Epidemiology and Preventative Medicine

Question 1

1.

A 53-year-old woman presents to the clinic for

her yearly physical. She is concerned about

heart disease because her mother recently had

a myocardial infarction at age 74 years and her

father passed away from heart disease at the age

of 63 years. She is a high school teacher who

smokes a half-pack of cigarettes per day. Her

blood pressure during the last two office visits

was 122/69 and 128/73 mm Hg. Her last mea-

sured HDL cholesterol level was 63 mg/dL.

On physical examination she is close to her

ideal body weight, and there are no abnormali-

ties. Which of the following is an appropriate

goal for this patient’s LDL cholesterol level?

(A) 100 mg/dL or less

(B) 130 mg/dL or less

(C) 160 mg/dL or less

(D) 200 mg/dL or less

(E) Direct therapy at raising the HDL cholesterol level, not reducing LDL cholesterol

Answer 1

1. The correct answer is C.

According to the

most recent report from the National Choles-

terol Education Program, the goal LDL cho-

lesterol level should take into account the indi-

vidual’s risk factors. This patient’s smoking

history is her only risk factor. In addition, her

relatively high HDL cholesterol level is protec-

tive. Therefore, she should be considered in

the group with a zero to one risk factor, and

her optimal LDL cholesterol level is 160 mg/

dL or less.

Question 2

2.

Investigators in a multisite trial are attempting

to determine how many patients are needed

before they break the blinding on their study

and analyze their data. They want to ensure

that there are enough patients to detect a dif-

ference between treatment and placebo if one

is actually there. It is a very costly trial, and the

study sponsors do not want to pay for more

work than is needed to prove a difference.

What calculation do the researchers need to

perform to determine how much funding to re-

quest from their sponsoring agency?

(A) Confidence interval

(B) P value

(C) Power

(D) Type I error

(E) Type II error

Answer 2

2. The correct answer is C.

Power is the proba-

bility that a study will fi nd a statistically signifi-

cant difference when one is actually there. It

relates directly to the number of subjects. A

power calculation is required in many grant

applications.

Question 3

3.

A 3-year-old boy is brought to the clinic by his

mother. She is concerned because the patient

has complained of a sore throat over the past 4

days. He is not in day care and has had no

known sick contacts. His 7-year-old sister is

currently healthy. The physician does a throat

swab for a rapid streptococcal test and sends a

second specimen for culture. Why does the

physician perform both tests?

(A) The culture may grow strains of bacteria

which are not detected by the rapid test

(B) The rapid streptococcal test and culture

both have high sensitivity

(C) The rapid streptococcal test and culture

both have high specificity

(D) The rapid streptococcal test has a high sen-

sitivity, while the culture has high specificity

(E) The rapid streptococcal test has a high

specificity, while the culture has high sensitivity

Answer 3

3. The correct answer is D.

Screening tests, such

as the rapid streptococcal test, have high sensi-

tivity and low specifi city. If the rapid strepto-

coccal test is positive, this indicates but does

not prove that the patient’s pharyngitis may be

due to group A streptococcal infection. If the

rapid streptococcal test is negative, then no fur-

ther testing is needed, because sensitive tests

effectively rule out disease. The throat culture

is highly specifi c and thus is able to confirm

(rule in) the disease. It may also indicate ex-

actly which organism is involved and narrow

treatment options.

Question 4

4.

A 34-year-old woman presents to a surgeon to

discuss the possibility of an elective splenec-

tomy. Several weeks ago she was diagnosed

with idiopathic thrombocytopenic purpura. At

that time her platelet count was 24,000/mm³.

Her primary care doctor started her on oral

prednisone, 50 mg/daily. At presentation today

she continues to have lower extremity pete-

chiae along with mucosal bleeding. Her repeat

platelet count is 29,000/mm³. Infection with

which of the following is most likely to result

in postsplenectomy sepsis?

(A) Haemophilus influenzae

(B) Moraxella catarrhalis

(C) Pseudomonas aeruginosa

(D) Staphylococcus aureus

(E) Viridans streptococci

Answer 4

4. The correct answer is A.

Asplenic patients are

at an increased risk of developing infections

compared to those patients with functional

spleens. These patients may develop over-

whelming postsplenectomy sepsis in which en-

capsulated organisms (including

Streptococcus pneumoniae, Neisseria meningitidis,

and Haemophilus influenzae) may cause fever,

lethargy, or upper respiratory infection that leads to

coma and death in up to 50% of patients. The

capsule that surrounds these organisms is an

antiphagocytic factor that permits these organ-

isms to survive and cause bacteremia. It is vital

for these patients to receive vaccination against

these encapsulated organisms to prevent the

development of postsplenectomy sepsis.

Question 5

5.

An investigator wishes to assess whether vacci-

nation increases the incidence of developmen-

tal diseases such as autism. He asks parents of

recently diagnosed cases about their child’s

vaccination history and compares their re-

sponses to those of parents of children who

have not been diagnosed with autism. What is

the most significant type of potential bias present

in this study design?

(A) Confounding bias

(B) Lead-time bias

(C) Length bias

(D) Measurement bias

(E) Recall bias

Answer 5

5. The correct answer is E.

Bias is any process

that causes results to systematically differ from

the truth. Recall bias occurs when cases and

controls remember information differently, that

is, when a recent diagnosis may have prompted

them to search their memory for recent events

that they feel may have contributed to the diag-

nosis. A false association may be found because

cases are more likely to remember recent vacci-

nations, not because of any pathological process.

Question 6

6.

A 65-year-old woman presents with 3 months

of unintentional weight loss, jaundice, and upper

abdominal pain that radiates to her back.

Her gallbladder is palpable on physical exami-

nation, and an ultrasound demonstrates dilated

bile ducts with no visible stones. Which of the

following is a known risk factor for this patient’s

condition?

(A) Chronic gastritis

(B) Diabetes insipidus

(C) Diabetes mellitus

(D) History of cholecystitis

(E) Smoking

Answer 6

6. The correct answer is E.

Patients with pancre-

atic cancer can present with weight loss, jaun-

dice, abdominal pain, dark urine, acholic

stools, and pruritus. On physical examination

the gallbladder or other abdominal mass is pal-

pable. Diagnosis is usually made with ultra-

sound with fi ndings of dilated bile ducts or visi-

ble mass, or CT scan which demonstrates the

pancreatic mass. The associated risk factors for

pancreatic cancer include smoking, chronic

pancreatitis, a fi rst-degree relative with pancre-

atic cancer, and high-fat diet.

Question 7

7.

A 21-year-old woman comes to the clinic for a

health check-up. She has been sexually active

since she was 17 years old and has never seen a

gynecologist before. The physician discusses

the importance of health screening with the

patient and performs a Papanicolaou (or Pap)

smear during the visit. Which of the following

is the most appropriate screening schedule

recommendation?

(A) Pap tests every 3 years beginning approxi-

mately 3 years after first intercourse or at

21 years of age

(B) Yearly Pap test and human papillomavirus

DNA testing beginning approximately 3

years after first intercourse or at 21 years of age

(C) Yearly Pap tests beginning approximately 3

years after first intercourse or at 21 years of age

(D) Yearly Pap tests beginning at menarche

and ending at menopause

(E) Yearly Pap tests once a patient is sexually

active or at 21 years of age

Answer 7

7. The correct answer is C.

The American Can-

cer Society and the US Preventive Services

Task Force recommend that cervical cancer

screening take place with yearly Pap tests ap-

proximately 3 years after beginning to have

vaginal intercourse, but no later than age 21

years. Women >30 years old who are at low risk

may then undergo Pap testing every 2–3 years

if they have had at least three normal consecu-

tive Pap tests prior to this time. Women >70

years old with three or more normal consecu-

tive Pap tests and no abnormalities within the

past 10 years may choose to stop having cervi-

cal cancer screening. Furthermore, women

who have had a total hysterectomy may stop

having cervical cancer screening unless they

had their hysterectomy due to cervical carci-

noma or preinvasive changes, or if they had a

hysterectomy without removal of the cervix.

Question 8

8.

A 78-year-old woman in otherwise good health

schedules a visit with her primary care physi-

cian because she has been experiencing blood

in her stool that she describes as “maroon.”

Her past medical history is signifi cant for psori-

asis and mild degenerative joint disease. In

thinking about the possible causes of her lower

gastrointestinal bleed, which of the following

lists is in order of most common to least common?

(A) Angiodysplasia > cancer/polyp > diverticulosis

(B) Angiodysplasia > diverticulosis > cancer/ polyp

(C) Cancer/polyp > diverticulosis > angiodysplasia

(D) Diverticulosis > angiodysplasia > cancer/ polyp

(E) Diverticulosis > cancer/polyp > angiodysplasia

Answer 8

8. The correct answer is E.

Diverticulosis ac-

counts for 42%–55% of lower gastrointestinal

bleeding, followed by cancer/polyps account-

ing for 8%–26%, and bleeding and angiodys-

plasia which accounts for 3%–12%. Other

causes include infl ammatory bowel disease

(2%–8%), anorectal disease (3%–9%), small

bowel disease (3%–5%), infectious colitis (1%–

5%), radiation colitis (1%–5%), and vas culitis

(13%).

Question 9

9.

A hypothetical study is created to examine the

effect of cigarette smoking on the development

of lung cancer. Patients who smoke at least one

pack per day are matched with an appropriate

group of nonsmokers. Ten years later, informa-

tion on the development of lung cancer is col-

lected, and the following data are observed.

What is the relative risk (risk ratio) of develop-

ing lung cancer for cigarette smokers?

(A) 1 / 20

(B) 19 / 100

(C) 1

(D) 20

(E) 20 / (80 / 99)

Answer 9

9. The correct answer is D.

This is an example of

a prospective cohort study. Using the letters

from the table, the relative risk is calculated as

[a / (a + b)] / [c / (c + d)] = 20 (rounded to the

nearest whole number), so smokers have 20

times the risk of nonsmokers of developing

lung cancer.

Question 10

10.

A study is performed to assess the relationship

of dietary cholesterol and myocardial infarc-

tion. Participants are assigned to either an ex-

perimental group, which eats a low-cholesterol

diet, or a control group, which eats a standard

American diet. Dietary analysis later reveals

that the group assigned a low-cholesterol diet

ended up also consuming less fat than the con-

trol group. In analyzing the relationship be-

tween dietary cholesterol and myocardial in-

farction, the amount of dietary fat consumed

represents what type of study characteristic?

(A) Confounding variable

(B) Enrollment bias

(C) Measurement bias

(D) Recall bias

(E) Self-selection bias

Answer 10

10. The correct answer is A.

A confounding vari-

able is a characteristic associated with both the

exposure of interest and the disease or condi-

tion being studied that may have an indepen-

dent effect on the relationship between the ex-

posure and disease of interest. In the study,

dietary cholesterol may infl uence the risk of

myocardial infarction, but dietary fat may also

influence myocardial infarction risk and thus it

is difficult to tell what proportion of decreased

risk is due to which dietary factor.

Question 11

11.

A 5-year-old boy is brought to his pediatrician

because he has been complaining of fatigue

and headache for several weeks. On examina-

tion he has enlarged lymph nodes and is sent

for a bone marrow biopsy. The biopsy shows

large lymphoblasts with prominent nucleoli

and light blue cytoplasm, and the patient is di-

agnosed with acute lymphoid leukemia. He is

treated with high-dose glucocorticoids, intrave-

nous and intrathecal methotrexate, cyclophos-

phamide, doxorubicin, and vincristine. He

achieves a full remission. Which of the follow-

ing accurately matches the causative drug with

the possible adverse effect that he may experi-

ence now or in the future?

(A) Cyclophosphamide: hearing loss

(B) Glucocorticoids: cataracts

(C) Glucocorticoids: peripheral neuropathy

(D) Methotrexate: cognitive deficit

(E) Methotrexate: pulmonary fibrosis

Answer 11

11. The correct answer is B.

Chronic use of high-

dose steroids, as those used to treat acute lym-

phoid leukemia, may result in formation of bi-

lateral cataracts. Patients should be monitored

closely, particularly those that are school-aged,

because they may suffer from visual defects.

Question 12

12.

A 72-year-old man presents to his primary phy-

sician with complaints of fatigue, weight loss,

dyspnea on exertion, abdominal pain, and dark

blood in the stool. Although the patient had a

negative sigmoidoscopy on routine examina-

tion 6 months ago, colon cancer is strongly sus-

pected. Which is the best diagnostic modality

to use in this patient?

(A) Colonoscopy

(B) CT of the abdomen

(C) Double contrast barium enema

(D) Sigmoidoscopy

(E) Upper gastrointestinal series

Answer 12

12. The correct answer is A.

Colonoscopy is the

method of choice in this individual because the

lesion is most likely right sided, as suggested by

a negative sigmoidoscopy 6 months ago. With

colonoscopy, the entire large bowel can be visu-

alized, and it also allows the biopsy of lesions or

removal of polyps found on examination.

Question 13

13.

A 23-year-old woman presents to her gynecolo-

gist for a refill of her birth control prescription.

She denies recent sexual activity, although she

has been sexually active in the past and is cur-

rently using oral contraceptives to regulate her

menstrual cycle and control acne. Her last Pap

smear was 13 months prior. She says that her

31-year-old sister just went for her annual ex-

amination and was told that she did not need

an annual Pap smear. In which of the follow-

ing populations may an annual Pap smear be

deferred?

(A) HIV-positive women with no documented

history of cervical pathology

(B) Women >30 years old who have had three

consecutive conventional cytology negative Pap smears

(C) Women >60 years old who are positive for

human papillomavirus DNA

(D) Women who have had a hysterectomy and

documented cervical intraepithelial neoplasia II/III

(E) Women with 2 or more negative conven-

tional cytologic studies

Answer 13

13. The correct answer is B.

Current recommen-

dations are that a Pap smear be done once ev-

ery 1–3 years based on risk factors and cytology

method. In 2003 the American College of Ob-

stetricians and Gynecologists recommended

that women younger than 30 years be screened

annually, regardless of liquid or conventional

culture method. However, the US Preventative

Services Task Force recommends that women

of any age extend time between screening to

every 2–3 years if they have no risk factors and

have had three or more consecutive negative

cytologic studies by conventional method. Risk

factors include diethylstilbestrol exposure in

utero, prior cervical intraepithelial neoplasia

II/III or abnormal Pap smear, smoking, or im-

munocompromised state. A gonorrhea and

chlamydia screen may be recommended if the

patient is sexually active.

Question 14

14.

A 53-year-old man presents to his physician’s

office in tears. A close friend of his was recently

diagnosed with lung cancer, so the patient is

concerned because he has smoked a pack of

cigarettes daily for 39 years and his father died

of lung cancer. He recalls that he had a pro-

ductive cough 2 months prior that resolved af-

ter several weeks. He is concerned that he

might have lung cancer or might develop it in

the future. He asks whether there is a test he

can undergo on a regular basis to “catch the

cancer early.” Which of the following is the

most appropriate screening test for this patient?

(A) Annual x-ray of the chest

(B) Biannual low-dose helical CT scan

(C) Biannual sputum cytology

(D) Bronchoscopy

(E) None; advise the patient to quit smoking

and monitor for clinical signs of lung cancer

Answer 14

14. The correct answer is E.

Lung cancer is not

hereditary but is based on environmental expo-

sures to radon, asbestos, or cigarette smoke.

There is evidence to suggest that a patient’s risk

of developing lung cancer from tobacco expo-

sure decreases somewhat after the patient quits

smoking, depending on the patient’s smoking

history and medical status. The patient should

be counseled about smoking cessation, and ap-

propriate adjustments to medications should

be made if the patient is started on nicotine

gum or patch. In 2004 the U.S. Preventive Ser-

vices Task Force determined that “the evidence

is insuffi cient to recommend for or against

screening asymptomatic persons for lung can-

cer with either low dose computed tomogra-

phy, plain chest radiographs, sputum cytology,

or a combination of these tests.”

Question 15

15.

A 34-year-old man was diagnosed with type 2

diabetes mellitus as a child and has been pre-

senting for annual examinations since he was

in his early 20s. Which of the following screen-

ing tests is indicated more than once a year?

(A) Hemoglobin A1c

(B) Lipid profile

(C) Microalbuminuria

(D) Ophthalmologic examination

(E) Podiatry examination

(F) Serum fructosamine

Answer 15

15. The correct answer is A.

A hemoglobin A1c

level should be checked every 3 months to as-

sess the average serum glucose levels over that

time period. This is important in adjusting med-

ications and to follow the disease progression.

Question 16

16.

Laboratory researchers are developing a sali-

vary test for systemic cocaine. The manufac-

turer has requested that their ideal test will

miss very few, if any, people who have used co-

caine recently. Which of the following best de-

scribes what the manufacturer wants in epide-

miologic terms?

(A) Of cocaine users, the probability of testing

positive is very high

(B) Of people with a negative test, the proba-

bility of having used cocaine is very low

(C) Of people with a positive test, the probabil-

ity of having used cocaine is very high

(D) Of those not using cocaine, the probability

of testing negative is very low

Answer 16

16. The correct answer is A.

This answer describes

sensitivity. A highly sensitive test will rarely

miss people with the disease, and is thus a good

“rule-out” if negative. It is calculated mathe-

matically by dividing the number of those with

disease (or in this case, condition of interest)

and a positive test by the total number of peo-

ple with disease (or condition).

Question 17

17.

The cut-off value of normal prostate-specific

antigen levels is 4.0 ng/dL. If this value were to

be decreased to 3.7 ng/dL, the sensitivity and

specificity of the test for detecting prostate can-

cer will change. How would lowering the nor-

mal value of prostate-specific antigen in cancer

screening alter the number of false-positives

and false-negatives?

(A) Decrease both false-positives and false-negatives

(B) Decrease the number of false-negatives

and increase the number of false-positives

(C) Increase both false-positives and false-negatives

(D) Increase the number of false-negatives and

decrease the number of false-positives

(E) It would not change either parameter

Answer 17

17. The correct answer is B.

By lowering the cut-off

value, the number of people who will be diag-

nosed as having prostate cancer will increase.

This will decrease the number of false-negatives

(those who are told they do not have the disease

when they in fact do), and increase the number

of false-positives (those told they have the dis-

ease when they in fact do not).

Question 18

18.

A 57-year-old man comes to his primary care

physician complaining of increasing fatigue in

the past few months. He is unable to walk up

to his third fl oor apartment without becoming

short of breath. His WBC count is 5000/mm³,

hemoglobin is 10.2 g/dL, hematocrit is 37%,

platelet count is 221,000/mm³, and mean cor-

puscular volume is 70 fL. Additionally, the pa-

tient’s stool is guaiac-positive. The physician

sends the patient for colonoscopy, which is

shown in the image. With the new diagnosis,

the patient is concerned about his 35-year-old

son. What recommendations should the physi-

cian make regarding the son?

(A) His son should be screened with a colonos-

copy every 1–2 years starting now

(B) His son should be screened with a colonos-

copy every 5 years starting at age 40 years

(C) His son should be screened with a colonos-

copy every 5 years starting at age 50 years

(D) His son should be screened with a colonos-

copy every 5 years starting now

(E) His son should be screened with a fecal

occult blood test every year starting at age

50 years

Answer 18

18. The correct answer is B.

The patient in the

question has colon cancer. His presentation

and blood tests are consistent with microcytic

anemia. The colonoscopy reveals an exophytic

mass in the colon consistent with adenocarci-

noma. The current American Gastroenterolog-

ical Association guidelines state that people

with fi rst-degree relatives diagnosed with colon

cancer or adenomatous polyps diagnosed at

<60 years of age should be screened with a

colonoscopy every 5 years beginning at age 40,

or 10 years younger than the earliest diagnosis

in the family, whichever comes fi rst. Since the

patient was diagnosed with colon cancer at the

age of 57 years, the son should be screened at

the age of 40 since that is >10 years younger

than his father’s diagnosis.

Question 19

19.

A study to evaluate the relationship of caffeine

consumption and gastric cancer is conducted.

Patients with gastric cancer are enrolled in the

study, and researchers seek to match each pa-

tient with an individual similar to him or her

in as many ways as possible, except that the

control subject does not have a diagnosis of

gastric cancer. Both case and control subjects

are then surveyed to examine possible expo-

sures, including caffeine exposure. Of 500 pa-

tients, 250 are cases and an equal number are

controls. Of cases, 150 met the minimum caf-

feine consumption limit set by the study,

whereas only 50 controls did. What is the odds

ratio defi ning the relationship of exposure and

disease in this study?

(A) 1/6

(B) 0.375

(C) 1.7

(D) 2.7

(E) 3

(F) 6

Answer 19

19. The correct answer is F.

The odds ratio can be

calculated as (number exposed who have dis-

ease/number not exposed who have disease)/

(number exposed without disease/number not

exposed without disease), which in this sce-

nario yields (150/100)/(50/200) = 6. Odds ratios

are used in studies employing a case-control de-

sign (typically retrospective) and can be used as

an approximation of the relative risk only when

the disease being studied is very rare in the over-

all population from which the controls are

drawn.

Question 20

20.

A 4-year-old girl is brought by her mother to

the pediatrician because of a rash. She had a

fever and headache yesterday, and this morn-

ing broke out in a rash on her torso. The le-

sions are erythematous macules and vesicles in

different stages, distributed diffusely over her

trunk but most prominent on her left upper

chest and right flank. A diagnosis of chicken-

pox is made. Of note, there is a 16-year-old sib-

ling in the household who has not been vacci-

nated and has never had chickenpox. Which

of the following interventions will most suc-

cessfully prevent infection of susceptible

household contacts?

(A) Administration of intravenous acyclovir to

the patient

(B) Administration of oral acyclovir to the pa-

tient and household contacts

(C) Administration of vaccine and intramuscu-

lar varicella zoster immunoglobulin to

household contacts

(D) Administration of varicella vaccine to

household contacts

(E) No prophylaxis is necessary for household

contacts under age 25 years

Answer 20

20. The correct answer is D.

Varicella develops in

approximately 90% of susceptible household

contacts with signifi cant exposure. The vac-

cine, if given in the fi rst 3 days postexposure,

has been shown to prevent or modify the

course of illness in susceptible individuals. Sev-

enty-eight percent of adults seroconvert after

the fi rst dose; a cumulative 99% have con-

verted after the second dose.

Question 21

21.

A researcher wants to examine the relationship

of childhood cigarette exposure and subse-

quent asthma diagnosis. She designs a study in

which telephone interviewers contact ran-

domly chosen study participants with questions

regarding their childhoods and whether they

have asthma. Which type of study is this re-

searcher conducting?

(A) Case-control study

(B) Cohort study

(C) Cross-sectional study

(D) Metaanalysis

(E) Randomized controlled clinical trial

Answer 21

21. The correct answer is C.

Cross-sectional study

involves assessing variables at one given point

in time. Exposure and outcome are measured

simultaneously. It is useful for estimating dis-

ease prevalence and distribution within a pop-

ulation, but cannot establish causal relation-

ships, although these can be estimated with

chi-square analysis.

Question 22

22.

A researcher studying the impact of drug A on

hypertension assigns patients randomly to ei-

ther a treatment group or a control group. The

treatment group receives drug A, and the con-

trol group receives the current standard medi-

cation. Neither the study staff nor the patients

know what drug a given patient is receiving.

What type of study is the researcher conducting?

A) Case-control study

(B) Cohort study

(C) Cross-sectional survey

(D) Meta-analysis

(E) Randomized controlled clinical trial

Answer 22

22. The correct answer is E.

The researcher is

conducting a randomized controlled clinical

trial. Patients have been assigned randomly to

minimize bias. In this instance, the control

group is not receiving placebo; this does not

mean that this study is not a randomized con-

trolled clinical trial. For diseases and condi-

tions where the patient would be unduly

harmed by remaining untreated for the study

duration, it is customary to compare the study

drug or procedure to the current standard of

care for that disease or condition and not to

placebo. In this scenario, the study is also dou-

ble blinded because neither the study staff nor

patients know who receives what treatment.

Question 23

23.

A 34-year-old G4P3 woman presents to the

clinic with her husband desiring contracep-

tion. She has a past medical history of endo-

metriosis, for which she was prescribed oral

contraceptive pills as a teenager. Her past sur-

gical history includes an exploratory laparo-

tomy with laser ablation and resection of an

endometrioma at the age of 26 years as part of

an infertility work-up. She subsequently deliv-

ered three healthy children with no obstetric

complications. She denies any history of sexu-

ally transmitted disease and is sexually active

with her husband only. She states that she and

her husband do not desire any more children.

Which of the following is the most effective

contraceptive option and will therefore have

the lowest failure rate for this couple?

(A) Bilateral tubal ligation

(B) Bilateral vasectomy

(C) Combination oral contraceptive pill

(D) Diaphragm

(E) Intrauterine device

(F) Male condom

(G) Progestin-only oral contraceptive pill

Answer 23

23. The correct answer is B.

Bilateral male steril-

ization has theoretical and actual failure rates

of 0.15% and 0.1%, respectively, the lowest fail-

ure rates of any contraceptive option other

than complete abstinence. Unlike nonsurgical

contraceptive options, however, sterilization is

a permanent intervention and thus must be

preceded by suffi cient patient counseling. This

couple states that they do not desire any fur-

ther children, and thus while other contracep-

tive options could be prescribed, male steriliza-

tion remains the most effective option for them.

Question 24

24.

A researcher wants to study outcomes after ex-

posure to a particular drug. Participants will be

randomized into an exposed group and an un-

exposed group, and observations will be made

and data collected regarding the outcome of

each study participant. What does it mean for

the researcher to “single-blind” the study?

(A) Neither participants nor researchers know

whether a participant is assigned to the

study group or the control group

(B) Participants do not know if they are as-

signed to the study group or the control group

(C) Researchers do not know if a participant is

assigned to the study group or the control group

(D) Researchers do not know if the drug will

be efficacious

(E) Researchers do not know if the drug will be safe

Answer 24

24.

The correct answer is B. A “blinded” or “sin-

gle-blinded” study is one in which the partici-

pant does not know whether he or she is an ex-

perimental subject or a control subject.

“Double blinded” means that neither the par-

ticipants nor the researchers know who is as-

signed to which group.

Question 25

25.

A 27-year-old primigravida at 35 weeks’ gesta-

tion presents to her obstetrician because of a

long bump on her leg. She denies ever having

had a problem like this before. Her pregnancy

has been without complication. Prior to her

pregnancy she used only barrier protection.

Age of menarche was 12 years. She denies any

travel history and has been “mainly in bed”

since 1 week ago. Her pulse is 78/min, respira-

tory rate is 10/min, and temperature is 37.2°C

(99°F). On physical examination she in no

acute distress. Her lungs are clear to ausculta-

tion bilaterally, and her extremities are warm

and well perfused. Examination of the extremi-

ties reveals a long, fi rm, cord-like mass on the

lateral aspect of her left leg. It is subcutaneous,

erythematous, and tender. Compression ultra-

sonography of the lower extremity shows nor-

mal compressibility and normal Doppler flow.

Which of the following is the most appropriate

management?

(A) Advise the patient to take heparin if the

mass does not resolve

(B) Advise the patient to take warfarin if the

mass does not resolve

(C) Advise the patient to use warm compresses

and elevate the affected area

(D) Reassure the patient that ibuprofen is safe

in pregnancy

Answer 25

25. The correct answer is C.

This patient is suffering

from a superficial thrombosis, which does not re-

quire anticoagulation. This is a non-life-threaten-

ing condition and it does not increase the risk of

pulmonary embolus. First-line treatment is warm

compresses applied so the clot does not extend to

the deep veins. Treatment should last for 5–7 days.

Question 26

26.

A group of researchers at the state university

conducts a study investigating the relationship

between cigarette smoking and vascular de-

mentia. Retrospective data are obtained from a

cross-sectional survey on smoking habits and

later neurologic symptoms as observed by close

relatives. Researchers fi nd that smokers are

four times as likely as nonsmokers to suffer

from vascular dementia and that they also con-

sume twice as much alcohol as nonsmokers in

their study. Which of the following statements

could be accurately made on the basis of the

available information?

(A) Both alcohol and cigarettes independently

increase the risk for vascular dementia

(B) Drinking alcohol increases the risk for vascular dementia

(C) Smokers are more likely to drink than non-smokers

(D) Smoking cigarettes increases the risk for

vascular dementia

(E) Smoking increases the risk for vascular dementia, but alcohol has no effect on the risk

Answer 26

26. The correct answer is C.

Without controlling

for the difference in alcohol consumption be-

tween smokers and nonsmokers, it is difficult

to know which is responsible for the observed

difference in vascular dementia incidence.

What can be defi nitively stated is that, among

the study population, smokers are more likely

to be drinkers than nonsmokers.

Question 27

27.

A cardiologist wishes to compare outcomes of

medical management and cardiac catheteriza-

tion for myocardial infarct presentation to the

emergency department. She conducts a litera-

ture search and statistically combines the data

from seven published studies. Which of the fol-

lowing is an advantage of this type of study?

(A) Able to overcome poor study design in individual studies

(B) Less bias than other types of studies

(C) May allow detection of small differences

between outcomes

(D) Pooled data already represent sufficiently

similar populations and interventions

(E) Statistical analysis of pooled data is

straightforward

Answer 27

27. The correct answer is C.

The type of study de-

scribed is known as a meta-analysis. Combin-

ing results from several studies enhances statis-

tical precision and may allow a statistically

significant result from the combined analysis

that did not reach a significant level when each

smaller study was analyzed alone.

Question 28

28.

A 26-year-old G2P1 woman at 19 weeks’ gesta-

tion comes into the clinic for her scheduled

prenatal visit. She complains only of mild fa-

tigue. Past obstetric history is notable for a

prior pregnancy 2 years ago. Although that

pregnancy was without complications, the

child has significant developmental delay. The

patient takes no medications other than prena-

tal vitamins. Her family history is significant

for two maternal aunts with mental retarda-

tion. The patient is an only child. Physical ex-

amination reveals a well-developed gravid fe-

male in no acute distress. The uterus is

appreciated well above the pubic symphysis. A

triple screen test is ordered. What other test is

most appropriate to order at this visit?

(A) α-Fetoprotein level

(B) Amniocentesis

(C) Biophysical profile

(D) Chorionic villus sampling

(E) Nonstress test

(F) Percutaneous umbilical blood sampling

(G) Ultrasound

Answer 28

28. The correct answer is G.

Ultrasound may be

done at 18–20 weeks’ gestation to determine

gestational age if it cannot be determined by

last menstrual period. It may also be done to

survey fetal anatomy, amniotic fluid volume,

and placental location. As she gave a history

significant for possible birth defects, ultrasound

is likely to be helpful in this patient. She would

also benefi t from a visit to a genetic counselor

in addition to the ultrasound.

Question 29

29.

A 55-year-old G2P2 woman presents to the gy-

necology clinic for a routine check-up; her last

check-up was 3 years ago. Both of her children

were delivered by spontaneous vaginal delivery

without complications. She is currently sexu-

ally active with her husband and has no other

partners. She says she has an occasional glass

of wine with dinner and has smoked about half

a pack of cigarettes per day for the past 25

years. She has no family history of cancer,

heart disease, or diabetes. Breast examination

reveals no masses. Pelvic and bimanual exami-

nations are likewise within normal limits. A

sample is taken for a Pap smear without caus-

ing significant cervical bleeding. Mammogra-

phy from 3 years ago shows no suspicious

masses. A Pap smear from 3 years prior showed

no atypical cells. Laboratory tests show:

WBC count: 7500/mm³

Hemoglobin: 12.4 g/dL

Platelet count: 220,000/mm³

Total cholesterol: 195 mg/dL

LDL cholesterol: 125 mg/dL

HDL cholesterol: 45 mg/dL

What is the most appropriate next step in management?

(A) Endometrial biopsy

(B) Mammography

(C) Measure cancer antigen-125 level

(D) Transvaginal ultrasound

(E) X-ray of the chest

Answer 29

29. The correct answer is B.

The recommenda-

tions for mammography are screening every

year when the patient is 50 years old or older.

Question 30

30.

A 48-year-old man is admitted to the hospital

with fulminant hepatitis leading to liver failure

following consumption of raw oysters. He is

treated with immediate liver transplantation,

which is performed successfully. Following a

prolonged hospital stay he is discharged in ex-

cellent condition. In addition to his antirejec-

tion medications, which of the following is rec-

ommended for prophylaxis in this patient?

(A) Acyclovir

(B) Ketoconazole

(C) Niacin

(D) Nystatin swish and swallow

(E) Trimethoprim-sulfamethoxazole

Answer 30

30. The correct answer is E.

Trimethoprim-sulfame-

thoxazole is indicated as prophylactic treatment

against Pneumocystis jiroveci

pneumonia in immunosuppressed patients for the duration of immunosuppression.

Question 31

31.

A 17-year-old girl with a history of refractory

B-lymphocyte lymphoma undergoes a bone

marrow transplant from a matched unrelated

donor. On day 19 posttransplant an erythema-

tous, maculopapular rash is noted on her trunk

and extremities. Within 3 days she has devel-

oped diffuse bullae and severe diarrhea. She

requires vigorous hydration and narcotic pain

medication. Jaundice is noted, and her serum

total bilirubin is 10 mg/dL. Which of the fol-

lowing interventions gives the patient the best

chance of survival?

(A) Hepatic transplantation

(B) The patient has little chance of survival;

donor T lymphocytes should have been re-

moved from the stem cells prior to infusion

(C) Total body irradiation to remove the graft

(D) Treatment with monoclonal antibodies directed at T lymphocytes

(E) Treatment with thalidomide

Answer 31

31. The correct answer is D.

The patient is experi-

encing severe acute graft-versus-host disease

(GVHD), caused by allogeneic T lymphocytes

that were transferred with the donor’s stem

cells reacting with antigenic targets on her own

cells. Acute GVHD is usually experienced

within 4 weeks of the initial transplant. It is

characterized by rash, diarrhea, and decreased

liver function, and is graded from I through IV.

Significant GVHD develops in up to 60% of

patients receiving stem cells from unrelated

donors, and 30% of those receiving transplants

from siblings. It is usually treated with gluco-

corticoids, antithymocyte globulin, or mono-

clonal antibodies targeted against T lympho-

cytes.

Question 32

32.

A 52-year-old man comes to the clinic worried

because he saw a television program on the in-

creased risk of thyroid cancer in people ex-

posed to radiation as a child. He says that when

he was a boy, his dermatologist used radiation

therapy to treat chronic cystic acne. After the

history and physical examination are com-

pleted, the physician shows the patient a jour-

nal article that details a case-control study

about the risk of radiation exposure and subse-

quent thyroid cancer. A table from the study is

shown in the image. What conclusions can be

drawn from this study?

(A) The odds of having been exposed to radia-

tion as a child are 0.33 times greater for

someone with thyroid cancer than for

someone without thyroid cancer

(B) The odds of having been exposed to radia-

tion as a child are 1.5 times greater for

someone with thyroid cancer than for

someone without thyroid cancer

(C) The odds of having been exposed to radia-

tion as a child are 3 times greater for some-

one with thyroid cancer than for someone

without thyroid cancer

(D) The relative risk of having been exposed to

radiation as a child is 1.5 times greater for

someone with thyroid cancer than for

someone without thyroid cancer

(E) The relative risk of having been exposed to

radiation as a child is 3 times greater for

someone with thyroid cancer than for

someone without thyroid cancer

Answer 32

32. The correct answer is C.

In a case-control

study, an odds ratio is used to compare the ef-

fects of exposure between two groups. An odds

ratio is a measure of the odds that a person

with a specifi c condition has been exposed to a

certain risk factor divided by the odds that the

control group has been exposed. To calculate

the odds ratio, take the number exposed to the

disease divided by the number not exposed to

the disease, divided by the number exposed

without the disease divided by the number not

exposed without the disease. In this case, this

equates to (100 / 50) / (200 / 300), which

equals 3.

Question 33

33.

A 75-year-old man presents to his physician

with a 4-week history of exertional shortness of

breath. He worked as a pipe fitter for 45 years,

retiring 5 years ago. He denies chest pain, pal-

pitations, swelling in his legs, cough, hemopty-

sis, and weight loss. He smokes 1 pack per day

and has done so for the past 45 years. His tem-

perature is 36.7°C (98°F), pulse is 85/min,

blood pressure is 120/80 mm Hg, respiratory

rate is 14/min, and oxygen saturation is 99% on

room air. Physical examination is unremark-

able. Pulmonary function testing shows a mild

restrictive pattern with a normal diffusing ca-

pacity. X-ray of the chest shows linear opacities

at the lung bases and pleural plaques. Which

of the following is the most appropriate intervention?

(A) High-resolution CT of the chest

(B) Pulmonary function testing

(C) Repeat sputum cytology every 6 months

(D) Repeat x-ray fi lms of the chest every 6 months

(E) Smoking cessation

Answer 33

33. The correct answer is E.

Squamous cell carci-

noma and adenocarcinoma are the most com-

mon cancers associated with asbestos exposure,

which is associated with a sixfold increase in

lung cancer. This risk increases to 59-fold with

a concurrent smoking history. Therefore, the

most appropriate intervention in this patient is

smoking cessation. The average time between

the exposure to asbestos and the development

of lung cancer is 15 years. The patient has

signs and symptoms of asbestosis (shortness of

breath, restrictive pattern on pulmonary func-

tion testing, and a chest radiograph showing

linear opacities and pleural plaques). Specific

therapy, such as steroids or immunosuppressive

or antifi brotic agents, may also be warranted.

Question 34

34.

A male infant is brought to his pediatrician’s of-

fice for a well-child visit. He has a temperature

of 37.2°C (99°F) and clear nasal drainage.

Physical examination is otherwise unremark-

able. The infant is able to lift his head when

prone, track past the midline, and coo. His im-

munization record indicates that he received

his first hepatitis B vaccination at birth. Assum-

ing this child is developing normally, which

vaccines should this infant receive today?

(A) Hepatitis B and diphtheria-tetanus-pertussis only

(B) Hepatitis B, diphtheria-tetanus-pertussis,

and inactivated poliomyelitis

(C) Hepatitis B, diphtheria-tetanus-pertussis,

Haemophilus influenzae type b, inactivated

poliomyelitis, and pneumococcal conjugate

(D) Hepatitis B only

(E) None; schedule a return visit when the

child’s nasal congestion subsides, and ad-

minister the immunizations then

Answer 34

34. The correct answer is C.

The developmental

milestones this infant has reached suggest that

the child is 2 months old. A mild illness and

low-grade fever are not contraindications to re-

ceiving immunizations. The standard immuni-

zations given at the 2-month visit are hepatitis

B (Hep B) vaccine, diphtheria-tetanus-pertussis

(DTaP) vaccine, Haemophilus influenzae type

b (HiB) vaccine, inactivated poliomyelitis vac-

cine (IPV), and pneumococcal conjugate vac-

cine (PCV). The Hep B vaccine is a hepatitis

B surface antigen. The DTaP vaccine is a com-

bined vaccine against diphtheria, tetanus, and

pertussis. The diphtheria and tetanus portions

are toxoids, whereas the pertussis is an acellu-

lar pertussis component (DTaP vs. DTP). The

HiB vaccine contains killed portions of the

H. influenzae type B bacterium. IPV contains

three forms of inactivated polio virus. PCV is

the pneumococcal conjugate vaccine contain-

ing seven strains of

Streptococcus pneumoniae.

Question 35

35.

A 28-year-old G1P0 woman is 37 weeks preg-

nant. Her maternal prenatal screening was un-

remarkable, and her pregnancy has been un-

eventful thus far. She has several questions

regarding what to expect for herself and her

child during the fi rst few days after delivery.

Which of the following vaccines is indicated

during the postnatal period?

(A) Diphtheria, pertussis, and tetanus vaccine

(B) Haemophilus influenzae B vaccine

(C) Hepatitis B vaccine

(D) Inactivated polio vaccine

(E) Measles, mumps, and rubella vaccine

(F) Varicella vaccine

Answer 35

35. The correct answer is C.

Hepatitis B vaccine

is the only childhood vaccine that is to be

given upon delivery. This vaccine is given

again when the infant is 2 months old.

Question 36

36.

A 29-year-old man approaches a physician to

ask about his target cholesterol level. He has

no personal or family history of cardiac disease.

He does not smoke, denies high blood pressure

and diabetes, and has a body mass index of 26

kg/m². The man says he has heard there are

multiple types of cholesterol, but wants to

know just one marker that will be the best for

him to follow. The physician advises that fol-

lowing the LDL cholesterol would be a reason-

able option. At what LDL cholesterol level

should pharmacologic therapy be considered?

(A) LDL cholesterol >100 mg/dL

(B) LDL cholesterol >130 mg/dL

(C) LDL cholesterol >160 mg/dL

(D) LDL cholesterol >190 mg/dL

(E) LDL cholesterol >200 mg/dL

Answer 36

36. The correct answer is D.

The National Cho-

lesterol Education Program guidelines recom-

mend that those with low risk for cardiac dis-

ease (0–1 risk factor) maintain an LDL

cholesterol level <160 mg/dL, but pharmaco-

logic treatment is recommended only if LDL

cholesterol levels go above 190 mg/dL. An

LDL cholesterol level between 160 and 190

mg/dL can be treated with therapeutic lifestyle

changes. Risk factors include older age, heart

disease, diabetes, hypertension, and smoking.

Question 37

37.

A 22-year-old woman from sub-Saharan Africa

comes to the clinic to be tested for HIV. She

denies illicit drug use and has not been sexu-

ally active since she moved to the United

States 3 years ago. Her initial enzyme-linked

immunosorbent assay is positive. Which of the

following would best confi rm the diagnosis of

HIV?

(A) A positive Western blot test

(B) A repeat enzyme-linked immunosorbent assay

(C) Clinical evidence of an opportunistic infection

(D) History of unprotected sex with an HIV-

positive partner

(E) Lymphopenia

Answer 37

37. The correct answer is A.

Because the enzyme-

linked immunosorbent assay test has a false-

positive rate of approximately 2%, the results

need to be confi rmed with a Western blot analysis.

Question 38

38.

A 24-year-old man presents with notably

slurred speech, stating, “I don’t want to live

anymore, I just want to take pills and make the

pain go away.” A psychiatric history reveals that

the patient has suffered from major depression

for 9 years, has had numerous psychiatric ad-

missions for violent behavior, and has at-

tempted suicide twice by overdose. The patient

currently has a blood alcohol level of 0.012

mg/mL. Which of the following is this patient’s

most significant risk factor for a completed

suicide attempt?

(A) Antisocial behavior

(B) Depression

(C) Male gender

(D) Past suicide attempts

(E) Substance abuse

Answer 38

38. The correct answer is D.

Many studies have

found that the greatest risk factor for a com-

pleted suicide attempt in any patient is whether

they have attempted suicide in the past. In fact,

some research shows that past attempts may in-

crease the risk of suicide by 22 times. It is also

important to assess whether the patient has a

plan for suicide, and whether the suicide at-

tempt was by lethal means.

Question 39

Select the mechanism of action of the antihyper-

tensive drug that would be the best choice to treat

each of the following patients.

39.

A 52-year-old man with diabetes and hyperten-

sion presents to a new primary care provider.

He currently uses insulin to control diabetes

mellitus and hydrochlorothiazide to control

hypertension. On physical examination he is

an overweight man with no concerning fi

ndings, except for a blood pressure of 171/93 mm

Hg. His creatine level is 1.7 mg/dL with a uri-

nalysis that shows proteinuria. His physician

wants to prescribe another antihypertensive

agent in addition to hydrochlorothiazide.

(A) Antagonizes aldosterone receptors

(B) Antagonizes β1-adrenergic receptors

(C) Antagonizes β1- and β2-adrenergic receptors

(D) Blocks angiotensin II formation

(E) Blocks calcium influx into vascular smooth

muscle and myocardium

(F) Blocks distal convoluted tubule sodium

and chloride reabsorption

(G) Blocks loop of Henle sodium and chloride

reabsorption

(H) Directly relaxes smooth muscle

(I) Stimulates α 2-adrenergic receptors

(J) Stimulates aldosterone formation

(K) Stimulates angiotensin II formation

Answer 39

39. The correct answer is D.

First-line treatment

for hypertension in diabetics with proteinuria is

an ACE inhibitor such as captopril and enal-

april. ACE inhibitors decrease mortality and

the risk for stroke in this patient population.

ACE inhibitors also slow the progression of re-

nal disease in diabetic hypertensive patients

with proteinuria. ACE inhibitors act by block-

ing ACE, the enzyme necessary for converting

angiotensin I to angiotensin II. Angiotensin II

causes increased aldosterone production, in-

creased retention of sodium and water, in-

creased output of the sympathetic nervous sys-

tem, and vasoconstriction of vascular smooth

muscle, all leading to increased blood pressure.

Therefore, if angiotensin II synthesis is

blocked, this leads to a decrease in blood pressure.

Question 40

Select the mechanism of action of the antihyper-

tensive drug that would be the best choice to treat

each of the following patients.

40.

A 63-year-old woman with a history of osteopo-

rosis presents for a second opinion regarding

hypertension management because she is wor-

ried about starting any medication that might

worsen her osteoporosis. Her only medication

is calcium supplements. She has smoked 1

pack of cigarettes per day for 15 years. Her

physical examination is normal except for a

blood pressure of 165/90 mm Hg. Laboratory

tests show a total serum calcium level of 7.0

mg/dL and mild hypercalciuria.

(A) Antagonizes aldosterone receptors

(B) Antagonizes β1-adrenergic receptors

(C) Antagonizes β1- and β2-adrenergic receptors

(D) Blocks angiotensin II formation

(E) Blocks calcium infl ux into vascular smooth

muscle and myocardium

(F) Blocks distal convoluted tubule sodium

and chloride reabsorption

(G) Blocks loop of Henle sodium and chloride

reabsorption

(H) Directly relaxes smooth muscle

(I) Stimulates α2-adrenergic receptors

(J) Stimulates aldosterone formation

(K) Stimulates angiotensin II formation

Answer 40

40. The correct answer is F.

First-line treatment

for hypertension in patients with osteoporosis is

a thiazide diuretic such as hydrochlorothia-

zide. Thiazide diuretics act by inhibiting a so-

dium/chloride cotransporter in the distal tu-

bule, thereby decreasing sodium reabsorption,

which leads to decreased blood pressure. Thi-

azide diuretics increase the secretion of sodium

and potassium and the reabsorption of cal-

cium. Therefore, patients with hypocalcemia,

hypercalciuria, and osteoporosis may benefit

from thiazide diuretics in terms of calcium balance.