Toxic gases Flashcards
Ammonia
-generated from sewage pits or fertilizers, poor ventilation in animal or poultry facilities
Clinical signs of acute ammonia exposure
-coughing
-sneezing
-dyspnea (pulmonary edema)
-lacrimation
Treatment for ammonia poisoning
Improve ventilation
Nitrogen oxide gases
-from incomplete reduction of nitrate ions in silos = NO2 and N2O4
-cause bronchiolitis obliternans in humans
Mechanism of actin of nitrogen oxide gases
Water in moist membranes of the lung tissue reacts with NO2 to nitric acid
resulting in irritation, pulmonary edema, and alveolar damage
Clinical signs of nitrogen oxide gases
-dyspnea
-coughing
-salivation, lacrimation
-red mucous membranes
-bronchitis
-emphysema
-methemoglobin produced
-secondary bacterial pneumonia
Treatment of nitrogen oxide gases
improve ventilation
DDx for nitrogen oxide gases
-ANTU
-nitrite
-OP/carbamates
-cyanide
-urea
Sulfur oxide gases
SO2 and SO3
-from high sulfur coal or oil combustion
-from smog and acid rain
-forage contamination = mineral imbalances = selenium and copper deficiency
Mechanism of sulfur oxide gases
React with water in lungs to form sulfuric acid = irritation, pulmonary edema and hemorrhage/emphysema
Clinical signs of sulfur oxide
-lacrimation, salivation
-coughing
-bronchoconstriction
-cyanosis
-red mucous membranes
Pathology of sulfur oxide
-pulmonary edema
-emphysema
-atelectasis
-hemorrhage
-fibrosis (chronic)
-secondary bacterial pneumonia
Treatment of sulfur oxide
-remove from contaminated areas
Hydrogen sulfide (H2S)
-from flare gas emissions and sewage pits
-very toxic; acute deaths
4 main gases fro sewage pits
-hydrogen sulfide
-ammonia
-CO2
-methane
Mechanism of action of hydrogen sulfide
A single breath can be fatal
- reacts with Na in lungs = pulmonary edema
- hypoxia = bonds with cytochrome oxidase enzyme = inhibiting enzyme use in ETC
3.sulfhemoglobin= from binding to hemoglobin
Clinical signs of hydrogen sulfide
-rotten egg smell if small amount; large amounts destroys sense of smell
-coughing
-lacrimation
-pulmonary edema
-bronchoconstriction
-cyanosis
-anoxic terminal convulsions
Pathology of hydrogen sulfide
-few gross lesions, might be smell in tissues
Treatment of hydrogen sulfide
-ventilation, oxygen
-usually fatal
DDx for hydrogen sulfide
-ANTU
-ammonia
-sulfur oxide gases
-OP/carbamates
-organochlorides
-nitrite
-cyanide
Carbon monoxide
-linked with poor ventilation
-car exhaust, or improper furnace function
Carbon monoxide mechanisms of action
Rapidly absorbed, reacts with hemoglobin to form carboxyhemoglobin
-CO and O2 are in competition but CO has a much greater affinity
Clinical signs of CO
-species variation = CNS depression vs excitation
-muscle weakness
-high heart rate and respiration
-dyspnea
-bright red blood and mucous membranes
-coma and death
Treatment of CO
-place animal on high levels of O2 to displace CO from hemoglobin
***resp stimulants increase O2 demand and should be avoided
