USMLE USMLE Certifications USMLE-STEP-2 Questions & Answers

• Question 521:

  You receive a call from the parents of a 1 year old who is due for his well-child visit next week. They have just received a letter from their daycare center that an employee has hepatitis A. Which of the following is the best treatment plan?

  A. Give hepatitis A immune globulin and hepatitis A vaccine.

  B. Treat with hepatitis A immune globulin.

  C. Obtain hepatitis A serology and give hepatitis A vaccine.

  D. Give hepatitis A vaccine.

  E. No treatment is needed.

  Correct Answer: A

  Children, especially those in daycare, commonly are infected with the hepatitis A virus.Unlike adults, children most often are asymptomatic. Frequently, outbreaks of hepatitis A in a daycare center are not recognized until a daycare worker or parent of an attendee becomes ill. Immunization against hepatitis A virus is now routinely recommended because of this. After exposure both immune globulin and vaccine should be given to the unvaccinated individual.

• Question 522:

  A young mother claims that her 4-week-old child sleeps best on his stomach. You tell her that the safest sleep position for infants is which of the following?

  A. on the back

  B. on the stomach

  C. on the side

  D. on the back with the head elevated by a pillow

  E. in the parents' bed

  Correct Answer: A

  Prone sleeping is a major risk factor for sudden infant death syndrome (SIDS). Since the 1992 American Academy of Pediatrics (AAP) recommendation that infants be placed to sleep on their backs, the frequency of prone sleeping has decreased from 70 to 20%, and the SIDS rate has decreased by >40%. Side sleeping has a slightly higher SIDS risk than supine but is still safer than the prone position. Other risk factors include maternal smoking, soft bedding, overheating, younger maternal age, prematurity, low birth weight, and male gender. Rates among African Americans and Native Americans are two to three times the national average. The issue of bed sharing or cosleeping is controversial. There are reports of overlying by adults leading to suffocation, especially when the adult uses drugs or alcohol. Bed sharing with multiple family members may be hazardous; there is increased risk of overlying, entrapment, rolling into prone position, and use of soft sleeping surfaces. Some studies show that infants have more arousals and less slow-wave sleep during bed sharing; however, there is no epidemiologic evidence that bed sharing is protective.

• Question 523:

  A parent brings in a 5-year-old boy being treated for acute lymphocytic leukemia (ALL). He states a friend who is staying with them at their home has just come down with chicken pox. Your patient has not had chicken pox or received immunization with varicella vaccine.

  What is the appropriate treatment?

  A. acyclovir given IV

  B. varicella vaccine

  C. varicella immune globulin (VZIG)

  D. varicella vaccine and VZIG

  E. acyclovir given IV for 7 days, varicella vaccine, and VZIG

  Correct Answer: E

  Children with chicken pox may be infectious for 1 or 2 days before the appearance of the rash. Once skin lesions have crusted, the patient is no longer infectious. Susceptible individuals can contract chicken pox from patients with zoster. In the cases of both chicken pox and zoster, transmission is thought to occur by the respiratory route rather than by direct contact. The virus can travel long distances in the air and remain viable. Transmission from one hospital patient to other susceptible hospitalized patients has been reported to occur through air vents. VZIG should be given within 3 or 4 days of exposure to varicella-susceptible individuals who are immunocompromised.

• Question 524:

  In an adolescent presenting with pityriasis rosea, which of the following would be an appropriate blood test to order?

  A. Venereal Disease Research Laboratory (VDRL)

  B. complete blood count (CBC)

  C. hepatitis A immunoglobulin M (IgM)

  D. fluorescent antinuclear antibody (FANA)

  E. glucose

  Correct Answer: A

  Pityriasis rosea is a papulosquamous eruption consisting of multiple oval-shaped scaling lesions which are truncal in distribution. This eruption resembles the papulosquamous eruption of secondary syphilis, although the rash of secondary syphilis often involves the palms and soles. The etiology of pityriasis rosea is unknown, but is felt to be viral. It is a self-limiting illness lasting several weeks to a few months, and there is no adequate treatment other than symptomatic treatment of pruritus, when necessary.

• Question 525:

  A baby is born to a mother who is positive for hepatitis B surface antigen (HBsAg). Your plan is to do which of the following?

  A. Give the infant a hepatitis B immunization.

  B. Give the infant hepatitis B immune globulin (HBIG).

  C. Give the infant a hepatitis B immunization and HBIG.

  D. Obtain liver function tests and hepatitis serology of the infant.

  E. Give the HBIG only if the child is positive for HBsAg.

  Correct Answer: C

  Transmission of perinatal hepatitis B virus (HBV) infection can be prevented in 95% of infants born to HBsAg-positive mothers by early active (immunization) and passive immunoprophylaxis (HBIG), preferably within 12 hours of life. The immunization series should be completed by 6 months of life. The child should have serology testing 13 months after completion of the series. Testing for anti-HBs will establish if additional vaccine doses are needed; testing for HBsAg will identify infants who are chronically infected. Mothers whose HBsAg status is unknown should be tested as soon as possible; the first vaccine dose should be given within 12 hours of birth. If the woman is found to be positive, HBIG should be given as soon as possible, not later than 7 days of age.

• Question 526:

  A 2-year-old child was recently adopted from India. She appears to be healthy, and there are no abnormal symptoms. Her weight and height are at 25th percentile for age. Her examination is normal. On screening, you find a positive TB skin test using purified protein derivative (PPD) with 20 mm induration. She has a history of receiving a BCG vaccination at birth. Your management plan is to do which of the following?

  A. Obtain a chest x-ray and treat only if this is abnormal.

  B. Obtain a chest x-ray and initiate prophylactic treatment with isoniazid (INH).

  C. Repeat the test in 36 months.

  D. Attribute the positive PPD to the BCG vaccination and do serial yearly x-rays.

  E. Obtain sputum cultures.

  Correct Answer: B

  Generally, the interpretation of tuberculin skin test (TST) is the same regardless of BCG status. Induration >5 mm is considered positive in children in close contact with known or suspected cases of tuberculosis disease or children suspected to have tuberculosis disease. Induration >10 mm is considered positive in children at greater risk of disseminated disease (age <4 years; other medical conditions such as lymphoma, diabetes, chronic renal failure, or malnutrition) or children at greater risk of exposure to tuberculosis disease (born in, or parents born in high-prevalence regions, travel to these regions, exposure to adults at high risk, such as HIV infected, homeless, or drug abusers). Induration >15 mm is positive in children >4 years without any risk factors. Radiographic evaluation of all children with positive TST is recommended. Latent tuberculosis infection is defined as an infection in a person with a positive TST, no physical findings of the disease, and a chest radiograph that is either normal or reveals only granulomas or calcifications in the lungs or regional lymph nodes. Children with latent tuberculosis infection should receive prophylaxis, usually 9 months of INH. Those with symptoms, signs, and/or radiographic manifestations are said to have tuberculosis dsease. There is no benefit to repeating the test in 36 months, and it will delay treatment. Sputum cultures are difficult to obtain in younger children. Gastric aspirate specimens obtained with a nasogastric tube are preferred. Culture material should be obtained in children with evidence of the disease in order to obtain information on drug susceptibility and resistance patterns.

• Question 527:

  Select the ONE best lettered option that is the most likely diagnosis of vaginal bleeding in pregnancy. Each lettered option may be selected once, more than once, or not at all.

  A34-year-old woman, gravida 5, has a 17-hour first stage, a 3.5-hour second stage ending with a spontaneous vaginal delivery of a 4400-g infant, and a 15-minute third stage of labor. Immediately after the placenta delivers, she has profuse vaginal bleeding. On examination, her perineum is intact and there are no vaginal or cervical lacerations. Her uterus is soft and the uterine fundus is 45 cm above her umbilicus.

  A. threatened abortion

  B. gestational trophoblastic disease

  C. cervicitis

  D. placenta previa

  E. placental abruption

  F. uterine rupture

  G. placenta accreta

  H. uterine inversion

  I. uterine atony

  J. vaginal laceration

  K. tubal pregnancy

  Correct Answer: I

  Prolonged labor with delivery of a macrosomic fetus (greater than 4000 g) in a highly parous woman are the risk factors for uterine atony. The diagnosis is confirmed by a boggy, noncontracted uterus that is larger than expected after a normal delivery. Treatment is a combination of manual massage of the uterus, oxytocin, blood transfusion to maintain hemodynamic stability, and careful inspection of the vagina, cervix, and uterus to exclude a vaginal or cervical laceration or retained placental fragments. Ergot derivatives or prostaglandins should be administered if the above measures fail to cause the myometrium to contract. Uterine artery embolization is an unproven therapy. Ahysterectomy is necessary if all measures fail to stop the postpartum hemorrhage

• Question 528:

  Select the ONE best lettered option that is the most likely diagnosis of vaginal bleeding in pregnancy. Each lettered option may be selected once, more than once, or not at all. A 31-year-old woman has an uncomplicated labor and vaginal delivery of a healthy 3400-g male infant. However, her placenta has not yet delivered 2 hours after the delivery of her child. Under appropriate anesthesia manual extraction of the placenta is attempted, but the placenta is removed in fragments. She continues to have excessive vaginal bleeding after manual removal of her placenta. Her first child was delivered by a low transverse cesarean section because of fetal distress.

  A. threatened abortion

  B. gestational trophoblastic disease

  C. cervicitis

  D. placenta previa

  E. placental abruption

  F. uterine rupture

  G. placenta accreta

  H. uterine inversion

  I. uterine atony

  J. vaginal laceration

  K. tubal pregnancy

  Correct Answer: G

  Placenta accreta is suggested by the difficulty with manual removal of the placenta in a woman with a prior cesarean section. Placenta accrete is also more common over any previous uterine incision, such as a myomectomy. Placenta accrete is also more common in women with placenta previa and there is greater than an eightfold increase in women with an AFP higher than 2.5 MOM. The safest and most appropriate treatment is a hysterectomy.

• Question 529:

  Select the ONE best lettered option that is the most likely diagnosis of vaginal bleeding in pregnancy. Each lettered option may be selected once, more than once, or not at all.

  A 29-year-old pregnant woman at 38 weeks' gestation presents to your labor and delivery unit complaining of dizziness, heavy vaginal bleeding, and loss of fetal movement. She had been having uterine contractions for approximately 4 hours, but these stopped when the bleeding began. Her previous pregnancy was delivered by classical cesarean section because of a transverse lie.

  A. threatened abortion

  B. gestational trophoblastic disease

  C. cervicitis

  D. placenta previa

  E. placental abruption

  F. uterine rupture

  G. placenta accreta

  H. uterine inversion

  I. uterine atony

  J. vaginal laceration

  K. tubal pregnancy

  Correct Answer: F

  The clinical features that make uterine rupture the most likely diagnosis are profuse bleeding coincident with cessation of uterine contractions and labor in a woman with a prior classical cesarean section (vertical incision in the uterine fundus). Uterine rupture is uncommon in women with a prior low transverse cesarean section and rare in women with no scar on her uterus. The standard of care is that all women with a previous classical cesarean section be delivered by repeat cesarean section at term before the onset of labor.

• Question 530:

  Select the ONE best lettered option that is the most likely diagnosis of vaginal bleeding in pregnancy. Each lettered option may be selected once, more than once, or not at all.

  A21-year-old woman last menstruated 6 weeks ago. Her menses are usually every 2830 days. She has a past history of chlamydia. One week ago she had a positive home pregnancy test. She complains of mild left lower quadrant pain. Quantitative serum chorionic gonadotropin (hCG) concentrations 2 days ago and today are 6850 and 7685 mIU/mL, respectively. No intrauterine pregnancy is identified by transvaginal ultrasound.

  A. threatened abortion

  B. gestational trophoblastic disease

  C. cervicitis

  D. placenta previa

  E. placental abruption

  F. uterine rupture

  G. placenta accreta

  H. uterine inversion

  I. uterine atony

  J. vaginal laceration

  K. tubal pregnancy

  Correct Answer: K

  Vaginal spotting accompanied by pelvic discomfort in a woman with a prior sexually transmitted infection suggests the diagnosis of an ectopic (tubal) pregnancy. Serum hCG concentrations should increase by at least 67% in 2 days during the first 68 weeks of pregnancy. The subnormal increase in this woman's serum hCG concentrations increases the probability of an ectopic pregnancy. However, approximately 15% of women with a normal intrauterine pregnancy will have a subnormal rise in hCG concentrations. Also, approximately 15% of women with an ectopic pregnancy will have a 48-hour rise in serum hCG concentrations greater than 67%. At hCG concentrations over 5000 mIU/mL, the absence of an intrauterine pregnancy by transvaginal ultrasound provides additional evidence for the diagnosis of an ectopic pregnancy.