Toxicology Exam 3

  1. Carbon monoxide gas
    • colorless
    • tasteless
    • non-irritating
  2. Common sources of human exposure to carbon monoxide
    • smoke inhalation in fires
    • automobile exhaust fumes
    • faulty or poorly ventilated charcoal
    • kerosene or gas stoves
    • cigarette smoke
    • methylene chloride
  3. Mechanism of toxicity with carbon monoxide
    • cellular hypoxia and ischemia
    • CO binds hemoglobin in place of oxygen decreasing oxygen carrying capacity
    • CO directly inhibits cytochrome oxidase C
    • binds myoglobin preventing contraction of muscles
  4. Carbon monoxide binds hemoglobin with an affinity ____ times that of oxygen
  5. Damage from CO is most severe in
    the brain
  6. CO intoxication correlates with
    severity of systemic hypotension
  7. More sensitive to binding CO
    fetal hemoglobin
  8. Recommended workplace limit (ACGIH TLV-TWA) for CO
    25 ppm as an 8 hour TWA
  9. Level of CO immediately dangerous to life or heath (IDLH)
    1200 ppm (0.12%)
  10. Several minutes of exposure to 1000 ppm (0.1%) may result in
    50% saturation of carboxyhemoglobin
  11. Symptoms of CO intoxication
    • predominantly in high O2 consumption organs such as brain and heart
    • headache
    • dizziness
    • nausea
  12. Predisposing factor for CO intoxication
    congestive heart failure
  13. Survivors of serious CO exposure may suffer from
    • neurological sequelae consistant with hypoxic ischemia
    • parkinsonism
    • persistant vegetative state
    • personality or memory disorders
  14. CO exposure during pregnancy may result in
    fetal death
  15. first sign of CO poisoning
  16. Diagnosis of CO poisoning
    • cherry red skin
    • bright venous blood (smokers may have too)
    • carboxyhemoglobin level
  17. Fetal hemoglobin may produce falsely elevated levels of ____ in young infants that may last up to ____ years.
    • carboxyhemoglobin
    • may last up to 2 years
  18. Treatment of CO poisoning
    • maintain open airway
    • assist ventilation
  19. Because smoke often contains other toxic gases, considter the posibility of ____, ____ and ____ along with CO intoxication.
    • cyanide poisoning
    • methemoglobinemia
    • irritant gas injury
  20. Specific drugs/antidotes for CO intoxication
    Administration of 100% oxygen for approximately 1 hour at normal temp and pressure
  21. Hyperbaric 100% oxygen at ____ atm can spead elimination of CO to ____ min.
    • 2-3 atm
    • 20-30 min
  22. Applications for Cyanide
    • chemical synthesis
    • laboratory analysis
    • metal plating
  23. _____ used in plastic manufacturing are metabolized to CN.
    • Aliphatic nitriles
    • acrylonitrile
    • propionitrile
  24. Natural sources of cyanide
    • amygdalin from apricot pits
    • cassava
    • plants in africa (tuber)
  25. In order to eat tuber from africa
    must ferment to release HCN
  26. component of artificial nail glue that has caused several pediatric deaths
    • acetonitrile
    • releases CN in the child
  27. Hydrogen Cyanide
    • gas generated by mixing hydrogen with cyanide salts
    • common product of burning plastics or wools
  28. HCN poisoning is an important cause of
    • death from structural fires
    • homicide
    • suicide
  29. Mechanism of CN toxicity
    • chemical asphyxiant
    • binds cytochrome oxidase to block aerobic utilization of oxygen in the muscle
  30. Difference between CO and CN mechanisms
    • CO acts on mitochondrial oxidase C in the mitochondria
    • CN acts on cytochrom oxidase in the muscle
  31. Unbound CN is detoxified by metabolism to ____ which is excreted in the ___.
    • thiocyanate
    • urine
  32. Air level of CN considered immediately dangerous to life or health
    50 ppm
  33. Fatal level of CN if exposed
    150-200 ppm
  34. Solutions of CN salts
    • can be absorbed through skin
    • 200 mg ingested can be fatal
  35. CN poisoning can result from ____ but is rare.
    • nitroprusside infusion
    • amygdalin-containing seeds
  36. Hallmark sign of cyanide poisoning
    abrupt onset of profound toxic effects
  37. symptoms of CN poisoning
    • headache
    • nausea
    • dyspnea
    • confusion
  38. When CN is ingested as a salt, as a capsule or with food
    brief delay in symptoms may occur
  39. clinical symptoms of CN poisoning
    • lactic acidosis
    • bitter almond odor may or may not be noted based on genetics
  40. Whole blood levels of CN ranging from ____ are considered toxic
    0.5-1 mg/L
  41. Smokers may have normal blood CN levels of ____.
    0.1 mg/L
  42. Rapid nitroprusside infusion may result in blood CN levels of ____ along with ____.
    • 1 mg/L
    • metabolic acidosis
  43. Cyanide antidote package consists of
    • amyl and sodium nitrites
    • sodium thiosulfate
  44. Amyl and sodium nitrite mechanism of action
    • break a pearl of amyl nitrite under the nose of the pt
    • infuse sodium nitrite 300 mg IV
    • causes conversion of hemoglobin to methemoglobin which binds CN
  45. Mechanism of sodium thiosulfate
    • administer 12.5 g IV
    • accelerates conversion of cyanide to thiocyanate
  46. Given empirically even if CN poisoning diagnosis is uncertain
    sodium thiosulfate
  47. useful in mitigating nitroprusside toxicity
    sodium thiosulfate
  48. Most promising alternative antidote
    • hydroxocobalamin
    • synthetic form of vitamin B12
  49. mechanism of action for hydroxocobalamin
    hydroxocobalamin exchanges its hydroxyl group with free cyanide in the plasma to produce non-toxic cyanocobalamin
  50. side effects of hydroxocobalamin
    bodily fluids become brownish-red
  51. hydroxocobalamin availability
    investigational orphan drug in the US
  52. most visible form of air pollution
  53. sources of air pollution
    burning fossil fuels, coal and oil.
  54. Five major pollutants which account for 98% of all air pollution from highest to lowest
    • CO (52%)
    • Sulfur Oxides (18%)
    • Hydrocarbons (12%)
    • Particulates (10%)
    • Nitrogen Oxidases (6%)
  55. Major air pollutants are generated from
    • fuels used in electric power plants and industry
    • car exhaust
    • waste/refuse disposal
  56. Average air CO concentration
    0.1 ppm
  57. in heavy traffic CO concentrations can reach
    100 ppm
  58. Sulfur Dioxide
    colorless irritant gas generated from combustion of sulfur-containing fossil fuels
  59. sulfur dioxide forms ____ on contact with mucous membranes
    sulfurous acid
  60. Primary signs of sulfur dioxide exposure
    conjunctival and bronchial irritations
  61. ____ ppm sulfur dioxide can cause severe bronchospasm
    5-10 ppm
  62. Treatment for SO2 exposure
    • removal from contaminated air
    • treatment of irritation and inflammation
  63. Nitrogen dioxide is formed in
    • fires
    • fresh silage on farms
  64. Effects of nitrogen dioxide
    • deep lung irritation capable of producing pulmonary edema
    • irritation of eyes, nose and throat
    • death of farmers in silos
  65. Treatment of nitrogen dioxide poisoning
    • no specific treatment
    • reduce inflammation and pulmonary edema
  66. Ozone
    • O3
    • bluish irritant gas
    • produced in air and water purification devices and in electrical fields
  67. Exposure to ____ ppm Ozone causes irritation and dryness of mucous membranes.
    0.1 ppm
  68. Higher concentrations of Ozone exposure may result in
    impaired pulmonary function
  69. Chronic Ozone exposure may result in
    • bronchitis
    • bronchiolitis
    • fibrosis
    • emphysema
  70. Treatment for Ozone poisoning
    • no specific treatment
    • reduce inflammation
    • reduce pulmonary edema
Card Set
Toxicology Exam 3
CO/CN & Air Pollution