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Nitrate/Nitrite Toxicity
Posttest

Course: WB 2342
CE Original Date: December 5, 2013
CE Expiration Date: December 5, 2015
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Instructions

To complete the assessment and posttest, go to http://www2a.cdc.gov/TCEOnline/registration/detailpage.asp?res_id=4035 and follow the instructions on that page. You can immediately print your continuing education certificate from your personal transcript online. No fees are charged.

Posttest

  1. Nitrites and nitrates are

    1. Naturally occurring organic ions.
    2. Relatively insoluble in water.
    3. Ions that readily migrate in ground water.
    4. All of the above.
  2. Which of the following water sources is generally most likely to contain high levels of nitrates or nitrites?

    1. Bottled water.
    2. Large municipal water supplies.
    3. Shallow, rural domestic wells.
    4. Water from deep wells.
  3. Which of the following is true regarding route(s) of exposure to nitrates and nitrites in humans?

    1. The primary route of occupational exposure is ingestion.
    2. The primary route of exposure for the general population is dermal.
    3. Primary routes of exposure are the same for occupational and non-occupational populations.
    4. None of the above.
  4. Which of the following subpopulations are most at risk of adverse effects from nitrate exposure?

    1. Girls age 13-18 years old.
    2. Telephone line workers.
    3. The elderly.
    4. Infants younger than 4 months of age.
    5. Individuals with anemia.
  5. Which of the following are possible sources of nitrate exposure?

    1. Certain topical burn medications.
    2. Shallow domestic wells in rural areas.
    3. Meat preservatives.
    4. Seepage from septic tanks.
    5. All of the above.
  6. Which statement about nitrates is true?

    1. Nitrates can be converted into more toxic nitrites in the gut.
    2. The higher alkalinity of an infant's gut protects it from nitrate toxicity.
    3. Vomiting and diarrhea do not affect the absorption of nitrates or nitrites.
    4. No case of nitrate poisoning has been reported since 1950.
    5. Adults are immune from nitrate toxicity if they drink water from public water systems.
  7. Which of the following is/are true?

    1. The present maximum contaminant level for nitrates in drinking water appears to adequately protect even sensitive populations from nitrate-induced toxicity.
    2. Some domestic and public-supply wells in the United States have nitrate levels above the U.S. EPA drinking water standard of 10 parts per million.
    3. The acceptable daily intake (ADI) for nitrate is 3.7 mg/kg/day or 222 mg nitrate per day for a 60 kg adult.
    4. All of the above.
    5. None of the above.
  8. All of the following are true regarding dietary nitrate intake EXCEPT

    1. Vegetables account for about 80% of nitrates in a typical human diet.
    2. Nitrate levels vary by type of vegetable with higher levels generally found in leafy vegetables.
    3. There are benefits from dietary intake of nitrates and nitrites.
    4. Cured and processed meats account for about 85% nitrates in a typical human diet.
    5. Nitrates in drinking water should not exceed 10 ppm.
  9. The toxicity of nitrates is enhanced by in vivo conversion to

    1. Urea.
    2. CO2.
    3. Protein.
    4. Nitrites.
  10. Effects of methemoglobinemia include which of the following?

    1. Cyanosis.
    2. Coma or convulsions.
    3. Dysrhythmias.
    4. All of the above.
  11. Methemoglobinemia can be induced by which of the following?

    1. Chloroquine.
    2. Lidocaine.
    3. Nitroglycerine.
    4. Dapsone.
    5. All of the above.
  12. Which of the following systems is most directly affected by nitrates?

    1. Reproductive system.
    2. Hematologic system.
    3. Neurological system.
    4. Immune system.
  13. Which statement is true?

    1. Signs and symptoms of methemoglobinemia are precisely correlated with percent total oxidized hemoglobin.
    2. Fetal hemoglobin is less readily oxidized by nitrites to methemoglobin than is adult hemoglobin.
    3. Methemoglobin causes arterial blood to be bright red in color.
    4. Standard pulse oximetry is the most useful diagnostic test for nitrate toxicity.
    5. None of the above.
  14. What key areas should be addressed in the exposure history?

    1. Recent use of medications by infant and mother.
    2. Type of formula, feeding regimen, and source of dilution water.
    3. Drinking water source and supply.
    4. All of the above.
  15. Which of the following is/are true regarding the clinical assessment?

    1. All cyanotic patients should be assessed for possible cardiac and lung disease (cardiac murmurs, gallops, arrhythmias, rales, rhonchi, wheezes, dullness, or hyperresonance in the chest).
    2. A central chocolate brown or slate gray cyanosis that does not respond to administration of 100% oxygen is suggestive of methemoglobinemia.
    3. The victim is often less ill than one would expect from the severity of 'cyanosis' (but not always).
    4. All of the above.
  16. Useful diagnostic test(s) for nitrate toxicity include which of the following?

    1. Measurements of nitrates in blood, urine, or saliva.
    2. Measurements of nitrites in blood, urine, or saliva.
    3. Blood methemoglobin level.
    4. All of the above.
  17. Which of the following treatments can be used for patients with nitrate toxicity?

    1. Hyperbaric oxygen therapy.
    2. Methylene blue.
    3. 100% oxygen.
    4. Exchange transfusion.
    5. All of the above.
  18. What condition is a relative contraindication to methylene blue treatment, especially in cases of non-life threatening methemoglobinemia?

    1. Psoriasis.
    2. G6PD deficiency.
    3. Methemoglobinemia.
    4. Diarrhea and vomiting.
    5. None of the above.
  19. Which of the following instructions regarding exposure to nitrates and nitrites is FALSE?

    1. Limit the consumption of processed or cured meats.
    2. Infants under 3 months of age should not be fed home prepared foods containing vegetables.
    3. Infants fed commercially prepared infant foods containing vegetables are at increased risk of nitrate poisoning.
    4. Households using private wells for drinking water should have the well tested for nitrates.

Relevant Content

To review content relevant to the posttest questions, see

Question Location of Relevant Content
1. What are nitrates/nitrites?
  • Describe what nitrates and nitrites are.
2. Where are nitrates and nitrites found?
  • Identify sources of nitrates and nitrites.
3. What are routes of exposure for nitrates and nitrites?
  • Describe the primary routes of exposure to nitrates and nitrites.
4. Who is at risk of adverse health effects from overexposure to nitrates and nitrites?
  • Identify the population most susceptible to adverse health effects from overexposure to nitrates and nitrites.
5. Where are nitrates and nitrates found?
  • Identify sources of nitrates and nitrites.
6. What is the biologic fate of nitrates and nitrites in the body?
  • Describe what happens to nitrates and nitrites once they enter the body.


What are the health effects from exposure to nitrates and nitrites?
  • Describe mechanisms contributing to health effects from exposure to nitrates and nitrites.
7. What are U.S. standards and regulations for nitrate and nitrite exposure?
  • Describe the U.S. Environmental Protection Agency's (EPA's) recommended limit for nitrates and nitrites in drinking water.
8. Where are nitrates and nitrites found?
  • Identify sources of nitrates and nitrites.

What are the U.S. standards and regulations for nitrate and nitrite exposure?
  • Describe the EPA's recommended limit for nitrates and nitrites in drinking water.
  • Describe the FDA's recommended limit for nitrates and nitrites in bottled water and foodstuffs.
9. What is the biologic fate of nitrates and nitrites in the body?
  • Describe what happens to nitrates and nitrites once they enter the body.

What are the health effects from exposure to nitrates and nitrites?
  • Describe mechanisms contributing to health effects from exposure to nitrates and nitrites.
10. What are the health effects from exposure to nitrates and nitrites?
  • Describe the health effects from exposure to nitrates and nitrites.
11. How should patient's potentially overexposed to nitrates and nitrites be evaluated?
  • Describe the clinical assessment of an infant overexposed to nitrates and nitrites.
12. What are the health effects from exposure to nitrates and nitrites?
  • Describe the health effects from exposure to nitrates and nitrites.


How should patient's potentially overexposed to nitrates and nitrites be evaluated?
  • Describe the signs and symptoms of methemoglobinemia.
13. What are the health effects from exposure to nitrates and nitrites?
  • Describe the mechanisms contributing to health effects from exposure to nitrates and nitrites.
  • Describe the health effects from exposure to nitrates and nitrites.


How should patient's potentially overexposed to nitrates and nitrites be evaluated?
  • Describe the clinical assessment of an infant overexposed to nitrates and nitrites.
  • Describe the signs and symptoms of methemoglobinemia.


What laboratory tests can assist with diagnosis of nitrate and nitrite toxicity?
  • Identify the laboratory test results that indicate methemoglobinemia.
14. How should patient's potentially overexposed to nitrates and nitrites be evaluated?
  • Describe the clinical assessment of an infant overexposed to nitrates and nitrites.
15. How should patient's potentially overexposed to nitrates and nitrites be evaluated?
  • Describe the clinical assessment of an infant overexposed to nitrates and nitrites.
  • Describe signs and symptoms of methemoglobinemia.
16. What laboratory tests can assist with diagnosis of nitrate/nitrite toxicity?
  • Identify laboratory test results that indicate methemoglobinemia.
17. How should patients exposed to nitrates and nitrites be treated and managed?
  • Describe treatment modalities in the management of methemoglobinemia caused by nitrate and nitrite toxicity.
18. How should patients exposed to nitrates and nitrites be treated and managed?
  • Describe treatment modalities in the management of methemoglobinemia caused by nitrate and nitrite toxicity.
19. What instructions should be given to patients' potentially overexposed to nitrates and nitrites?
  • Describe care advice the clinician can provide to patients to prevent overexposure to nitrates and nitrites
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