Definition of death. Post-mortem changes

Define death

• cessation of life in a previously living organism

• medically + scientifically it is a process in which cellular metabolic processes in different tissues + organs cease to function at different rates

What are the indications of death

• cessation of heartbeat and respiratory movements

• cessation of circulation by absence of carotid pulse

• ECG is unchallengeable and the electric brain waves are completely flat in EEG

• muscular flaccidity happens after failure of cerebral and cerebellar function

• all muscle tone is lost- but muscle are able to contract for many hours

• eye signs- more later

What are the eye sign indications of death

• loss of corneal and light reflexes

• eye globe tension decreases rapidly

• cornea soon loses its glistening reflectivity

• exposed sclera → yellow discolouration within hours

• “Tache noire” → sclera becomes brown and sometimes almost black

What is the definition of natural death

Attributed to an illness or an internal malfunction of the body not directly influenced by external forces

What are the types of natrual death

• sudden death

  • non violent death occuring fast and unexpectedly- <24h from onset of symptoms

• unexpected death

• “regular” natural death

What are the types of violent death

• without crime

  • suicide

  • accidents- fall, car, hypothermia

• with crime

  • homocide

  • accidents- running over pedestrian, car crash with multiple cars, overdosing a patient

Define cellular death

Cessation of respiration and normal metaoblic activity in the body tissues and cells

What are the characteristics of cellular death

• cessation of respiration → autolysis and decay

• skin + bone remain metabolically aline for hours → can be cultured days after somatic death

• WBCs can move up to 12h after cardiac arrest

• cortical neurons die after 3-7min of complete oxygen deprivation

• body dies cell by cell- can take hours

define somatic death

Loss of vital signs- reflexes, heartbeat, respiration

what are the characteristics of somatic death

• person is unconscious, cannot communicate, unable to react to sensory stimuli

• will never be able to communicate or interact with environment

• irreversibly unconscious and unaware

• Advances in resuscitation techniques in ventilation and in the support of the unconscious patient have resulted in the survival of patients that would otherwise have died as a result from direct cerebral trauma or of cerebral hypoxia from whatever cause (e.g., artificial ventilation in brain stem death)

Define brain death

Clinical diagnosis

Irreversible damage of brain

What are the characteristics of brain death

• failure of functioning vital centre- respiration, circulatioin

• virtually same as somatic death

• happens after hypoxia, intracranial haemorrhages, brain trauma or poisoning

• legal and ethical significance

What are early post mortem changes where you’d suspect death

• no pulse

• no breathing

• occular signs

• algor mortis

  • cold temperature change after death

What are early post mortem definite signs of death

• livor mortis

• rigor mortis

What is livor mortis

• PM lividity/ hypostasis → pooling of blood in lower portions of body → red/ purple colouration

• time of onset 2-3h

• Tardieu spots→ small haemorrhages in skin

What is rigor mortis

• PM stiffening of muscles caused by decrease of ATP from muscles

• starts from small muscles and gradually in larger muscles

• onset after 30min-3h- completed in 6-12h

• in next 24-36h rigor starts to decay and takes about 24h to disappear → secondary flaccidity

what are late post mortem changes

• decomposition

• changes in week 1

• changes in weeks 2-3

• aipocere

• mummification

what are signs of decomposition

• green discolouration of abdomen after 36h

• marbling after 2-3 days

• gas formation after 2.5-3days

• 1 week decomposition on land, 2 weeks in water, 8 weeks buried

what are late post mortem changes during the first week

• discolouration, marbling, onset of bloating

• skin slippage- looks like grade 2 burn

• dominant colours → grey, green, red

what are the late post mortem changes in week 2 and 3

• pressure inside the body increases

• excessive bloating

• faeces and urine leave the body

• appearance of fluid through orifices- mouth, nose

• dominant colours→ green, grey

Define adipocere

Greyish waxy substrance formed by decomposition of soft tissue in dead bodies due to moisture

Define mummification

Process of embalming or preserving a body after a person has died