Blood & Cellular Toxins Quiz
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Questions and Answers

Which of the following toxins can cause Methemoglobinemia?

  • Carbon monoxide
  • Cyanide
  • Substances that precipitate Methemoglobinemia (correct)
  • Hydrogen Sulfide

    • Which toxin is known for its affinity to bind with hemoglobin?

  • Cyanide
  • Substances causing Methemoglobinemia
  • Carbon monoxide (correct)
  • Hydrogen Sulfide

    • Which toxin interferes with cellular respiration?

  • Substances causing Methemoglobinemia
  • Carbon monoxide
  • Cyanide (correct)
  • Hydrogen Sulfide

    • How can hydrogen cyanide gas be absorbed into the body?

    <p>Inhalation, ingestion, mucous membrane, and skin absorption</p> Signup and view all the answers

    Why is hydrogen cyanide gas faster in action compared to salts of cyanide?

    <p>It enters quickly through the extensive pulmonary area</p> Signup and view all the answers

    In what forms is cyanide most lethal?

    <p>Hydrogen cyanide gas and salts such as sodium and potassium cyanide</p> Signup and view all the answers

    What can be a source of cyanide poisoning in fires?

    <p>Silk</p> Signup and view all the answers

    Which pharmaceutical can lead to cyanide poisoning as a metabolite?

    <p>Nitroprusside</p> Signup and view all the answers

    What is a combustion product of compounds that can lead to cyanide poisoning?

    <p>HCN gas</p> Signup and view all the answers

    Where is cyanide found in apricot, apple, and pear plants?

    <p>In the seeds</p> Signup and view all the answers

    How is cyanide liberated from cyanogenic plants?

    <p>Through metabolic action</p> Signup and view all the answers

    Why is oral route toxicity of cyanide higher than IV route?

    <p>Due to metabolic action in the intestines</p> Signup and view all the answers

    Linamarin es un glicosido cianogenico trovate in le planta de cassava.

    <p>False</p> Signup and view all the answers

    Acetonitrile, o methil cianide, es convertite in vivo a cianuro de hydrogeno.

    <p>False</p> Signup and view all the answers

    Linamarin se trova in le planta de cassava.

    <p>False</p> Signup and view all the answers

    Which route of cyanide exposure results in the most rapid toxicity?

    <p>Inhalation of HCN gas</p> Signup and view all the answers

    Which compound requires hydrolysis to release cyanide, leading to delayed toxicity after ingestion?

    <p>Amygdalin</p> Signup and view all the answers

    Which compound's oxidative metabolism by the hepatic cytochrome P450 system delays toxicity symptoms for 2 to 6 hours after ingestion?

    <p>Acetonitrile</p> Signup and view all the answers

    What is the primary endogenous pathway for CN detoxification?

    <p>Conversion by Rhodanase in the presence of thiosulfate</p> Signup and view all the answers

    Where does the majority of CN detoxification take place?

    <p>Blood and liver</p> Signup and view all the answers

    How is thiocyanate, a product of CN detoxification, eliminated from the body?

    <p>Excreted in urine</p> Signup and view all the answers

    What is the primary mechanism of toxicity in cyanide poisoning?

    <p>Disruption of cytochrome oxidase system</p> Signup and view all the answers

    Which cellular component does cyanide bind to, causing disruption of the electron transport chain?

    <p>Mitochondrial cytochrome oxidase</p> Signup and view all the answers

    What consequence does cyanide binding to cytochrome oxidase have on the cell?

    <p>Prevents utilization of oxygen in ATP production</p> Signup and view all the answers

    What is the primary cause of death in cyanide poisoning?

    <p>Lactic acidosis</p> Signup and view all the answers

    Which organs are the critical targets of cyanide poisoning?

    <p>Brain &amp; heart</p> Signup and view all the answers

    What symptom is suggestive of cyanide poisoning?

    <p>Hypoxia without cyanosis</p> Signup and view all the answers

    What is the primary cause of death in cyanide poisoning?

    <p>Cellular asphyxia due to an overwhelming lactic acidosis</p> Signup and view all the answers

    Which organs are the critical targets of cyanide poisoning?

    <p>Brain &amp; heart</p> Signup and view all the answers

    What symptom is suggestive of cyanide poisoning?

    <p>Hypoxia without cyanosis</p> Signup and view all the answers

    What is the primary cause of death in cyanide poisoning?

    <p>Cellular asphyxia</p> Signup and view all the answers

    What symptoms are suggestive of cyanide poisoning?

    <p>Hypoxia without cyanosis</p> Signup and view all the answers

    Which organs are the critical targets of cyanide poisoning?

    <p>Brain &amp; heart</p> Signup and view all the answers

    What are the products of the reaction between rhodanase, thiosulfate, and cyanide?

    <p>Thiocyanate and sulfite</p> Signup and view all the answers

    How is thiocyanate, a product of cyanide detoxification, eliminated from the body?

    <p>Excreted into the urine</p> Signup and view all the answers

    Why can't the pathway involving rhodanase keep up with large amounts of cyanide in a poisonous ingestion?

    <p>The pathway is easily overwhelmed</p> Signup and view all the answers

    What is the recommended treatment for a patient who arrives with minimal symptoms soon after an oral exposure to cyanide?

    <p>Gastric decontamination and charcoal</p> Signup and view all the answers

    How does the administration of oxygen contribute to treating cyanide poisoning?

    <p>It can displace cyanide from cytochrome oxidase and restore enzyme function</p> Signup and view all the answers

    What is a significant challenge in providing effective antidotes for cyanide poisoning?

    <p>Rapid onset of cyanide action</p> Signup and view all the answers

    What is the primary function of nitrites in the cyanide antidote kit?

    <p>Convert hemoglobin to methemoglobin, which competes with cytochrome oxidase for cyanide</p> Signup and view all the answers

    Why is it possible to produce much more methemoglobin than the entire bodily content of cytochrome oxidase using hemoglobin oxidizing agents?

    <p>Cytochrome oxidase is present in much smaller amounts than hemoglobin in the body</p> Signup and view all the answers

    What role does methemoglobin play in countering the effects of cyanide?

    <p>Competes with cytochrome oxidase for cyanide binding due to its ferric ion</p> Signup and view all the answers

    What is the initial step in the cyanide antidote kit?

    <p>Inhalation of amyl nitrite</p> Signup and view all the answers

    What is the product of the reaction between cyanmethemoglobin and thiosulfate?

    <p>$SCN^- + SO_3^{2-}$</p> Signup and view all the answers

    Why is sodium thiosulfate included in the cyanide antidote kit?

    <p>To eliminate cyanide from the body</p> Signup and view all the answers

    What is the final product of the reactions involving thiosulfate in the cyanide antidote kit?

    <p>$SCN^- + SO_3^{2-}$</p> Signup and view all the answers

    What is the final product of the reactions involving thiosulfate in the cyanide antidote kit?

    <p>SCN$^-$</p> Signup and view all the answers

    What is the primary endogenous pathway for CN detoxification?

    <p>Rhodanase pathway</p> Signup and view all the answers

    How is thiocyanate, a product of CN detoxification, eliminated from the body?

    <p>Excreted in urine</p> Signup and view all the answers

    What can be administered by inhalation to quickly counteract cyanide poisoning?

    <p>Amyl nitrite</p> Signup and view all the answers

    What is the primary concern when administering the antidote for cyanide poisoning?

    <p>Formation of methemoglobin and potential tissue oxygenation issues</p> Signup and view all the answers

    What is the role of nitrites in the treatment of cyanide poisoning?

    <p>Cause vasodilatation and pose a risk of hypotension</p> Signup and view all the answers

    What is the mechanism by which hydroxycobalamin (vitamin B12) functions as an antidote for cyanide poisoning?

    <p>CN couples with the cobalt component of hydroxycobalamin, producing non-toxic cyanocobalamin</p> Signup and view all the answers

    Hydroxycobalamin is an antidote for cyanide poisoning.

    <p>True</p> Signup and view all the answers

    Methemoglobin levels must be kept below 40% in the treatment of cyanide poisoning.

    <p>True</p> Signup and view all the answers

    Nitrites in the treatment of cyanide poisoning can cause hypotension.

    <p>True</p> Signup and view all the answers

    What is the primary cause of carbon monoxide formation in automobile engines?

    <p>Insufficient heat and/or oxygen during combustion</p> Signup and view all the answers

    Why is carbon monoxide described as the 'silent killer'?

    <p>It is odorless, invisible, tasteless, and nonirritating</p> Signup and view all the answers

    What additive in gasoline promotes a more complete oxidation with less carbon monoxide emission from automobile engines?

    <p>Methyl tert butyl ether</p> Signup and view all the answers

    Carbon monoxide is odorless, invisible, tasteless, colorless, and nonirritating.

    <p>True</p> Signup and view all the answers

    Methyl tert butyl ether added to gasoline causes a more complete oxidation of the gasoline with less carbon monoxide emitted from the engine.

    <p>True</p> Signup and view all the answers

    Carbon monoxide has been described as the silent killer.

    <p>True</p> Signup and view all the answers

    What is a significant source of carbon monoxide (CO) in the atmosphere?

    <p>Tobacco products</p> Signup and view all the answers

    How does exposure to methylene chloride (CH2Cl2) affect the concentration of carboxyhemoglobin (HbCO) in the blood?

    <p>Increases HbCO concentration to 5-15%</p> Signup and view all the answers

    What is the primary source of the normal amount of carboxyhemoglobin (HbCO) in the blood?

    <p>Metabolism of endogenous hemoglobin</p> Signup and view all the answers

    Carbon monoxide (CO) is a significant source of carboxyhemoglobin (HbCO) in the blood.

    <p>True</p> Signup and view all the answers

    Tobacco products are a significant source of carbon monoxide (CO) in the atmosphere.

    <p>True</p> Signup and view all the answers

    Methylene chloride (CH2Cl2) is metabolized by the body, leading to increased carboxyhemoglobin (HbCO) concentrations in the blood.

    <p>True</p> Signup and view all the answers

    What is the primary mechanism of toxicity in carbon monoxide (CO) poisoning?

    <p>Displacement of oxygen from hemoglobin</p> Signup and view all the answers

    Why is the human body highly dependent on hemoglobin for oxygen transport?

    <p>Cells cannot complete metabolic processes without oxygen</p> Signup and view all the answers

    What is the major toxicity of carboxyhemoglobin (HbCO) in carbon monoxide (CO) poisoning?

    <p>Displacement of oxygen with resulting failure to adequately oxygenate tissue</p> Signup and view all the answers

    Carbon monoxide has a stronger affinity for hemoglobin than oxygen does.

    <p>True</p> Signup and view all the answers

    Cells cannot complete the metabolic degradation of carbohydrate and other foodstuffs without oxygen.

    <p>True</p> Signup and view all the answers

    The major toxicity of carboxyhemoglobin (HbCO) is the displacement of oxygen with resulting failure to adequately oxygenate tissue.

    <p>True</p> Signup and view all the answers

    What effect does HbCO have on the hemoglobin dissociation curve?

    <p>Causes a left shift, resulting in a higher percent of oxygen being bonded to hemoglobin</p> Signup and view all the answers

    What is the consequence of a left shift in the hemoglobin dissociation curve due to HbCO?

    <p>Reduction of tissue perfusion and intensification of hypoxia</p> Signup and view all the answers

    Why is a left shift in the hemoglobin dissociation curve disadvantageous within the tissue?

    <p>More oxygen remains bonded to hemoglobin, reducing the amount released to perfuse the tissue</p> Signup and view all the answers

    What is the primary reason high HbCO fails to oxygenate tissue?

    <p>Occupation of hemoglobin by CO rather than oxygen</p> Signup and view all the answers

    What impact does CO binding to myoglobin have on skeletal muscle?

    <p>Reduces the uptake of oxygen by skeletal muscle</p> Signup and view all the answers

    What is the major effect of CO in terms of binding with hemoglobin and oxygen?

    <p>Diminishing the overall level of oxidative respiration within the body</p> Signup and view all the answers

    High levels of HbCO can oxygenate tissue effectively.

    <p>False</p> Signup and view all the answers

    CO binding to myoglobin affects the uptake of oxygen by skeletal muscle.

    <p>True</p> Signup and view all the answers

    CO has a greater affinity for myoglobin than oxygen.

    <p>True</p> Signup and view all the answers

    What does the equation for calculating %HbCO indicate?

    <p>The percent of HbCO achieved in the blood is proportional to the amount of CO in the environment and the duration of exposure.</p> Signup and view all the answers

    What factor is represented in the equation for calculating %HbCO?

    <p>Tidal volume</p> Signup and view all the answers

    In what way does the concentration of HbCO in the blood relate to morbidity associated with CO exposure?

    <p>It is directly proportional to morbidity associated with CO exposure.</p> Signup and view all the answers

    What symptoms are associated with a blood HbCO level of 40%?

    <p>Confusion, nausea, vomiting, tachypnea</p> Signup and view all the answers

    At what blood HbCO level do symptoms such as headache, dyspnea, and dizziness occur?

    <p>30%</p> Signup and view all the answers

    What is the approximate blood HbCO level when no symptoms are present?

    <p>10%</p> Signup and view all the answers

    What is a common reason for the misdiagnosis of carbon monoxide (CO) poisoning?

    <p>Symptoms of CO poisoning are similar to those of influenza</p> Signup and view all the answers

    What is a potential effect of CO on the heart?

    <p>Anginal pain and electrocardiogram irregularities</p> Signup and view all the answers

    What is a possible long-term neurological effect of CO exposure?

    <p>Neuropsychiatric damage and personality deterioration</p> Signup and view all the answers

    What is the recommended intervention when the lab result shows 15% HbCO?

    <p>Rest patient and assure removal from CO source</p> Signup and view all the answers

    What is the goal of CO therapy?

    <p>Improve oxygenation of vital organs, especially the heart and brain</p> Signup and view all the answers

    At what HbCO level should hyperbaric oxygen (2-3 atmospheres pressure) be given?

    <p>40%</p> Signup and view all the answers

    At what pressure level is hyperbaric therapy considered?

    <p>2 atmospheres</p> Signup and view all the answers

    What is the advantage of hyperbaric oxygen therapy in treating carbon monoxide poisoning?

    <p>It decreases the half life of HbCO</p> Signup and view all the answers

    For which patient should hyperbaric oxygen therapy be considered?

    <p>Healthy adult with 40% HbCO</p> Signup and view all the answers

    Why is fetal toxicity more than maternal toxicity in CO exposure during pregnancy?

    <p>CO binds more strongly to fetal hemoglobin</p> Signup and view all the answers

    What contributes to the appearance of fetal toxicity in the absence of significant maternal toxicity in CO exposure during pregnancy?

    <p>Slower elimination of fetal HbCO compared to maternal HbCO</p> Signup and view all the answers

    What allows CO to reach the fetus during pregnancy?

    <p>CO can cross the placenta</p> Signup and view all the answers

    What contributes to the appearance of fetal toxicity in the absence of significant maternal toxicity in CO exposure during pregnancy?

    <p>Stronger binding of CO to fetal hemoglobin</p> Signup and view all the answers

    At what HbCO level should hyperbaric oxygen (2-3 atmospheres pressure) be given?

    <p>40%</p> Signup and view all the answers

    What is the primary cause of carbon monoxide formation in automobile engines?

    <p>Incomplete combustion of carbon-containing fuels</p> Signup and view all the answers

    What is the mainstay of therapy for patients with cyanide or hydrogen sulfide toxicity in the emergency department?

    <p>High flow (100%) oxygen</p> Signup and view all the answers

    What is formed by the reaction between methemoglobin and hydrogen sulfide (H2S)?

    <p>Sulfmethemoglobin</p> Signup and view all the answers

    When should patients with cyanide or hydrogen sulfide toxicity be considered for hyperbaric oxygen therapy (HBO)?

    <p>When they are unresponsive to IV nitrites</p> Signup and view all the answers

    What is methemoglobinemia?

    <p>A clinical state with more than 1-2% of oxidized hemoglobin</p> Signup and view all the answers

    What happens to the heme moiety in methemoglobin?

    <p>It is oxidized from the ferrous to the ferric state</p> Signup and view all the answers

    What is the impact of methemoglobinemia on oxygen transport?

    <p>Causes decreased efficiency of oxygen delivery to tissues</p> Signup and view all the answers

    Is Methemoglobinemia a clinical state in which more than 1-2% of total hemoglobin is in the oxidized form?

    <p>True</p> Signup and view all the answers

    Methemoglobinemia causes decreased efficiency of oxygen delivery to tissues.

    <p>True</p> Signup and view all the answers

    Hemoglobin must be maintained in the ferric state to perform the physiologic role of oxygen transport properly.

    <p>False</p> Signup and view all the answers

    Is methemoglobinemia always an inherited condition?

    <p>False</p> Signup and view all the answers

    Can exposure to certain therapeutic agents and chemicals induce methemoglobinemia?

    <p>True</p> Signup and view all the answers

    Is nitric oxide considered an environmental and industrial chemical that can induce methemoglobinemia?

    <p>False</p> Signup and view all the answers

    Which is an acquired cause of methemoglobinemia?

    <p>Illness associated metHb of infancy</p> Signup and view all the answers

    Which of the following is a therapeutic agent known to induce methemoglobinemia?

    <p>Primaquine</p> Signup and view all the answers

    Which chemical is an environmental and industrial inducer of methemoglobinemia?

    <p>Arsine</p> Signup and view all the answers

    What factors determine the rate, magnitude, and duration of toxin-induced methemoglobin formation?

    <p>Rate of entry of the compound into RBC, rate of metabolism of toxin in the body, rate of excretion of toxin, effectiveness of RBC methemoglobin reduction systems</p> Signup and view all the answers

    Which factor is critical for effective reduction of methemoglobin in RBCs?

    <p>Effectiveness of RBC methemoglobin reduction systems</p> Signup and view all the answers

    What determines the rate of toxin-induced methemoglobin formation within red blood cells?

    <p>Rate of entry of the compound into RBC</p> Signup and view all the answers

    At what approximate blood HbCO level do symptoms like malaise, fatigue, and dyspnea occur?

    <p>More than 30%</p> Signup and view all the answers

    What clinical findings are associated with a blood metHb concentration of more than 50%?

    <p>Tissue ischemia</p> Signup and view all the answers

    At what blood HbCO level do clinical findings include cyanosis and symptoms related to tissue hypoxemia?

    <p>More than 10%</p> Signup and view all the answers

    What is the predominant pathway for reducing methemoglobin back to the ferrous state?

    <p>Cytochrome b5 methemoglobin reductase dependent on NADH</p> Signup and view all the answers

    Which mechanism accounts for less than 5% of the reduction of methemoglobin?

    <p>Flavin-dependent pathway</p> Signup and view all the answers

    What enhances the activity of the NADPH diaphorase pathway for reducing methemoglobin?

    <p>Methylene blue</p> Signup and view all the answers

    Reduced nicotine adenine dinucleotide (NADH) is involved in the predominant pathway for reducing methemoglobin.

    <p>True</p> Signup and view all the answers

    The alternate pathway for reducing methemoglobin involves a reduced nicotine adenine dinucleotide phosphate (NADPH) diaphorase.

    <p>True</p> Signup and view all the answers

    Methylene blue can greatly enhance the activity of the alternate pathway for reducing methemoglobin.

    <p>True</p> Signup and view all the answers

    What is the recommended treatment for patients with signs of tissue hypoxia, CNS depression, or cardiovascular instability?

    <p>Antidotal therapy with IV methylene blue 1-2 mg/kg</p> Signup and view all the answers

    What may be a potential side effect of using methylene blue as an antidote?

    <p>Blue-green discoloration of urine</p> Signup and view all the answers

    What is the initial step in the recommended treatment approach?

    <p>Observing the patient's airway, breathing, circulation, and neurologic function</p> Signup and view all the answers

    Supplemental oxygen should be administered to patients with signs of tissue hypoxia, CNS depression, or cardiovascular instability.

    <p>True</p> Signup and view all the answers

    The antidote therapy with IV methylene blue may cause skin and urine discoloration.

    <p>True</p> Signup and view all the answers

    The primary treatment approach for cyanide poisoning involves observing the patient's airway, breathing, circulation, and neurologic function.

    <p>True</p> Signup and view all the answers

    What is the primary reason why methylene blue is not effective in patients with glucose 6 phosphate dehydrogenase deficiency?

    <p>Decreased capacity to form NADPH</p> Signup and view all the answers

    What is the role of IV ascorbic acid in the treatment of methemoglobinemia?

    <p>Increase nonenzymatic reduction of methb</p> Signup and view all the answers

    What effect does glucose 6 phosphate dehydrogenase deficiency have on the capacity for antidotal methemoglobin reduction?

    <p>Decreases the capacity for antidotal methemoglobin reduction</p> Signup and view all the answers

    Is methylene blue effective in rapidly reversing methemoglobinemia through activation of the NADPH diaphorase pathway?

    <p>True</p> Signup and view all the answers

    Is methylene blue reduced to leukomethylene blue by NADPH diaphorase?

    <p>True</p> Signup and view all the answers

    Is methylene blue effective in patients with glucose 6 phosphate dehydrogenase deficiency?

    <p>False</p> Signup and view all the answers

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