Toxicology -Kulczycki Flashcards
What is toxicology?
Branch of biology, chemistry, and medicine (pharmacology) concerned with the study of adverse effects of chemicals on living organisms
What is decontamination? What is the most important goal?
Decontamination is the process of removing a toxic substance from the body.
Single most important goal is to prevent any ongoing exposure and prevent exposure to health care workers.
What is the main method used for decontamination? What is the ideal ratio? When must it be administered? What are the other, less used, methods?
#1 = Activated charcoal! • Ideal ratio is 10:1 (charcoal:toxin) • Must be administered w/n the first hour. Other Methods: 1. Whole bowel irrigation 2. Gastric Lavage 3. Serum of Ipecac 4. Dilution/Neutralization
What is a toxidrome?
Clinical syndrome that results from a specific toxin or class of toxins.
What are the 4 most commonly encountered toxidromes?
Anticholinergic, cholinergic, sympathomimetic, opioid
What are the sx associated w/ anticholingergic toxicity? Examples? Tx?
Anticholinergic – similar symptoms as sympathomimetic but dry skin
•Symptoms: Dry, red, hot, blind, mad, stuffed.
Ex: Jimson Weed, Atropine, antihistamines
•Treatment = Physostigmine
What are the sx associated w/ cholingergic toxicity? Examples? Tx?
Cholinergic – stimulate parasympathetic
•Symptoms: DUMBBELSS (Diarrhea, urination, miosis, bronchospasm, bradycardia, excitation of skeletal and CNS, lacrimination, sweating and salivation)
Ex: MC=Organophosphates (Parathion, insecticide):
• MOA: irreversibly inhibit AChE
• Others: Bethanecol, Carbecol, Pilocarpine, Neostigmine, Physostigmine
• Tx = atropine (blocks muscarinic receptors)-Titrate to drying of bronchial secretions (Also, Pralidoxime)
What are the sx associated w/ Sympathomimetic toxicity? Examples? Tx?
Sympathomimetic – wet skin
•Symptoms: mydriasis, braonchodilation, tachy, HTN, urinary retention, psychomotor agitation, euphoria
Ex: Meth, cocaine, diet medications
• Others: epi, NE, isoproterenol, dopamine, dobutamine, phenylephrine, albuterol
•Treatment = supportive, cooling measures, benzodiazepines
What are the sx associated w/ Opioid toxicity? Examples? Tx?
Opioids:
• Natural: heroin, morphine, codeine, hydrocodone, oxycodone
• Synthetics: fentanyl, hydromophone
• Symptoms: (“Turns everything DOWN”) miosis, respiratory and CNS depression, hypothermia, hypotension, bradycardia.
• Treatment = naloxone or naltrexone (opioid receptor antagonist)
What are the sx associated w/ Acetaminophen toxicity? What is the MOA? Tx? How fast must you tx?
- Symptoms: N, V, abdominal pain (can be delayed), Centilobular necrosis w/n the liver hepatocytes.
- MOA: Glutathione stores get depleted w/ toxic doses → development of toxic metabolites. (Shifts metabolism to Cytochrome P450 instead of glucouronidation.)
Treatment = N-acetylcysteine
• Replenishes glutathione stores
• Use w/n 8 hours
How is the Rumack-Matthew Nomogram used in the treatment of acetaminophen toxicity? What are its limitations?
Rumack-Matthew Nomogram: • Acute ingestions only • Check 4 hour acetaminophen level • Toxic Level: 140 at 4 hours o Anywhere above pink line, treat the patient
Limitations: Less than 4 hours; have to wait till 4 hours to get blood test, Chronic ingestions, Unknown time of ingestion
What metabolizes antifreeze?What is antifreeze and what does it cause? How do you diagnose toxicity? Tx?
-Metabolism by alcohol dehydrogenase
•Ethylene glycol → Oxalic acid – renal toxicity
Diagnosis:
-Anion Gap Metabolic Acidosis (MUDPILES)
•Increased d/t formic acid and oxalic acid (the metabolites)
-Elevated Osmolar Gap
• Increased d/t methanol, ethylene glycol and isopropanol (the original substances)
Treatment: • Fomipazole 8000x affinity for ADH – prevent toxic metabolites • Ethanol 15x affinity for ADH • Folic Acid • Thiamine
