Forensic Medicine: Death

As a doctor you will inevitably have to deal with death and dying. Its hard and emotionally testing but you have to know what to do. There is a chance that you will be called to certify a death and you may have to make a decision about whether an autopsy is needed. I hope to cover everything about death in this post. disclaimer: I attend an international medical school so the laws may be different in different countries, most of the laws described here fit English and Italian law, I have tried to be as general as possible so to cover most countries. 

First of all how does one certify a death and how can you be sure that someone is in fact dead?
The respiratory, cardiovascular and neurological systems are regarded to be essential for life. therefore most assessments of life will address these systems. 
When the authorities come to you for a death certification, what they need is a proof of death, they don't need you to determine the cause of death. Usually there will be an ECG at hand and you will certify death by verified lack of cardiac activity (20min continuous ECG). If there is no ECG, then you will have to determine death based on post-mortal phenoma and other physical signs. 
There is anyway a mandatory 24hour period of observation of the body (usually in the morgue) just to make sure the body is in fact dead. the observation is mandatory except for putrified bodies (rotting bodies) or with decapitated bodies. 

In the UK you can certify death by fulfiling the following criteria:

• No palpable pulses.
• No heart sounds on auscultation (or asystole on ECG).
• No reaction to painful stimuli
• No breath sounds on auscultation and no observed respiratory effort. 
• Pupils dilated and not reactive to light.

Its important to assess without any unnecessary delay and ensure accurate documentation in the patient notes with your assessment and the time of death. 

In order to bury a body the national mortuary regulation requires a complete MCCD (medical certificate of cause of death form) with a cause of death. This makes determining the cause of death more important than certifying death as the body cannot be buried without it. The form is used for statistical purposes. The form has three spaces for the cause of death; a final cause of death, an immediate cause of death and an initial cause of death. Its not easy to state what the actual causes and potential chain reaction to death is. Frequently the final cause of death is cardiac arrest or respiratory arrest, but what caused it? 
A couple of examples:
Stab wound - massive hemorrhage - cardiac arrest
Abdominal aortic aneurysm - anuerysm rupture - cardiac arrest
(dont use an abbreviations when filling out this form).

There is an area whee you state comorbidities that may have contributed to the death and a separate area to fill in regarding traumatic deaths (was the death a suicide, homicide or accident). after filing the in the form you simply sign it and state your registration number. 
The aim of the MCCD is to monitor deaths in the country, and still quite often we don't know what caused some deaths. For example a patient arrives in ER and dies shortly after or a patient with a history of heart disease dies at the GP practice. You have to pay attention when filling in this form, you should fill in the form with "scientific knowledge and good conscious" as the Italians put it. 
a physician should fill in this form only is he or she feels relatively confident about the cause of death (you can never be 100% sure). Any cause of death can be put on the form, if the cause of death is not filled in or the form not submitted then an autopsy will be requested by the national health system (NHS) (hospitals themselves can also request an autopsy). Never feel forced to fill in the form. With autopsies the system feels safer. 

If a normal national health autopsy is conducted and suspicious lesions are found for example a neck hematoma, then the autopsy is automatically stopped and referred over to the judicial system. Before a judicial autopsy no one can touch the body (no tampering). There is sometimes are threats to pathologists dealing with a body from gang members.

Its important to note that the families have no say in what happens to the dead body, dead bodies do not belong to the family. Although ethical and morally its good to inform the family about what is happening to the body of course.

Just to highlight, if you are not sure about the cause of death do not sign the form!

There are two laws that protect the dead a first law protecting the dead against maiming and a second law basically saying that family's have no say in what happens to the body. Many religions don’t want the body tampered with and this clashes with the law, the law needs to be respected.

Judicially speaking, a dead body is not a person and therefore loses the rights of a person. There are many controversies and questions related to privacy, however the answer usually swings to the fact that dead bodies have no rights like living people. 

Every year in Milan 2-3 bodies and in Italy over 1000 unidentified bodies are discovered and buried without a name. Some places tried to provide a facility where you could put a picture online of the cadaver in hope of an identity such as the  UK missing persons bureau. Although these can clash with some authorities over privacy issues. 

When a person dies the family will need more support than ever. 60-70% complaints to doctors regarding life-death issues are due to the family not  being given enough attention and feeling like they were not appropriately listened to. After a death, sit down and talk to the relatives. There usually is a bereavement team at the hospital you can contact, who will liaise with the family. 

Pathological phenoma following death

These phenoma can be used to identify a person, the time of death and sometimes even the cause.

After immediate death there is an early post mortum period, then after the decomposition period and finally after that taphonomic factors.

The early post mortum period is what forensic pathologists and doctors certifying death will mostly be dealing with. You may even get a call to certify death when the body is already full of worms, but a doctor is still needed to certify death even in this case.

Three phenoma are seen during the early postmortum period

• Algor mortis (cooling)
• Rigor mortis (rigidity)
• Livor mortis (a hydrostatic phenoma)

Algor mortis (not Al Gore mortis)

Algor mortis starts as soon as the vital activity of the body stops. We cannot see with the naked eye the metabolic changes on a cellular level but you can feel and measure the temperature. The body will start at around 37 degrees on death and will slowly reach the temperature of the surrounding environment. Never trust if a body just feels cold, always use an objective measured reading.  Depending on the reference textbook you use, Below 34 degrees is considered not compatible with life. Use an internal measure of temperature, for example the mouth or rectum (or even tympanic temperature, see below). The time from death is linked to the temperature but depends on many variables.

You may be asked if the death was recent or not. You can try and correlate the environment with the temperature you record, there are in fact many equations that can be used to estimate the time of death but even the best of these will give you a result with plus or minus 2 hours minimum from time of death (plus or minus 4 hours is probably a better considerate). Many of these equations insist on rectal temperature and hence the error because the rectal temperature ha a large plateau in which it does not alter, it takes a while to change.

Ear temperature is much more representative of cooling, the speed and for how long for. This is because the variables change less in the head (no difference in body fat surrounding for example). Often many doctors with take the temperature with the back of the hand, never do that! use a thermometer!

Rigor mortis

The physiology of rigor mortis is well understood. The lack of ATP production after death causes ATP to eventually run out and the actin-myosin contractile unit of muscles to be locked in place (the myosin heads cannot detach without ATP). The onset takes a little while, while there is still ATP in the muscle. Eventually the muscle becomes locked in place and it is a very strong contraction. I read about pathologists forcing the joints (breaking the joints) in order to get arms or limbs straight.  It tends to start at the head and extend down to the feet and it devolves in the same way from head to feet. It can even take a few days to resolve in some cases.

Livor mortis

Livor mortis sets in after a few hours. It is quite simply the pooling blood in the body due to gravity. Slowly as time goes by, the endothelium collapses and the blood infiltrates the tissues. The pooling of blood will cause discoloration of the tissues, and you will see pink purple areas on the skin. If the cadaver was on it's back, the lower part of the body will be pink and the compressed areas of contact will be white. A handy test is if you compress the pink area with your finger, if the death was less than 6-10 hours ago then the blood will move away on finger compression (become white). If you were to roll the body  less than 6-10 hours after death then the pink areas would move, if the death was greater than 6-10 hours ago then the pink areas will stay pink .

Time frames

First considering algor mortis there are four stages after death with related time periods

Algor mortis:

0-3hours Plateau phase (no change in temp)

6-8hours Fast cooling stage (most accurate for determining time of death)

10-12hours Final plateau phase

11-30hours End of cooling.

Rigor mortis depending on the textbook tends to begin at around the 3hours-12hours mark, with the highest intensity of contractions between 12 and 48hours, resolution is around the 72hours mark.

Livor mortis has an onset around the 2hour mark with the highest intensity of discoloration at the 12hour mark, at 10hours-12hours the blood can still migrate at the 48-72hour mark it becomes fixed.

(Note that compression areas will be white and hanging limbs will be pink, consider gravity).

Transformative processes

When you are asked to certify a dead body you have to know what to expect. If the death happened a long time ago you will see the so called transformative processes. When these processes kick in you need to be aware that its impossible to determine the time of death. The onset and time frames are incredibly variable and depends on many variables and environmental factors.

Transformative processs can be either destructive or conservative.

Destructive:

Autolysis

Putrefaction

Maceration

Conservative:

Mummification

Adipocere

Corification

Mummification is caused by the loss of water from the soft tissues, and can preserve the tissues for a very long time. In theory if you rehydrate the tissue you will see the same tissue as before. True mummification is very rare. 

Adipocere usually occurs when the body is left in water, the tissue becomes a weird creamy soft texture and then sets after a while to an incredibly rock hard shell. 

Damp bodies may not putrefy and can undergo so called wet mummification where all the cells are lost and just the fibrous collagen based skeleton of the tissues remains, it appears very similar to mummification with brown appearance.

Criminal cases look at the exterior limits of these processes. It can be hard to not lose body parts when these processes kick in when you are collecting the body. 

Putrefaction is the main transformative process for dead bodies at our latitude. Putrefaction is decomposition of the body and causes a marble like green discoloration to the body (green due to hemoglobin catabolism), usually the processes start in the lower right quadrant of the body (this is because the cecum contains the highest concentration of bacteria in the GI tract). There is also bloating due to the gases produced. Eventually everything breaks down and turns to water. When you come across a putrefied decomposed body this is one of the rare scenarios where on the MCCD you can write the cause of death as indeterminate.

Many factors affect these processes: temperature, wind, season, soil pH, moisture content of soil, morphological characteristics, patient age, cause of death, laceration or discontinuations of the skin.

Forensic Pathology

Forensic pathology regards the diagnosis of when a lesion occurred and how it occurred. All physicians will have to deal with violence and trauma at some point. It is important you can describe a lesion well and accurately as your report may be used as evidence in a court case. You should be able to diagnose a lesion, age it, describe it and know what to do to preserve evidence.

There is a branch called humanitarian forensic medicine, for example proving migrants underwent torture in their home country. For these migrants, the evidence you present may determine whether they will be allowed political exile or not. Your report is the only piece of paper that will be able to support the evidence of ill treatment or torture when presented to regional councils and police.

In humanitarian forensic medicine you may also be needed to age unaccompanied minors of undetermined age. For example migrants  without any documents, is the migrant above 18 years age? it could make all the difference. Police can refuse territory to migrants over 18yrs. You need to know what to do to verify age.

Forensic pathology starts with a physical exam. You need to assess the whole body (you also need to listen to the patient, don’t forget!). If you don’t document a lesion or ‘crime’ and the victim doesn’t talk, then any evidence of the ‘crime’ will disappear. No sign of a crime can remain if there is no documentation. You need to have a keen eye to spot scars or bruises on darker skin.

Description of lesions needs to be metric and repeatable, there is no reason to not take a photo of a difficult to describe lesion. (although now there are issues with tampering of photos with programmes such as photoshop). If you take a picture, place a ruler in the periphery of the lesion at the same level of the lesion and consider putting a coin in the photo to help spot distortion or modification of the image later. Lastly make sure you take the picture perpendicular to the skin surface.   

How do you describe a lesion?

Need to address:

•   area of body affected
•   type of lesion
•   colour
•   edges/limits
•   shape
•  orientation
•  size

Types of lesions:

Blunt force trauma

Sharp force trauma

Gun shot wounds

Asphyxia

Thermal injuries

Poisoning

Blunt force trauma

• Excoriations
• Bruising
• Lacerations

Cause by any force against the body surface by a blunt object. You can tell on a cadaver if the blunt force was performed when the cadaver was alive or dead by looking at histology. On histology, live tissue injury will show an inflammatory reaction with extravasation of red blood cells into the tissue. On dead tissue there is no inflammatory reaction, you can also use immunohistochemistry to spot the presence of cytokines and see if there are inflammatory cells present.

Excoriations

Excoriations are loss of the superficial layers of skin due to blunt force trauma (not an abrasion, an abrasion is loss of the superficial layers of the skin caused by an object with a sharp margin like a knife). Excoriations often reproduce the shape of the object that cause it. 

Often the excoriation will heal with a scab and at this point it will become impossible to age the lesion. ED physicians may be the only people able to preserve material evidence of assault from the lesion. It’s easy, you simply swab the lesion for 30 seconds before cleaning  the lesion (moisten the swab with sterile water or saline before), store the swab in a tamper proof container and dry or freeze it (you can later give it to the police if necessary). Often under the nails of victim there is often attacker DNA (there can even be attacker DNA on the surface of a bruise from punches etc).

With excoriations you can often tell in which direction the blunt injury was caused and this can help reconstruct the event. (yet another reason for a good description and often there is some material left on the lesion from whatever object was used to create the lesion).

Scratch marks are a very typical and specific form of excoriation. Triangular or droplike in shape. They contain a lot of information about the author of the lesion and genetic information. A tyre mark may be another kind of distinct lesion (often the actual lesion is caused by the negative pressure by the treads in the tyre not the actual tyre surface).

Bruising

A bruise means the trauma was in that place, a hematoma is a collection of blood and the trauma causing the hematoma may be elsewhere on the body. When in doubt it is best to describe the lesion as a cutaneous discoloration. 

Great example; black eye can be caused by a direct trauma (punch to the face) forming a BRUISE or may be caused by a basilar fracture of the cranium creating the so called racoon eyes this is a HEMATOMA. They will look almost identical.

Note that MRI can be used to age and discover origin of a bruise/hematoma. Not that bruising may be difficult to spot for example of North African darker skin.

A bruise is different to a hematoma!

Bruises are closed lesions that show a distinct discoloration. The colour relates to the age of the lesion but also the size is important. You may have different colours at the edge compared to  the centre of the lesion due to difference in breakdown. You need to assess them carefully. For example a patient with multiple small bruises of same colour you can hypothesise were all caused at the same time. One large bruise may be purple while a neighbouring small bruise caused at the same time may be yellow.

Colour therefore depends on physiology, depth of injury and size.

Remember not to confuse a bruise with a hematoma.

Hematoma = filling of blood into a virtual space

Bruise = forcing of blood into a tissue

Note that old people bruise very easily and may even bruise spontaneously.

Lacerations

Third kind of blunt injury is a laceration. A laceration is simply a discontinuation of the skin, you can put the two skin edges together as normal and reconstruct the skin as there is no loss of substance. Bear in mind that a skin discontinuation may also be cause by a sharp force trauma. You have to describe the margins well.  Big clues that the laceration was caused by a blunt force trauma is irregular skin edges or frayed edges and bridges of tissue. You can look at the subcutaneous tissue and it will be irregular and not smooth with a blunt force trauma.

Sharp force trauma

• Penetrating injury
• Cut marks
• Stab wounds and mixed injuries

Penetrating injury

Depending on the book you use, pointed objects may or not be included in this category. A very distinct lesion to look for is needle tracks or syringe wounds. Always look for syringe marks in any unconscious patient, observe the whole skin surface, needles may be injected behind the ear or even on the genitals.

The shape of penetrating object lesions can tell you the shape of the object tip used to cause the lesion. The flaps of the skin lesions will match the penetrating object tip for example a squared end will cause an X shaped flap, a triangular tip will cause a Mercedes sign skin flap and a circular point a circular lesion.

An example is a penetrating injury to the cranium, surgeons keep the piece of cranial bone with the penetrating injury, the shape of the hole in the bone can tell you what kind of object caused the injury.

Cut marks

Cut marks are caused by a sharp edge weapon and cause a neat discontinuation of the skin edge and tissue. The cut mark usually has a tail at the edge of the skin discontinuation and this can give you a lot of information about where pressure was least and hence in what direction the cut was performed (obviously this depends on the curvature of the skin area and the object used, its still difficult to tell entry and exit point).

Stab wounds

Mixed weapons can give you stab wounds. These are weapons that can stab and can also cut. The cut mark is the result of passing the sharp edge and the penetrating injury the result of the pointed edge. Stab wounds contain a lot of information and will often reproduce the cross section of the blade. For example a double edged blade will produce a wound with two acute ends, a single edged blade will produce a wound with a single acute angled corner and an obtuse angled corner.  Sometimes the going in wound will not match well the going out wound and stab wounds may crossover each other making the lesion more complex and difficult to describe.

Remember that on skin and bones you may have residues of the instruments used to cause the lesions and you should always keep any debrided material.

Gun shot wounds (GSWs)

See future post on gun shot wounds...

Asphyxia

Asphyxia is a manner of death or disease that has distinct signs left depending on the method of asphyxia, the main types of asphyxia are:

•         Smothering
•         Choking
•         Manual strangulation
•         Ligature strangulation
•         Hanging
•         Drowning
•      Traumatic (compression) asphyxia
•         Plastic bag suffication

Unfortunately due to frequency of plastic bag suffocations in forensic pathology it has managed to deserve its own type of asphyxia.

With asphyxia there are many different types lesions that can be seen on the cadaver such as liver mortis, early rigor, delayed cooling etc. however, only one type of lesion is found on living bodies, petechiae! 

Petechiae is a very distinct sign of asphyxia and is caused by high pressure in the capillaries causing them to burst. Not always seen, it can be subtle, for example on the conjunctiva it is a common sign with strangulation.

Smothering is a good way to get away with murder there is often no sign apart from petechiae. There may be scratch marks, compression marks from teeth inside the lips or fibres from the object (usually a pillow).

Choking is usually accidental often people with neurologic or psychiatric disease or issues with the swallowing reflex.

Strangulation is a mechanism of death and not necessarily the lack of air. The death can be caused by nervous factors such as compression of the glomus body of the carotid artery and reflexive cardiac arrest. There are many anecdotal deaths where an aggressive attacker grabs an old man by the neck and he just drops dead almost instantly (the attacker will be mentioning in court how he hardly touched him). You usually see bruising with compression of the airways. Fracture of the hyoid or cricothyroid cartilage can have a distinct pattern with strangulation too. A ligature strangulation will often have a linear bruise of uniform depth sometimes with fibres still around the area (eg. rope burn).

With hanging there are often distinct fractures and ligature signs. You can tell easily if the person was hung before or after death by again looking at the haemorrhaging in the neck and the presence of an inflammatory response which is lacking with a dead body.

Traumatic asphyxia is caused by a heavy object compressing the rib cage restricting breathing.

Drowning is an awful way to die, often taking longer than 6 minutes as you alternate between periods of consciousness and unconsciousness. An important note is that water in the lungs is not proof of drowning! There is often water in the lungs in cadavers and it may have many origins (although sometimes it can be obvious with the post autopsy lung able to stand by itself it’s so full of water). Often the only proof of drowning is the presence of diatoms (microscopic algae) in the blood and organs (the diatoms being distinct to the body of water where the drowning occurred). When you drown the alveoli burst and water mixes with the blood providing an entry point for diatoms to enter the blood.  A long period after drowning there may be characteristic skin wrinkling and pink discoloration but this is more for shipwreck victims for example.

Thermal injuries, a common form of abuse. (see post on burns)

Poisoning

History is so important! Diagnosis of poisoning will require; anecdotal evidence, autopsy and clinical toxicology. If suspected keep a sample of blood/urine for a specific toxicology test that may be needed later. Many poisons are not included in the general toxicology screen performed in most ER’s. Also consider keeping a small lock of hair (from the roots), with this you can prove that the drug was not present in the victims system at time zero. 

There were far too many gruesome images that were associated to this post so here is a raccoon reacting to them