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THANATOLOGY. thanatos- death; logos- science Assoc. Prof. Beatrice Ioan MD, PhD, MA. Death. Irreversible loss of the properties of the living matter. Cessation of life in a previously viable organism
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THANATOLOGY thanatos- death; logos- science Assoc. Prof. Beatrice Ioan MD, PhD, MA
Death • Irreversible loss of the properties of the living matter. • Cessation of life in a previously viable organism • Process - different rates of cellular death - internal organs have different functions with different cellular metabolic processes which cease to function at different rates
Stages of death 1. Agony (vita minima) • irreversible stage between life and death • mixture of vital and thanatologic processes • Decreased activity of cortical neurons • Bulbar centers are no longer controlled by cortical and sub-cortical centers- functioning of the organism is no longer unitary
Agony • Progressive disappearance of psychical functions- psychical chaos • Decreased contact with the environment • Complete immobility • Progressive disappearance of senses • Diminished vegetative functions
Agony Classification I. According to duration: • absence of agony- death occurs very rapidly • short agony (seconds, minutes) • long agony (hours) II. According to the psychical condition: • conscious agony- no changes of consciousness; • unconscious agony; • alternation of conscious and delirious periods Importance: • Validity of the documents signed during agony
Stages of death 2. Clinical death • Short interval (about 5-10 minutes) • Cardiac activity and respiration are absent • Cortical neurons still function • The patient can be reanimated by medical means 3.False death • Very diminished respiration and heart activity • Cannot be detected by ordinary means • Loss of consciousness
Stages of death 4. Biological death (real death) • irreversible • characterized by cessation of cellular metabolism and structural changes of cells Stages: • Somatic (systemic) death • complete and irreversible cessation of vital functions • life ceases in the body but still persists in some of its parts b. Molecular (cellular) death • death of the tissues and cells individually • due to anoxia- different tissues die at different rates
Signs Of Death I. Diagnosis of death in clinics- immediate signs of death - Cerebral death - Absence of cardiac activity and circulation - Absence of respiration Diagnosis of death in the autopsy room II. Early signs of death - Postmortem lividity (hypostasis) - Rigor mortis - Cooling - Dehydration - Autolysis III. Late signs of death - Putrefaction (postmortem decomposition) - Conservatory processes
Postmortem lividity (hypostasis) Mechanism • the circulation ceases ↓ • accumulation and stagnation of blood in the capillaries and small veins of the skin and organs ↓ • the blood is pulled by gravity in the lowest areas of the body Aspect • discoloration of the skin in lowest parts of the body • red-bluish/ compression areas
Postmortem lividity (hypostasis) Stages: Hypostasis- 10-12 hours Stasis- 18-20 hours Imbibition- after 20-24 hours Differentiation of the postmortem lividity from bruise Forensic relevance • Diagnosis of death • Position of the body • Postmortem interval • Cause of death
Rigor mortis (cadaveric rigidity) Mechanism • Decrease/ disappearance of ATP in the muscles - ATP concentration fails to 85 per cent of normal Factors affecting the timing of rigor mortis - temperature of the environment - physical activity before death - cause of death Stages- Nisten rule Installation- 3-6 hours Generalization- 24 hours Disappearance- 24-36 hours Forensic importance • Diagnosis of death • Position of the body • Postmortem interval • Cause of death
Postmortem cooling (Algor mortis) Mechanism - Failure of heat production and thermo-regulation → the body is loosing heat (conduction, convection, radiation) → temperature of the body decreases progressively → equilibrium with the environmental temperature Factors affecting postmortem cooling Environmental temperature Air moving and humidity Clothing and coverings Posture Surroundings Dimensions of the body Hemorrhage Particular: postmortem caloricity 18 degrees Celsius - 1 degree Celsius per hour Forensic importance- diagnosis of death, postmortem interval
Dehydration Mechanism • Cessation of circulation and metabolic processes → the body looses water Aspects - pergamentation - finger pads’ skin and lips-wrinkled - opaque cornea - soft eyes
Autolysis auto- self; lysis- destruction • enzymes released from the cells soften and liquefy the tissues of the body • internal examination • organs with a high content of enzymes (e.g. pancreas, stomach) • prepares the field for putrefaction • can be prevented by freezing the body/tissues
Putrefaction (postmortem decomposition) • The last stage in the resolution of the body from organic to inorganic state → skeleton Bacterial process Factors affecting putrefaction - environmental temperature - concentration of oxygen - concentration of water (brain) - age- old age • cause of death
Putrefaction (postmortem decomposition) Aspects • green spot of putrefaction- 2-3 days • all the skin - dark green or almost black • gases of putrefaction- increased volume • marbling Particular situation * New born
Forensic entomology • Study of the insects that infest the corpses • Flies lay their eggs on the corpse- opened wounds and moist sheltered natural orifices- 18/36 hours (high temperature) • Maggots or larvae - 24 hours -inside the body- destroy soft tissues • Pupae - 4-5 days • Adult flies - 3-5 days 7 series - 3 months→ 3-4 years One species at one time on one body fragment- different nutrients
Conservatory processes Natural processes which, prevent putrefaction and preserve the corpses • Mummification Very rapid dehydration - warm climate + good ventilation - Bacterial activity stops- high temperature - 3-12 months after death Aspect Skin- dry, shrunken, leathery, brown to dark skin adhering closely to the bones Odorless Preserved features Reduced body volume Internal organs - dried mass
Conservatory processes II.Saponification(Adipocere) - Fatty tissues are hydrolyzed - saturated fatty acids (stearic, palmitic acids) → calcium soaps • 3-12 months Aspect • yellowish- white greasy wax like substance • rancid smell - floats on water - can be easily cut • burns - yellow flame Factors affecting saponification • Environment- moisture; warm temperature; absence of air • Lecithinase from Clostridium Welchii
Conservatory processes III. Lignification Environment with great concentration of tanic and humic acid (swamps, mines, volcanic lava) Aspect • brownish, hard skin • soft bones (loosing of calcium); • good preservation for a long interval Tolund Man- Denmark
Conservatory processes IV. Refrigeration Exposure of the corpse to low temperature Aspect • whole body is stiffen; • perfect preservation for a long period of time; • when the body is bring into an warm environment putrefaction develops rapidly
Forensic Autopsy Mandatoryin the following situations (Criminal Law): • Violent death • Sudden death • Suspect death • Medical malpractice allegation • Corpses with unknown identity Rules: • performed in the base of the order of juridical authority • complete