Week 1 Flashcards
Definition of pathology
Study of disease
Definition of disease
Any deviation from the normal structure or function. May or may not have characteristic clinical signs. May or may not affect the whole body or any of its parts. Of known or unknown cause.
Definition of etiology
Cause. (can be bacterial, viral, etc. agent)
Definition of pathogenesis
Sequence of events from initial stimulus to ultimate expression of disease. (e.g. bacteria stimulates lots of neutrophils to come into the tissue)
Definition of molecular and morphological changes
Biochemical and structural alterations infuced in cells and organs of the body (e.g. dark red lungs- the affected part is the lesion)
Definition of clinical manifestations
Clinical signs resulting from functional abnormalities of affected tissues (e.g. coughing, respiratory distress)
Definition of diagnosis
Concise statement or conclusion concerning the nature, cause or name of a disease. Diagnosis enable the clinician to predict the prognosis (i.e. outcome)
Definition of disease name
Aims to encapsulate the host, morphology and cause of disease (e.g. Bovine viral diarrhea). Definitive diagnosis is confirmed using a variety of tests. Differential diagnoses (DDx) i.e. DAMNIT-V scheme.
Definition of lesion
Any morphological change in tissues during disease. Lesions caused by disease manifest morphologically as alterations in color, shape, size, texture, etc. Macro or microscopic. Pathognomic lesions are characteristic of a specific disease.
Definition of morphological diagnosis (MDx)
Includes pathological process, location, distribution, duration and severity (e.g. pneumonia)
Definition of etiologic diagnosis (Edx)
Includes pathological process, location and cause (e.g. bacterial pneumonia)
What are the 5 pathological processes?
Degeneration/Necrosis Inflammation and repair Circulatory disorders Growth disorders Deposits and Pigmentations
What are the 3 different subcategories of growth disorders?
Cell adaptations
Neoplasia
Developmental anomalies
What is the difference between general pathology and systemic pathology?
General pathology includes the main pathological processes incited by various injurious stimuli. It applies to all cells/tissues.
Systemic pathology includes system-specific disease processes. It builds on main pathological processes but takes into account unique responses to injury of each tissue and specific diseases for each system.
Which BSL is required for:
a) routine necropsy of domestic animal
b) rabies suspect
c) pregnant/immunosuppressed person
d) necropsy under field conditions
a) 2
b) 3
c) 4
d) 1 or 2
What are the 5 post-mortem steps for any species? (No particular order)
External examination Open body cavities Collect microbiological samples Remove and dissect organs Collect histological samples
Describe/define autolysis as a method of post-mortem decomposition.
Self-digestion or degradation of cells and tissues by the hydrolytic enzymes normally present in tissues.
Occurs after somatic death due to total diffuse hypoxia.
Cells degenerate as for hypoxic injury.
Describe/define putrefaction as a method of post-mortem decomposition.
Process by which post-mortem bacteria break down tissues.
Gives color, texture changes, gas production and odors.
Which tissues will autolyze quickest?
Those tissues with greater concentration of proteolytic enzymes:
GI tract, pancreas, gall bladder, endocrine tissues, nervous tissues, eye, etc.
What factors influence rate of decomposition?
Cause of death Environmental and body temperature (refrigerate to prolong) Microbial flora (GI tract, gas and heat produced after death bc of continuation of bacterial fermentation)
Rigor mortis- definition, timing, causes
Morphological change of PM decomposition
Definition: Contraction of the muscles after death
Timing: Begins 1-6 hours post death, persists 1-2 days. Occurs faster in small animals than large.
Causes: Due to depletion of ATP and inability of myosin to detach from actin binding site. High heat and high activity before death accelerate its onset.
What is livor mortis (aka hypostatic congestion)?
Morphological change of PM decomposition
Gravity pulls blood post death. This causes variation in color of tissues (red to pale).
What is post-mortem blood clotting? Timing, appearance.
Morphological change of PM decomposition
Occurs several hours post death in the heart and vessels. Coagulopathies can delay or cause failure of blood to clot. Chicken fat clot appearance is due to separation of RBCs and clotted serum.
Differentiate antemortem clot (thrombus) and postmortem clot.
An antemortem clot (thrombus) is attached to vessel walls, dry and dull, lamellated and friable.
A postmortem clot is unattached to vessel walls, shiny and wet, elastic and is a perfect cast of the vessel lumen.
What is hemoglobin inhibition?
Morphological change of PM decomposition
Red staining of tissue, especially the intima of heart, arteries and veins. Hemoglobin is released by lysed RBCs, penetrates the vessel wall and extends into the adjacent tissues.
What is bile inhibition?
Morphological change of PM decomposition
Bile in the gallbladder starts to penetrate the wall and stains the adjacent tissues yellowish to greenish brown.
Tissues stained are those in contact with the gall bladder (liver, intestines, diaphragm)
What is bloat?
Morphological change of PM decomposition
Bloat results from PM bacterial gas formation in the GI lumen. Associated changes include rectal/vaginal prolapse, froth in trachea and ruptured viscera.
What are some common postmortem eye changes?
Corneal opacity due to dehydration of cornea
Cold cataracts
What is pseudomelanosis?
Morphological change of PM decomposition
Decomposition of blood by bacterial action forming hydrogen sulfide with iron occurs soon after death and results in greenish black discoloration of tissues (kidney, liver, spleen, gut wall).
What are the features of a description?
No SLo DiSCo CoMas!
Number Size Location Distribution Shape Color Consistency Margins/Surface
What are some words that describe distribution of a lesion? What can they tell you?
Focal- one isolated lesion
Multifocal- numerous similar lesions that can be of variable size (can mean embolic/ hematogenous route)
Diffuse- throughout a large prtion of the effected tissue
Locally extensive (can mean local introduction via penetrating wound or anatomic pathway)
Symmetrical or asymmetrical (symmetrical indicates systemic/ metabolic cause of the lesion)
% of total tissue affected
Define miliary
a type of multifocal where there are numerous pin-point foci
What does a lesion with straight lines indicate?
The lesion is following an anatomic structure ( blood vessel, bronchiole, etc.)
What does a geometric lesion (triangle, diamond, wedge, rhomboid, circles) indicate?
The lesion involves vasculature
What does a raised lesion indicate?
Something has been added (edema, blood, inflammatory cells, neoplastic/ hyperplastic cells)
What does a depressed lesion indicate?
Something has been lost (necrosis) or the tissue has contracted (connective tissue)
What does the red color of a lesion indicate?
hemorrhage (focal)
congestion (more diffuse/ patchy)
What does the white color of a lesion indicate?
Leukocytes Necrosis (soft) Calcium Keratin (off-white) Fibrin Connective tissue (firm) Urates Lipid Bone
What does the yellow color of a lesion indicate?
Leukocytes
Bilirubin
Fat
Fibrin
What does the green color of a lesion indicate?
Bile pigment
Hemosiderin
Eosinophils
Algal or fungal infection
What does the black color of a lesion indicate?
Melanin
Fluke pigment
Exogenous pigment (carbon)
Decomposition (hydrogen sulfide from digestion of blood by bacteria)
What does the translucency of a lesion indicate?
Mucous
Parasite cytes
If a lesion has the consistency of being able to spread with a knife, what does this indicate? If unable to spread with a knife?
Spreadable- Necrosis and exudate
Not spreadable- viable tissue and cells
If a lesion is well demarcated, what is indicated?
The lesion represents different tissue (tumors)
Infarcts
Chronic lesions with fibrous capsule
If a lesion is poorly demarcated, what is indicated?
The lesion and adjacent tissue may be similar
The process is gradually infiltrating into the normal tissue and/or is poorly contained.
What are the features of a MDx?
(Summary of the lesion) Organ Pathological process *Distribution *Chronicity (acute, subacute, chronic, chronic-active) *Severity (mild, moderate, severe)
*Not needed when dealing with growth disorders:
What are the features of an Etiologic Dx?
Cause
Organ
Pathological Process
