Etiologies Exam 2 Flashcards
The cause/study of causes pertaining to a disease or abnormal condition.
Etiology
How often a disease occurs in a specific area or population
Morbidity
A cause that has specifically resulted in the disease or lesion in question
Causative agent AKA Etiologic agent
Abrasions, lacerations, penetrating wounds, blunt force trauma injuries, and mechanical obstructions are all examples of ________ injury.
Mechanical
Too hot or too cold are examples of _____ injury.
Thermal
A type of heat injury PLUS __________ disturbance.
Electrical. = electrical injury
This type of wound is caused by scraping away superficial layers of the skin/mucosal surface.
Abrasions.
- no deeper than epidermis/mucosal surface
- less severe than laceration/ulcer
True or false? Secondary infections decrease the severity of otherwise mild abrasions.
False.
Secondary infections INCREASE the severity of otherwise mild abrasions.
This type of wound results from the tearing of soft tissue.
Laceration.
Edges are often irregular and contamination is frequent.
Focal laceration that penetrates deeply into underlying tissues.
Puncture wound.
A surgical cut whose edges are smooth.
Incision
This type of wound opening can close trapping bacteria resulting in abscesses, lymphangitis, or cellulitis.
AND/OR it can damage nerves/muscles AND/OR it can penetrate into a body cavity/joint AND/OR it can penetrate an organ.
Puncture wounds
May look innocuous on surface but are dangerous!
Shotgun pellets subcutaneously or dog bites are an example of what?
Penetrating injury. Consequences related to anatomic location and the presence of bacteria on surface.
A contusion is an example of what type of injury?
Blunt force trauma.
A specific type of contusion wherein clotted blood forms a mass.
Hematoma
In regards to bone fracture, what term applies to broken sections being separated?
Displaced
Bone fragments align
Nondisplaced
The skin may be pierced by the bone or by a traumatic blow that breaks the skin at the time of fracture.
Open, compound fracture.
Fracture straight across
Transverse fracture
Fracture occurs in a healthy, normal bone due to a force greater than the tensile strength of the bone.
Traumatic fracture.
Fracture occurs from pre-existing bone disease resulting in decreased inherent tensile strength. (Osteomyelitis, tumor, osteoporosis, osteomalacia, etc.)
Pathologic fracture
Obstruction due to calculi, ingestion of foreign object, entrapment of organ, volvulus, etc
Mechanical obstruction
Decrease in temperature.
Increase in temp.
Hypothermic
Hyperthermia
Internal changes and lesions that accompany lightning strike or electrocution.
Pulmonary edema, hemorrhage, cardiac arrhythmias/cardiac arrest, bone fractures, damage to solid organs.
The majority of nutritional etiologies are ____________
Inadequate intake!
Reasons for inadequate intake of feed
Refusal of feed Inadequate quantity Poor quality Impaired acquisition Lack of specific nutrients Secondary nutrient deficiencies
In the past, what was a nutrient deficiency in cats?
Taurine! Led to DCM in cats.
What are some nutrient deficiencies seen in vet med?
Selenium - vitamin E Calcium, phosphorus Vitamins A, C, D, E, K Metals (zinc, copper, iron) Protein Fats
What is the most common reason for protein-caloric malnutrition?
Neglect, cruelty, chronic disease or stupidity.
What diagnostic test can be done in cruelty/neglect cases to determine if an animal was starved to death?
Bone marrow fat analysis at Purdue
Intake of a substance which results in the breakdown or diminish production of an essential nutrient
Secondary nutrient deficiency
Ex. Vitamin K (inhibited by rodenticides, clotting disorder)
Thiamine (CNS necrosis)
Obesity has been shown to decrease dog’s lifespan from a range of ____ to ____
5 months (German shepherds) to 2.5 years (yorkies)
In excess intake of nutrients, what occurs when there’s metastatic calcification of soft tissue and renal tubular necrosis.
Vitamin D toxicosis
This occurs when there is liver fibrosis and exostosis of vertebrae
Vitamin A toxicosis
When does salt poisoning (water deprivation) occur?
- water restriction = increased sodium in CNS
- access to water with rapid, excessive intake causes severe CNS edema w/ cerebral cortical necrosis.
A poisonous substance
Toxin
Material that interferes with normal biological processes resulting in adverse health effects
Toxicant
The degree to which a substance can damage an organism
Toxicity
Toxicosis
Pathologic condition caused by a toxin
A chemical compound (such as a drug, pesticide, or carcinogen) that is foreign to a living organism
Xenobiotic
What are the 3 categories of toxins with some examples.
Chemicals: heavy metals, solvents, antifreeze
Pharmaceuticals: acetaminophen, NSAIDS, aminoglycoside antibiotics
Biologic toxins from plants, bacteria or fungi
5 mechanism by which toxins work
- damage DNA
- damage cell membranes
- block protein synthesis
- destroy/block enzymes
- block normal physiologic receptors
Dose of compound that will cause 50% of individuals to die
Common measure of toxicity is LD50
What factors influence an individual’s LD50?
Genetics, age, previous exposure, physiology
A compound is not toxic in the form that the animal is exposed, but is biotransformed into a toxin via bacteria or metabolic processes designed to eliminate the compound usually involving cytochrome P450
Indirect toxicity
A compound is in a toxic form when the animal is exposed
Direct toxicity
Ex. Mannheimia haemolytica
What must happen for a toxicity to be indirect?
A nontoxic compound must be altered in the body to become toxic.
Normal method of inactivation (detoxification) of drugs, chemicals, and toxins by hydrolysis or oxidation
Phase 1 biotransformation
What is the goal of phase 1 biotransformation?
To make the compound more water soluble to increase the rate of excretion in urine or bile/
What is an unwanted consequence (occasionally) of biotransformation?
Biotransformation can lead to BIOACTIVATION (makes nontoxic compound more reactive and toxic - indirect toxicity)
Some compounds are further acted on in the liver to become water soluble.
The mechanism is by conjugating inactive compounds with glucuronide for bile excretion.
Phase 2 biotransformation
What is the goal of phase 2 biotransformation?
Excrete compound in the bile for removal
What is a POSSIBLE unwanted consequence of phase 2 biotransformation?
Conjugation may make compound more toxic or allows concentrated toxin in the GI tract (indirect toxicity)
What is the normal blood flow in hepatic lobule?
From portal triad to central hepatic vein
Why is the pattern of necrosis in indirect toxic hepatic necrosis centrolobular?
Centrolobular hepatocytes have highest concentrations of cytochrome P450.
What is an example of a phase 1 biotransformation?
Pyrrolizidine alkaloids: metabolized in the liver to pyrroles which bind proteins and DNA causing hepatocytes necrosis and secondary fibrosis.
“Megalocytosis” (large cells with large nuclei) occurs due to inhibition of mitosis.
In what pattern are toxins excreted in bile?
Liver -> bile -> intestine.
Phase 2 binds toxin to carrier protein that can be readily excreted in bile.
__________ ______________ can occur while attempting excrete toxins. Bacteria breakdown carrier and toxin are reabsorbed into circulation.
Enterohepatic recirculation
Some bedlington terriers store large concentrations of ___ in the liver causing severe chronic hepatic disease due to the absence of a _____ binding gene COMMD1.
Copper
In what substances or places is lead present in?
Contaminate water/soil
Discarded batteries
Old engines/parts
Old lead-based paints
Necrosis of gray matter of brain
Polioencephalomalacia
What lesions can be seen in common animal toxicosis?
Acute renal tubular necrosis
Polioencephalomalacia
What mechanism is used during common animal toxicosis?
Direct toxicity. With inhibition of neurotransmitters, heme synthesis, or proximal convoluted tubule metabolism
What species is acetaminophen extremely toxic to?
Cats
What form of toxicity is acetaminophen toxicity to cats?
Indirect. Metabolized in liver to highly reactive metabolite via P450 activity.
Cats can’t form less toxic sulfate metabolite well and are deficient in glucuronyl transferase sooo they can’t excrete metabolites (phase 2)
What lesions can be seen with acetaminophen toxicity in cats?
Methemoglobinemia and Heinz body anemia
Liver, centrolobular necrosis
What type of toxicity results from aminoglycoside antibiotics, gentamicin, neomycin, kanamycin, etc.
Direct toxicity.
What type of toxicity results from ethylene glycol (antifreeze)?
Indirect.
In liver via alcohol dehydrogenase, converts to sodium oxalate + toxic metabolites. Sodium oxalate exchanges sodium for calcium in the blood = calcium oxalate which is filtered into urinary filtrate and ppt in renal tubules as calcium oxalate crystals -> renal tubular obstruction and necrosis
Energy released in form of particle or electromagnetic wave that carry enough kinetic energy to liberate an electron from an atom or molecule
Ionizing radiation
What does ionizing radiation result in?
Generation of reactive species (free radicals)
What are the 2 main categories of sources for radiant energy?
Natural and Iatrogenic
____ is the most important direct radiation target.
DNA
What phase of the cell cycle is most sensitive to radiation?
Mitotic phase. Rapidly dividing cells.
- hematopoietic precursors
- crypt epi
- germ cells
- developing fetus
- Epithelia
- lymphocytes
____ water is a major target resulting in _____________ causing secondary effects to RNA, proteins, lipid membranes.
Intracellular
Oxygen free radicals
What are the cellular outcomes for the following?
- minor damage
- massive injury
- minor to major damage
Minor -> repair -> return to homeostasis
Massive -> cell death
Minor to major -> ineffectual DNA repair -> gene mutations -> neoplastic transformation
What happens from acute localized radiation injury?
Skin or mucosal necrosis, ulceration and sloughing.
What are some long term effects of localized radiation injury?
Skin cancer, hair or skin depigmentation, corneal opacity and cataracts.
What happens from a massive dose of radiation?
Acute hemorrhage and necrosis of the brain and other vital organs causing rapid death.
What happens from a lesser but potentially lethal dose of radiation?
Acute radiation sickness
- death of intestinal crypt cells causing loss of epithelium, severe diarrhea
- intestinal lesion is similar to parvo viral enteritis (radiomimetic disease - imitating radiation sickness)
- necrosis of bone marrow leading to non-regenerative anemia, severe leukopenia, and myelofibrosis
What are some clinical signs of radiation sickness from large, whole body doses?
Mucosal hemorrhage, mucosal exudation and ulceration, fluid/electrolyte imbalance, ileus, impaired nutritional absorption, localized and systemic bacterial infection
What happens to those who survive whole body severe irradiation?
Scarring of intestines: chronic D+ and weight loss
Chronic increased susceptibility to disease: due to reduced #s of lymphocytes and other leukocytes
Cancer due to radiation-induced mutations especially leukemia
