Respiratory Toxins

Question 1

source & exposure of ammonia (NH3)

Answer 1

caustic agent
animal facilities, esp where excretment can decompose on solid floor
urea also produced by colon, liver, kidney which goes into systemic circulation

Question 2

source & exposure of carbon dioxide

Answer 2

end product of metabolism, fuel burning heaters, decomposing manure

Question 3

source & exposure of carbon monoxide

Answer 3

car exhaust, fires
incomplete combustion of hydrocarbons
carboxy-hemoglobin forms which reduces ability to carry O2

Question 4

source & exposure of methane

Answer 4

cow belching
product of microbial degradation, formed by rumen microflora in ruminants

Question 5

source & exposure of hydrogen sulfide

Answer 5

anaerobic bacterial composition of protein & other sulfur containing organic matter
holding tanks, manure pits
rapidly release with agitation

Question 6

source & exposure of nitrogen dioxide

Answer 6

NO2 combines with water and O2 in air/tissues to form corrosive nitric acid
silages of forage

Question 7

source & exposure of environmental tobacco smoke

Answer 7

dogs living with smoking owners
brachycephalic breeds or dogs with small/medium length noses

Question 8

source & exposure of overheated frying pans -teflon toxins

Answer 8

birds in kitchens exposed to PTFE (teflon) pyrolysis products that are toxic

Question 9

source & exposure of tryptophan and perilla mint toxicity

Answer 9

lush green forage consumption

Question 10

What are three factors that can influence respiratory toxicosis across species?

Answer 10

1. variability in metabolizing enzymes
2. regional variation in cell populations
3. anatomy configuration

Question 11

acute respiratory signs

Answer 11

asphyxiation
irritation
pulmonary edema
airway reactivity

Question 12

chronic respiratory signs

Answer 12

fibrosis
asthma
emphysema
lung cancer

Question 13

What factors are associated with Hydrogen Sulfide production and release that make it potentially dangerous?

Answer 13

• lethal gas formed by anaerobic bacterial composition of protein & other sulfur containing organic matter
• accumulates in manure pits, holding tanks
• rapidly released when waste is agitated
• olfactory paralysis blocks the odor so you can no longer smell that you are exposed

Question 14

what ppm of H2S causes olfactory paralysis

Answer 14

> 200 ppm

Question 15

What is the mechanism of action of Carbon Monoxide and how is that related to observed toxicities and treatments?

Answer 15

• CO 250x greater affinity for Hb than O2
  carboxy-hemoglobin forms, reducing O2 carrying ability
• cherry-red blood, pink tissues, can range from headache/fatigue/irritability to tachycardia, tachypnea, confusion, EEG changes, coma and death
• treatment: restore O2 to brain & heart, fresh air, artificial resp if needed, hyperbaric or 100% O2 for faster recovery, sig response should be within 1-4 hrs

Question 16

Why does Nitrogen Dioxide cause considerable damage to the lungs but may not cause as much damage in the upper respiratory tract?

Answer 16

insoluble in water – no damage to URT, but damages lungs due to increased contact time and moisture content is higher
toxicity depends on duration & concentration

Question 17

What kind of animal is susceptible to toxicosis caused by overheating of cookware?

Answer 17

avians/birds due to their anatomy of respiratory system (unidirectional airflow + efficient gas exchange)

Question 18

How can cows eating forage high in tryptophan possibly lead to lung damage?

Answer 18

• tryptophan converted by the rumen into 3-MI
• 3-MI converted to reactive intermediates by cytochrome P450s which enter bloodstream and spread to lungs
• results in pulmonary edema, emphysema, death

Question 19

how is perilla mint toxic

Answer 19

lush green forage
4-ipomeanol converted into reactive intermediates by cytochrome P450s that spread to lung and cause lung toxicity