A husband and wife, both aged 30, come to the community health center for advice and evaluation prior to a month-long mission trip to central Africa. Both are in good health. She takes oral contraceptive pills and he is on no prescription medication. Review of their records shows that they have had all of the appropriate vaccinations for their ages, have completed a three dose hepatitis B series and had dT boosters 2 years ago. Their mission will involve building a school and health clinic in a rural area of Cameroon. How would you advise them regarding food safety?
A. Carbonated soft drinks served with ice cubes are considered safe to drink.
B. Locally grown oranges and bananas are safe to eat.
C. Water is safe to drink after filtering through an absolute 1 m filter.
D. Brushing teeth with untreated water is safe as long as it is not swallowed.
E. Salads are generally safer to eat than cooked meats.
Correct Answer: B Section: (none)
Explanation:
Encounters with persons traveling to other countries are common in primary care or community health settings. The advice and interventions provided are dependent on where the person is going, what he or she will be doing, and for how long he or she will be there. The most accessible and up-to-date source of this information in the United States is at the Centers for Disease Control web site, which provides detailed recommendations on vaccinations, health, and safety risks involved in overseas travel. In this series of questions, the travelers are going to the region of central Africa and, more specifically, to a rural area of Cameroon. This is an area of the world where polio remains a risk. As most Americans have not been vaccinated against polio since childhood, booster immunization against polio is recommended. The injectable polio vaccine is recommended as it does not carry with it the risk of vaccine-induced disease that the oral (live virus) vaccine does. Smallpox has been eliminated as a naturally occurring disease, although it remains of importance in bioterrorism discussions. The smallpox vaccine is not necessary for travel to any part of the world, but is used by the military or medical first responders who may be exposed in the event of a biowarfare attack. The traveling couple is up-to-date on their dT status with boosters within the past 2 years. They have completed a series of both MMR and hepatitis B, which is felt to confer lifetime immunity. Malaria prevention is an important consideration for travel to many areas of the developing world. Different regimens may be used depending on the area to which the travel will occur. All regimens, however, require the institution of prophylaxis prior to travel and the continuation of prophylaxis for up to 4 weeks after completion of travel. This is due to the life cycle of organisms that cause the disease. Prevention of malaria also involves attempts to reduce one's risk of exposure to the Ixodes mosquito which can transmit the disease. This mosquito tends to be more active early in the morning and at dusk, and less active in the middle of the day. Wearing long sleeved clothing, using mosquito nets, and insect repellent is important. DEET-containing insect repellents are recommended as the most effective products available and are safe when used appropriately. The most common cause of injury during travel is motor vehicle accidents. The risk of injury is higher in many developing countries than in the United States due to poor roads, poor vehicle maintenance, lack of seat belts, and other issues. Very cautious driving and avoidance of driving after dark may help to reduce the risk somewhat. While swimming is an ideal exercise in such hot climates as central Africa, freshwater lake swimming should be avoided due to the risk of exposure to schistosomiasis. The Schistosoma species that cause this disease are endemic in standing freshwater bodies. Swimming or bathing in salt water or chlorinated swimming pools is safer. Traveler's diarrhea and exposure to foodborne pathogens is a common cause of illness during travel to developing countries. The guideline with food is to cook it, peel it, purify it, or forget it. Fruits that can be peeled, such as oranges or bananas, are generally safe to eat. Carbonated beverages are also safe. However, ice cubes made from local water supplies are a common, and sometimes ignored, source of infection. Water purification can be accomplished by boiling or by filtering through an absolute 1 m filter and then purifying with iodine. Filtering alone does not provide adequate protection. Salads that are not made of carefully cleaned vegetables should be avoided and salad dressings may also be contaminated. Meats that are well cooked and served hot would be considered less likely to transmit an infection. Finally, brushing one's teeth with unpurified water carries a significant risk of transmission of waterborne illness and should be avoided. Purified water or bottled water should be used instead.
Question 142:
A husband and wife, both aged 30, come to the community health center for advice and evaluation prior to a month-long mission trip to central Africa. Both are in good health. She takes oral contraceptive pills and he is on no prescription medication. Review of their records shows that they have had all of the appropriate vaccinations for their ages, have completed a three dose hepatitis B series and had dT boosters 2 years ago. Their mission will involve building a school and health clinic in a rural area of Cameroon.
What advice would be the most appropriate to provide?
A. Swimming in freshwater lakes would be a recommended type of exercise in the hot African climate.
B. The mosquito that transmits malaria is most active in the middle of the day.
C. The risk of motor vehicle related injuries is much lower because there are fewer cars on the road.
D. Due to its potential toxicity, N, N diethylm-toluamide (DEET)-containing insect repellents should be avoided.
E. Medication for malaria prophylaxis should be started before their trip and continued after they return home.
Correct Answer: E Section: (none)
Explanation: Encounters with persons traveling to other countries are common in primary care or community health settings. The advice and interventions provided are dependent on where the person is going, what he or she will be doing, and for how long he or she will be there. The most accessible and up-to-date source of this information in the United States is at the Centers for Disease Control web site, which provides detailed recommendations on vaccinations, health, and safety risks involved in overseas travel. In this series of questions, the travelers are going to the region of central Africa and, more specifically, to a rural area of Cameroon. This is an area of the world where polio remains a risk. As most Americans have not been vaccinated against polio since childhood, booster immunization against polio is recommended. The injectable polio vaccine is recommended as it does not carry with it the risk of vaccine-induced disease that the oral (live virus) vaccine does. Smallpox has been eliminated as a naturally occurring disease, although it remains of importance in bioterrorism discussions. The smallpox vaccine is not necessary for travel to any part of the world, but is used by the military or medical first responders who may be exposed in the event of a biowarfare attack. The traveling couple is up-to-date on their dT status with boosters within the past 2 years. They have completed a series of both MMR and hepatitis B, which is felt to confer lifetime immunity. Malaria prevention is an important consideration for travel to many areas of the developing world. Different regimens may be used depending on the area to which the travel will occur. All regimens, however, require the institution of prophylaxis prior to travel and the continuation of prophylaxis for up to 4 weeks after completion of travel. This is due to the life cycle of organisms that cause the disease. Prevention of malaria also involves attempts to reduce one's risk of exposure to the Ixodes mosquito which can transmit the disease. This mosquito tends to be more active early in the morning and at dusk, and less active in the middle of the day. Wearing long sleeved clothing, using mosquito nets, and insect repellent is important. DEET-containing insect repellents are recommended as the most effective products available and are safe when used appropriately. The most common cause of injury during travel is motor vehicle accidents. The risk of injury is higher in many developing countries than in the United States due to poor roads, poor vehicle maintenance, lack of seat belts, and other issues. Very cautious driving and avoidance of driving after dark may help to reduce the risk somewhat. While swimming is an ideal exercise in such hot climates as central Africa, freshwater lake swimming should be avoided due to the risk of exposure to schistosomiasis. The Schistosoma species that cause this disease are endemic in standing freshwater bodies. Swimming or bathing in salt water or chlorinated swimming pools is safer. Traveler's diarrhea and exposure to foodborne pathogens is a common cause of illness during travel to developing countries. The guideline with food is to cook it, peel it, purify it, or forget it. Fruits that can be peeled, such as oranges or bananas, are generally safe to eat. Carbonated beverages are also safe. However, ice cubes made from local water supplies are a common, and sometimes ignored, source of infection. Water purification can be accomplished by boiling or by filtering through an absolute 1 m filter and then purifying with iodine. Filtering alone does not provide adequate protection. Salads that are not made of carefully cleaned vegetables should be avoided and salad dressings may also be contaminated. Meats that are well cooked and served hot would be considered less likely to transmit an infection. Finally, brushing one's teeth with unpurified water carries a significant risk of transmission of waterborne illness and should be avoided. Purified water or bottled water should be used instead.
Question 143:
A husband and wife, both aged 30, come to the community health center for advice and evaluation prior to a month-long mission trip to central Africa. Both are in good health. She takes oral contraceptive pills and he is on no prescription medication. Review of their records shows that they have had all of the appropriate
vaccinations for their ages, have completed a three dose hepatitis B series and had dT boosters 2 years
ago. Their mission will involve building a school and health clinic in a rural area of Cameroon.
Which of the following immunizations would be recommended prior to the trip?
A. MMR booster
B. dT booster
C. hepatitis B booster
D. injectable polio vaccine
E. smallpox vaccine
Correct Answer: D Section: (none)
Explanation:
Encounters with persons traveling to other countries are common in primary care or community health settings. The advice and interventions provided are dependent on where the person is going, what he or she will be doing, and for how long he or she will be there. The most accessible and up-to-date source of this information in the United States is at the Centers for Disease Control web site, which provides detailed recommendations on vaccinations, health, and safety risks involved in overseas travel. In this series of questions, the travelers are going to the region of central Africa and, more specifically, to a rural area of Cameroon. This is an area of the world where polio remains a risk. As most Americans have not been vaccinated against polio since childhood, booster immunization against polio is recommended. The injectable polio vaccine is recommended as it does not carry with it the risk of vaccine-induced disease that the oral (live virus) vaccine does. Smallpox has been eliminated as a naturally occurring disease, although it remains of importance in bioterrorism discussions. The smallpox vaccine is not necessary for travel to any part of the world, but is used by the military or medical first responders who may be exposed in the event of a biowarfare attack. The traveling couple is up-to-date on their dT status with boosters within the past 2 years. They have completed a series of both MMR and hepatitis B, which is felt to confer lifetime immunity. Malaria prevention is an important consideration for travel to many areas of the developing world. Different regimens may be used depending on the area to which the travel will occur. All regimens, however, require the institution of prophylaxis prior to travel and the continuation of prophylaxis for up to 4 weeks after completion of travel. This is due to the life cycle of organisms that cause the disease. Prevention of malaria also involves attempts to reduce one's risk of exposure to the Ixodes mosquito which can transmit the disease. This mosquito tends to be more active early in the morning and at dusk, and less active in the middle of the day. Wearing long sleeved clothing, using mosquito nets, and insect repellent is important. DEET-containing insect repellents are recommended as the most effective products available and are safe when used appropriately. The most common cause of injury during travel is motor vehicle accidents. The risk of injury is higher in many developing countries than in the United States due to poor roads, poor vehicle maintenance, lack of seat belts, and other issues. Very cautious driving and avoidance of driving after dark may help to reduce the risk somewhat. While swimming is an ideal exercise in such hot climates as central Africa, freshwater lake swimming should be avoided due to the risk of exposure to schistosomiasis. The Schistosoma species that cause this disease are endemic in standing freshwater bodies. Swimming or bathing in salt water or chlorinated swimming pools is safer. Traveler's diarrhea and exposure to foodborne pathogens is a common cause of illness during travel to developing countries. The guideline with food is to cook it, peel it, purify it, or forget it. Fruits that can be peeled, such as oranges or bananas, are generally safe to eat. Carbonated beverages are also safe. However, ice cubes made from local water supplies are a common, and sometimes ignored, source of infection. Water purification can be accomplished by boiling or by filtering through an absolute 1 m filter and then purifying with iodine. Filtering alone does not provide adequate protection. Salads that are not made of carefully cleaned vegetables should be avoided and salad dressings may also be contaminated. Meats that are well cooked and served hot would be considered less likely to transmit an infection. Finally, brushing one's teeth with unpurified water carries a significant risk of transmission of waterborne illness and should be avoided. Purified water or bottled water should be used instead.
Question 144:
A 19-year-old woman comes in for a routine obstetrical follow-up visit at 24 weeks' gestation. She is here
with her boyfriend, who is the father of the baby. She is wearing dark sunglasses in the examination room.
When you ask her to remove the glasses, you see that she has a bruise around her left eye. Her boyfriend
quickly states that she accidentally bumped into a door and she quietly nods in agreement.
Which of the following would be the most appropriate intervention at this time?
A. Provide the woman with information about domestic violence, including the phone number of shelters and counseling services.
B. Confront the boyfriend with your concerns regarding physical abuse.
C. No intervention is necessary, as partner violence usually stops while a woman is pregnant.
D. Encourage the woman to have ready access to a weapon to defend herself at home.
E. Report the boyfriend to Child Protective Services at the time of delivery of the baby, so that they can intervene before child abuse occurs.
Correct Answer: A Section: (none)
Explanation:
Domestic violence is an abuse of power in a relationship in which a more powerful person exerts inappropriate control or domination over a less powerful person. Abuse is not only physical, but also can be emotional, sexual, or economic. Intimidation and psychological abuse also occur and are used sometimes by batterers in place of physical violence. Domestic, or partner, violence occurs in all types of relationships, regardless of the gender of the partners. The risk of violence increases in many situations, which exaggerate the disparity in power in the relationship, such as illness or disability in one of the partners. Pregnancy, especially unintended pregnancy, may also increase the risk of battery. Laws regarding the reporting of domestic violence vary from state to state. Many states do not require the reporting of domestic violence when the abused is a competent adult. Marriage, in and of itself, does not prevent a partner from making a sexual abuse charge against the other partner. Management in the setting of partner violence can be difficult. Providing information and referrals to appropriate shelters and services is critical. Assisting with the development of emergency plans may be of benefit as well. Asking about the availability of weapons in the home is important, as up to half of female murder victims are killed by a current male partner or ex-partner. At this time, reporting to the Child Protective Services is inappropriate, as they cannot intervene. After the baby is born, however, any sign of child abuse should be immediately reported.
Question 145:
A 19-year-old woman comes in for a routine obstetrical follow-up visit at 24 weeks' gestation. She is here
with her boyfriend, who is the father of the baby. She is wearing dark sunglasses in the examination room.
When you ask her to remove the glasses, you see that she has a bruise around her left eye. Her boyfriend
quickly states that she accidentally bumped into a door and she quietly nods in agreement.
Which of the following statements about domestic violence is true?
A. All states require that physicians report partner violence to the police.
B. Domestic violence is rare in same sex couples.
C. A woman cannot make a sexual assault claim against her husband.
D. Domestic violence is less likely when one partner is ill or disabled.
E. Psychological intimidation without violence is considered a form of abuse.
Correct Answer: E Section: (none)
Explanation:
Domestic violence is an abuse of power in a relationship in which a more powerful person exerts inappropriate control or domination over a less powerful person. Abuse is not only physical, but also can be emotional, sexual, or economic. Intimidation and psychological abuse also occur and are used sometimes by batterers in place of physical violence. Domestic, or partner, violence occurs in all types of relationships, regardless of the gender of the partners. The risk of violence increases in many situations, which exaggerate the disparity in power in the relationship, such as illness or disability in one of the partners. Pregnancy, especially unintended pregnancy, may also increase the risk of battery. Laws regarding the reporting of domestic violence vary from state to state. Many states do not require the reporting of domestic violence when the abused is a competent adult. Marriage, in and of itself, does not prevent a partner from making a sexual abuse charge against the other partner. Management in the setting of partner violence can be difficult. Providing information and referrals to appropriate shelters and services is critical. Assisting with the development of emergency plans may be of benefit as well. Asking about the availability of weapons in the home is important, as up to half of female murder victims are killed by a current male partner or ex-partner. At this time, reporting to the Child Protective Services is inappropriate, as they cannot intervene. After the baby is born, however, any sign of child abuse should be immediately reported.
Question 146:
One of your responsibilities at the community health center is to serve as director of the tuberculosis (TB)
screening and prevention program.
You see a 2-week-old child for a routine wellbaby check-up. The mother is feeding him formula that she
prepares by mixing powdered formula with her home tap water that comes from a well. The local health
department considers the water to be nonfluoridated. Which of the following suggestions would be
appropriate?
A. She should start giving her baby a fluoride supplement now.
B. Powdered infant formula contains an adequate amount of fluoride, so a supplement will not be required as long as she continues formula feeding.
C. A fluoride supplement would be recommended starting at age 6 months.
D. She should take a fluoride supplement during subsequent pregnancies for the benefit of the fetus.
E. There is no risk to fluoride supplementation, so any dosage may be used.
Correct Answer: C Section: (none)
Explanation:
The widespread use of fluoride has been a major factor in the decline in the prevalence and severity of tooth decay in the United States. In most communities public water supplies are fluoridated. Supplementation is recommended by the Centers for Disease Control, American Academy of Pediatrics, American Academy of Family Physicians, and other authorities, for those who do not have access to fluoridated water. Fluoride supplementation can occur from both ingestion and from topical supplementation, such as in fluoride-containing toothpaste. Current guidelines recommend no supplementation until 6 months of age and then a dietary fluoride supplement of 0.25 mg/day from the age of 6 months to 3 years, 0.5 mg/day for ages 36 years, and 1.0 mg/day for ages 616 years for those persons who do not have access to fluoridated water. Current powdered infant formulas do not provide a significant amount of fluoride because of the risk of a child receiving too much fluoride if the formula is mixed with fluoridated water. The chronic ingestion of high levels of fluoride can result in fluorosis, a state of hypomineralization of tooth enamel. Studies have shown that fluoride supplements taken by pregnant women do not benefit their offspring.
Question 147:
One of your responsibilities at the community health center is to serve as director of the tuberculosis (TB)
screening and prevention program.
Which of the following statements regarding the management of an asymptomatic person with a positive
TB skin test is true?
A. Because of the development of resistant TB strains, recent converters both with and without symptoms should be treated with four drug therapy.
B. A pregnant woman with a positive skin test should not have a chest x-ray until after she delivers because of the risk of radiation exposure to the fetus.
C. A positive reaction in a person who has previously received a BCG vaccine should be considered a false positive and ignored.
D. Isoniazid should not be given to an asymptomatic person over the age of 50 because the risk of the medication is higher than the risk of developing active TB.
E. Isoniazid daily for 9 months is the preferred treatment for most asymptomatic persons with positive TB skin tests.
Correct Answer: E Section: (none)
Explanation:
Current guidelines for TB control emphasize testing of those who are at high risk for the development of TB and who would benefit from the treatment of a latent TB infection, if detected. Based on that principle, testing is encouraged in those who are at high risk and discouraged among those who are at low risk. Further, anyone who is at high risk for the development of TB and who tests positive should be offered treatment, regardless of age. The preferred testing modality for asymptomatic persons of all ages is the intradermal (Mantoux) method of testing with PPD. Multiple puncture tests (e.g., Tine) are not sufficiently accurate and should not be used. The test should be read at 4872 hours and the diameter of induration, not redness, should be measured and recorded. Previous BCG vaccination is not a contraindication to skin testing and a positive skin reaction should be used as an indication of TB infection when the tested person is at increased risk for infection or has medical conditions that increase the risk of the disease. Delayed-type hypersensitivity reactions may wane over time. This is especially a problem in older individuals. Repeating a PPD placement may result in a "booster" phenomenon, in which a person who initially tests negative develops a positive reaction. This increases the overall sensitivity of the testing process. Three cutoff points for the determination of a positive test are currently in use: 5 mm of induration is used for those who are at the highest risk of disease, such as those immunosuppressed from HIV or medications, or those recently exposed to TB; 10 mm induration is used as a positive result for persons who have an increased probability of infection (such as immigrants from endemic areas), who have clinical conditions that increase the risk for TB (such as injection drug users) or who are residents or employees in high-risk settings (nursing homes, hospitals, prisons, and so on); 15 mm is used as a cutoff for those who have no known risk factors. In question 46, ignoring the amount of redness and using only induration as the criteria for positive or negative, the nursing home resident (option B) is the only one with a positive test. All persons who test positive by a skin test should then have a chest x-ray to evaluate for evidence of pulmonary TB. In an asymptomatic person, sputum studies are not necessary to determine the need for treatment. Pregnant women should still get a chest x-ray, with appropriate abdominal shielding, as soon as feasible. As stated above, a history of BCG vaccination should not deter from the need for further evaluation and treatment of a positive test result. Age should also not be a determining factor in treating someone who is at risk for the development of TB. Currently, there are four acceptable treatment recommendations for latent TB infections. Daily isoniazid for 9 months is the most widely used regimen and has the highest level of recommendation because of its effectiveness, relative safety, ease of administration, and low cost. Twice-weekly isoniazid may also be used but should only be given as directly observed therapy, due to the fact that a missed dose of this regimen represents a substantial risk of under treatment. Rifampin alone or rifampin plus pyrazinamide are alternative regimens for use in certain, specified situations.
Question 148:
One of your responsibilities at the community health center is to serve as director of the tuberculosis (TB)
screening and prevention program.
Which of the following test results would be considered positive?
A. 10 mm redness and 3 mm induration in a man with HIV
B. 10 mm redness and 10 mm induration in a nursing home resident
C. 20 mm redness and 8 mm induration in a person with no known risk factors
D. 5 mm redness and 5 mm induration in a physician having a routine, annual screening
E. 10 mm redness and 5 mm induration in an immigrant from Southeast Asia
Correct Answer: B Section: (none)
Explanation:
Current guidelines for TB control emphasize testing of those who are at high risk for the development of TB and who would benefit from the treatment of a latent TB infection, if detected. Based on that principle, testing is encouraged in those who are at high risk and discouraged among those who are at low risk. Further, anyone who is at high risk for the development of TB and who tests positive should be offered treatment, regardless of age. The preferred testing modality for asymptomatic persons of all ages is the intradermal (Mantoux) method of testing with PPD. Multiple puncture tests (e.g., Tine) are not sufficiently accurate and should not be used. The test should be read at 4872 hours and the diameter of induration, not redness, should be measured and recorded. Previous BCG vaccination is not a contraindication to skin testing and a positive skin reaction should be used as an indication of TB infection when the tested person is at increased risk for infection or has medical conditions that increase the risk of the disease. Delayed-type hypersensitivity reactions may wane over time. This is especially a problem in older individuals. Repeating a PPD placement may result in a "booster" phenomenon, in which a person who initially tests negative develops a positive reaction. This increases the overall sensitivity of the testing process. Three cutoff points for the determination of a positive test are currently in use: 5 mm of induration is used for those who are at the highest risk of disease, such as those immunosuppressed from HIV or medications, or those recently exposed to TB; 10 mm induration is used as a positive result for persons who have an increased probability of infection (such as immigrants from endemic areas), who have clinical conditions that increase the risk for TB (such as injection drug users) or who are residents or employees in high-risk settings (nursing homes, hospitals, prisons, and so on); 15 mm is used as a cutoff for those who have no known risk factors. In question 46, ignoring the amount of redness and using only induration as the criteria for positive or negative, the nursing home resident (option B) is the only one with a positive test. All persons who test positive by a skin test should then have a chest x-ray to evaluate for evidence of pulmonary TB. In an asymptomatic person, sputum studies are not necessary to determine the need for treatment. Pregnant women should still get a chest x-ray, with appropriate abdominal shielding, as soon as feasible. As stated above, a history of BCG vaccination should not deter from the need for further evaluation and treatment of a positive test result. Age should also not be a determining factor in treating someone who is at risk for the development of TB. Currently, there are four acceptable treatment recommendations for latent TB infections. Daily isoniazid for 9 months is the most widely used regimen and has the highest level of recommendation because of its effectiveness, relative safety, ease of administration, and low cost. Twice-weekly isoniazid may also be used but should only be given as directly observed therapy, due to the fact that a missed dose of this regimen represents a substantial risk of under treatment. Rifampin alone or rifampin plus pyrazinamide are alternative regimens for use in certain, specified situations.
Question 149:
One of your responsibilities at the community health center is to serve as director of the tuberculosis (TB)
screening and prevention program.
Which of the following statements about testing for TB is true?
A. Multiple puncture (Tine) testing is recommended for children.
C. If a patient has a positive skin test, the next test is collection of sputum for acid-fast bacilli (AFB).
D. Any patient with 10 mm induration at the site of injection 72 hours after skin test placement should have a chest x-ray.
E. Repeat skin testing 2 weeks after a negative purified protein derivative (PPD) can increase the sensitivity of the test.
Correct Answer: E Section: (none)
Explanation:
Current guidelines for TB control emphasize testing of those who are at high risk for the development of TB
and who would benefit from the treatment of a latent TB infection, if detected. Based on that principle,
testing is encouraged in those who are at high risk and discouraged among those who are at low risk.
Further, anyone who is at high risk for the development of TB and who tests positive should be offered
treatment, regardless of age. The preferred testing modality for asymptomatic persons of all ages is the
intradermal (Mantoux) method of testing with PPD. Multiple puncture tests (e.g., Tine) are not sufficiently
accurate and should not be used. The test should be read at 4872 hours and the diameter of induration,
not redness, should be measured and recorded. Previous BCG vaccination is not a contraindication to skin testing and a positive skin reaction should be used as an indication of TB infection when the tested person is at increased risk for infection or has medical conditions that increase the risk of the disease. Delayed-type hypersensitivity reactions may wane over time. This is especially a problem in older individuals. Repeating a PPD placement may result in a "booster" phenomenon, in which a person who initially tests negative develops a positive reaction. This increases the overall sensitivity of the testing process. Three cutoff points for the determination of a positive test are currently in use: 5 mm of induration is used for those who are at the highest risk of disease, such as those immunosuppressed from HIV or medications, or those recently exposed to TB; 10 mm induration is used as a positive result for persons who have an increased probability of infection (such as immigrants from endemic areas), who have clinical conditions that increase the risk for TB (such as injection drug users) or who are residents or employees in high-risk settings (nursing homes, hospitals, prisons, and so on); 15 mm is used as a cutoff for those who have no known risk factors. In question 46, ignoring the amount of redness and using only induration as the criteria for positive or negative, the nursing home resident (option B) is the only one with a positive test. All persons who test positive by a skin test should then have a chest x-ray to evaluate for evidence of pulmonary TB. In an asymptomatic person, sputum studies are not necessary to determine the need for treatment. Pregnant women should still get a chest x-ray, with appropriate abdominal shielding, as soon as feasible. As stated above, a history of BCG vaccination should not deter from the need for further evaluation and treatment of a positive test result. Age should also not be a determining factor in treating someone who is at risk for the development of TB. Currently, there are four acceptable treatment recommendations for latent TB infections. Daily isoniazid for 9 months is the most widely used regimen and has the highest level of recommendation because of its effectiveness, relative safety, ease of administration, and low cost. Twice-weekly isoniazid may also be used but should only be given as directly observed therapy, due to the fact that a missed dose of this regimen represents a substantial risk of under treatment. Rifampin alone or rifampin plus pyrazinamide are alternative regimens for use in certain, specified situations.
Question 150:
The results of your study in question 43 find two risk factors associated with the development of the disease that you are studying. Risk factor "X" was found to have an odds ratio for the development of the disease of 2.5 (95% CI: 1.34.0). Risk factor "Y" had an odds ratio of 1.9 (95% CI: 1.13.3).
Which of the following statements is true?
A. Both risk factors X and Y are now proven to cause the disease.
B. Persons with risk factor X will have a worse prognosis than those with risk factor Y.
C. Risk factor X was more common in your study population than risk factor Y.
D. Both risk factors occurred more commonly in persons with the disease than in persons who did not have the disease.
E. For every 100 people with the disease, 25 will have risk factor X and 19 will have risk factor Y.
Correct Answer: D Section: (none)
Explanation: Explaination: All types of study designs have potential benefits and drawbacks and it is important to understand this when designing research or reviewing research reports. A cross-sectional study is one in which information is gathered from a certain population at one point in time with no follow-up period. This type of study is very useful for the determination of the prevalence of a disease or risk factor in a population at a certain point in time. Cross-sectional studies cannot determine cause and effect because there are no interventions being made and there is no follow-up. A case-control study is very useful and efficient at studying diseases that occur rarely. In a case-control study, persons with a disease are identified and then information is determined by looking back in time (i.e., retrospective review). Apopulation of those without the disease (controls) is also defined and studied in the same way.
The prevalence of a risk factor in the cases and controls can then be determined and compared. A case-control study cannot prove cause and effect, but it can be a powerful tool to determine risk factors that can generate hypotheses for further study. Acohort study is one in which a population is defined and then followed over time. A cohort study may be either prospective or etrospective. Cohort studies can be used to describe the incidence of diseases over time or to determine associations between predictors and outcomes. Cohort studies are inefficient for the study of rare outcomes, as a very large sample size would be required in order to find a few events. Aprospective, randomizedcontrolled trial is the gold standard study for determining the effect of a treatment or intervention. It is not the type of study that would be used to determine the prevalence of a disease in a population or to determine what risk factors are associated with the development of a disease. A meta-analysis is a systematic review of completed research studies. By evaluating similarly done studies, the meta-analysis technique can allow for an evaluation of a body of literature and can be used to increase the overall statistical power by creating a larger sample by combining studies.
The odds ratios given in question 44 show that both risk factors X and Y occurred more often in those with the disease (cases) than they did in those without the disease (controls). Neither of the CIs given cross 1, therefore, these are statistically significant findings. We cannot use this type of study to definitively prove cause and effect, therefore option A is false. While risk factor X had a higher odds ratio for the development of the disease than risk factor Y, no prognostic data are supplied and none can be inferred from the information given, therefore B is false. The odds ratios as given in this case compare the prevalence of a risk factor in the case group with the control group, not the prevalence of one risk factor compared to another. For this reason, we cannot say which risk factor is more common in the population and option C is false. No absolute numbers are presented in this question and therefore we cannot determine how often each of the risk factors occurs in our population, so E is false as well
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