Epidemiology and Preventative Medicine Flashcards
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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%).
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)
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.”
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
- 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.
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
- 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).
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
- 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).
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- The correct answer is B.
The recommenda-
tions for mammography are screening every
year when the patient is 50 years old or older.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
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
- 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.
