Lec 29/30 Toxicology Flashcards
What are two different treatments for cyanide poisoning?
give D50 and 100% O2 then:
- (amyl) nitrite + thiosulfate
- hydroxycobalamin
What acid/alk problem in TCA overdose?
mixed metabolic and respiratory acidosis –> decreased pH, decreased bicarb, decreased K, increase CO2
What is the treatment for TCA toxicity?
NaHCO3 for cardio toxicity
What is the treatment for methanol/ethylene glycol intoxiation??
fomepizole [inhibits alcohol dehydrogenase]
OR use ethanol IV infusion
What is the difference in presentation between asphyxiant gases and irritant gases?
asphyxiants: CO, cyanide, hydrogen sulfide = react with hemoglobin or cytochromes and cause lactic acidosis
irritants: sulfur dioxide, NOs, ozone, phosgene = act in upper airway cause bronchospasm/ irritation/ tearing –> eventually get into lower airway and cause edema
What is presentation of methanol poisoning?
blindness, aniona gap metabolic acidosis
What is presentation of ethylene glycol poisoning?
renal failure, anion gap metabolic acidosis
What is presentation of trichloroethyleme poisoning?
peripheral neuropathy, arrhythmias
What is the presentation of carbon tetrachloride poisoning?
hepatic dysfunction, cancer
What is the presentation of dioxin poisoning?
dermatitis, chloracne, non-hodgkins lymphomas
What is the presentation of benzene poisoning?
bone marrow depression
What is the presentation of toluene poisoning?
renal tubular acidosis, hypokalemia
Sympathomimetic toxicity: what vital signs, temp, mental status, pupil, bowel sounds, and skin [wet/dry]?
- high BP/HR/HR
- high temp
- agitated
- dilated pupils
- increased bowel sounds
- wet skin
Cholinergic [nicotinic] toxicity: what vital signs, temp, mental status, pupil, bowel sounds, and skin [wet/dry]?
- normal BP, high HR/RR
- normal temp
- agitated
- mydriasis = dilated
- increased bowel sounds
- no change in skin
Cholinergic [muscarinic] toxicity: what vital signs, temp, mental status, pupil, bowel sounds, and skin [wet/dry]?
- normal BP/HR/RR
- no change temp
- agitated
- miosis
- increased bowel sounds
- wet skin
bronchospasma, bradycardia, bronchorrhea
Anticholinergic toxicity: what vital signs, temp, mental status, pupil, bowel sounds, and skin [wet/dry]?
- normal BP/RR, increased HR
- increased temp
- agitated
- dilated pupils
- decreased bowel sounds
- dry skin
What is a toxicity associate with ipecac?
myocardial toxicity
What 5 toxins do not bind charcoal?
CHILE
- Caustics
- Hydrocarbons
- Iron
- Lithium
- Ethanol
What type of receptors on sweat glands?
ACh muscarinic
What is presentation of sedative hypnotic toxicity [barbituates, benzos, ambien, etc]?
decrease BP/HR/RR/temp
depressed mental status
dilated pupils
What is presentation of sedative hypnotic withdrawal [barbituates, benzos, ambien, etc]?
increase BP/HR/RR/temp
agitated mental status
no change in pupils
wet/sweaty skin
What is presentation of opioid toxicity?
decrease BP/HR/RR/temp depressed mental status pinpoint pupils decreased bowel sounds euphoria, resp and CNS depression, seizures [overdose]
What is presentation of opioid withdrawal?
increase BP/HR, no change RR/temp anxious dilated pupils increased bowel sounds wet/sweaty skin piloerection (cold turkey), fever, rhinorrhea, yawning, nausea, stomach cramps, diarrhea (flu-like)
What drug is associated with pinpoint pupils and respiratory depression?
opioids
What is a major side effects of TCAs [amitriptyline, other -iptylines + -ipramines + doxepin and amoxapine]?
a1 blocking = anticholinergic
postural hypotension, atropin-like side effects [tachycardia, urinary retntion, dry mouth
tri-C –> convulsions, coma, cardiotoxicity (arrhythmias), hyperpyrexia
What is the mech of action TCAs [major mech + other side mechanisms]?
block reuptake of NE and 5HT; block Na + alpha, anti-GABA, anti-cholinergic, anti-histaminic
What is the mech of TCAs causing seizures?
bind picrotoxin site of GABA-A receptor and block Cl entering –> cause hyper-excitable site
treat: give benzos or barbiturates try to open the Cl channel again
Why do you get wide QRS in TCA? treat?
block Na channels
treat –> give NaHCO3 to increase Na going in and reversal of Na blockade
What is mech of action pralidoxime?
displaces anticholinesterase inhibitor from the target = preserves anticholinesterase action
What is mech of action physostigmine?
inhibits acetylocholinesterase
What can you see on xray in lead poisoning?
lead lines in bone
What things cause anion gap met acidosis?
MUDPILES
- Methanol
- Uremia
- DKA
- Propylene glycol
- INH/Iron
- Lactic acidosis [cyanide,CO]
- Ethylene glycol
- Salicylates [late]
What are indications for acute hemodialysis?
- severe metabolic Acidosis
- severe Electrolyte disorder [esp hyperkalemia]
- drug Intoxication
- refractory fluid Overload
- Uremia
AEIOU
What are top 3 things you can use acute dialysis for?
ethylene glycol
methanol
salicylates
What is the use of intralipid?
lipid emulsion with different types of carbon chains –> creates a lipid compartment so when they overdose some of it goes into that compartment instead of target organ
How do you treat salicylate intoxication?
give Na bicarbonate to alkalinize urine = ion trapping
What is the body’s own chelator for Fe?
hemoglobin = has high affinity for iron
What 3 big symptoms of metal poisoning?
GI: N/V/GI bleed
Nervous system
Renal toxicity as eliminated
What acidosis/alkalosis change in iron toxicity?
metabolic acidosis
What are symptoms of lead toxicity?
butonian line in gums lead lines in bone metaphysis growth plate microcytic anemia GI and kidney disease mental deterioration, memory loss
lead palsy = leg drop with one leg
What enzymes are inhibited by lead poisoning?
ferrochelatase, ALA dehydratase
What substances are accumulated in lead poisoning?
protoporphyrin, d-ALA
What is treatment for lead tox?
succimer if Pb
What are some major sources of mercury poisoning?
jewelers, ceramic workers, paints
more potent = organic = more lethal
vs elemental and inorganic
What are symptoms of organic mercury tox?
acrodynia/pinks disease = reddish hands
+ GI + CNS + renal
What are sources of arsenic poinsoning?
pesticides, herbicides, well water
trivalent = most potent
What is mech of arsenic poisoning?
alters thiol-containing protein and impairs mitochondrial respiration
inhibits succinic dehydrogenase
What is presentation of arsenic tox?
GI/Renal/CNS
skin cancers, megaloblastic anemia, BM suppression
