Decomposition Processes PDF

Decomposition Tissues break down in many different ways No one way is dominant This occurs cell by cell Day 1 Day 7 Day 9 Day 10 Autolysis Self digestion of cells by lysosome enzymes liberated from within This is occurring in your body right now, but you have ce...

Decomposition Tissues break down in many different ways No one way is dominant This occurs cell by cell Day 1 Day 7 Day 9 Day 10 Autolysis Self digestion of cells by lysosome enzymes liberated from within This is occurring in your body right now, but you have cells replacing these But after death…. Fermentation Enzymic reduction (anaerobic) of body carbohydrates to simpler substances Decay Decomposition of proteins in an aerobic environment Protein oxidizes to stable compounds devoid of foul odour and no identifiable colour change Putrefaction Last normal post mortem change Anaerobic reduction of protein producing foul smelling gases and a colour change Maceration Moistening and softening of any tissue decomposing in a liquid medium E.g. fetus dying in utero and remaining in womb for some time Imbibition Tissues absorbing moisture To imbibe is to drink Particularly tertiary edema (associated with sludging of blood) Wildlife Animals and insects contribute to the breaking down process by chewing and then digesting tissues (Note the pig at the start) Saponification Transformation of adipose tissue into adipocere, or ‘grave wax’ Rare. Usually seen in disinterments Body needs to be cold and isolated from other forces of decomposition Promotes preservation (adipocere resistant to putrefactive organisms) Mummification Complete dehydration of body Becomes resistant to decomposition Final state following dehydration and dessication Order of Decomposition of Body Compounds Carbohydrates Proteins (e.g. muscle) Fat Firm proteins (e.g. connective tissue) Bones (often years) Signs of Decomposition - Colour Hemolysis – begins light pink then red Colour darkens as oxygen in hemoglobin metabolized Becomes reddish brown as blood pigment decomposes  Putrefactive green spreads over body, beginning in abdominal quadrants Dark lines (marbling) due to blood decomposition in superficial blood vessels Odour Gases formed during putrefaction and then released Hydrogen sulfide Hydrogen phosphate Ammonia Evacuation of Contents of Hollow Organs Due to gas pressure Most likely purge will intially occur through mouth and nose, but possible through any orifice Desquamation (skin slip) Separation of the dermis from the epidermis causes burns, rashes, caustic chemicals, edema, blisters, frostbite, x-rays, IV bruises, Poison Ivy, Tissue Gas, subdermal hemorrhages, advanced decomp. Epidermis separated from Dermis by Accumulation of liquids Accumulation of gas Autolysis Too dilute arterial solution Lack of blood drainage/too much drainage of arterial fluid mistaking rigor for tissue fixation Tx of Desquamation 1. Peel away epidermis to firm margin 2. complete arterial injection 3. apply searing agents to affected area 4. allow air to dessicate overnight 5. area must be smooth and dry if waxing or diaper if able to Additional Info for Desquamation Not always a post mortem change may occur over pre-gangrenous or pre-cancerous tissues because nutrition faulty and cellular necrosis beginning area of impending skin slip often feel moist, clammy Intrinsic Factors Governing Rate of Decomposition – Age Slow – stillborns (no M.O.’s in intestinal tract), elderly (tissues frequently more dehydrated) Faster – ages in between Biological Sex Characteristics Females tend to have higher moisture content, so faster in those situations Obesity Heat retention by fat Moisture content slightly higher in adipose tissue Cause and Manner of Death Acute infections (septic or inflammatory conditions (-itis) can accelerate putrefaction via Bacteria Emaciating diseases retard putrefaction – less moisture State of Hydration As moisture increases, so does rate of decomposition Autolysis Each person decomposes at a different rate, depending on genetics, lifestyle… Extrinsic Factors Governing Rate of Decomposition – Atmospheric Temperatures 37oC optimal for most micro- organisms.5 -10 C slows putrefaction oC o 0 C or less inhibits putrefaction o Above 49oC bacterial growth and metabolism halted Humidity Warm and humid accelerates decomposition Access of Air Air flow carries micro- organisms and insects Bacteria Putrefaction will vary in rate and intensity according to number and type of micro-organisms present at time of death and during post- mortem period HCHO kills bacteria