29: Forensic Toxicology Flashcards
clinical tox testing is only done if
it is likely to influence tx fo pt
TDM has a limited menu of drugs such as
immunosuppressants and some anticonvulsants
clinical tox usually tests
serum or plasma
the medical examiner system may be lead by
a forensic pathologist
the coroner system may
or may not be headed by a phyusician
what is the “cause” of death
immediate medical cause of death, not the circumstances of death (i..e blunt force trauma, and not the MVA)
what is the “manner” of death? what are the 6 “manners” of deaht?
specific categories like accident (44%), natural (40%), suicide (14%), undetermined (2%), homicide (1.5%), unclassified (MAID deaths)
T or F: time of death is usually not possible to determine
T
what is the most common manner of death
accident
postmortem toxicology uses specimens other than serum or plasma such as
whole blood, vitreous, urine (workplace testing, saliva/ oral fluid), liver, stomach contents, other tissues (sometimes b/c decomp), hair (sometimes for criminal cases)
Bile, CSF, virtually any fluid
Lungs, kidney, muscle, or any solid tissue
Bone, nails, hair
what is the principle of using specimens other than plasma or serum in postmortum toxicology
most drugs are distributed to virtually all fluids and tissue in the body
what is the main difference between postmortem and clinical toxicology
postmortem tox must consider all aspects of death. postmortem has to think about CONTEXT of death, and INTERPRETATION of samples is more difficult.
why are medication counts important in forensic tox
in order to determine if death was due to build up or suicide
deaths due to impaired metabolism may be due to (3)
Genetic impairment due to enzyme deficiency
Drug drug impairment of enzyme system
Impairment due to reduced liver function (age, alcohol)
imipramine’s metabolite is _____________, which can accumulate if the patient has a _______ deficiency
desipramine
2D6
___________ decreases metabolism of desipramine
chlorpromazine
3 main mechs of postmortem redistribution
Release and diffusion of drugs from major structures
Occurs as cells die, pH changes, and protein binding weakens
Time and concentration dependent
what are 2 characteristics of candidate drugs for post mortem redistribution
Drugs with high volume of distribution typically >5L/kg
Drugs with “basic” character (ex- from HCL salts)
postmortum distribution increases ____x drug concentrations
2-10
list the order of increasing magnitude of PM redistribution in the 3 major blood vessels: subclavian, cardiac, femoral
cardiac > subclavian >femoral
in interpreting postmortem narcotic blood levels, we need to know
the degree of tolerance
if the postmortem exam is done on an opioid naive person, interpretation is _______
easier
what is the reference chloroform concentration for homicide
10-49mg/L
what is the reference chloroform conc for suicide
17-43mg/L
what is the reference chloroform conc for anesthesia
50-150mg/L
chloroform concs for homicide and suicide may be lower due to
asphyxiation death
