gastrointestinal - 14

Learning Objectives: Lecture #14 Gastrointestinal & Dermal Toxicants (Part 1) Be able to recognize, define, and properly use the following terminology: Coagulative necrosis Liquifaction necrosis Be able to answer the following:  Know which type of cleaning agents are of the most concern toxicologically o Corrosive agent: acids, alkalis, batteries  Describe how the appearance of corrosive burns change over time Milky white to gray  turn black within a few hours due to coagulation  Know which type corrosive agent causes coagulative necrosis o Dry cell batteries (dry acid cells)  Know which type of corrosive agent causes liquefaction necrosis o Dey cell batteries (Alkaline dry cells)  deeply penetrating ulcers  Why are esophageal burns more likely to be encountered with a strong alkali (base) instead of a strong acid? o The action of alkalis is immediate, and there is an increased viscosity in alkaline agents  Which type of corrosive agent causes deep penetrating ulcers? o Alkalis (pH > 7.0)  Know the recommended treatment protocol for corrosive agent ingestion in animals o Removal of battery, analgesics, and antibiotics  Recognize which type of battery is of most concern clinically and explain the mechanism of toxicity o Lithium disc/button batteries  one 3-volt battery can cause esophageal necrosis in 15 minutes because it is trapped. o Electric current in battery is passed from bettery to the GI tract  GI perforations and hemorrhage  fistulation into vessels and tracheoesophageal fistulas  Explain how the concentration (%) of the detergent in cationic detergents correlates with the severity of damage in the oropharyngeal cavity o 1.0% detergent: irritation and damage to mucous membranes o >7.5% detergent: corrosive burns in mouth, pharynx, and esophagus o >20% detergent: some fatalities reported due to dermal exposure alone o The HIGHER the percentage the WORSE the severity  Describe how cationic detergents can affect the nervous system o CNS depression 1