AD lecture #1

Pathology

the study of disease

Pathogenesis

The sequence of events from the onset of a disease process to reolution of a lesion

Disease

Any deviation from the normal phyiologic function of the body

Etiology

This is simply the cause of disease - the causative agent

Symptoms

This is a feeling that a patient notices as a result of disease (human)

clinical signs

These are signs of disease that are found by direct observation of the patient

Signalment

Age, sex, breed

Syndrome

A group of clinical signs seen together in the course of a disease or condition

Lesion

These are anatomic alterations that are a result of disease - can lead to a functional disturbance (ex. corneal ulcer)

Differential Diagnosis (DDX)

This is basically a list of possibilities of the cause of disease

Histopathology

Examination of section of tissues obtained at necropsy under the microscope

How do we create a DDX

Evaluation clinical signs then make a list of possible CAUSES of those signs using "DAMN-IT-V"

"D"

Degenerative

"A"

Anomalous

"M"

Metabolic

"N"

Nutritional OR Neoplastic

"I"

-Immune

-Infectious

-Inflammatory

-Ischemic (vascular disorder)

-Idiopathic (unknown)

-Inherited

-Iatrogenic

"T"

Traumatic OR Toxin

"V"

Vascular

What are the two things a cell can do when it experiences physiologic stress or pathologic stimulus

Adapt or degenerate (die)

Necrosis

"cell death" - cell swells, membrane is broken

Apoptosis

"programmed cell death" - cell condenses, membrane stays intact

Coagulative Necrosis

Most common type, usually caused by sudden stop in blood flow - architecture of tissue is preserved, still have cellular shpae but look different - phagocytes clean up dead cells

Liquefactive necrosis

Characterized by focal bacterial or fungal infection (ex. cat bite infection)

Caseous necrosis

Cheesy, white appearance of the material in the necrotic area, secondary to a bacterial infection, architecture is destroyed

Causes of necrosis

-Chemicals/drugs (insecticies, meds, etc)

-toxins/poisons (snakebites)

-Ischemia (lack of blood supply)

-mechanical/thermal injury (temp extremes)

-Pressure (crushing inuries)

-Microbiologic agents (viruses, bacteria, fungi)

-Immunologic injury (response/rxn to foreign proteins)

-Nutritional deficiencies (imbalances)

What are the four ways the body copes with necrosis

-liquefaction (removal by phagocytes/circulation)

- wall it off (cyst or abscess)

-sloughing (animal that is HBC, drug on pavement)

-calcification (adhesions around outside of lesion)