Lecture 2: Toxicology II Flashcards
List the Metals that can cause intoxication (6)
- Lead (Pb)
- Mercury (Hg)
- Cadmium (Cd)
- Arsenic (As)
- Iron (Fe)
- Copper (Cu)
List the Gases that can cause intoxication (2)
- Carbon Monoxide (CO)
- Hydrogen cyanide (HCN)
List the Inhaled Particles that can cause intoxication (2)
- Silica
- Asbestos
List the Drugs that can cause intoxication (6)
- Methylenedioxymethamphetamine (MDMA)
- Gamma-hydroxybutyrate (GHB)
- Acetaminophen
- Benzodiazepines
- Opioids
- Tricyclic antidepressants (TCA)
List the Antidotes & Treatments that treat intoxication (13)
- N-acetylcysteine
- Flumazenil
- O2
- Na Thiosulfate
- Fomepizole
- Succimer
- DImercaprol
- Naloxone
- Atropine
- Pralidoxime
- Penicillamine
- Deferoxamine
- Charcoal
What ways can you be exposed to Arsenic (As)?
- Drinking H2O in Ganges delta in India & Bangladesh (natural minerals)
- Commerical applications in semiconductors, wood preservatives, ant bait
Explain the toxicodynamics of Arsenic
Toxicodynamics: effects of toxic on the organisms
- Interfere with enzyme activity & cell signal transduction, oxidative stress, alter gene expression
What are the acute toxic effects of Arsenic (As)?
- GI: N/V/D, abdominal pain, diffuse capillary leak & fluid loss→hypotension, shock,death
- Cardiopulmonary: Pulmonary edema, ventricular arrhythmias (promptly or delay of several days), pancytopenia
- CNS/PNS: Delirium, encephalopathy, coma, neuropathy (2-6 weeks onset)→proximal muscles & respiratory failure
What are the chronic toxic effects of Arsenic (As)?
- Fatigue, weight loss, weakness
- Anemia, GI complaints, peripheral neuropathy
- Hyperpigmentation & hyperkeratoses of skin on hands & feet
- Cancer: Lung, skin, liver
What is the treatment for Arsenic (As) toxicity?
Dimercaprol
For the Metal, Arsenic (As)
- Exposure
- Mechanism of Action
- Physiological Effects
- Treatment
- Exposure: Drinking H2O, commerical applications, ant bait
- MOA: Oxidative stress
- Physiology Effects:
1. Acute: Hypotension, shock, death (GI), Venticular arrhythmias (cardiopulmonary), encephalopathy (CNS/PNS)
2. Chronic: Hyperpigmentation & Hyperkeratoses of skin on hands & feet - Treatment: Dimercaprol
In what ways can you be exposed to Iron (Fe)?
- Ingesting of Fe tablets by young children ≥ 10 tablets can be lethal (acute toxicity)
What are the acute toxic effects of Fe?
- Necrotizing gastroenteritis, Vomiting Abdominal pain, Bloody diarrhea
- Followed by shock, lethargy, dyspnea
- Subsequent improvement followed by severe metabolic acidosis, coma, death
What can cause chronic toxicity of Fe?
- Pts w/ Excessive Fe absorption (inherited hemochromatosis)
- Recieve many blood transfusions (thalassemia, sickle cell anemia, aplastic anemia)
- Excess Fe deposits on heart,liver,pancreas (Can cause organ failure & death)
List the treatments for acute toxicity of Iron (Fe).
- Whole bowel irrigation: Instillation of large volumes of polyethylene glycol (PO, NGT), Osmotically balanced electrolyte solution which prevents fluid & electrolyte shifts, Rapidly flush out unabsorbed Fe tablets
- Deferoxamine (IV): Fe chelator for absorbed Fe which promotes excretion in urine & feces
What are the side effects of Deforxamine?
Deforxamine used as treatment for acute toxicity of Fe
- Ocular & auditory disturbances (blurred vision, tinnitus)
- Renal effects (↑ serum creatinine)
- Acute respiratory distress syndrome (children)
- Rapid infusion → histamine release → hypotension
List the treatments for chronic toxicity of Iron (Fe)
- Intermittent phlebotomy: in the absence of anemia
- DeFEroxamine (IM, SQ)
- DeFErasirox (PO): Fe chelator for absorbed Fe which promotes excretion 1° in feces
What are the side effects of Deferasirox?
Deferasirox used for treatment for chronic toxicity of Fe
- GI bleeding (elderly, fatal)
- Nephrotoxic
- Hepatotoxic
- Rash
- Pyrexia
For the Metal, Iron (Fe)
- Exposure
- Mechanism of Action
- Physiological Effects
- Treatment
- Exposure
1. Acute: Ingestion of Fe tablets
2. Chronic: Excessive Fe absorption, many blood transfusions, Fe deposits on the heart, liver, and pancreas - MOA: N/A
- Physiological Effects
1. Acute: Necrotizing gastroenteritis, severe metabolic acidosis
2. Chronic: Organ failure and death - Treatment:
1. Acute: Whole bowel irrigation, DeFEroxamine
2. Chronic: Intermittent phlebotomy, DeFEroxamine, DeFErasirox
What ways can you get acute toxic exposure to Cooper (Cu)?
- Inhalation of Cu fumes or dust
- Ingestion of Cu salts (sulfate)
What are the physiolgical effects of acute toxicity to Cu?
- Severe cough, dyspnea, fever, leukocytosis, pulmonary infiltrates (Inhalation)
- N/V (blue-green), GI bleeding, gastroenteritis, hepatotoxicity, shock (Ingestion)
List the treatments for acute toxicity caused by Cu?
- Supportive treatment (O2)
- Decontamination
- Chelators:
1. Dimercaprol
2. Penicillamine
What are the side effects of Penicillamine?
Penicillamine used as treatment for acute toxicity of Cu
- Myelosuppression
- Proteinuria
- Lupus-like syndrome
- Neurologic worsening (10%)
What can cause chronic toxicity of Cooper (Cu)?
- Bordeaux mixture: Cu salt, fungicide, vineyard workers
- Wilson disease: Disorder of copper metabolism, ↑ concentration of Cu in CNS & viscera
What are the physiological effects of chronic toxicity to Cooper (Cu)?
- Pulmonary fibrosis, lung cancer, cirrhosis, angiosarcoma, & portal hypertension (Bordeaux mixture)
- Hepatic & neurologic dysfunction (e.g., tremor)(Wilson disease)
List the treatments for chronic toxicity to Cu
- Penicillamine (PO, dimethylcysteine)
- Trientine (PO)
- Dietary Cu below 2 mg/d
Treatments for Wilison disease
What are the side effects of Trientine?
Low yield
Trientine used as a treatment for chronic toxicity to Cu
- Anemia because Fe deficiency
- Arthralgia
For the Metal, Cooper (Cu)
- Exposure
- Mechanism of Action
- Physiological Effects
- Treatment
- Exposure
1. Acute: Inhalation of Cu fumes or dust/Ingestion of Cu salts
2. Chronic: Bordeaux mixture, Wilson disease - MOA
1. Acute: N/A
2. Chronic: ↑ Cu in CNS & viscera (Wilson disease) - Physiological Effects
1. Acute: Dyspnea, Leukocytosis (Inhalation)
2. Chronic: Pulmonary fibrosis (Bordeaux mixture); Hepatic and neurologic dysfunction (Wilson disease) - Treatment
1. Acute: Dimercaprol, Penicillamine
2. Chronic: Penicillamine, Trientine
Explain how gases (CO, HCN) affect the body systems
Inhaled gases travel to the alveoli, Distribute to the blood & other tissues
What are the chemical properties of Carbon monoxide (CO) and in what ways can you get exposed to it?
- Chemical properties: colorless, odorless, tasteless
- Exposure: combustion of carbonaceous material: cars, poorly vented furnaces, fireplaces, wood-burning stoves, kerosene space heaters, charcoal grills
Explain the mechanism of action of CO intoxication
- CO avidly binds to hemoglobin → carboxyhemoglobin, more than O2
- ↓ unloading of O2 to other tissues by ↑ O2 affinity to hemoglobin at other O2 binding sites
- Further ↓ O2 delivery
What are the physiological effects caused by CO toxicity?
- Hypoxia: CNS & heart especially sensitive
- Clinical presentation: HA, dyspnea, drowsiness, lethargy, confusion, Higher doses can cause seizures, coma & death
What is the treatment for CO toxicity?
- Promptly remove CO source
- 100% O2 via non-rebreathing facemask or endotracheal tube
- Hyperbaric chamber with severe intoxication
For the Gas, Carbon Monoxide (CO)
- Exposure
- Mechanism of Action
- Physiological Effects
- Treatment
- Exposure: Cars (combustion of carbonaceous material)
- MOA: CO binds to hemoglobin, ↓O2 delivery
- Physiological Effects: Hypoxia
- Treatment: Remove CO source, 100% O2, Hyperbaric chamber w/ severe intoxication
What ways can you be exposed to Hydrogen cyanide (HCN)?
- Burning of plastics, wool
- CN- (cyanide) salts in cassava, apple, peach, & apricot seeds
HCN has an almond-like odor
Explain the mechanism of action and side effects of HCN intoxication
- Inhibits cytochrome a3 mediated electron transfer, which prevents energy production by oxidative phosphorylation
- Death can occur quickly because of lack of ATP production