalemia in these particular patients

If bradycardia, atropine
ACLS if needed

10

Heparin toxicity

excessive bleeding
easy bruising
gross hematuria
treatment: protamine sulfate

11

Isoniazid

peripheral neuropathy
hepatotoxicity
treatment: B6

12

Isopropyl alcohol

decreased consciousness, nausea, abdominal pain, treatment
treatment: supportive care

13

Methanol (wood alcohol), used in antifreeze

amounts as small as 10mL can cause permanent blindness

14

Ethylene glycol (also in antifreeze), sweet- tasting

vomiting, hyperventilation, dizziness, slurred speech, metabolic acidosis, acute kidney failure
elevated anion gap

15

Treatment for methanol or ethylene glycol toxicity

ABC
NG tube gastric aspiration if ingestion of a large amount within the last 60 minutes (rare)
Sodium bicarbonate to correct acidosis and limit penetration of toxic metabolites into tissues (such as retina)

inhibit the alcohol dehydrogenase enzyme with fomepizole or ethanol
-fomepizole- preferred drug
-ethanol- if fomepizole is unavailable, dose to serum level of 100mg/dL

dialysis if severe acidosis or organ damage (vision changes or renal failure)

folic acid, thiamine, and pyridoxine supplementation to optimize elimination pathways

16

Opioids

CNS depression, pinpoint pupils, respiratory depression

Tx: naloxone, naltrexone

17

Salicylates

Tinnitus
hyperthermia (oxidative uncoupling)
Alkalosis (drom hyperventilation), then mixed respiratory alkalosis and metabolic acidosis with elevated anion gap
-tachypnea results from ASA stimualation of medullary respiratory center
-acidosis results from accumulation of lactic acids and ketoacids
N/v, dehydration, AMS

Treatment:
charcoal, dialysis, sodium bicarb

18

Sulfonylureas

hypoglycemia
Treatment: octreotide, dextrose

19

TCAs

tachycardia, dry moutn, urinary retention (anticholinergic effects), seizures, QRS widening on ECG

Treatment: sodium bicarbonate, diazepam which is used for seizures

20

Warfarin

INR9
hold dosing until INR in therapeutic range + administer vitamin K 5-10 mg PO once and as needed subsequently +lower routine dose