Transcript File - BIOL-104: Forensic Biology

Bellevue Hospital in NYC, First “Official” Morgue in the U.S.
What is an Autopsy?
• An autopsy is a post
mortem examination
preformed on a corpse
to determine the cause
and manner of death.
• The prefix 'auto-' means
'self', and so autopsy
means 'to see for
oneself‘.
Why is a Forensic Autopsy preformed?
• Forensics autopsies
are preformed when
the cause of death of a
victim may be a
criminal case, often
involving foul play.
• A forensic autopsy
applies science to legal
law.
Classification
• In a forensic autopsy, death is
placed into five different categories.
• Natural
• Accident
• Homicide
• Suicide
• Unknown
• Following an in-depth examination of all the evidence, a medical
examiner or coroner will assign a manner of death as one of the five
listed above; and detail the evidence on the mechanism of the death.
Natural Death
• Death by natural cause is a term used by coroners
to describe the death of someone by occurring
disease process, or is not apparent given medical
history or circumstances.
• The majority of natural death is caused by old age.
• Other causes of natural death are heart disease,
stroke, gentic disorders, etc.
Accidental Death
• Accidental death is a death that is often caused
by mistake or in a freak occurrence. These
deaths are not planned yet can be explained by
surrounding circumstances.
• In the City of Philadelphia, any death as a
result of a medical procedure can warrant an
autopsy by the Medical Examiners Office.
Homicidal Death
• The term ‘homicide’ refers to the act of
killing another person.
• Homicide is often the most investigated death,
therefore making it the most autopsied.
Suicidal Death
• The act of ending ones own life.
• These autopsies often easily identify source,
cause, and other factors of the death.
• Suicide is often identified in the forensic
autopsy as a cause of toxic, firearms, blunt
force trauma, etc.
Unknown Death
• In some jurisdictions, the Undetermined
category may include deaths in absentia,
such as deaths at sea and missing persons
declared dead in a court of law; in others,
such deaths are classified under "Other".
Experts Who Perform Forensic Autopsies
• A forensic autopsy is usually preformed by a
specialized medical doctor called a forensics
pathologist or medical examiner.
• To be a pathologist, the doctor must have
completed a four-year undergraduate program,
four years of medical school training, and three to
four years of postgraduate training in the form of a
pathology residency.
What Warrants an Autopsy
(Post-Mortem) by The ME’s Office
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Questionable Death-as determined by the coroner
Homicide
Drowning
Auto Accidents
Death of a child
***Most teaching hospitals will offer a post-mortem to
any family of a patient that dies.
Benefits of Autopsy
Discover cause of death for:
• Criminal cases
• Family peace of mind
• Genetic disease or deformity
• Insurance claims
• Medical advancement
Autopsy
Room
Physical
Examination
• The physical examination of the body is
broken up into two parts.
• External Examination
• The external examination consists of inspecting the
physical outer layer of the body for signs of foul
play that would result in injury or death.
• Internal Examination.
• The internal examination consists of inspecting the
internal organs of the body for evidence of trauma
or other indications of the cause of death.
External Examination
Steps of an external examination.
1. Photographed.
2. Physical evidence collected off body.
3. Samples of hair, nails, etc. are collected.
4. Undressed, examined for wounds.
1. Lacerations, abrasions, bruises.
5. Measured, weighed, cleaned.
External Examination
• Trace Evidence
• Sign of injury or
mistreatment
• Sign of illness,
disease, or
abnormalities
Livor Mortis
• Defined as ‘Color of Death’.
• Coloration of the skin.
• At death, the heart stops working. When the heart
stops working, the blood stops pumping. The blood
stops pumping, the red blood cells and plasma
gather on the bottom part of the body, closet to the
floor.
• A line forms after 8 hours if the body hasn’t been
moved. If moved, a new line starts to form. It is
impossible to tell which was first. The thinker the
line, the longer the position the body was in.
Algor Mortis
• Defined as ‘Coolness of Death’.
• Temperature of body.
• In a controlled environment, stating at 98.6 degrees, the body
will drop one degree per hour.
• This happens because at death, the respiratory system stops
working, the body stops functioning, it is no longer moving.
• When taking the temperature of a corpse, you can’t take it in
the mouth because the muscles will be relaxed and the tongue
wont stay on top of the thermometer.
• Thinner people cool faster then fat people.
Rigor Mortis
• Defined as ‘Stiffness of Death’.
• Flexibility of the body.
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Shows up 2 hours after death
Peaks 12 hours after death.
Takes 12-24 hours for entire rigor mortis effect to take place.
At approximately 0 hours after death, the body is at its stiffest.
The eyelids are affected first, the the jaw, face, trunk, arms,
legs.
• Ends after 24-36 hours.
Pallor Mortis
• Defined as ‘Paleness of Death’.
• Tone of the body.
• Happens 15-20 minutes after death.
• Happens due to lack of capillary circulation in the
body.
• Can not be used to determine time of death except if
body is found still with color.
Body Block
bsapp.com
Internal Examination
• Steps of an internal examination.
1. Incisions
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A “Y” shaped cut from behind each ear and running
down the neck, meeting at the breastbone, continuing
towards the groin. Most often used in cases of suspected
strangulation.
A “T” shaped cut from each shoulder ,meeting at the
breastbone, continuing towards the groin. Used to create
a better looking finished product as this cut is not often
seen.
Single vertical cut from throat to groin.
All cut are deviating towards the left.
Internal Examination (cont’d)
2. Cuts
1. The chest cavity is cut open using shears.
2. The ribs are sawed away, letting them be lifted off the
body, exposing the heart and lungs.
3. Removal
1. En masse technique of Letulle – All organs removed at
once.
2. En bloc method of Ghon – organs divided into four
groups and removed in sections.
4. All removed organs are now weighed and examined
for unusual markings or signs.
Trunk Dissection
• Y-shaped
incision
• From the
shoulders to the
pelvic bone
• This incision is
deep
bsapp.com
Opening the Chest
• Skin & muscle, are
pulled from the
chest wall
• Chest Plate is
extracted
• Heart is extracted
Opening the Chest
Removal and Dissection of the Organs
• One organ at a time
• All body organs at once - ”Rokitansky Method”
• Upon removal each organ is:
• Weighed & measured
• Examined
• Sliced in cross sections
• Sampled for microscopic & chemical analysis
Internal Examination (cont’d)
• In addition,
• The cardiovascular system, the respiratory
system, the central nervous system, and all
other “systems” in the body that help control
activity are examined.
Tags & Heart Needle
Samples
“Running the Gut”
The contents of the stomach, intestines,
and bowels must be inspected as well
Removing the Brain
The Scalp is cut
ear to ear across
the crown of the
head
Exposing the Skull
Next the scalp is pulled forward and back to
expose the skull
Exposing the Brain
Cutting the skull cap
Removal of the Brain
• Spinal Cord is cut
• The soft brain is
removed
• Brain is so soft it
must be placed in
formaldehyde for
about a week before
an in depth
examination
Close Up
• Skull cap is replace
• Skin pulled back in
place
• Body Organs may
or may not be
replaced
• Incisions are sown
up with the use of
a baseball stitch
Close Up
High Risk Autopsy
As Recommended by CDC
Source Material
High Risk Autopsies
• Case Selection
• Permissions
• Local
• NPDSU (required for genetic testing)
• Precautions
• Autopsy - BSL 2
• Tissue
- BSL 3
• Equipment
• Procedure
• Tissue Handling
• Shipping
High Risk Autopsies - Goals
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Obtain diagnostic tissue
• Limit Exposure
• Respirator
• Vacuum
• Limited personnel
• Limit Contamination
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Disposables
Shroud
Coverings
Dissection container
Dedicated tool set
High Risk Autopsies - Decontamination
• Stainless steel
• Autoclavable
• 1M NaOH
• 30’
• Non-autoclavable
• Immersible
– 1-2M NaOH, 1hr, RT
• Non-Immersible
– 1-2M
• Aluminum
• Sodium hypochlorite
(2% free chlorine)
DO NOT AUTOCLAVE
• Liquid waste
• 1M NaOH
• Autoclave 132°, 4.5hr
• Dry waste
• Incineration
• Autoclave 132°, 4.5hr
Tissue Processing
• Post-fixation Formic Acid
• >95%, 1hr, RT with post-treatment formalin
48hr.
• Process as usual
• Discard waste as biohazardous waste
Post-Mortem Forensic Toxicology
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)
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 for toxicology
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Blood
Urine
Stomach contents
Bile
Liver
Hair
Vitreous humor
Blood
• Antemortem  ideal blood sample
• “just before death”
• Postmortem blood is not truly “blood”
• Anatomical site of collection at autopsy
should be noted
• Central sites
• Heart
• Peripheral sites
• Femoral
• Iliac
• Subclavian
• Other sites
• Head blood
• Hematoma blood
Sites for Blood
Collection
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
• 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?
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
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
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Sodium citrate
Potassium oxalate
EDTA
Heparin
Not imperative for postmortem blood samples
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
• Quality of samples is diminished
• Putrefaction produces alcohols
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Ethanol
Isopropanol
Acetaldehyde
n-propanol
Postmortem redistribution
• A phenomenon whereby increased
concentrations of some drugs are observed in
postmortem samples and/or site dependent
differences in drug concentrations may be
observed
• Typically central blood samples are more prone
to postmortem changes (will have greater drug
concentrations than peripheral blood samples)
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 ?
Evaporation of volatiles
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Ethanol
Carbon monoxide
Cyanide
Toluene
Other alcohols
Interpretation
Therapeutic, toxic or fatal? How do you know?
• Compare measured blood concentrations with
concentrations reported in the literature:
• Clinical pharmacology studies
• Incidental drug findings
• Plasma  blood
• Consider case history:
• Symptoms observed by witnesses?
• Tolerance of the individual to the drug