Forensic Toxicity Flashcards

1
Q

what is medical examiner system

A

its headed by a forensic pathologist (MD)

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2
Q

what is a coroner system

A

it may not be headed by a physician

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3
Q

what are 2 things that you do in clinical toxicology

A
  • emergency screening (overdose)

- therapeutic drug monitoring

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4
Q

when do you do clinical toxicology testing

A

if it is likely to influence treatment of the patient

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5
Q

why do we do forensic toxicology

A

for legal purposes

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6
Q

what are 4 examples of forensic toxicology

A
  • postmortem (cause of death)
  • impaired driving/sexual assault
  • workplace drug testing
  • sports
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7
Q

what kind of specimen do you get from veins post mortem + why

A

whole blood (not serum or plasma) because the blood hemolyzes

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8
Q

what are 6 examples of tissues used for post mortem toxicology

A

-whole blood
-vitreous (eye)
-liver
-urine
-stomach contents
-hair
etc

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9
Q

what is the main methodology for forensic tox

A

GC/MS(MS) and LC/(Q)TOF

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10
Q

what are 2 main differences for instrumentation for clinical and forensic tox (so these 2 points are about forensic)

A

1-does not rely only on immunoassay

2-must use better extraction and chromatography

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11
Q

is blood reliable own its own for assessing the presence of alcohol at the time of death + why

A

no because postmortem BAC can increase (from bacteria and contamination)

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12
Q

what part of the body is better than blood when it comes to assessing alcohol

A

the vitreous of the eyeball

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13
Q

what is the main mechanism of postmortem redistribution

A

release and diffusion from major organs

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14
Q

what 2 things does postmortem redistribution dependent on

A

time and concentration dependent

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15
Q

what are candidates of postmortem redistribution (2)

A

high volume of distribution (like 3L/kg)

“basic character”

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16
Q

how much can concentrations increase with postmortem redistribution

A

2-10 fold

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17
Q

what are the 4 orders of decreased postmortem redistribution

A

cardiac > subclavian > femoral > antemortem

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18
Q

what is antemortem

A

when the sample is taken before death

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19
Q

are central or more distant areas more effected by postmortem redistribution

A

central

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20
Q

what is bad about postmortem redistribution

A

it can lead to mis-interpretation of toxicological results

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21
Q

what are 4 main difficulties of interpreting postmortem data

A
  • dont know when drug was last taken
  • dont know metabolism for person
  • increase and decrease conc
  • dont know tolerance
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22
Q

can you take a post mortem drug and then figure out the concentration

A

no, because of metabolism, tolerance… not that easy

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23
Q

why is it much tricker to interpret postmortem levels of opioids

A

because there is a wide range of tolerance levels

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24
Q

what is the drug that the kid died from (7 yo ADD)

A

imipramine

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25
Q

how does imipramine get metabolized

A

CYP2D6 and CYP3A4

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26
Q

what happens when imipramine gets metabolized by CYP2D6

A

it is metabolized again by CYP3A4 then removed by the body

27
Q

what happens when imipramine gets metabolized by CYP3A4 (Compound name + rest of pathway)

A

desipramine => it is metabolized again by CYP2D6 then removed by the body

28
Q

what is desipramine

A

when imipramine gets metabolized by CYP3A4, still active

29
Q

what happens if you are deficient in CYP2D6 and take imipramine

A

you get a build up of desipramine because it needs CYP2D6 to get excreted

30
Q

what happens if you are deficient in CYP2D6 and take codeine

A

it wont be metabolized into morphine

31
Q

what happens if you are deficient in CYP3A4 and take codeine

A

nothing, its CYP2D6 that metabolizes it

32
Q

which enzymes metabolizes codeine into morphine

A

CYP2D6

33
Q

which enzymes metabolizes imipramine into desipramine

A

CYP2D6

34
Q

what is the half life of THC in blood like

A

relatively short

35
Q

what is the half life of THC in brain like

A

longer than in blood

36
Q

what is the half life of THC in body like

A

much longer than blood and brain

37
Q

with THC, does a certain blood concentration directly correlate to impairment

A

no, not like alcohol

38
Q

what are 4 “past wisdom” things about THC that have been debunked

A
  • that blood level of 2-3ng/mL means you used it within the past 6h
  • THC drops to near zero a few hours after last smoke
  • can use THC:THC-CPPH ratio to estimate time of last use
  • little postmortem change
39
Q

what is the typical baseline blood THC several hours after smoking in light smokers

A

often less than 2ng/mL

40
Q

what is the typical baseline blood THC several hours after smoking in heavy smokers

A

can be more than 5ng/mL

41
Q

what is the typical baseline blood THC 7 days after smoking in heavy smokers

A

1.2-5.5 ng/mL 7 days after use

42
Q

why does THC stay high in the blood

A

because THC is slowly released into the blood

43
Q

does THC go through postmortem redistribution

A

yes

44
Q

how much can THC levels in femoral blood be diff in cardiac blood with postmortem redistribution

A

it can be 6 fold higher in femoral blood than cardiac blood

45
Q

where may THC concentrate before redistributing postmortem

A

in muscle tissue

46
Q

why might you get super high levels of THC in the femoral blood post mortem

A

because there may be fat in the blood draw

47
Q

what are the 2 main things to interpret when trying to find the manner of death

A

circumstance of death and investigations (medical history, autopsy, toxicology on multiple specimens)

48
Q

what shouldnt you do if you dont have enough information

A

dont offer interpretation or give clear caveats

49
Q

what is poison hemlock

A

primary alkaloid coniine

50
Q

what are the effects of poison hemlock / coniine like

A

similar to nicotine but more toxic - paralyzes muscle by blocking nACh

51
Q

what does it look like when you die from hemlock / coniine

A

(asecnding paralysis, lower limbs affected first) respiratory paralysis leads to cessation of breathing, death from lack of oxygen

52
Q

is the hemlock tree poison

A

no

53
Q

what is the water hemlock poison

A

yes

54
Q

what is the toxin in water hemlock

A

circutoxin

55
Q

what does circutoxin do

A

disrupts CNS

56
Q

what are symptoms of circutoxin

A

nausea, emesis, abdominal pain, tremors, seizures

57
Q

what is an example of a poison nut

A

cerbera odollam

58
Q

What are the active ingredients in cerbera odollam

A

cerberin and neriifolin

59
Q

what are cerberin and neriifolin

A

potent cardiac glycosides

60
Q

what are 6 symptoms of cerberin and neriifolin overdose (cardiac glycosides)

A

nausea, vomiting, hypotension, bradycardia, heart block, arrhythmias

61
Q

what are some pretty things that can kill you

A

rosary pea seeds

62
Q

what is the toxin in rosary pea seeds

A

abrin

63
Q

what does abrin do

A

ribosome inhibiting protein