Animal Disease

Why is terminology important?

For communication, respect, medical records, interpretation, and understanding what you are reading.

What is pathology?

The study of disease.

What is pathogenesis?

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

What is a disease?

Any deviation from the normal physiological function of the body.

What is etiology?

The cause of disease, such as a virus, bacteria, or fungus

- The causative agent

What are symptoms?

Feelings that a patient notices as a result of the disease (Human)

What are clinical signs?

Signs of disease found by direct observation of the patient.

What is signalment?

Age, sex, and breed

What is a syndrome?

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

- when a disease is not well defined

What is Horner syndrome?

A syndrome characterized by a sunken eye, small pupil, droopy upper eyelid, or prominent third eyelid.

enophthalmus

sunken in eye

miosis

small pupil

madryosis

large pupil

ptosis

droopy upper eyelid

What is a lesion?

Anatomic alterations that are a result of disease.

-leading to functional disturbances

-mass/lump/corneal ulcer

What is a differential diagnosis?

A list of possibilities for the cause of disease.

What is histopathology?

Examination of sections of tissue obtained at necroscopies under the microscope.

How do we create a differential diagnosis?

By evaluating the animal's clinical signs and making a list of possible causes.

What does DAMN-IT-V stand for?

Degenerative, anomalous, metabolic, nutritional, inflammatory, and traumatic

What does the D in DAMN-IT-V stand for?

Degenerative, which occurs over a period of time

Examples of degenerative dz.

- Chronic Renal Failure

- Myelopathy (dz. of spinal cord)

- arthritis, hip dysplasia

- spinal degeneration (IV disc dz.)

What does the A in DAMN-IT-V stand for?

Anomalous, related to congenital (genetics) problems

Examples of Anomalous dz.

- young with a heart murmur

- hydrocephalus (brain abnormalities)

- Autoimmune dz.

- porto-systemic liver shunt

What does the M in DAMN-IT-V stand for?

Metabolic, related to the animal's metabolism.

Examples of Metabolic dz.

- hormone imbalance

- enzyme deficiencies

- hypoglycemia in starving animal

- insulinoma (tumor in ferrets)

- Ca/Phos imbalance (abnormal done growth)

- Mechanical (thermal injury)

- Mental (behavioral)

What does the N in DAMN-IT-V stand for?

- Nutritional, related to starvation or physical eating issues

- Neoplasia, cancer

Examples of Nutritional dz.

Starvation

-Ca/Phos imbalance causes ostromalacia (softening of bone)

Examples of Neoplasia dz.

- brain tumors

- benign or malignant

- osteosarcoma

What does the I in DAMN-IT-V stand for?

immune, infectious, inflammatory, idiopathic, iatrogenic

Examples of immune system dz.

- defenses against dz is impaired

- disruption of body's mechanical barriers to invasion

- Ag/Ab complex (immune system suppressed)

- AIHA

Examples of Infectious dz.

Viral/bacterial

- rickettsial

- parasitic

- fungal

- lyme dz

- Osteomyelitis

Examples of Inflammatory dz.

- granulomatous lesions from FIP

- arthritis/panosteitis

Examples of Idiopathic dz.

Epilepsy

Examples of Iatrogenic dz.

drug toxicity (overdose)

What does the T in DAMN-IT-V stand for?

Traumatic, Toxin

Examples of Traumatic dz.

internal or external injuries

- brain swelling

- Hit by a car

- laceration

- uroliths

What does the V in DAMN-IT-V stand for?

Vascular

Examples of vascular dz.

- Infarction/Thrombosis (clot in blood vessel that gets stuck)

- necrosis/inflammation

Do cells change over time?

Yes, Constantly adjusting their structure and function

(trying to say at Homeostasis)

What is the definition of physiologic?

characteristic of an organism's normal functioning

What is the definition of pathologic?

indicative of disease

What is necrosis?

The common definition of cell death

1. cell starts to swell

2. proteins begin to denature

3. organelles inside explode

4. membrane is broken

What is apoptosis?

Programmed cell death with a fixed lifespan

1. cell condenses

2. membrane stays intact

What are the three types of cell necrosis?

coagulation, liquefactive, and caseous.

What is coagulative necrosis?

Cell rotting

- most common type

- caused by ishemia (sudden stop in blood flow)

- Phagocytes clean up dead cells :)

What is liquefactive necrosis?

bacterial/fungal infections

1. Inflammation 2. vasodilation 3. WBC go to tissue

- attractants for WBCs

- WBC release enzymes that digest the dead cells

- bite infection, abscess

What is caseous necrosis?

A form of coagulative necrosis in which a thick, yellowish, cheesy substance forms

- architecture is destroyed

- ex. tumor, pasteurella, tuberculosis

What are common causes of necrosis?

Chemicals, toxins, ischemia, mechanical/thermal injuries, and nutritional deficiencies.

Chemicals and drugs that cause necrosis

- insecticides, ect.

- incorrect amount of meds

- wrong route of meds

toxins and poisons that cause necrosis

snakebite, spider bit, bee sting

Ischemia that cause necrosis

laminitis (no circulation = cell death)

Mechanical/thermal injury that causes necrosis

- temp extremes

- crushing injury

- tearing injury

- burns

- HBC

Pressure that causes necrosis

- downer animals

- ulcerative sores

- urine scald

Microbiologic agents that cause necrosis

dermatologic problems

- viruses, bacteria, fungi, produce toxins

Immunologic injury that cause necrosis

reaction to foreign proteins that stimulates the immune system

- vaccines

- autoimmune dz

What is the definition of DDX?

Differential diagnosis.

How does the body get rid of necrosis?

1. Liquefaction: removal of phagocytes through circulation (abscess, urine)

2. Wall it off: cyst or abscess (gradually)

3. Sloughing: HBC, drug on pavement

4. Calcification: tendons, ligaments