Stages of human death

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The stages of death of a human being have medical, biochemical and legal aspects. The term taphonomy from palaeontology applies to the fate of all kinds of remains of organisms. Forensic taphonomy is concerned with remains of the human body. [1]

Contents

History

The academic study of death is called thanatology, a field pioneered by Élie Metchnikoff in the early 20th century. Thanatology focuses on describing postmortem bodily modifications, as well as perspectives concerning psychosocial, medical, ethical, and spiritual aspects of death.

Definition of death

Prior to the 1980s, the legal standard defined death as the absence of cardiopulmonary function including the loss of all vital signs. [2] However, as medical technology advanced, there were situations where one might lose brain function and maintain cardiopulmonary function. [3] This led the American Medical Association, the American Bar Association in collaboration with the National Conference of Commissioners on Uniform State Laws to come together in the 1980s to expand the definition of death through the Uniform Determination of Death Act (UDDA). [3] Under this law, death can be defined as the loss of cardiopulmonary function or the loss of brain function including the brainstem and cortex.

Clinical signs and stages of death

Signs of death or strong indications that a human is no longer alive are:

The heart and lungs are vital organs for human life due to their ability to properly oxygenate human blood (lungs) and distribute this blood to all vital organs (heart). Hence, failure of the heart to pump blood or the lungs to obtain oxygen can lead to a cardiopulmonary death where the heart stops pumping and there is no pulse. In the brain, this can be manifested by a hypoxic state which leads to cerebral edema and thus an increase in intracranial pressure. The rise in intracranial pressure can lead to further disruption in cerebral blood flow, leading to necrosis or tissue death. [4] The aforementioned mechanism is the most common cause of brain death; however, this increase in intracranial pressure does not always occur due to an arrest in cardiopulmonary function. [5] Traumatic brain injuries and subarachnoid hemorrhages can also increase the intracranial pressure in the brain leading to a cessation of brain function and hence death. [6] While cardiopulmonary death can be easily assessed by looking for the presence of a pulse, or identifying electrical activity through EKG tracings, assessment of brain death is slightly more nuanced. Per the United Kingdom Medical Royal Colleges, a diagnosis of brain death is a two-fold process including 1) identifying the cause of irreversible brain damage and excluding reversible causes of brain damage and 2) conducting a series of clinical and laboratory tests to assess brain stem function. [7] [8]

The definition of legal death, and its formal documentation in a death certificate, varies according to the jurisdiction. The certification applies to somatic death, corresponding to death of the person, which has varying definitions but most commonly describes a lack of vital signs and brain function. [9] Death at the level of cells, called molecular death or cell death, follows a matter of hours later. [10] These distinctions, and the independence of physicians certifying legal death, are significant in organ procurement. [11]

Post-mortem changes

Timeline of postmortem changes (stages of death). Postmortem interval changes (stages of death).png
Timeline of postmortem changes (stages of death).
An example of postmortem corneal opacity. Postmortem changes of the eye.jpg
An example of postmortem corneal opacity.

Post-mortem changes refer to the series of changes that occur to a body after death. These changes can generally be divided between early post-mortem changes and late post-mortem changes (also known as decomposition). [12] These changes occur along a continuum and can be helpful in determining the post-mortem interval, which is the time between death and examination.

The stages that follow shortly after death are:

Of these, with obvious mortal damage to the body, the textbook conclusive signs of death clear to a lay person are: algor mortis, rigor mortis, livor mortis, and putrefaction. [13]

The cardinal signs of death may refer to the ending of breathing, heartbeat and circulation, or to algor mortis, livor mortis and rigor mortis; the adoption of brain death as a definition has lessened the centrality of these signs. [14] [12] In a clearer contemporary terminology, algor mortis, livor mortis and rigor mortis are called "early postmortem" changes, in distinction from the "immediate postmortem" changes associated with the cessation of bodily functions, as indicated by vital signs. [15] With an ophthalmoscope, changes to the blood in the retina are quickly visible. [16]

Those stages are followed, in taphonomy, by

Decomposition stages

Descriptions of decomposition have had varying numbers of discrete stages. A 5-stage process developed by Galloway and colleagues that is commonly used in forensic pathology is detailed below: [17] [18]

Post-mortem interval

The post-mortem interval (PMI) is also called the time since death. It is the time lapse between death and discovery. After death, decomposition occurs. Decomposition includes physical, chemical, and biological changes. [19]

Below are some of the biochemical changes that happen during decomposition which can help estimate the time since death (keeping in mind that there is variation between species). [19]

Macroscopic changes

Microscopic changes

Early after death

  • cellular autolysis (with loss of cell adhesions) [19]
  • morphologic changes in WBCs [19]
  • changes in blood glucose [19]
  • changes in electrolyte concentrations [19]
  • changes in enzyme activities [19]

Biological methods for estimation of the early PMI

Applied techniques in veterinary medicine

Techniques in veterinary medicine help estimate how long since bodies in animals have been dead.

  • In pigs, the decrease in body temperature occurs in the eyeball, orbit soft tissue, rectum, and muscle tissue. Up to 13 hours after death, eyeball cooling in pigs provides a reasonable estimate of time since death. After 13 hours, muscle and rectal temperatures in pigs are better estimates of time since death. [19]
  • In dogs, the eye K+ decreases from 1.5 to seven hours after death. Rigor mortis of hindlimbs may persist up to 24 hours, and elbow rigidity is lost after three to seven days. [19]

Tissue autolysis may also be used to measure the PMI.

  • In rat livers, hepatocyte nuclear chromatin condense over 6 hours of autolysis after death. Hepatocytes individualize over 6 hours after death. [19]
  • In canine livers, the bile duct epithelium detaches from the basement membrane after 3 days. Hepatocyte nuclei autolyze by 7 days. [19]
  • In equine livers, autolysis can occur as early as 1 hour after death. Autolysis progresses over 72 hours. [19]

See also

References

  1. ↑ Sorg, Marcella H.; Haglund, William D. (13 December 1996). Forensic Taphonomy: The Postmortem Fate of Human Remains. CRC Press. p. 13. ISBN   978-1-4398-2192-3.
  2. ↑ Sarbey, Ben (1 December 2016). "Definitions of death: brain death and what matters in a person". Journal of Law and the Biosciences. 3 (3): 743–752. doi:10.1093/jlb/lsw054. ISSN   2053-9711. PMC   5570697 . PMID   28852554.
  3. 1 2 Smit, Hans (1962). "The Uniform Interstate and International Procedure Act Approved by the National Conference of Commissioners on Uniform State Laws: A New Era Commences". The American Journal of Comparative Law. 11 (3): 415–417. doi: 10.2307/838593 . ISSN   0002-919X. JSTOR   838593.
  4. ↑ Machado, Calixto (25 February 2010). "Diagnosis of brain death". Neurology International. 2 (1): 2. doi:10.4081/ni.2010.e2. ISSN   2035-8377. PMC   3093212 . PMID   21577338.
  5. ↑ Spinello, Irene M. (September 2015). "Brain Death Determination" . Journal of Intensive Care Medicine. 30 (6): 326–337. doi:10.1177/0885066613511053. ISSN   0885-0666. PMID   24227449. S2CID   39103031.
  6. ↑ Wijdicks, Eelco F.M. (May 1995). "Determining brain death in adults [RETIRED]". Neurology. 45 (5): 1003–1011. doi: 10.1212/wnl.45.5.1003 . ISSN   0028-3878. PMID   7746373.
  7. ↑ "Diagnosis of death. Memorandum issued by the honorary secretary of the Conference of Medical Royal Colleges and their Faculties in the United Kingdom on 15 January 1979". BMJ. 1 (6159): 332. 3 February 1979. doi:10.1136/bmj.1.6159.332. ISSN   0959-8138. PMC   1597667 . PMID   421104.
  8. ↑ "Diagnosis of brain death. Statement issued by the honorary secretary of the Conference of Medical Royal Colleges and their Faculties in the United Kingdom on 11 October 1976". BMJ. 2 (6045): 1187–1188. 13 November 1976. doi:10.1136/bmj.2.6045.1187. ISSN   0959-8138. PMC   1689565 . PMID   990836.
  9. ↑ Shedge, Rutwik; Krishan, Kewal; Warrier, Varsha; Kanchan, Tanuj (2021), "Postmortem Changes", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID   30969563 , retrieved 13 September 2021
  10. ↑ Bardale, Rajesh (October 2011). Principles of Forensic Medicine & Toxicology. Wife Goes On. p. 133. ISBN   978-93-5025-493-6.
  11. ↑ Peitzman, Andrew B.; Rhodes, Michael; Schwab, C. William (2008). The Trauma Manual: Trauma and Acute Care Surgery. Lippincott Williams & Wilkins. p. 415. ISBN   978-0-7817-6275-5.
  12. 1 2 Prahlow, Joseph A. (10 March 2010). Forensic Pathology for Police, Death Investigators, Attorneys, and Forensic Scientists. Springer Science & Business Media. p. 163. ISBN   978-1-59745-404-9.
  13. ↑ Pollak, Andrew N.; Browner, Bruce D.; Surgeons, American Academy of Orthopaedic (2002). Emergency Care and Transportation of the Sick and Injured. Jones & Bartlett Learning. p. 19. ISBN   978-0-7637-2046-9.
  14. ↑ Fox, Renée C. (1981). "The Sting of Death in American Society". Social Service Review. 55 (1): 47–48. doi:10.1086/643890. ISSN   0037-7961. JSTOR   30011444. PMID   10250829. S2CID   33834100.
  15. ↑ Almulhim, Abdulaziz M.; Menezes, Ritesh G. (2020). "Evaluation of Postmortem Changes". StatPearls. StatPearls Publishing. PMID   32119351.
  16. ↑ Saukko, Pekka; Knight, Bernard (4 November 2015). Knight's Forensic Pathology. CRC Press. p. 57. ISBN   978-1-4441-6508-1.
  17. ↑ Wescott, Daniel J. (13 August 2018). "Recent advances in forensic anthropology: decomposition research". Forensic Sciences Research. 3 (4): 327–342. doi:10.1080/20961790.2018.1488571. ISSN   2096-1790. PMC   6374978 . PMID   30788450.
  18. ↑ William D. Haglund; Marcella H. Sorg, eds. (1997). Forensic taphonomy : the postmortem fate of human remains. Boca Raton: CRC Press. ISBN   0-8493-9434-1. OCLC   35236386.
  19. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Wenzlow N, Mills D, Byrd J, Warren M, Long MT. Review of the current and potential use of biological and molecular methods for the estimation of the postmortem interval in animals and humans. Journal of Veterinary Diagnostic Investigation. 2023;35(2):97-108. https://doi.org/10.1177/10406387231153930
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