post mortem ppt

• Necrosis


  Focal death along with degradation of tissue by hydrolytic enzymes liberated by cells. It's invariably accompanied by an inflammatory reaction

  
• Necrosis


  • Cell death to lethal injury
• Types of cell death


  • Apoptosis - Programmed Cell Death
  • Necrobiosis - Physiologic Death
  • Necrosis - Pathological Death
• Nuclear changes in cell death

  • Karyolysis
  • Pyknosis
  • Karyorrhexis

  
• Cytoplasmic changes in cell death

  • Increased eosinophilia

  
• Coagulative necrosis


  The most common type of necrosis caused by irreversible focal injury

  
• Coagulative necrosis


  • Foci are pale, firm, slightly swollen in early stage
  • Become more yellowish, softer and shrunken with progression
• Coagulative necrosis


  1. Denaturation of proteins

  2. Enzymatic digestion of the cell
• Liquefactive necrosis


  • Occurs commonly due to ischaemic injury and bacterial or fungal infections
  • Degradation of tissue by the action of powerful hydrolytic enzymes
• Liquefactive necrosis


  • Infarct brain
  • Abscess cavity
• Liquefactive necrosis


  • Affected area is soft with a liquefied center containing necrotic debris
  • Cystic space contains necrotic cell debris & macrophages
  • Later a cyst wall is formed by proliferating capillaries, inflammatory cells & gliosis (brain) or proliferating fibroblasts (abscess cavity)

  
• Gangrenous necrosis


  • Type of necrosis is usually coagulative due to ischaemia
  • Characterized by primarily inflammation provoked by virulent bacteria
• Types of gangrenous necrosis


  • Dry
  • Wet
  • Gas gangrene

  
• Dry gangrene


  • Affected part is dry, shrunken & dark black, resembling the foot
  • Black due to the liberation of hemoglobin from hemolysed red blood cells

  
• Wet gangrene


  • Affected part is soft, swollen, putrid, rotten and dark
• Gas gangrene


  • Affected area is swollen, edematous, painful & crepitant due to the accumulation of gas bubbles within the tissues
  • Affected tissue becomes dark black and foul smelling
  • At the periphery, a zone of leukocytic infiltration, edema, and congestion are found
• Caseous necrosis


  • Found in the centre of foci of tuberculosis infections
  • Combines features of both coagulative and liquefactive necrosis
  • Resembles dry cheese and is soft, granular, and yellowish
  • Necrosed foci are structureless, eosinophilic and contain granular debris
• Fat necrosis


  • Special form of cell death peculiar to fatty tissue
  • In the case of pancreas, there is liberation of pancreatic lipase from injured or inflamed tissue that results in necrosis of the pancreas
  • Fat necrosis results in hydrolysis of neutral fat present in adipose cells into glycerol & free fatty acid
• Fibrinoid necrosis


  • Characterized by deposition of fibrin-like material which has the staining properties of fibrin
  • Encountered in various examples of immunologic tissues injury, arterioles in hypertension, peptic ulcer etc.
  • Does not have any distinctive gross appearance
• Primary changes in somatic death


  • Circulatory failure - immediate death
  • Respiratory failure - absence of oxygen
  • Nervous failure - loss of reflexes
• Secondary changes in somatic death


  • Algor mortis
  • Rigor mortis
  • Livor mortis
  • Post-mortem clotting
  • Desiccation
  • Putrefaction
  • Autolysis
• Algor mortis


  Cooling of the body
• Rigor mortis


  Stiffening of the muscles
• Livor mortis


  Purplish discoloration of the skin
• Putrefaction


  • Production of foul-smelling gases
  • Greenish blue discoloration
  • Softening of the muscles
  • Retraction of the cornea
  • Loss of rigor mortis
  • Peeling of the skin with crepitation
• Autolysis


  Cell-digestion of the cells
• Autopsy


  • Process of taking pieces of tissue from a dead person
  • Purpose: Determine cause of death, investigate cause of death, preserve tissue
• Pre-requisites of autopsy procedure


  • Written consent
  • Type of autopsy to be performed
  • Apparatus or instruments needed
  • Pathologist on duty
• Types of autopsy according to purpose


  • Routine hospital autopsy
  • Medico-legal autopsy/forensic/coroner's
  • Anatomical or academic
• Types of autopsy according to completeness


  • Partial
  • Complete
• Types of autopsy according to manner of incision


  • Y-shaped incision - shoulder-xiphoid-pubis
  • Straight cut incision - suprasternal-pubis
• Other techniques of dissection

  • Rudolf Virchow's - one by one removal of the organs
  • Anton Ghon's - organs are removed by block
  • M. Letulle's - organs are removed "en masse"
  • Carl Rokitansky's - in situ dissection + en bloc removal
• Common apparatuses or instruments needed during autopsy procedures


  • Bone marrow borer
  • Sterile syringes and needles
  • Spatula
  • Electric saw for bones
  • Culture medium
  • Specimen bottles with fixatives
  • Different sizes and types of forceps
  • Clean dry slide
  • Weighing scale
  • Knives, scissors
  • Alcohol lamp
  • Surgical gloves, surgical masks
• Normal weight of organs


  • Brain - 1300 grams
  • Heart - 300 grams
  • Kidney - 150 grams
  • Liver - 1500 grams
  • Lungs - 550/450 grams
  • Uterus - 50/100 grams
  • Ovary - 10 grams
  • Prostate - 20 grams
  • Pancreas - 100 grams
  • Pituitary - 0.7 grams
  • Spinal cord - 25 grams
  • Spleen - 150 grams