Postmortem Changes-Descriptions (Exam 1) Flashcards
Define Disease
Any deviation from the normal structure or function
What are the 5 pathological processes?
- Degeneration/Necrosis
- Inflammation and Repair
- Circulatory Disorders
- Disorders of Growth
- Deposits and Pigmentations
Define Lesion
Any morphological change in tissues during disease
What does a Morphologic Diagnosis include?
- Pathological process
- Location/organ
- Distribution
- Duration/chronicity
- Severity
What does an Etiologic diagnosis include?
- Pathological process
- Location
- Cause
Define Pathognomonic lesions
Characteristic of a specific disease
What are areas to avoid doing a necropsy?
- Areas accessible to animals
- Areas which may contain food
- High traffic areas
- Areas difficult to disinfect
What are good spots to do a necropsy?
- Concrete
- Dirt area in the sun
- Straw bed
What are the PM steps for a necropsy?
- External examination
- Open body cavities
- Collect microbiologic samples
- Remove and dissect organs
- Collect histologic samples
What is the proper ratio of foramlin:tissue?
How far will the formalin penetrate the tissue?
10:1 ratio of formalin:tissue
No more than 1/2 cm of the tissue
What is autolysis?
- Self-digestion or degradation of cells and tissues by hydrolytic enzymes
- Occurs after somatic death due to hypoxia
What is putrefaction?
- Process by which PM bacteria break down tissues
- Gives color, texture changes, gas production, and odors
What is Rigor Mortis?
What causes it/accelerates it?
- Contraction of the muscles after death
- 1-6 hours post death for 1-2 days
- High heat and activity before death accelerate the onset
- Caused by depletion of ATP and inability of myosin to detach from actin binding site
What is liver mortis?
- gravity pulls blood post death
- pools in one area
Describe an Antemortem blood clot
- attached to vessel walls
- dry and dull
- lamellated
- friable
Describe a Postmortem blood clot
- unattached
- shiny and wet
- elastic
- perfect cast of vessel lumen
What is hemoglobin imbibition?
- Hemoglobin is released by lysed RBCs, penetrates vessels walls, and diffuses into adjacent tissues
- Stains the tissues red
What is bile imbibition?
- Bile from gallbladder penetrates the wall and stains adjacent tissues a yellow-green
- Tissues stained are those in contact with gallbladder: liver, intestines, diaphragm
What causes postmortem bloat?
How can you distinguish it from ruminal tympany?
- Results from PM bacterial gas formation in GI tract
- Tympany will cause an esophageal bloat line from lack of blood
What are cold cataracts?
corneal opacity due to dehydration of cornea
What is pseudomelanosis?
- Decomposition of blood by bacterial action forming hydrogen sulfide with iron
- Greenish-blackish discoloration
- Tissues in contact with the gut
What are the features of a description?
number, size, location, distribution, shape, color, consistency, margins/surface
Focal distribution refers to?
one isolated lesion
Multifocal distribution refers to?
What can it tell you about the route of spread?
- numerous similar lesions that can be of variable size
- embolic/hematogenous route
Diffuse distribution refers to?
lesion throughout a large portion of the effected tissue
What does locally extensive distribution tell you about the route of spread?
local introduction via penetrating wound or anatomic pathway
What does a symmetrical lesion indicate?
systemic/metabolic cause of the lesion
What does a raised lesion tell you?
Something has been added
- edema, blood, hyperplastic cells
What does a depressed lesion tell you?
Something has been lost (necrosis) or the tissue has contracted
What does a geometric lesion tell you?
the lesion involves vasculature
What could a red lesion be due to?
- hemorrhage
- congestion
What could a white lesion be due to?
- necrosis
- leukocytes
- fibrin
- connective tissue
What could a yellow lesion be due to?
- leukocytes
- bilirubin
- fat
- fibrin
What could a green lesion be due to?
- bile pigment
- eosinophils
- algae of fungal infection
- hemosiderin
What could a black lesion be due to?
- melanin
- decomposition
- exogenous pigment
What could a translucent lesion be due to?
- mucous
- parasite cyst
What is the lesion if it “can spread with a knife?”
necrosis and exudate
What is the lesion if it “can’t spread with a knife?”
viable tissue and cells
What does a lesion with a well demarcated margin tell you?
- lesion represents a different tissue
- infarcts
- chronic lesion with fibrous capsule
What does a lesion with a poorly demarcated margin tell you?
- the lesion and adjacent tissue may be similar
- the process is gradually infiltrating into the normal tissue
