Pathology

Pathology: Study of disease and trauma leading to death.
Autopsy: Dissection of a dead body to determine cause and manner of death; declines in frequency, losing a quality control tool for the medical profession.
Morgue: Can be as important as the crime scene.

Key Terms

Algor Mortis: Postmortem cooling of the body.
Asphyxia: Condition of being deprived of oxygen.
Autolysis: Self-dissolution by body enzymes.
Blunt Force Trauma: Injury caused by a non-sharp object.
Carboxyhemoglobin: Hemoglobin saturated with carbon monoxide; bright red color.
Cause of Death: The reason for the cessation of life; divided into primary, secondary, and immediate causes.
Contact Gunshot Wound: GSW where the muzzle is in contact with the skin.
Contusion: Bruise; accumulation of blood in tissues.
Coroner: Official who investigates deaths; may not require medical training.
Defensive Wounds: Injuries sustained while trying to fend off an attack.
Defibrillatory: Having the effect of stopping fibrillation (chaotic heart rhythm).
Distant Gunshot Wound: GSW from a distance where gunpowder doesn't cause stippling.
Embalming: Chemical treatment to preserve a body.
Exhumation: Digging up a body after burial.
Exsanguination: Death due to blood loss.
Hematoma: Large contusion with a tumor-like collection of blood.
Histology: Microscopic study of tissues.
Immediate Cause of Death: The final condition leading to death.
Incised Wounds: Cuts with more depth than length.
Intermediate Gunshot Wound: GSW with stippling from gunpowder.
Lacerations: Tears in tissue caused by blunt force.
Ligatures: Cords or similar items used to bind or strangle.
Livor Mortis: Postmortem settling of blood, causing discoloration; also known as postmortem lividity.
Manner of Death: The way in which the cause of death occurred (homicide, suicide, accidental, natural).
Mechanical Trauma: Physical injury due to force.
Medical Examiner: Physician who investigates deaths, often a forensic pathologist.
Medico-legal Autopsy: Autopsy for legal purposes.
Microtome: Instrument for slicing tissues thinly for microscopy.
Petechiae: Pinpoint hemorrhages, e.g., around eyes in strangulation.
Postmortem Clock: The sequence of postmortem changes used to estimate time since death.
Primary Cause of Death: The initial condition leading to death.
Putrefaction: Decomposition by microorganisms.
Rigor Mortis: Stiffening of muscles after death.
Secondary Cause of Death: Conditions contributing to death but not directly related to the primary cause.
Sharp Force Trauma: Injury caused by a sharp object.
Shored Exit Wound: Exit wound supported by a surface, like clothing.
Smears: Preparations of fluids spread on a slide for examination.
Stippling: Punctate marks from gunpowder in intermediate GSWs.
Tardieu Spots: Postmortem petechiae, especially in asphyxia.
Tetany: Sustained muscular contraction.
Toxicology Screen: Analysis for the presence of toxins and drugs.
Ventricular Fibrillation: Uncoordinated contraction of heart ventricles.

Case Example: Gloria Ramirez

Gloria Ramirez, dubbed 'The Toxic Lady', had advanced cervical cancer and was brought to the ER with breathing and heart issues in 1994.
ER staff experienced nausea and dizziness. Some staff passed out and had convulsions with manila-colored crystals were seen in the blood.
Ramirez died of kidney failure; no known toxic chemicals found in her system or the hospital.
An autopsy wearing protective suits with respirators was conducted by professionals.

Introduction

Pathologist: Medical doctor studying and diagnosing human diseases.
Forensic Pathologist: A pathologist studying disease and trauma related to death.
Autopsy (autopsia, “seeing with one’s own eyes): Standardized corpse dissection to determine the cause and manner of death.
The rate of autopsies has declined as of late.
Medico-legal autopsies are used to solve a murder, helping provide information such as who conducts them, when, how, and their purpose.

Cause and Manner of Death

Cause of death: Primary (immediate) and secondary causes.
Primary/immediate cause: a three-link causal chain explaining the cessation of life, starting with the recent condition and moving backward in time. Can also use less than three links.
Secondary cause: unrelated conditions that contribute to the demise, such as extreme temperatures.
Hospital autopsy: conducted based on a doctor’s request and the family’s permission. If family denies it, autopsy is not performed.
Medico-legal autopsy: performed pursuant to a medical investigation of death for legal purposes.
Manner of death: how the causes of death came to be; four acknowledged manners: homicide, suicide, accidental, and natural.

Coroners and MEs

Coroner: Office originated in England (AD 925). Investigates unusual, untimely, suspicious deaths, may or may not have medical training.
Medical Examiner (ME): Physician with pathology and forensic pathology training; appointed positions.
Death Certificates: Any licensed physician is permitted to sign death certificates in cases of natural death. Some guidelines exist to assist in the completion of this form (Council of American Pathologists, 2006).

The Postmortem Examination (Autopsy)

Visual, or external examination: Description of clothing, photographs of the body, and a detailed examination of the entire body. Attention to detail, damage to clothing should correlate to trauma.
GSWs: entrance and exits wounds and the path of the bullet through the body are recorded. Defensive wounds are noted.
Traumatic deaths may be classified as mechanical, thermal, chemical, or electrical. Medical doctors and surgeons classify wounds differently than MEs and forensic pathologists.

Classification of Trauma

Mechanical Trauma

Mechanical trauma occurs when force applied to tissue exceeds its strength, which can be described as resulting from sharp or blunt force.
Sharp force trauma: injuries caused by sharp implements, like knives, axes, or ice picks.
Blunt force trauma: caused by dull or nonsharpened objects, like baseball bats, bricks, or lamps; produce lacerations, or tears in the tissue, typically the skin whereas sharp objects produce incised wounds, wounds that have more depth than length or width.
Size, shape and kind of wound may allow the pathologist to determine if a sharp or blunt object caused it.
Death from blunt and sharp trauma results from multiple processes, but sharp trauma most commonly causes death from fatal loss of blood (exsanguination) when a major artery or the heart is damaged. Blunt trauma causes death most often when the brain has been severely damaged.
Contusion: accumulation of blood in the tissues outside the normal blood vessels and is most often the result of blunt impact. The pattern of the object may be transferred to the skin and visualized by the blood welling up in the tissues.
Hematoma: extreme contusion (blood tumor).
Abrasions: scraping of the skin surface, while rarely fatal in themselves can often corroborate or help explain the circumstances surrounding death.
Asphyxia: A type of mechanical trauma in which the body is deprived of oxygen.
- brain is the most susceptible organ to asphyxia, and unconsciousness typically follows loss of oxygen flow in 10 s with irreversible coma resulting in a matter of a few minutes.
- Suffocation: occurs by covering the nose and mouth blockage of the major airways with a foreign object.
- Strangulation: manual or ligature compression of the structures of the neck, often leaving characteristic physical evidence, such as the fracture of the hyoid bone and bruising.
- Chemical asphyxiation: occurs when the oxygen in the air is replaced by some other gas, such as carbon monoxide (CO).
Gunshot Wounds: The projectile from a discharged firearm produces a special kind of blunt force trauma.
- Contact (entrance): Blackening of skin, lacerations, bright-red coloration of blood from carboxyhemoglobin.
- Intermediate (entrance): Stippling (gunpowder penetrates skin).
- Distant (entrance): Circular defect with abraded rim.
- Shored exit: Transfer of shoring material (such as the weave of cloth) may be transferred to skin.

Chemical Trauma

Chemical trauma refers to damage and death which results from the interaction of chemicals with the human body.
If the damage from chemicals is external, as in the case of acid or alkaline burns, then this is still the purview of the pathologist.

Thermal Trauma

Extreme heat or cold may produce death.
Hypothermia: Too much exposure to cold.
Hyperthermia: Excessive heat.
Persons who die in a fire do so generally because of the inhalation of combustion products, like carbon monoxide (CO). The level of CO in the tissues and the presence of soot in the throat tissues can determine whether the person was alive or dead when the fire burned him or her.

Electrical Trauma

Electricity can cause death by a number of means.
Circuits of alternating current (AC) at low voltages that cross the heart cause ventricular fibrillation, a random quivering that does not pump the blood through the body properly.
At high voltages, the amount of current causes the heart to stop beating (it becomes defibrillatory), pushing the heart into tetany , a sustained contraction that is broken only when the circuit is broken.
High voltages produce severe burns and cellular damage within a fraction of a second.
Trace evidence that may be later submitted to a forensic science laboratory should be preserved when the clothing is removed; wet clothes should be suspended to air dry at room temperature and not folded.
The age, sex, ancestry, height, weight, state of nourishment, and any birth-related abnormalities are noted.
Death-related phenomena that may provide information, such as presence of rigor mortis and livor mortis, is noted.
Rigor mortis: the stiffening of the body after death due to the membranes of muscle cells becoming more permeable to calcium ions. Onset typically begins 2–6 h after death and releases after 24 h.
Livor mortis: settling of blood due to gravity after the heart no longer circulates it through the body resulting in a purplish discoloration in the skin; begins to set in about an hour after death and peaks in about 3 or 4 h. Pattern of lividity can indicate if a body has been moved.
Eyes are examined for indications, such as petechiae, pinpoint hemorrhages that are found around the eyes, the lining of the mouth and throat, as well as other areas often seen in hanging or strangulation victims. In older pathology literature, petechiae may be referred to as Tardieu spots.
Mouth area and oral cavity is examined for trauma, trace evidence, and indications of disease.

History: The Autopsy

Chinese text, Hsi Yuan Chi Lu, written in 1247, describes trauma patterns and weapon identification.
Greek physicians performed autopsies as early as the fifth century.
Christian Europe discouraged autopsies until the death of Pope Alexander V in 1490.
Emperor Charles V issued the Constitutio Criminalis Carolina in 1530, promoting medical pathology.
Rudolf Virchow added microscopic examinations in 1858.
The first ME’s office in the United States was in Baltimore in 1890.
New York City abolished the coroner system in 1915, establishing the ME’s office headed by Milton Helpern.
Maryland established the first state-wide ME system in 1939.

Other Evidence Collected

In cases of sexual assault three sets of swabs will be used to collect foreign body fluids.
- Females: vaginal swab, oral swab, and rectal swab are collected.
- Males: oral and rectal swabs alone are taken.
One set will be for smears, where the collected fluid on each swab is wiped across a separate clean glass microscope slide and microscopically examined for the presence of spermatozoa.
The second and third sets are for serological examinations, including testing for the acid phosphatase in seminal fluid and possible blood typing.
Known head hairs and pubic hairs are extensively photographed, sketched, and then collected. The knots should be retained for later examination by the forensic science laboratory because hairs, fibers, or other trace evidence may have been trapped in the knot when it was tied.
If the decedent’s identity is unknown, a full set of fingerprints are taken to be referenced against any databases.
For badly decomposed remains, the jaws may be removed to facilitate a forensic dental examination and identification.

Internal Examination and Dissection

The pathologist then removes the internal organs, either all together or individually; this latter method is called the Virchow method, in which each organ is removed, examined, weighed, and sampled separately to isolate any pathologies or evidence of disease.
The stomach and small intestines can provide crucial clues to the decedent’s last actions. Liquids digest faster than solids.
Each organ is sectioned and viewed internally and externally. Samples for microscopic analysis of the cellular structure (histology) and for toxicology screening tests are taken.

In More Detail: Cereal Killer in Spokane

James Cochran’s residence was found engulfed in flames, and Kevin, the 11-year-old son of # James Cochran, was missing. Cochran claimed no knowledge of Kevin’s location, suggesting Kevin had started the fire while playing with matches and had run off. Two days later, the fully clothed body of Kevin Cochran was found along a road north of Spokane.
At autopsy, the pathologist determined the cause of death to be strangulation. The boy’s stomach contents, fingernail clippings, hand swabs, and clothing were collected as evidence for laboratory examination.
Stains from the bed of the pickup truck were compared to the vomit and gastric contents of Kevin Cochran. The cereal ingredients were consistent with Marshmallow Mateys , the final meal of Kevin Cochran. ®
On Memorial Day of 1999, James Cochran committed suicide in his jail cell using a coaxial cable from a television set. Investigators theorized Cochran killed his son and set fire to his house for the insurance money.

Determining Time Since Death (Postmortem Interval)

Following death, numerous changes occur that ultimately lead to the dissolution of all soft tissues. The importance of these changes to the forensic pathologist is that they provide a sequence of events that may allow an estimate of time since death ensued. This determination is based on the principle of sequential changes called the postmortem clock.
The evaluation may include the following phenomena:
- Changes evident upon external examination of the body, such as temperature, livor, rigor, and decomposition;
- Chemical changes in body fluids or tissues;
- Physiological changes with progression rates, such as digestion;
- Survival after injuries, based on the nature, severity and other factors such as blood loss.
Examples: stiffness of the joints (rigor mortis), settling of blood on the skin surface (livor mortis), decrease in body temperature (algor mortis), chemical measurements of body fluids and physiological changes such as digestion.
Decomposition of the body begins almost immediately after death and consists of two parallel processes:
- Autolysis: the disintegration of the body by enzymes released by dying cells.
- Putrefaction: the disintegration of the body by the action of microorganisms, such as bacteria.
- The body passes through four main stages of decomposition: fresh, bloated, decay (ranging from wet to mushy to liquid), and dry.
  Insect activity, when present, greatly assists the decomposition process.

Laboratory Analysis

Histology

The samples of the tissues of interest are taken, embedded in plastic, and sectioned using a microtome (a machine that makes very thin, very precise slices) to a thickness of only a few microns. A medical technologist or histologist will then examine the sections microscopically, write a report, and pass this along to the pathologist.

Toxicology

A broad-based screen test is requested (a toxicology screen) to determine the absence or presence of drugs and their metabolites, chemicals such as ethanol and other volatile substances, carbon monoxide and other gases, metals, and other toxic chemicals in human fluids and tissues.

Autopsy Report

The autopsy report is a crucial piece of information in a death investigation. Because the results, hospital, or medico-legal, may end up in court, it is imperative that certain basic and specific information be included in every autopsy file:
- Police report,
- Medical investigator report,
- Witness reports,
- Medical history of the decedent

Exhumations

If questions about cause or manner of death arise once the deceased is buried, he or she must be dug up or removed from his or her mausoleum; this process is called an exhumation.
Embalming is a chemical process to reduce microorganisms, retard decomposition, and restore appearance; Tim Tracy and Pete Gannett have developed methods to analyze drugs and poisons in embalmed tissues.

Consultations

The forensic pathologist, when presented with challenging cases of burned, decomposed or dismembered bodies, may consult with any of a variety of forensic specialists. Forensic anthropologists, entomologists, and odontologists all may play a role in a death investigation.

Back to the Case: Gloria Ramirez

Dimethyl sulfone (DMSO ) was found in Ramirez’s blood. DMSO is a metabolic product of dimethyl sulfoxide (DMSO), a solvent sometimes used by cancer patients and athletes as a pain remedy.
Due to Ramirez’s use of DMSO and her urinary blockage, DMSO accumulated in her bloodstream and the oxygen the paramedics gave her in the ambulance converted the DMSO in her blood into a high concentration of DMSO . Some unknown catalyst, converts the DMSO into DMSO and induces the unhealthy effects.
When the nurse draws the blood and it cools to room temperature, the straw-colored crystals form. The DMSO evaporates, leaving no clues behind.