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33 Cards in this Set
- Front
- Back
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What is laetrile and what route of administration is at risk for cyanide toxicity
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A substance thought to have anti-neoplastic properties. Contains amygdalin, therefore cyanide can develop after ingestion.
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Toxic component of pitted fruits
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Amygdalin
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Cassava root is major food source. Improper processing leads to cyanide formation
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What is linmarin
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Major cyanogenic glycoside of cassava root
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What enzymes facilitate biotransformation of acetonitrile and acrylonitrile to cyanide
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Cytochrome P450 2E1
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Cyanide is biotransformed to what substance for excretion
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Thiocyanate
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Enzyme that catalyzes cyanide to thiocyanate
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Rhodanese
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Most important enzyme inhibited by cyanide
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Cytochrome oxidase
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What lactate level is associated with 94% sensitivity for cyanide
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8 mmol/L
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Goal methemoglobinemia level when treating cyanide with sodium nitrite
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20-30%
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Forms of cyanide
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Hydrogen cyanide Cyanide salts Cyanogens Inorganic cyanides |
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Common medication associated with iatrogenic cyanide toxicity
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Sodium nitroprusside
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Tobacco amblyopia
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Chronic cyanide exposure. Loss of visual function among men who smoke cigarettes. Thought to be secondary to decreased rhodanese
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Tropical ataxic neuropathy
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Chronic cyanide exposure associated with cassava consumption
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Leber hereditary optic neuropathy is associated with what enzyme deficiency
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Rhodanese deficiency
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Dose of hydroxycobalamin
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5g over 15 minutes
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How does methemoglobinemia effect cyanide
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Cyanide will preferentially bind to Methemoglobinemia over cytochrome oxidase a3.
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Sodium thiosulfate mechanism
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Donates sulfur ion to form thiocyanate
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Sodium thiosulfate has 2 indications
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Cyanide toxicity Calciphylaxis |
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Cyanide combines with hydroxycobalamin to form what product
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Cyanocobalamin
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Cyanide has 5 potential pathways (including antidotes)
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1. binds cytochrome oxidase 2. forms MetHbCN (combines with metHb) 3. forms thiocyanate (rhodanses/sodium thiosulfate) 4. forms cyanocobalamin (hydroxycobalamin) 5. forms Cobalt(CN) via chelator |
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Industrial sources of hydrogen sulfide |
Pulp paper mills Leather industry Wastewater treatment plants Roofing asphalt tanks Rubber vulcanization Viscose rayon production |
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Environmental sources of hydrogen sulfide |
Volcanoes, caves, springs, and decomposition of organic matter |
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Smell associated with hydrogen sulfide |
Rotten eggs |
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Odor threshold of hydrogen sulfide (ppm) |
0.2 ppm |
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What level (ppm) does hydrogen sulfide cause eye and respiratory irritation |
50 ppm |
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Tissues most sensitive to hydrogen sulfide |
Mucous membranes and those with high oxygen demands |
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Mechanism of toxicity of hydrogen sulfide |
Inhibits cytochrome oxidase |
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Level (ppm) that hydrogen sulfide will cause loss of conciousness |
750 ppm |
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Why is knockdown effect dangerous |
Patients will be knocked to ground where typically hydrogen sulfide is at greater concentrations |
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What is "gas eye" |
Reversible corneal ulcerations and keratoconjunctivitis secondary to hydrogen sulfide |
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Is rotten egg smell reliable for detecting hydrogen sulfide |
No. Olfactory fatigue and olfactory paralysis can occur at 150 ppm |
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Major metabolite of hydrogen sulfide |
Thiosulfate |
