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:• 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)

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• 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

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

• 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

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.