exam 1 Flashcards
main aspects of clinical toxicology
diagnosis
and treatment
foreign chemicals that the body does not produce
xenobiotics
any substance when applied to the body may interfere with life processes or biological functions of the cells of the animal
poison - toxicant
T/F
majority of poisons are organic synthetic
TRUE
a poison from a biological process
toxin - biotoxin
used to describe the deleterious or undesirable effects of poisons
toxic
the disease caused by exposure to a toxin
toxicosis or poisoning
the amount of poison the under certain circumstances will cause toxic effects
toxicity
LD 50 mammals
LC 50 birds
how is lethal dose expressed in mammals?
in birds? in fish?
LD 50 in mg/kg body wt mammal
LC 50 in mg/kg feed in birds
LC 50 in mg/L water in fish
the effect of a single dose or multiple doses in a 24 hour period
acute
the effect from daily exposure for 1 to 30 days
subacute
effect of exposure from 30-90 days
sub chronic
effect produced by daily exposure for 3 months of more
chronic
the ratio between acute LD50 and chronic LD50
chronicity factor
What does a small value chronicity factor mean
the chemical is not cumulative
what does it mean if the value of the chronicity factor is 2 or greater
the chemical is cumulative
T/F
if the chemical is not cumulative it is always acute toxicity
TRUE
relative toxicity of 1mg/kg or less
extremely toxic
relative toxicity of > 1-50 mg/kg
highly toxic
relative toxicity of > 50-500 mg/kg
moderately toxic
relative toxicity of > .5 - 5 g/kg
slightly toxic
relative toxicity of > 5-15 g/kg
practically non toxic
relative toxicity of > 15 g/kg
harmless
the highest dose which dose not result in undesirable or toxic alterations
highest nontoxic dose (HNTD)
the lowest dose which produces toxic alterations and administering twice this dose will not cause death
toxic dose low (TDL)
the dose which produces toxic alterations and administering twice this dose will result in death
toxic dose high (TDH)
is the amount of a chemical that can be ingested without causing any deaths or alterations in any of the animals for the stated period
no-effect level
max non toxic level
LD0
highest dose that does not cause any death
LD100
lowest dose that kills all the animals in a group
the danger from the possibility of exposure
hazard
ratio between LD50 and ED50
therapeutic index
T/F
a low therapeutic index = low toxicity
FALSE – lower index is more toxic
who is more sensitive to toxins:
dogs or cats
cats
dogs are more susceptible
what species is sensitive to monensin
horses
T/F
compounds with cumulative effects have a lower chronicity factor -
false – higher chronicity factor
T/F
warfarin is a cumulative toxicant
TRUE
t/F
caffeine is a slowly excreted toxin
false - rapidly excreted
defined by a comparison of toxicity and use level
risk
T/F
monensin is much more toxic than urea
TRUE
the most common method of expressing concentrations in vet toxicology
ppm on wt/wt basis
how to convert from ppm to percentage
move decimal 4 places to the left
convert from percentage to ppm
move the decimal 4 places to the right
100 g/ton = ___ ppm
110ppm
units for toxicity
mg/kg
1 ounce = ___ g
30g
1 fluid oz = ___ ml
30
1 ml = __ cc
1 cc
1 kg = ___ pounds
2.2 lbs
most common route of exposure of toxicants
oral
2nd most common route of exposure of toxicants
inhalation - toxic gases
least common route of exposure of toxicants
injection
what is lethal synthesis
when the metabolite is more toxic than the parent compound
how do most xenobiotics cross the membrane
simple diffusion – depends on concentration gradient
they go from high to low
high lipid solubility will cross faster
higher degree ionization will go faster
most commonly used species in safety testing
dogs and rats
observation period for acute toxicity
1 - 14 days
induction of chromosomal changes
mutagenicity
can be obtained through detailed case history and thorough clinical and post mortem examinations
tentative diagnosis
can be reached when the history and the clinical signs are supported by circumstantial evidence and identification of the toxic source
presumptive diagnosis
main approach to diagnosis
history
unique to toxicology and involves ante/postmortem specimens for Dx
chemical analysis
T/F
most diseases do not have pathognomonic signs
TRUE
chemical tests results
positive does not always mean intoxication
negative does not always mean not poisoned
T/F
specimens submitted to lab should be washed
FALSE - not washed
T/F specimens submitted to lab should be frozen
true
blood samples should be ___ and other body fluids should be ___ when submitted
refrigerated
frozen
only preservative that can be added to samples when histopathology is needed
10% formalin
or
70% alcohol
T/F
an acutely poisoned animal must be treated as an emergency
TRUE
what are the 4 principles of treatment
symptomatic/supportive
removal of poison
antidotal
observation
what is the time window to give an emetic
1-2 hours following ingestion
emetic of choice in dogs
apomorphine
**can be given all routes but IV is fastest or given in the conjunctiva
contraindications for giving an emetic
unconscious corrosives petroleum products dehydration animals showing convulsions
MOA of apomorphine
stimulates the dopamine receptors to stimulate the CRTZ and induce vomiting
this is an indirect stimulation
opioid antagonist that will reverse the emetic effects of apomorphine
naloxone
T/F
too much apomorphine can actually inhibit vomiting centers
TRUE
T/F
acepromazine is an emetic
FALSE - anti emetic
also a dopamine antagonist
emetic of choice in cat
xylazine
how can xylazine be given to a cat?
what is a side effect?
IV or IM
causes CNS depression for several hours
typical gastric lavage fluid
tap water
T/F
gastric lavages are done in awake alert animals
FALSE – unconscious or anesthetized animals
physical binding of a toxicant – no electrons or chemical interactions involved
adsorption
adsorbent of choice
activated charcoal
activated means more porous – more surface area to bind the toxicants
T/F
charcoal with a large particle size is most effective
false - small particle size most effective
10 things that charcoal sucks for
ethanol methanol heavy metal salts fluoride iodides nitrate nitrite sodium chloride bleach fertilizer
top 2 diuretics used in fluid therapy of toxins
mannitol
furosemide
when is peritoneal dialysis used
when animal is suffering from oliguria or anuria
how long are organophosphate pesticides persistent in the environment
2-4 weeks
where are organophosphates absorbed
GIT
skin
mucous membranes
or inhalation
they are distributed throughout the body
most common form of toxicosis for organophosphates
acute
T/F
some organophosphates are teratogenic in chickens
TRUE
which receptors are most sensitive to organophosphates
muscarinic
irreversible inhibition of cholinesterases - myopathies
what is the cause of death in high exposure of organophosphates
respiratory failure
organophosphate acute toxicity signs
salivation
lacrimation
urination
diarrhea
bronchial secretions
anxiety and restlessness
could be muscle paralysis
if animals survive acute toxicity of organophosphates what is seen in the delayed toxicity signs
muscle weakness and ataxia
rear limb paralysis – may not be reversible
degeneration and demyelination of peripheral and spinal motor neurons
what is the acetycholinesterase level in whole blood with organophosphate toxicosis
usually less than 25% the normal level
how can you tell if s patient was poisoned with organophosphates using atropine
patients who were not OP poisoned will show dry mucous membranes and tachycardia when given atropine
treatment for OP poisoning
atropine sulfate - every 3 to 6 hours
2PAM chloride - every 12 hours
diphenhydramine - antagonize nicotinic effects
oxygen therapy if dyspnea or cyanosis
T/F
there is no storage activation with carbamate pesticides
TRUE
what age is most sensitive to carbamates
YOUNG – especially if deficient in liver enzymes
T/F
carbamates require enzymatic activation
FALSE
T/F
carbamate is easily detectable in tissues and blood samples
FALSE – it is too rapidly metabolized and so rarely detected
what species is most sensitive to organochlorines
cats
