Introduction, Necropsy, PM, Descriptions Flashcards
What is disease ?
Any deviation from the normal structure or function
What is etiology
Cause of a disease
____________ is the sequence of events from initial stimulus to ultimate expression of disease
Pathogenesis
What are the 5 pathological processes?
Degeneration/necrosis Inflammation and repair Circulatory disorders Disorders of growth Deposits and pigmentation
A concise statement or conclusion concerning the nature, cause, or name of a disease
Diagnosis
What is a lesion?
Any morphological change in tissues during disease
Alteration in color, shape, size, texture
Micro- or Macro- scopic
What is the difference between morphologic diagnosis and etiologic diagnosis?
Morphological has pathological process, location, and distribution
Etiologic has CAUSE
What is a pathognomomic lesion
Lesion that is characteristic of a specific disease
What areas should be avoided during a post mortem?
Area accessible to animals
Food containing areas
High traffic area
Areas that are difficult to disinfect
What are disposal options following a PM?
Burial Renderer Transport to a disposal site Incineration Composting
What area is ideal for a PM exam??
Concrete (easy to clean)
Sun exposure
Straw bed
What biosafety level should you operate at in a standard PM exam
BSL 2
Associated with human disease
Limited access, sharps and biosafety precautions
PPE: lab coat, gloves, face protection (as needed)
What are the steps of a PM exam
External exam Open body cavities Collect microbiological samples Remove and dissect organs Collect histological organs
How should microbiological samples collected?
Aseptic technique
Intensities last
Generous samples
Fresh samples and clean containers
Keeps samples cold
How should histological samples be collected from a PM exam?
All organs- especially those with lesions
Label tissues
Direct samples toward most likely cause
Tox- urine, stomach, fat, and liver
10:1 ratio formalin:tissue
No larger than 1cm thickness- formalin will not penetrate greater than a 1/2 cm tissue
Capsule organs to be incised
PM decomposition is due to what two processes
Autolysis
Putrefaction
What is autolysis
Self-digestion/degradation of cells and tissues by the hydrolytic enzymes normally present in tissues
After somatic death due to total diffuse hypoxia
Cell degeneration
What is putrefaction
Post mortem bacteria break down tissue
What types of tissues autolyze the quickest and why?
GI tract
Pancreas
Gall bladder
High concentration of proteolytic enzymes
Rate of decomposition is dependent on?
Cause of death
Environmental and body temp
Microbial flora
The presence of ___________ is most likely to be microscopically obscured by decomposition
Cell injury (necrosis)
Contraction of the muscles after death
Rigor mortis
Due to depletion of ATP and inability to detach from actin binding site.
What factors can accelerate onset of rigor mortis?
High heat or activity before death
What is liver mortis?
Hypostatic congestion
Gravity will pull blood post death
Variation in color of tissues: skin, lungs, and kidney
Is this antemortem or postmortem clot?
Attached to vessel walls
Dry and dull
Lamellated
Friable
Antemortem
Thrombus
Is this antemortem or postmortem clot?
Unattached
Shiny and wet
Elastic
Postmortem clot
Red staining of tissue especially the intima of heart, arteries and veins
Hemoglobin imbibition
Hb is released by lysed RBC and penetrates the vessel wall into adjacent tissues
Yellowish to greenish brown staining of liver/intestines/diaphragm?
Bile imbibition
Bile from gallbladder stains adjacent tissues
Postmortem bacterial gas formation in lumen of GI tract
Bloat
What are associated changes with bloat?
Rectal/vaginal prolapse
Froth in trachea
Ruptured viscera
What common PM changes occur in the eye?
Corneal opacity due to dehydration of cornea
“Cold cataracts”
What is pesudomelanosis?
Greenish-black discoloration of tissues post mortem
Decomposition of blood by bacteria forming hydrogen sulfide with iron
Seen in tissues associated with the gut
How do you differentiate antemortem vs postmortem ingesta in the trachea
Antemortem aspiration: inflammation and deep in lungs
Postmortem: due to relaxation of sphincter after death
A red-brown fluid coming from the nose during PM exam could be due to?
Capillaries in nose autolyse quickly with congestion
What PM changes could lead to pulmonary edema and congestion? How do you determine antemortem disease?
PM: heart stops and blood pools in the lungs
Rigor mortis redistributes blood centrally
Antemortem: respiratory problems prior to death
What is the difference between a description and a MDx?
Description: what you see, not subjective, no interpretation
MDx: interpretation of the description making subjective conclusions
What are the features of a good description ?
Number Size Location Shape Color Consistency Margins/Surface
No SLO DiSCo CoMas
What is the appropriate way to measure size in a description ?
Actual measurement in metric units
What should you include in the when describing the location of a lesion ?
Organ
Location within that organ
Position relative to other organs
What should be included in the description of the distribution of the lesion?
Pattern and extent of the lesion Eg focal/multifocal Diffuse/locally extensive Symmetrical/asymmetrical
Present of total tissue effected
Route of spread
How should shape be described in a description of a lesion
Geometric shapes/straight line
Raised/depressed
Do not use regular irregular -> what does that even mean?
A well demarcated lesion margin can represent what types of lesions?
Tumors
Infarcts
Chronic lesions with fibrous capsules
What does a poorly demarcated lesion margin usually represent?
Lesion and adjacent tissues may be similar
Process gradually infiltrating to normal tissue -> poorly contained
What are the features of a MDx?
Organ Pathological process Distribution Chronicity Severity
What are the features of an Etiological diagnosis?
Cause
Organ
Pathological process
