Introduction

What is Forensic Pathology?

Forensic pathology is the branch of medicine that  primarily concerns itself with determining the cause and manner of death. An individual who practices forensic pathology is usually referred to as a forensic pathologist or a medical examiner. We are the people who investigate deaths within defined jurisdictions in the United States. Our cases are usually deaths that occur where the cause is legitimately unknown or a circumstance exists that lends an air of suspicion. In addition to death investigation, we are sometimes called upon to testify in court or to offer consultation services to attorneys. We usually work in close conjunction with local police and district or state attorneys. However, we are independent of these agencies. First, let’s take a look at how we do our jobs.

Tools of the Forensic Pathologist

The autopsy examination:

An autopsy is a procedure by which a body is thoroughly examined. This consists of a detailed description of the external portions of the body that includes anything that is on or in it at the time of death:

• Clothing, including the contents of the pockets
• Descriptions of scars and other identifying features such as tattoos
• Descriptions of injuries

When that is complete, an internal examination follows. This is a complete examination and description of each organ system in the body and any disease process or injury that may involve them. During the examination, many specimens are procured from the body and stored for the following purposes:

• Tissue:
  • A representative sample of all organs are saved in case further microscopic study is necessary
  • Tissue can also be triaged for genetic studies where a familial syndrome exists or is suspected.
  • Occasionally tissue can undergo toxicology testing. The usual specimens are liver, brain, and spleen.
• Blood
  • Blood from various sites in the body is the preferred specimen for toxicology testing.
  • It will also be blotted onto a paper card that can be used for DNA testing at a later date, if necessary.
  • Occasionally, individuals can be identified via blood testing if they are in the Combined DNA Index System (CODIS).
• Vitreous fluid (the fluid that fills the eye)
  • This can be used for toxicology testing. Drugs are not metabolized here the same that they are in blood or tissue, so certain drugs can be detected easier
  • Glucose and electrolyte testing can give you a rough idea of an individual’s state of health prior to death
• Urine
  • Urine can undergo toxicology testing, but it is not a preferred specimen
  • In some jurisdictions, this is the preferred specimen for alcohol testing
    

Forensic pathologists are mostly associated with autopsy exams, but we have many ways of gathering information. Some examples are:

Crime Scene Investigation

The medical examiner is often involved, either directly or indirectly, in the examination of the scene where a body is found. Whether or not actually present, review of photos taken from the scene is a routine part of most death investigations. If something is particularly unusual, law enforcement may ask a pathologist to be present. I was trained with a very large exposure to crime scenes, and I think the experience was invaluable. I never turn down the opportunity to participate in a scene investigation.

Record Reviews

It’s rarely mentioned as part of our job, but we gain an incredible amount of information by reviewing records. Usually these are medical records, but they can also include other things likes prescription records and arrest records. These can not only provide necessary information about medical conditions, but can also be used to establish patterns of behavior that may be vital in determining a cause of death.

This is far from a comprehensive list of our day-to-day activities. But, with that, we’ve come full circle. The overarching point is that all this information is used to toward our eventual goal, which is the determination of cause and manner of death.

Cause and Manner of Death

These two terms are incredibly important and are defined as follows:

• CAUSE OF DEATH: This refers to the event or sequence of events that directly lead to the death of an individual. 
  
• MANNER OF DEATH: This can best be thought of as the summation of the circumstances surrounding the death.

On paper, this seems pretty straightforward, but accurately classifying cause and manner of death is something that causes a lot of confusion in other specialties. One reason for this may be how “cause of death” is often defined statutorily and in medical texts. Oftentimes, the word “proximate” is used; as in “proximate” cause of death. This can give the (mistaken) impression that the cause of death is accurately described by the event that immediately preceded expiration. This is often true, but not always. Let’s take a look at an example.

Example 1: Delayed deaths

A 34 year-old man with a history of diabetes and hypertension is out at a bar with friends on a Friday night. He stays a little later than he intends to and is quite intoxicated by the time that he leaves. He figures that he only lives a short distance away and decides to drive. He is driving at a high rate of speed and begins to swerve into the shoulder. This individual over-corrects, which causes the vehicle to roll over. He is ejected from the car during this event. Luckily, the accident is witnessed and emergency services respond and rush him to the hospital. He is diagnosed with an upper cervical fracture that renders him paralyzed from the shoulders down. 

Five years later, this individual is noted to have a high fever by a nurse at the facility in which he resides. The on-call doctor notices some abnormal breath sounds so decides to send him to the local emergency department for evaluation. Laboratory and imaging studies reveal that he is in a state of severe sepsis and he has right middle and lower lobe pneumonia. He is admitted to the intensive care unit, but despite aggressive care, he succumbs to his illness and expires four days after admission. You are the doctor who cared for him at the original facility.

Now, it may seem logical that this individual died of septic shock or pneumonia, as these are the diagnoses that brought him to the hospital. Indeed, these are very common things that we see on death certificates that are incorrectly completed. It is true that these two diagnoses are part of the overall pathophysiology that resulted in this individual’s death, however, they don’t tell the whole story by themselves. What happened to this person that caused them to be susceptible to a life-threatening infection at the age of 39? It was because he was bed-bound and immobilized for a number of years (which is big predisposing factor for pulmonary disease for the non-medical people out there). What caused this prolonged immobility? That would be the injuries sustained in his previous car accident. So, in summation, the cause of death is related to the car accident, even if it was several years prior. If you keep these considerations in mind and stick to a logical thought process, you will always arrive at a reasonable cause of death.

Note: It is easy to go down a deep rabbit hole when it comes to determining cause of death in complex cases, and even experienced pathologists disagree in complex cases. We’re not so interested in the nitty-gritty of signing death certificates in this post, but a more in-depth discussion can be found here.

The next order of business is to assign a MANNER to this death. Manner of death is much simpler, for the most part, because you only have a few options:

• Natural – A natural death is one that occurs as a consequence of a well-characterized disease process that is usually diagnosed by another doctor before death. The big ones here are cardiac disease, cancer, and stroke. When someone says that a person died of “natural causes,” this is technically what they mean.
• Accident – This is a death that is caused by a chance, or usually inadvertent event. The big ones here are accidents involving means of conveyance (cars, motorcycles, bicycles, etc.). But any accidental trauma, such as a fall, would fit here.
• Suicide – This is a death that is due to an action that an individual undertakes of his or her own volition that results in his or her death. The vast majority of suicides in the United States involve firearms, with hangings being a close second.
  
• Homicide – This is a death that is due to an action that an individual undertakes of his or own volition that results in the death of another person. Like with suicides, most homicides in the United States involve firearms. You will note that this does not imply culpability (more on that below).
  
• Undetermined – This can be a little more difficult to understand and apply directly. An undetermined death means one of two things. Either there is not enough information to accurately determine the manner, or there is evidence that can make more than one manner equally likely. It usually,  but doesn’t always, imply that the cause of death is undetermined as well. An example of this might be a skeleton found in a forest that doesn’t have any demonstrable injuries. 
• Pending – A pending case is one where the cause and manner of death will not be known until an ancillary study is completed. This usually means toxicology, but the full range of chemistry, histology, microbiology, genetic, and anthropology services that we sometimes utilize apply here too.

So in our example above, it should be pretty easy to determine that the manner of death is accident.

With that in mind, it is easy to see why accurate death certification is so important. How would one classify a death due to a well-characterized disease process such as pneumonia? That’s right, it would be incorrectly classified as “natural.” Incorrect death certification can have a number of effects such as error that would be introduced into the gathering and analysis of local vital statistics or even impacting any life insurance payout to which the individual’s family may be entitled. Now let’s take a look at a few situations that aren’t so straightforward.

Unique Situations 

Manner of death isn’t always so easy to determine. Here we’ll cover a few special situations. Disagreement amongst forensic pathologists do exist in some of these gray areas, but what I’ll present below is what is considered to be the consensus approach to these situations. In these situations, two common strategies are used.

Volition vs. intent

Intent can be a tricky topic considering we deal with the dead. This clearly refers to suicides and homicides as both of these actions are USUALLY undertaken with a goal in mind. I may be saying something controversial here, but I don’t usually place much weight on an individual’s intent. As I stated above, a homicide classification does not imply culpability. Determining fault and applying appropriate reprimands is something that occurs on the lawyer and judicial side of the equation. We don’t apply the standard of intent there and I feel we shouldn’t apply it unequally. Furthermore, no matter how much evidence I review, I will never be able to ascertain the intent of an individual after he or she has undertaken a specific act, especially if they are dead. It is too much of a judgment call that I cannot apply equally in all situations. Much greater weight is given to volition. A volitional act is one that occurs without any undue influence, such as coercion or duress. We will illustrate the a volition vs. intent argument more fully in an example.

The “but-for” principle

What, you ask, is a “but-for?” Jokes aside, this is a useful, logical argument that can help reconcile circumstances in a difficult case.  It goes like this: “would this individual have died but for [INSERT CIRCUMSTANCE HERE]. As with most things, this will become more clear with an example.

With that out of the way, let’s cut to the chase and work through some hypothetical scenarios.

Example #2: Russian Roulette

For those who are not familiar with the term, Russian roulette is a high-risk game where a revolver is loaded with a single round. The chamber of the gun is spun and people take turns placing the gun against their heads and pulling the trigger. Eventually, the round will travel to the hammer, and the individual unlucky enough to pull the trigger at that point will be shot in the head. What should the manner of death be here? Did the individuals int his game all have clear intent to end their own lives? Most people would argue that the answer to that question is “no.” If we cannot make a comment on intent, does this exclude suicide? This is a good illustration of why I don’t like to get too involved in discussions of intent. There will never be a strong answer to questions about it. But, we can look at the other circumstances in this situation. These individuals are involved in a game that utilizes a firearm. One would assume that all adults of normal capacity would recognize that a firearm is a tool that can end one’s life. Despite that, an individual participating in this game has taken that gun, placed a round in it, and then placed the barrel of the gun against his head. He then, of his own volition, pulled the trigger. The evidentiary weight provided by his volition in this case, far outweighs his intent. Even if his intent was to live through the night, he voluntarily undertook an action that he knew had a non-zero percent chance of causing his death. This death is best classified as SUICIDE.

Example #3: A Hunting Trip

Three friends are going on a hunting trip in the forest. Before the sun fully rises, a deer runs across the field of vision of one of the hunters. He tracks the movement and fires, but the bullet strikes one of his companions in the back of head, killing him instantly.

This is similar to the previous case. We can safely assume that the individual did not intend to kill his friend. However, he did all the same actions that the previous person did of his own volition. He loaded the gun and pulled the trigger. Again, it is common knowledge that the use of firearms may result in loss of life. This is further bolstered by the fact that you are required to obtain a license to legally own and use a firearm, and there is a degree of firearm education that must occur before the license is issued. If you really wanted to include intent in the argument, you could say that his intent was to strike a target, he just hit the wrong one. I think this is a stretch though. This death is best classified as a HOMICIDE.

Example #4: The Cat Did It

A man has a poorly maintained firearm that he does not store properly. He usually keeps it loaded. One evening, he places the gun on his kitchen table while he begins to prepare his dinner. His cat jumps onto the kitchen table and knocks the gun to the floor. It hits the ground and discharges. The bullet strikes the man in the back, following an upward course that lacerates his heart. He dies shortly after this event. Investigating officials respond to the scene and confiscate the gun. It is handed off to the ballistics laboratory where they are able to replicate discharges without pulling the trigger.

I don’t think we can apply volition or intent to the cat. Although this is a somewhat amusing scenario, the main takeaway here is that we are able to prove that this firearm is capable of discharging a bullet without a trigger pull. This is actually pretty uncommon with most modern firearms, but it does happen. It should make sense that this death is best classified as an ACCIDENT.

Example #5: Drug Overdoses

I don’t think this requires a specific scenario. Deaths due to the acute, toxic effects of substances obtained both pharmaceutically and illicitly are incredibly common in the United States. These deaths are generally classified as accidents. I have heard the argument that a drug user should know that every time he or she administers a particular substance he or she should know that it has the capacity to end his or her life. There are some who routinely classify these deaths as suicide or undetermined, but this is not a common practice. In general, death resulting from the toxic side effects of an acute exposure are classified as accidents. I follow this practice unless there is convincing evidence that an individual intended self-harm, such as a suicide note. Then it can be classified as a suicide.

Example #6 Chronic Effects of Drugs

A 49 year old man experiences weight gain, darkening of his skin, and extreme fatigue over a three month period. He drinks approximately one-half of a 750 mL bottle of vodka per day, and has for many years. He experiences a day of high fever and confusion before a friend of his drives him to the emergency department. There, he is found to have abdominal distention, elevated liver enzymes, low albumin, and an increased white blood cell count. Approximately 1000 mL of cloudy, yellow fluid is drained from his abdomen. His blood alcohol content (BAC) upon admission is .120. He is admitted but quickly becomes hemodynamically unstable. Resuscitation attempts are unsuccessful and he expires later that day. An autopsy is performed and the major finding is macronodular cirrhosis of the liver.

Cases like this are where things start to get pretty confusing. These cases used to be difficult for me when I first started. One one hand, this individual did have acute exposure to a substance (alcohol) that would generally be accepted as “intoxication” in most states (usually .08 – .1). But recognition of the rest of the evidence supports a different conclusion. This man is a very heavy drinker, so the acute effect of that level of alcohol is debatable. Furthermore, the rest of his symptoms (edema, confusion, fatigue, jaundice) are indicative of liver disease that is inextricably linked to his alcohol consumption. Since he died of a well-described, end-organ based disease process, this death is best classified as NATURAL. This reasoning applies to any disease process that is secondary to chronic exposure, such as heart disease in the context of long-term cocaine use, or infectious endocarditis (infection of heart valves) due to chronic intravenous drug use. 

Example #7: A Violent Robbery

An 85 year-old woman is out shopping for groceries. She is a life-time smoker, has high blood pressure, high cholesterol, and coronary artery disease. She takes two medications for her blood pressure and one for her cholesterol. Despite this, she does her best to get as much exercise as she can tolerate. As she is walking home, a man approaches her and pulls out a gun, demanding her purse and its contents. She hands it over and he flees the scene, running away from the woman. She staggers a few steps and collapses to the ground. A passerby sees her on the ground several hours later and calls 911. She is pronounced dead at the scene. This description of the event is procured from a security camera at a nearby store. An autopsy is performed. No injuries, defensive or otherwise, are noted during the external examination. The internal examination is significant for an enlarged heart, critical stenosis of the three major coronary arteries, and hyper-expansion of the lungs, consistent with pulmonary emphysema. 

This woman was not injured by her assailant. It is clear based on her history and autopsy findings that she died of a cardiac event (heart attack). Should we classify this as a natural death? Here is a good application of the “but-for” principle. What was special about this particular moment in which the heart attack occurred? In other words, would she have died but for the alleged assault? I think the answer is no. She had a compromised heart that was ill-equipped to handle the perfusion demands of an increased heart rate and a stress response. This response was deemed necessary by her body because she likely believed that she was in extreme danger. Therefore, her death is attributable to a volitional action undertaken by another individual and should be classified as a HOMICIDE. We tend to draw a somewhat arbitrary line in these cases. If it is reasonable that the decedent had reason to believe that his or her life was in danger, then this logic applies. If the circumstances don’t fit this criteria, it would probably be classified as a natural death. 

Example #8: A Police Chase

A 55 year-old police officer is pursuing a suspect on foot. The officer is overweight and has a history of high blood pressure. Last year, he underwent percutaneous stent insertion of the proximal left anterior descending coronary artery due to unstable angina pectoris. A short while into the chase, his partner sees him suddenly collapse. He attempts to render aid, but the officer is without a pulse. He is pronounced dead at the local emergency department.

This is the inverse of the prior case. Like the previous person, this individual is not able to compensate well for increased perfusion demand required by physical exertion. However, the circumstances do not fit the above example as the fleeing suspect had no aggressive action toward the police officer. His death is primarily due to the effects of his existing natural disease process, and so this death is classified as NATURAL. 

Example #9: Police Involved Shootings

This is a case type that is unfortunately common in our line of work and are usually very sensitive cases for all parties involved. I won’t provide a specific example as there are many to choose from in recent history. These deaths should be classified as HOMICIDE, and they are in most jurisdictions. This may seem strange to a lot of people. From a forensic pathology standpoint, an important thing to remember is questions of justification and possible wrongdoing will not be answered by the medical examiner. As I stated above, we are primarily concerned with cause and manner of death. A homicide designation by the medical examiner does not imply culpability the same way a homicide charge applied by a judge would. The most important thing in these cases is accurate documentation of all injuries. This information will be utilized by the investigating agency. Furthermore, medical examiners are often called to provide testimony in these cases.