Transcript Autopsy and Tox

AUTOPSY AND
TOXICOLOGY
AUTOPSY
• Medical examination of a dead body to determine
the cause of death
• Most states under US law require investigations of
certain types of deaths:
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injury
delayed complications of injuries
poisoning
infectious complications
foul play
people who die with no attending physician
AUTOPSY
• A death that meets the criteria listed will be
reported to the local medical examiner or coroner
for:
• investigation
• legal determination of the cause of death
• There are two types of autopsies:
• Forensic
• Clinical
TYPES
• Forensic:
• also known as a medical-legal autopsy
• These try to find answers to the cause of death as part of an
overall police investigation
• Clinical
• usually performed in hospitals by pathologists or the
attending physician
• interested in the disease processes that are going on
MANNER OF DEATH
• There are five legally defined manners of death
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Natural
Accident
Homicide
Suicide
Undetermined
• The forensic pathologist acting as a medical
examiner or coroner will assign a cause of death
• Example:
• if the autopsy reveals a natural disease process such as
leukemia or cancer, then the death would be considered
natural
DR KIESEL STATES:
• “Let's say, somebody 30 years ago received
a gunshot wound to the head and they
developed a seizure disorder. It's 30 years
later, and they die from the seizure disorder.
Well, the seizure disorder was caused by the
gunshot wound; the gunshot wound is an
unnatural event. That case would actually
be classified as a homicide ... there's no time
limit to that trauma. There's a time limit if you
wanted to take it to court and sue
somebody, but there's not a time limit as far
as our making the call. “
AUTOPSY PROCEDURE
• External Investigation
• The body Is received as a medical
examiners office or hospital in a body bag
or evidence sheet
• Body Bag
• brand new bag is used for each body
• ensuring that only evidence from that
body is contained within the bag
• Evidence sheet
• alternate was to transport the body
• sterile sheet that the body is covered in
when it is moved
• brand new sheets are used for every
corpse
AUTOPSY PROCEDURE
• Body bag seals are broken and the body is
photographed inside the bag
• The medical examiner will note the clothing and the
position of the clothing
• evidence is collected off of the external surfaces of
the body
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hair samples
fingernails
gunshot residue (if present)
fibers
paint chips
any other foreign objects
Body Removed from Bag…
undressed
wounds are examined
body is cleaned
measured and weighed
Body placed on autopsy table with a body block
underneath
• General description
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Race
Sex
hair color and length
Eye color
Approximate age
Any identifying features (scars, tattoos, birthmarks, etc.)
INTERNAL EXAMINATION
• Y-shaped incision
• made from shoulder to shoulder
meeting at the breast bone and
extends all the way down to the
pubic bone
• Peel back the skin, muscle and soft
tissue using a scalpel
• the ribcage and the neck muscles
are exposed
• Detach
larynx
esophagus
various arteries an ligaments
organ’s attachment tot the spinal
cord, bladder, and rectum
• entire organ set can be pulled out in
one piece
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• An average autopsy case takes about four
hours. That's including all the paperwork.
There is about a half an hour before and
after the autopsy for doing the external
examination, the dictation, the paperwork.
The autopsy can take anywhere from one
hour to two hours if it's an uncomplicated
case. If it's a complicated case like a
homicide ... it can take many hours -- 4 to 6
hours.
TIME OF DEATH CERTAINTY
PRINCIPLE
• If you know with certainty when the person was last
known to be alive, and if you know with certainty
when they were found dead, then you know with
100% certainty that they died within that interval.
• There are changes that occur after death. Most of
them are chemically related.
• lividity Blood settles by gravity within the body, and
there's a purple discoloration that occurs.
• rigidity or rigor  The body will become rigid.
• vitreous humor, which is the fluid in the eye; the corneas
become cloudy
• gastric contents [food left in the stomach or intestines]. You
know, when did they last eat, and that can be helpful. Do
they have a full bladder or not?
POSTMORTEM FORENSIC
TOXICOLOGY
• Qualitative and quantitative analysis of drugs or
poisons in biological specimens collected at
autopsy
• Interpretation of findings in terms of:
• Physiological effect at time of death
• Behavioural effect at time of death
QUANTITATIVE VS.
QUALITATIVE
• Qualitative analysis – determines the presence or
absence of a drug or poison in a submitted sample
• Quantitative analysis – determines the amount of
drug or poison that is present in the submitted
sample
POSTMORTEM FORENSIC
TOXICOLOGY
Types of cases:
• Suspected drug intoxication cases
• Fire deaths
• Homicides
• Driver and pilot fatalities
• Therapeutic drug monitoring
• Sudden infant death (SIDS)
SAMPLES OF FORENSIC
INTEREST
ISSUES IN SPECIMEN COLLECTION
• Selection
• Multiple, varied sites of collection
• Collection
• Appropriate method of collection
• Adequate volumes for analysis
• Storage and handling
Important to ensure analytical results are accurate
and interpretations are sound
TYPICAL AUTOPSY SPECIMENS
• Blood
• Urine
• Stomach contents
• Bile
• Liver
• Hair
• Vitreous humor
BLOOD
• Antemortem  ideal blood sample
• Postmortem blood is not truly “blood”
• Anatomical site of collection at autopsy should
be noted
• Central sites
Subclavian
Heart
Iliac
• Heart
• Peripheral sites
• Femoral
• Iliac
• Subclavian
• Other sites
Femoral
• Head blood
• Hematoma blood
HEMATOMA
• Extravascular blood clot
• Protected from metabolism
• Analysis will indicate what drugs were present in
the blood at the time of formation
HEMATOMA CASE EXAMPLE
• A 26 year old man was found dead at the
bottom of a staircase. Death was due to
physical injuries.
• Question as to alcohol use prior to fall down
stairs
• No urine available at autopsy
• Alcohol not detected in femoral blood
• Alcohol in hematoma blood 150 mg/100 mL
• The deceased had been drinking prior to
receiving the head trauma.
• The deceased had survived for several hours
after the injury.
HEMATOMA
• Caution: There may be a delay between the
incident which resulted in hematoma and the
actual formation of the hematoma
• Therefore, this alcohol concentration does not
necessarily indicate the BAC at the time of the fall
down the stairs.
URINE
• Produced by the kidneys
• Blood filtered by the kidneys
• Stored in the bladder until voided
• Qualitative - the presence of a drug in the urine
of an individual indicates that some time prior to
death the drug or poison was present in the
blood of the individual
STOMACH CONTENTS
• Visual examination may reveal tablets
• Drugs that have been orally ingested may be
detected in stomach contents
• Caution: drugs administered by other routes
may also diffuse into stomach contents from
the blood
• Generally qualitative:
• Stomach contents are not homogeneous
• Only a portion of stomach contents collected
(unmixed?)
• Useful for directing further analysis
CASE EXAMPLE
• A 26 year old woman is found dead in bed
• Numerous medications in her home:
• Amitriptyline, Oxycodone, Morphine, Paroxetine,
Diphenhydramine, Pseudoephedrine, Phenobarbital,
Codeine, Temazepam, Diazepam
• Only 3 mL of blood collected at autopsy
• Point out that 3 mL of blood is not a lot of blood for
analyses – in fact, probably only enough blood to
perform one or two quantitative analyses.
• Qualitative analysis of stomach contents:
• Amitriptyline: detected
• Nortriptyline: detected
• Quantitation can now be performed in blood
LIVER
• Drug metabolism occurs in the liver
• Both parent compounds and metabolites may be
present in higher concentrations in the liver than in
the blood  ease of detection
• Limitation is that drugs are not uniformly distributed
throughout the liver  confounds interpretation
BILE
• Digestive secretion
• Continuously produced by the liver
• Stored in the gallbladder
• Qualitative - the presence of a drug in the bile of
an individual indicates that sometime prior to
death, the individual was exposed to the drug
VITREOUS HUMOR
• Fluid that occupies the space between the lens
and the retina of the eye.
• Sequestered from putrefaction, charring and
trauma, microorganisms.
• Useful in cases where decomposition is
advanced, body is exhumed or in fire deaths
• Limitation is blood:vitreous ratio may not be
known
HAIR
• Recent specimen of interest
• Metabolism does not occur in hair
• Can provide a historical record of drug or poison
exposure
• Pros and cons of hair analysis still being
uncovered  racial variability?
CASE EXAMPLE
Poklis, A. 2002. Abstract SOFT, Dearborn, Michigan.
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30 year old woman, previously in good health
Nausea, vomiting, diarrhea, rash, fever
Weakness in hands and feet  Guillian Barre?
Hospitalized with hypotension, seizures
Misplaced laboratory result  Arsenic!
Sequential hair analysis for arsenic showed chronic
arsenic poisoning over 8 month period
NON-BIOLOGICAL SUBMISSIONS
• Used to direct analysis of biologicals
• May indicate the nature of substances that may
have been ingested, inhaled or injected
• Examples:
• Containers found at the scene
• Syringes
• Unidentified tablets or liquids
SAMPLES TAKEN AFTER EMBALMING
• Methanol is a typical component of embalming
fluid
• Most drugs are soluble in methanol
• Embalming process will essentially “wash” the
vasculature and tissues
• Qualitative analysis can be performed on body
tissues
STORAGE AND HANDLING
PROPER SPECIMEN HANDLING
• Identification of samples
• Continuity
• Contents
• Specimens delivered to lab without delay
• Specimens should be analyzed as soon as
possible
• Storage areas should be secure
STORAGE AND HANDLING
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Not feasible to analyze specimens immediately
Sample should be in well-sealed container
Sample containers must be sterile
Use of preservatives and anti-coagulants
Refrigeration vs. Freezing
• Both inhibit bacterial action; esp. freezing
• Freezing results in  prep time
• Freeze-thaw cycle may promote breakdown
STORAGE OF SAMPLES
• Preservative
• Sodium fluoride
• Anti-coagulants
• Sodium citrate
• Potassium oxalate
• EDTA
• Heparin
• Not imperative for postmortem blood samples
• Anticoagulants are not really necessary in postmortem
blood samples since the blood is hemolyzed!
• But any changes that have occurred before the sample
is put into the proper container cannot be reversed.
DETERMINING ANALYSES
• Case history
• Medical history
• Autopsy findings
• Symptomatology
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Experience of the toxicologist
Amount of specimen available
Nature of specimens available
Policies of the organization
PITFALLS IN POSTMORTEM
FORENSIC TOXICOLOGY
DECOMPOSITION
• Autolysis
• The breakdown of cellular material by enzymes
• Putrefaction
• A septic/infectious process
• The destruction of soft tissues by the action of bacteria and
enzymes
• Traumatic deaths may demonstrate  putrefaction
DECOMPOSITION
• Fewer samples available for collection
• Fewer samples available for collection - liquefication means fewer
intact vessels from which to sample
• Quality of samples is diminished - “dirty” samples; interfering
compounds during GC analysis
• Quality of samples is diminished
• Putrefaction produces alcohols
• Ethanol
• Isopropanol
• Acetaldehyde
• n-propanol
DRUG STABILITY
• Knowledge of a drug’s stability is necessary to
facilitate interpretation of concentrations
• Breakdown of drugs may occur after death and
during storage via non-enzymatic mechanisms
• Cocaine  Benzoylecgonine (Hydrolysis)
• LSD  degradation due to light sensitivity
• Others ?
• Cocaine will hydrolyze spontaneously especially under alkaline
conditions (e.g. blood) to benzoylecgonine. Mechanism is the action
of plasma cholinesterase. This process occurs both in vivo and in vitro,
which further complicates interpretation. Fluoride and refrigeration
help to prevent the conversion to benzoylecgonine.