USMLE USMLE Certifications USMLE-STEP-2 Questions & Answers

• Question 541:

  A 53-year-old woman with five adult children complains of losing urine shortly after coughing or jumping. She occasionally loses urine while lying in bed if she happens to cough vigorously. She is unable to stop the urine once it has begun to flow.

  Which of the following would most likely confirm the cause of this woman's incontinence?

  A. a urine culture

  B. a Q-tip test

  C. urethroscopy

  D. urethrocystometry

  E. an intravenous pyelography (IVP)

  Correct Answer: D

  Although a urine culture is a standard part of the evaluation of women with loss of urine, this woman's history is not consistent with acute cystitis. AQ-tip test is done to assess the angle the urethra makes with the horizontal in the relaxed and voiding circumstances. Though intended to differentiate GSI from other causes of incontinence, it has not proved to be sufficiently sensitive to make this distinction reliably. Urethroscopy is appropriate if a urethrovaginal fistula or urethral diverticulum is suspected. Urethrocystometry is one name for a test that measures the pressure-volume relationship in the bladder. It should be done in most women with incontinence as the most sensitive test to distinguish the various causes of incontinence. An IVP is of little value in determining the cause of incontinence.

• Question 542:

  Why does ligation of the hypogastric (internal iliac) artery effectively control intractable pelvic hemorrhage?

  A. There is no collateral circulation to the uterus.

  B. Uterine blood flow is stopped.

  C. Arterial pulse pressure to the uterus is reduced.

  D. Clotting in uterine capillaries is enhanced.

  E. Blood flow is shunted to the ovarian veins.

  Correct Answer: C

  Bilateral hypogastric artery ligation converts the arterial system into a venous system; thereby, reducing the pulse pressure by as much as 85%. Subsequent menstrual function and fertility are normal, in part because of the rich collateral circulation to the uterus. The procedure is successful in approximately 50% of cases. The procedure is not technically easy to perform, and an intimate knowledge of the local anatomy is essential to prevent injury to the hypogastric vein or ureter. Uterine hemorrhage not controlled by other means requires a hysterectomy

• Question 543:

  A woman at 31 weeks' gestation complains of feeling dizzy and lightheaded when she lies on her back. She is Rh negative but denies vaginal bleeding, abdominal trauma, or abdominal pain. The diagnosis is probably the supine hypotensive syndrome.

  She has an uncomplicated spontaneous vaginal delivery with an estimated blood loss of 450 mL. Her infant is Rh positive and she receives 300 g of Rh immunoglobulin (one vial) within 72 hours after delivery. This dose is sufficient to prevent Rh isoimmunization after what amount of fetal red cells enters the maternal circulation?

  A. 5 mL

  B. 30 mL

  C. 100 mL

  D. 200 mL

  E. 300 mL

  Correct Answer: B

  One vial of Rh immunoglobulin will prevent Rh isoimmunization if the amount of fetal whole blood entering the maternal circulation is 30 mL or less. If the woman has a condition where a greater amount of fetal blood may enter the maternal circulation, the amount of fetal blood should be estimated by submitting a maternal blood sample for a Kleihauer-Betke test. The dose of Rh immunoglobulin is then based on the results of this test.

• Question 544:

  A1-cm carcinoma of the breast is diagnosed by an excisional biopsy in a 36-year-old woman at 14 weeks' gestation. The axillary nodes are negative.

  Which of the following is the best management of this patient?

  A. terminate the pregnancy immediately and treat the breast cancer

  B. monitor the mass throughout pregnancy with serial breast ultrasounds

  C. induce labor at 34 weeks' gestation, then give chemotherapy

  D. perform a cesarean delivery at 36 weeks and treat the breast cancer

  E. modified radical mastectomy at the time of diagnosis

  Correct Answer: E

  Breast cancers in young women tend to be aggressive tumors and estrogen receptor negative, both of which worsen the prognosis. For his reason, the cancer should be treated surgically, usually a modified radical mastectomy to minimize the need for adjuvant radiation or chemotherapy with wide local excision or a lumpectomy. There is little convincing evidence that termination of pregnancy improves the prognosis.

• Question 545:

  A woman at 31 weeks' gestation complains of feeling dizzy and lightheaded when she lies on her back. She is Rh negative but denies vaginal bleeding, abdominal trauma, or abdominal pain. The diagnosis is probably the supine hypotensive syndrome.

  This results in which of the following?

  A. a decreased fetal heart rate

  B. an increased frequency of uterine contractions

  C. a decreased tolerance to pain

  D. a decreased effect of epidural analgesia

  E. an increased risk of placental abruption

  Correct Answer: A

  In late pregnancy, the large uterus commonly compresses the inferior vena cava and impedes return of blood from the lower extremities to the heart. This may be sufficient to reduce cardiac output. In approximately 10% of women, arterial hypotension occurs, which can result in diminished uteroplacental blood flow and a decreased fetal heart rate. None of the other options occur as a result of this syndrome. Management is to have the woman roll on to her side or lean forward if she is sitting. Both these maneuvers cause the uterus to fall away from the inferior vena cava.

• Question 546:

  A woman at 31 weeks' gestation complains of feeling dizzy and lightheaded when she lies on her back.

  She is Rh negative but denies vaginal bleeding, abdominal trauma, or abdominal pain. The diagnosis is

  probably the supine hypotensive syndrome.

  In which of the following circumstances is the administration of anti-D immune globulin not necessary?

  A. threatened abortion and first-trimester bleeding

  B. genetic amniocentesis at 16 weeks' gestation

  C. at 28 weeks

  D. at 40 weeks with the onset of labor

  E. after delivery of an Rh-positive fetus

  Correct Answer: D

  Anti-D immune globulin should be given at the time of any vaginal bleeding, trauma, or invasive procedure (e.g., amniocentesis) during pregnancy. Although maternal isoimmunization usually occurs as a result of fetomaternal transfusion at the time of delivery, a small percentage of women become isoimmunized during pregnancy. Anti-D immune globulin is routinely given to unsensitized Rh- negative women at 28 weeks' gestation to reduce this risk. Anti-D immune globulin must also be administered within 72 hours after the birth of an Rh-positive infant. Administration at 40 weeks' gestation before the onset of labor is unnecessary if the infant is Rh negative and may be ineffective if the infant is Rh positive and there is a significant fetomaternal transfusion.

• Question 547:

  A 35-year-old woman at 30 weeks' gestation discovers a lump in her left breast. Examination reveals a 23 cm, firm nodule in the upper outer quadrant. Which of the following is the most appropriate next step in the management of this patient?

  A. observation until after delivery

  B. thermography

  C. application of hot packs

  D. breast ultrasound

  E. fine-needle aspiration

  Correct Answer: E

  Breast cancer is rare in women younger than 35 years, and the approximate incidence of breast cancer in pregnancy is 1 in 3000 deliveries. Survival rates from breast cancer in pregnancy are less than in nonpregnant women of comparable age. This is due to delayed diagnosis, not a biological effect of pregnancy. Pregnant women, when matched for disease stage, have identical survival rates as nonpregnant women. Despite the pregnancy, the presence of a dominant mass requires histologic evaluation. Temporizing measures (choices A through D) are inappropriate in the presence of a dominant mass. Imaging studies of the breast during pregnancy are difficult to interpret because of the ductular and glandular hypertrophy of pregnancy.

• Question 548:

  A45-year-old woman has bilateral breast pain that is most severe premenstrually. On palpation, there is excessive nodularity, tenderness, and cystic areas that diminish in size after menses. Which of the following is the most likely diagnosis?

  A. fibrocystic disease

  B. fibroadenomas

  C. intraductal papilloma

  D. breast cancer

  E. engorgement attributable to increased prolactin

  Correct Answer: A

  The classic symptom of fibrocystic breast disease is cyclic bilateral breast pain. The pain and associated diffuse breast engorgement is most severe premenstrually. Cystic changes palpated premenstrually typically are smaller postmenstrually. Fibroadenomas are firm, rubbery, freely mobile, solid, and usually solitary masses. Intraductal papilloma does not cause diffuse breast symptoms. Spontaneous and intermittent nipple discharge is the classic sign of an intraductal papilloma. Intraductal carcinoma is more likely if there is a discharge from multiple ducts. Breast cancer should be suspected when a solitary firm nodule does not change throughout the menstrual cycle. A mammogram is helpful, but any suspicious mass should be biopsied. Hyperprolactinemia can cause breast engorgement, but the pain is usually mild, and cystic areas tend not to vary in size

• Question 549:

  A pediatrician asks you to see a 13-year-old girl who has not begun to menstruate and has a 6-month history of pelvic and lower abdominal pain at approximately 1-month interval. She has Tanner stage 3 pubic hair and breast development. Her growth spurt occurred about 1 year ago and her current height is 65 in. (165 cm). She has never had sexual intercourse. On examination of her external genitalia the presence of Tanner stage 3 pubic hair is confirmed. The labia are normal. There is no obvious vaginal opening and there is bulging between the labia minora.

  Which one of the following laboratory tests is increased in women with gonadal dysgenesis?

  A. serum FSH concentrations

  B. serum TSH concentrations

  C. serum prolactin concentrations

  D. serum estradiol concentrations

  E. serum testosterone concentrations

  Correct Answer: A

  Women with gonadal dysgenesis have fibrous streaks instead of functioning gonads. As a result secretion of estradiol and testosterone is decreased. Serum FSH concentrations are increased because of the lack of negative feedback to the hypothalamus and pituitary as a result of diminished sex steroid secretion by the streak gonads. Other pituitary hormones, such as TSH and prolactin are not regulated by sex steroids and their concentrations are normal.

• Question 550:

  A pediatrician asks you to see a 13-year-old girl who has not begun to menstruate and has a 6-month history of pelvic and lower abdominal pain at approximately 1-month interval. She has Tanner stage 3 pubic hair and breast development. Her growth spurt occurred about 1 year ago and her current height is 65 in. (165 cm). She has never had sexual intercourse. On examination of her external genitalia the presence of Tanner stage 3 pubic hair is confirmed. The labia are normal. There is no obvious vaginal opening and there is bulging between the labia minora. Which one of the following is the most likely diagnosis?

  A. androgen insensitivity syndrome

  B. mittelschmerz (ovulation pain)

  C. Müllerian and vaginal agenesis

  D. gonadal dysgenesis

  E. imperforate hymen

  Correct Answer: E

  The presence of pubertal events except external menstruation and the bulging of the hymen causing retrograde menstruation as a cause of her cyclic pain establish the diagnosis of imperforate hymen. Strictly, these women have cryptomenorrhea, not amenorrhea. Women with mittelschmerz (ovulation pain) menstruate cyclically. While pubertal events except menstruation occur normally in women with Müllerian/ vaginal agenesis, cyclic pain is absent because the uterus is hypoplastic or absent and there is no endometrium to shed. Women with gonadal dysgenesis do not develop breasts or pubic hair and have primary amenorrhea. The most common form of gonadal dysgenesis is 45,X Turner syndrome and affected females are less than 62 in. tall.