autopsy and toxicology. autopsy medical examination of a dead body to determine the cause of death...
TRANSCRIPT
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:• 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• 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• 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• 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
• 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)
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
Blood
• Antemortem ideal blood sample
• 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
Femoral
Iliac
Subclavian
Heart
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
• 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
Poklis, A. 2002. Abstract SOFT, Dearborn, Michigan.
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
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
• 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
• Experience of the toxicologist• Amount of specimen available• Nature of specimens available• Policies of the organization
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.