Toxicology of Specific Agents Flashcards
What is the study of poisonous substances, their effects on living organisms, detection by laboratory methods, and counteracting measures?
Toxicology
What field of toxicology focuses on the dose-response relationship between a xenobiotic and its adverse effects?
Mechanistic toxicology
What field of toxicology predicts harmful exposure levels using animal experiments?
Descriptive toxicology
What field of toxicology establishes safe exposure levels by interpreting mechanistic and descriptive studies?
Regulatory toxicology
What field of toxicology deals with the medicolegal consequences of chemical or drug exposure?
Forensic toxicology
What field of toxicology evaluates the impact of environmental pollutants on human health?
Environmental toxicology
What field of toxicology studies the relationship between xenobiotics and disease states, including diagnostic testing and therapeutic interventions?
Clinical toxicology
What are exogenous agents that have adverse effects on living organisms?
Xenobiotics
What are agents that cause adverse effects on biological systems?
Poisons
What are biologically synthesized substances from living cells or microorganisms?
Toxins
What are toxic environmental chemicals?
Toxicants
What is the most common route of toxic exposure in clinical settings?
Ingestion
What route of exposure leads to systemic effects through blood circulation when absorbed in the gastrointestinal tract, or causes local effects like diarrhea, bleeding, and malabsorption if not absorbed?
Ingestion
What are the other routes of toxic exposure besides ingestion?
Inhalation
Transdermal absorption
What process involves the release of a drug?
Liberation
What process involves the transport of a drug from the site of administration to the blood?
Absorption
What process involves the delivery of a drug to tissues?
Distribution
What process involves the chemical modification of a drug in the body?
Metabolism
What process involves the removal of drugs and metabolites from the body?
Excretion
What describes the change in health effects based on the change in xenobiotic exposure levels?
Dose-response relationship.
What describes the change in health effects of a defined population based on changes in xenobiotic exposure?
Individual dose-response relationship.
What type of dose-response relationship is used to assess population-based toxic effects?
Quantal dose-response relationship.
What type of toxicity results from a single, short-term exposure to a substance, with a dose sufficient to cause immediate toxic effects?
Acute toxicity.
What type of toxicity results from repeated exposure to a substance for extended periods (>3 months), with doses insufficient to cause immediate acute effects?
Chronic toxicity.
What are the major categories of toxic agents?
Alcohol, carbon monoxide, caustic agents, cyanide, metals, pesticides.
What type of substance is alcohol in terms of its effects on the central nervous system?
Central nervous system depressant.
What are the common symptoms of alcohol intoxication?
Disorientation, euphoria, confusion, unconsciousness, paralysis, death.
How does ethanol affect diuresis?
Inhibits antidiuretic hormone (ADH).
What are the acute metabolic effects of ethanol?
Acidosis, ketone/lactate accumulation, increased blood osmolality.
What are the effects of chronic ethanol consumption?
Lipid accumulation, alcoholic hepatitis, cirrhosis.
What are the symptoms of ethanol intoxication?
Blurred vision, incoordination, slurred speech, coma, hangover.
What is the antidote for ethanol-induced alcoholic mania?
Diazepam
What precautions are needed for serum alcohol testing?
Capped tubes, benzalkonium chloride (not isopropanol).
What are preferred ethanol testing methods?
Enzymatic assay, gas-liquid chromatography (GLC), electrochemical oxidation.
What lab results indicate ethanol toxicity?
GGT, AST, AST/ALT ratio, HDL, MCV
What is the fatal ethanol dose?
300 – 400 mL in 1 hour.
What is the toxic ethanol blood level?
400 mg/dL; >500 mg/dL (for hemodialysis).
When does peak ethanol blood concentration occur?
1 hour post-intake.
What are methanol toxicity symptoms?
Blindness, metabolic acidosis.
What is the preferred methanol detection method?
Gas Chromatography-Mass Spectrometry (GC-MS).
What is the fatal methanol dose?
60 – 250 mL.
What is the toxic methanol blood level?
50 mg/dL.
How is isopropanol absorbed?
Rapid GIT absorption.
What are isopropanol toxicity symptoms?
CNS depression, hypertension.
What is the preferred detection method for isopropanol?
Gas chromatography.
What is the antidote for isopropanol toxicity?
Activated charcoal.
What is the fatal isopropanol dose?
250 mL.
What is a common industrial source of ethylene glycol?
Hydraulic brake fluid.
How is ethylene glycol poisoning treated?
Inhibit alcohol dehydrogenase.
What indicates ethylene glycol toxicity in renal tubules?
Calcium oxalate crystals.
What is the major toxic metabolite of ethylene glycol?
Glycolic acid.
What is the preferred detection method for ethylene glycol?
High-Performance Liquid Chromatography (HPLC).
What is the fatal ethylene glycol dose?
100 grams.
What are symptoms of ethylene glycol toxicity?
Metabolic acidosis, depressed reflexes, anuria, necrosis.
What method quantifies alcohol and metabolites?
Gas-Liquid Chromatography (GLC).
What enzymatic assay quantifies alcohol?
Alcohol dehydrogenase reagent assay.
What specimens are used for alcohol testing?
Blood, urine, exhaled breath.
What toxic gas results from incomplete combustion and binds heme 200x more than oxygen?
Carbon monoxide.
What are the main effects of carbon monoxide poisoning?
Tissue hypoxia, carboxyhemoglobin formation.
What gas stimulates nitrous oxide, causing hypotension and neurologic changes?
Carbon monoxide.
What is the toxic level of carboxyhemoglobin, and what is a key sign of poisoning?
20% CO; cherry red skin.
What are the treatments for carbon monoxide poisoning?
100% oxygen, hyperbaric oxygen.
What is the specimen and test for carbon monoxide toxicity?
EDTA whole blood; co-oximetry.
What substances cause damage due to strong acidity or alkalinity?
Caustic agents.
What are complications of caustic agent exposure?
Pulmonary edema, shock, GI lesions, esophageal perforation, hematemesis, abdominal pain.
What metabolic imbalance and treatment are linked to caustic agents?
Metabolic acidosis/alkalosis; dilution.
What toxic compound exists in solid, gas, or solution and is found in insecticides and burned plastics?
Cyanide.
How does cyanide cause toxicity, and what is its distinctive odor?
Binds iron, causing hypoxia; bitter almond breath.
What is the toxic blood level of cyanide?
2 µg/mL.
What toxic metal is found in poisons, paints, and alloys, and what are its forms?
Arsenic; arsine gas, organic arsenic, inorganic arsenic.
What is the half-life of inorganic arsenic, and how does it cause toxicity?
10 hours; inhibits sulfhydryl enzymes, crosses placenta.
How does arsenic accumulate, and what are the best specimens for detection?
Bioaccumulation; hair, nails (long-term), blood, urine (short-term).
What poisoning causes garlic breath and metallic taste?
Arsenic
What is the fatal dose of arsenic, and what is its antidote?
120 mg arsenic trioxide, 30 ppm arsenic gas; British Anti-Lewisite (BAL).
What tests confirm arsenic poisoning?
Reinsch test, Atomic Absorption Spectroscopy (AAS).
What metal is used in electroplating, galvanizing, pigments, and nickel-cadmium batteries?
Cadmium
How does cadmium enter the food chain?
Binds to soil
Absorbed by plants
Consumed in crops.
What are the main toxic effects of cadmium?
Lung epithelial cell destruction, renal tubule accumulation.
What disease is caused by cadmium-contaminated rice consumption?
Itai-itai disease (osteomalacia, osteoporosis).
What is the half-life of cadmium?
10-30 years.
What is the best specimen for cadmium testing?
Urine or whole blood.
What renal marker indicates cadmium toxicity?
Gamma-glutamyl transferase (GGT) in urine.
What method detects cadmium in the lab?
Atomic Absorption Spectroscopy (AAS).
What metal inhibits enzymes like ALA synthetase and Na-K ATPase?
Lead
What are common sources of lead exposure?
Paints, gasoline, lead pipes.
How is lead acquired?
Ingestion, inhalation.
What body systems are most affected by lead toxicity?
CNS, PNS.
What are the toxic effects of lead?
Heme synthesis interference, RBC membrane damage, peripheral neuropathy.
How does lead accumulate in bones?
Combines with bone matrix (half-life: 32 years).
What condition is characterized by wrist or foot drop?
Lead-induced peripheral neuropathy.
What lab indicators suggest lead poisoning?
Urinary delta-ALA, RBC protoporphyrin, basophilic stippling in RBCs.
What are the chelating agents for lead poisoning?
EDTA, dimercaptosuccinic acid (DMA).
What specimens are used for lead testing?
Whole blood (quantitative), urine (recent exposure), morning urine (delta-ALA).
Why is serum/plasma not used for lead testing?
Lead is rapidly cleared from plasma.
What screening and confirmatory tests detect lead?
Zinc protoporphyrin test, ALAD test, AAS, ICP-MS.
What are the three forms of mercury?
Elemental (metallic), inorganic (salts), organic (alkyl/methyl).
How does mercury cause toxicity?
Binds sulfhydryl proteins, inhibits catecholamine methyltransferase.
How is mercury acquired?
Inhalation, skin absorption, ingestion.
What are general toxic effects of mercury?
Organ dysfunction.
What diseases are linked to mercury poisoning?
Pink disease (acrodynia), Minamata disease.
What is the main excretion route for mercury?
Bile
What lab method detects mercury?
Reinsch test.
What specimens are used for mercury testing?
Whole blood, 24-hr urine.
What toxic substances inhibit acetylcholinesterase, leading to acetylcholine buildup?
Organophosphates, carbamates.
What are common routes of pesticide exposure?
Ingestion (food contamination), transdermal absorption, inhalation.
What drug is a cyclooxygenase inhibitor used as an analgesic, antipyretic, and anti-inflammatory?
Aspirin (Acetylsalicylic acid).
How does aspirin work?
Inhibits thromboxane and prostaglandin synthesis.
What are the side effects of aspirin?
GI disturbance, platelet aggregation interference.
What are the toxic effects of salicylates?
Reye’s syndrome hepatotoxicity, mixed acid-base disturbance, hypoglycemia
What lab methods detect salicylates?
Trinder assay, enzyme assay, HPLC.
What drug is used as an analgesic and antipyretic by inhibiting prostaglandins?
Acetaminophen
What are the toxic effects of acetaminophen?
Hepatotoxicity, cyanosis (methemoglobinemia), CNS depression, seizure.
What is the preferred lab method for acetaminophen detection?
High-Performance Liquid Chromatography (HPLC).
