Test 1 Flashcards
What are the pathological processes?
- Deposits & pigmentations
- inflammation & repair
- Circulatory disorders
- Disorders of growth
- Degeneration/necrosis
A concise statement or conclusion concerning the nature, cause, or name of a disease is known as the ______.
Diagnosis
What is the prognosis?
What enables a clinician to predict the prognosis?
The outcome
The diagnosis heps to predict the prognosis.
What is a lesion?
Any morphological change in tissues during disease. They may manifest as alterations in color, shape, size texture. They can be macroscopic or microscopic.
What are the key factors of a morphological diagnosis?
Pathological process
Location
Distribution
Duration
Severity
What are the components of an etiological diagnosis?
Pathological process
location
Cause
What is a pathognomonic lesion? List some examples.
It is a lesion characteristic of a specific disease.
Ex: multifocal necro-hemorrhagic nephritis caused by Canine Herpesvirus-1
Lesions cased by Cryptosporidium serpentis
What are some types of etiologies?
Genetic/inherited
Infectious - bacterial, viral, parasitic, etc.
Metabolic
Toxicologic
Autoimmune
Idiopathic
Iatrogenic
What factors does a disease name aim to capture?
Host
Morphology
Cause of disease
e.g. Bovine viral diarrhea
What is the difference between a definitive diagnosis and a differential diagnosis?
Definitive Dx is confirmed using a variety of tests.
A differential diagnosis is determined using the DAMNIT-V scheme
What is the difference between general pathology and systemic pathology?
General pathology applies to all cells/tissues/organs, while systemic pathology focuses on system-specific disease processes.
Systemic pathology builds on the main pathological process but takes into account the unique responses to inury of each tissue and specific diseases for each system.
TRUE/FALSE.
If the cause of death is know, there is no need to do a necropsy.
FALSE.
Something can be learned from every patient. There may be some health anomaly that is not seen.
What are the reasons to do a PM?
- Confirm/reject clinical diagnosis
- Dealing w/ an unknown disease - ID what disease processes are ocurring to explain cause of death or clinical findings and to collect tissues for testing to establish a cause. (may be needed to prevent/treat in other animals)
- Testing for agents without documenting pathological process is of limited use
What are some things to consider when selecting a PM site?
- Avoid: areas accessible to animals (including birds), areas with food, high traffic areas, and areas difficult to disinfect.
- Favorite spots: concrete, dirt area in the sun, straw bed
What are some disposal options after a PM?
- Burial
- Renderer
- Transport to disposal site
- Incineration
- Composting
TRUE/FALSE.
All specimens should be handled and treated as though they are a potential zoonosis threat.
TRUE.
What are some routes of exposure to pathogens during a PM?
Oral
Splash into eye
Aerosolization
Percutaneous (sharps)
Which BSL is required for a routine necropsy of a domestic animal?
BSL-2
Which BSL is required for a routine necropsy under field conditions?
BSL-1 - BSL-2
Which BSL is required for a necropsy of an animal suspected to have rabies?
BSL-2
Which BSL is required for a person with immunosuppresion/pregnancy?
Extra care should be taken - extra layer of gloves, nasal mask.
When getting ready to do a PM, what are somethings to do first?
- Prepare equipment (gloves, coveralls, boots, knife, rib cutters, jars/bags, swabs/tubes)
- Inspect the premises
- Inspect other animals (ask for history but it may lead to bias during necropsy)
What are the first steps in a PM for any species?
- External examination
- Open body cavities
- Collect microbiological samples (ASAP to avoid contamination)
- Remove and dissect oragns (each has its own specific technique
- Collect histological samples
When opening the body cavity of a ruminant, which side should you open it on? Explain.
RIGHT.
This is because if you approach the body cavity from the left, all you will see is the RUMEN.
When collecting microbiological samples, which organ should be sampled last? Why?
Intestine due to the large population of microbes. This will prevent contamination of other organs.
What kind of cavitary effusions are used for the following tubes:
- Red top or plain sterile tube
- EDTA- purple top
- Red top or plain sterile tube for culture
- Fluid analysis and cytology
When dissecting organs, what are some general techniques to keep in mind?
- Breadloaf solid organs
- Open lumens
- Evaluate mucosal surfaces
What histological samples should be collected during a PM?
ALL ORGANS - especialy those with lesions.
Direct sampling towards the most likely cause.
Samples should contain lesion + normal tissue
What is analyzed for toxicology?
Urine, stomach contents, fat
When fixing tissues, what should you remember?
- 10:1 ratio of formalin:tissue
- Tissue will not penetrate more than 1/2 cm tissue and so samples should not exceed 1cm thickness
- Organs with a capsule need to be incised
- Don’t use narrow neck bottles
What should you do once your PM is complete?
- Clean and disinfect work surfaces
- Decontaminate self (remove gloves, coveralls, wash boots/wheels)
- Record necropsy findings
- Complete forms & Package samples
TRUE/FALSE
Formalin does not need to be frozen.
TRUE.
What are some things that tend to be overlooked during necropsy?
- Skeletal muscle
- Repro organs
- Checking joints
- Rib snap test
- Live snap test
- Thyroid/adrenal glands
- Thymus in young animals
- Opening urinary bladder
What are the mechanisms of PM decomposition?
- Autolysis - self-digestion by hydrolytic enzymes present in tissues
- Putrefaction: breakdown process by PM bacteria. Gives color/texture changes and gas/odor production
What tissues autolyze the quickest? Why?
GI tract
Pancreas
Gall bladder
*this occurs as a result of higher concentrations of proteolytic enzymes
What does the rate of decomposition depend on?
- Cause of death
- Environmenta and body temperature
- Microbial flora (GI tract; bacterial fermentation continues after death and produces gas/heat)
TRUE/FALSE
MDx are typically not given to non-lesions and PM change.
TRUE.
What is rigor mortis?
Contraction of muscles after death.
Begins 1-6 hours post death and persists 1-2 days.
High heat and high activity before death accelerates the onset.
Caused by the depletion of ATP and inability of myosin to detach from actin binding sites.
What is livor mortis?
AKA hypostatic congestion
Pooling of blood to one side as a result of gravity. Results in change in color of tissue (skin, lung, kidney).
Describe the features of PM blood clotting.
- Occurs several hours post death in the heart and vessels.
- Coagulopathies can delay or cause failure of blood clot.
- Chicken fat clot –> suggestive of anemia in all species except horses.
Compare Antemortem clot vs. PM clot
- Antemortem clot (thrombus): attached to vessel wally, dry and dull, lamellated, friable, irregular shape
- PM clot: unattached, shiny and wet, elastic, perfect cast of vessel lumen
TRUE/FALSE
A thrombus is only considered pathological if it is associated with clinical symptoms.
FALSE.
It is ALWAYS pathologic.
TRUE/FALSE
Hemoglobin imbibition is the staining of tissue as a result of bacterial breakdown of blood and forming hydrogen sulfide with iron.
FALSE.
That’s pseudomelanosis.
Define hemoglobin imbibition.
Red staining of tissue, especially the intima of the heart, arteries and veins. Hb is released by lysed RBCs, penetrates the vessel wall, and extends into adjacent tissue.
Define bile imbibition.
What tissues are affected?
When bile in the gallbladder penetrates the wall and stains adjacent tissues. Results in yellowish-greenish/brown color changes.
Tissues affected are those in contact with the gallbladder- liver, intestines, diaphragm
What causes PM bloat?
Who bloats faster, herbivores or carnivores? Why
Bacterial gas formation in the lumen of the GI tract.
Herbivores bloat faster due to the greater bacterial population in the GI tract.
What are some PM changes associated with bloat?
Rectal/vaginal prolapse
Froth in trachea
Ruptured viscera
Define pseudomelanosis.
What tissues are affected?
Greenish/black discoloration of tissues PM. Results from bacterial decomposition of blood and the formation of hydrogen sulfide iron. This occurs soon after death.
Tissues affected are those in contact with the gut: kidney, liver, spleen, gut wall.
What are the features of a description?
- Number
- Shape
- Location
- Distribution
- Size
- Color
- Consistency
- Margins/surface
No SLo DiSCo CoMas
What is an acceptable way to describe size?
Use actual measurements. If using approximations, convert them.
What are some things to consider when describing location?
Be as specific as possible
Describe the position in relation to adjacent organs
What is distribution used to describe?
Pattern & extent of lesions
Focal, multifocal, diffuse, locally extensive, symmetrical/asymmetrical, miliary
Based on the following distributions, what is the route of spread?
- Multifocal
- Locally extensive
- Symmetrical
- Multifocal: embolic/hematogenous route
- Locally extensive: local introduction via penetrating wound or anatomic pathway
- Symmetrical: indicates systemic/metabolic cause
What do the following shapes of a lesion indicate?
- Geometric
- Straigh lines
- Raised
- Depressed
- Geometric: lesion involves vasculature
- Straight line - lesion is following an anatomic structure (blood vessel, bronchiole, nerve)
- Raised: something has been added (edema, blood, inflammatory cells, neoplastic/hyperplastic cells)
- Depressed - something has been lost (necrosis) or the tissue has contracted (CT)
Red
- Hemorrhage (focal)
- congestion (more diffuse/patchy)
White
- Leukocytes
- necrosis (soft)
- calcium
- Keratin (off-white)
- Fibrin
- Connective Tissue (firm)
- Urates
- Lipid
- Bone
Yellow
- Leukocytes
- bilirubin
- Fat
- Fibrin
Green
- Bile pigment
- Hemosiderin
- Eosinohils
- Algal or fungal infection
Black
- melanin
- Fluke pigment
- Exogenous pigment (carbon)
- Decomposition (hydrogen sufide from bacterial blood digestion)
Transluscent
Mucous
parasite cytes
If the consistency is such that you can spred it with a knife, this tells you that…..
necrosis and exudate
If the consistency is such that you cannot spread it with a knife, this tells you that…..
It is viable tissue and cells
Define etiology (2)
- The study or theory of the factors that cause disease and the method of their introduction to the host.
- The causes or origin of a disease or disorder
What are the 2 major classes of factors causing disease?
Genetic (inherited mutations and disease-associated gene variants, or polymorphisms)
Acquired (infectious, nutritional, chemical, physical)
What interaction is important to consider when studying disease?
The interaction between the host, pathogen and environment.
