USMLE USMLE Certifications USMLE-STEP-2 Questions & Answers

• Question 571:

  A 46-year-old G3P3 woman has had postcoital spotting for 6 months. On pelvic examination, she has a fungating, exophytic lesion arising from her cervix that is approximately 2 cm in diameter. Biopsy of this lesion is interpreted as invasive squamous cell carcinoma of the cervix. There is no evidence of extension of the cancer onto the vagina. The parametria are indurated on bimanual examination, though not to the pelvic sidewall. CT scan of her pelvis and abdomen discloses enlarged paraaortic lymph nodes and metastatic lesions in the parenchyma of her liver. This woman's childbearing is complete. She is a healthy woman who is close to ideal body weight, exercises regularly, and does not smoke. Which of the following is the most appropriate treatment of this woman?

  A. TAH-BSO

  B. radical hysterectomy with pelvic and paraaortic lymph node dissection

  C. pelvic exenteration

  D. multiagent chemotherapy

  E. combined brachytherapy and external radiation therapy

  Correct Answer: E

  Although this 46-year-old woman is staged as a IIB, she should be treated as a stage IVBbecause of the findings on CT scan. Methods of staging that are similar allow institutions to compare results of treatment without having to account for different staging procedures and criteria. Asimple TAH-BSO is appropriate therapy only for women with carcinoma in situ of the cervix (CIN III, stage 0). Women with stage I or IIA may be treated with radical hysterectomy or with radiation therapy. Beyond stage IIA, only radiation therapy is acceptable. A pelvic exenteration is indicated when there is a central recurrence after maximal dose radiation therapy. Platinum-based chemotherapy has been used for women with metastases or recurrence after radiation therapy. It is considered palliative. Also, some suggest that a lymphadenectomy be performed before the start of radiation. Recently, several have used chemotherapy as primary therapy for bulk disease. There are no randomized-controlled trials to document that chemotherapy is superior to surgery or radiation.

• Question 572:

  A 22-year-old woman and her 24-year-old partner have been attempting to conceive for 12 months. They have sexual intercourse two to three times per week and use no contraception or coital lubricants. She has never been pregnant and her husband has fathered no pregnancies. She has no history to suggest damage to her Fallopian tubes and her menses occur at 28- to 31-day intervals. The statistic in question 60 is fecundability. Fecundity is defined as the probability of having a liveborn child per ovulation. What is the fecundity of normally fertile couples?

  A. 5%

  B. 10%

  C. 20%

  D. 35%

  E. 50%

  Correct Answer: B

  While the probability of conception per ovulation is approximately 20%, about 50% of all conceptions in humans end as a pregnancy loss. Of this percentage, 35% of pregnancies end so early that women never realize they conceived. The remaining 15% are recognized pregnancy losses, most in the first trimester. Stated otherwise, only 10% of women who conceive will have a liveborn child (50% of the 20% conception rate per ovulation). Fecundity in the future (probability of having a liveborn child) is not reduced after a single pregnancy loss.

• Question 573:

  A 46-year-old G3P3 woman has had postcoital spotting for 6 months. On pelvic examination, she has a fungating, exophytic lesion arising from her cervix that is approximately 2 cm in diameter. Biopsy of this lesion is interpreted as invasive squamous cell carcinoma of the cervix. There is no evidence of extension of the cancer onto the vagina. The parametria are indurated on bimanual examination, though not to the pelvic sidewall. CT scan of her pelvis and abdomen discloses enlarged paraaortic lymph nodes and metastatic lesions in the parenchyma of her liver.

  Which of the following is the FIGO stage of her cancer?

  A. IA

  B. IB

  C. IIB

  D. IIIB

  E. IVB

  Correct Answer: C

  Cervical cancer is currently the only female reproductive tract cancer staged clinically according to FIGO standards. FIGO also requires that the clinical staging be based on technologies generally available worldwide, including third world countries. For this reason, lymphangiography, angiography, CT or MRI scans, laparoscopy, or hysteroscopy are not permitted to stage cervical cancer. Stage I cancer is confined to the cervix. Stage IA is microscopic cancer without a visible lesion. Stage IB is macroscopic cancer visible to the eye. Stage IB is further subdivided into stage IB1 (clinically visible lesion 4.0 cm or less in greatest dimension) and stage IB2 (clinically visible lesion more than 4.0 cm in greatest dimension). Stages IIIV have spread beyond the cervix. Stage IIB is lateral spread into the parametria, but not extending to the pelvic sidewall. Because of the presence of abnormal paraaortic lymph nodes and hepatic changes consistent with metastases, she is actually a stage IVB.

• Question 574:

  A 22-year-old woman and her 24-year-old partner have been attempting to conceive for 12 months. They have sexual intercourse two to three times per week and use no contraception or coital lubricants. She has never been pregnant and her husband has fathered no pregnancies. She has no history to suggest damage to her Fallopian tubes and her menses occur at 28- to 31-day intervals. What is the probability of conception per ovulation in normally fertile couples?

  A. 5%

  B. 10%

  C. 20%

  D. 35%

  E. 50%

  Correct Answer: C

  Fecundability is the ability to achieve a pregnancy, and the rate per ovulation in couples with no impediment to fertility is approximately 2025%. This figure is reduced as the woman enters her early 30s, if sexual intercourse occurs fewer than one to two times per week, or if the couple use coital lubricants in the periovulatory part of her menstrual cycle. Using the 20% fecundability rate, 20 of 100 couples will achieve a pregnancy in the first menstrual cycle of effort. In the second cycle, 20% of the remaining 80 couples will achieve a pregnancy, that is 16 women. This is a cumulative pregnancy rate of 36%. Twenty percent of the remaining 64 women will conceive in the third cycle, approximately 13 women. The cumulative conception rate after three cycles is approximately 49%. Continuing this calculation, 9095% of normally fertile couples will achieve a pregnancy within 12 ovulations. Based on this calculation, infertility is defined as the inability to conceive after 12 ovulatory cycles.

• Question 575:

  A 19-year-old primigravida at term has been completely dilated for 21/2 hours. The vertex is at 2 to 3 station, and the position is occiput posterior. She complains of exhaustion and is unable to push effectively to expel the fetus. She has an anthropoid pelvis. Which of the following is the most appropriate management to deliver the fetus?

  A. immediate low transverse cesarean section

  B. immediate classical cesarean section

  C. apply forceps and deliver the baby as an occiput posterior

  D. apply Kielland forceps to rotate the baby to occiput anterior

  E. cut a generous episiotomy to make her pushing more effective

  Correct Answer: C

  The station of the vertex indicates that the fetal head is on the perineum. A cesarean section, either low transverse or classical, is inappropriate unless an operative vaginal delivery is unsuccessful. In women with an anthropoid pelvis, the transverse, interspinous diameter of the bony pelvis is narrow, and the anteroposterior diameter of the pelvis is relatively long. In this circumstance, a forceps rotation should not be done and delivery should be in the occiput posterior. The indication for forceps is maternal exhaustion; women with an anthropoid pelvis usually have a spontaneous vaginal delivery. In women with a gynecoid pelvis, the transverse and anteroposterior diameters are more equal, and rotation of the fetal head to occiput anterior would be an acceptable choice. Soft-tissue resistance to delivery is not great enough that an episiotomy will permit slight expulsive efforts by the mother to deliver the fetal head

• Question 576:

  A 23-year-old pregnant woman at 5 postmenstrual weeks took coumadin until about 3 days after her menses was due. She has monthly menses. A home pregnancy test was positive on the day she took coumadin. She takes coumadin because of a history of deep vein thrombosis and pulmonary embolism. She is concerned that the coumadin will cause birth defects.

  You advise this woman to do which of the following?

  A. Abort the pregnancy because the fetus is likely to have birth defects.

  B. Have an ultrasound in 12 weeks to search for fetal anomalies.

  C. Have a genetic amniocentesis at 16 postmenstrual weeks.

  D. Begin prenatal care because the probability of birth defects is low.

  E. Take 10 mg vitamin K to reverse the effects of coumadin.

  Correct Answer: D

• Question 577:

  A 23-year-old pregnant woman at 5 postmenstrual weeks took coumadin until about 3 days after her menses was due. She has monthly menses. A home pregnancy test was positive on the day she took coumadin. She takes coumadin because of a history of deep vein thrombosis and pulmonary embolism. She is concerned that the coumadin will cause birth defects. Which of the following is the treatment of choice during pregnancy for this woman?

  A. coumadin

  B. heparin

  C. aspirin

  D. tissue plasminogen activator (TPA)

  E. vena caval filter

  Correct Answer: B

  Heparin is the drug of choice for anticoagulation in pregnancy. Little of it crosses the placenta, and it is not associated with congenital birth defects. Experience with low molecular weight heparin in pregnancy is increasing and appears to be safe for mother and fetus. In full therapeutic doses, low molecular weight heparin offers the advantage of less or no monitoring of its anticoagulant effect. Coumadin readily crosses the placenta and is associated with birth defects in 1525% of fetuses exposed throughout the first trimester. Aspirin is ineffective as an anticoagulant, although the risk of maternal or fetal bleeding (e.g., placental abruption, fetal intracranial bleeding) is increased. There is no clinical experience with TPA in pregnancy. Because pregnancy itself is a thrombogenic condition, anticoagulation throughout pregnancy is indicated. Vena caval filters offer no advantage over heparin and require an invasive procedure.

• Question 578:

  A 23-year-old pregnant woman at 5 postmenstrual weeks took coumadin until about 3 days after her menses was due. She has monthly menses. A home pregnancy test was positive on the day she took coumadin. She takes coumadin because of a history of deep vein thrombosis and pulmonary embolism. She is concerned that the coumadin will cause birth defects.

  You tell her that the conceptus is most susceptible to teratogenesis at what stage of pregnancy?

  A. between menses and ovulation

  B. from ovulation to implantation

  C. between implantation and the day of expected menses

  D. between the day of expected menses and 12 postmenstrual weeks

  E. during the second and third trimesters

  Correct Answer: D

  The conceptus is remarkably resistant to the toxic and teratogenic effects of most drugs until about 2 postconceptual weeks (4 postmenstrual weeks). Although certain drugs may be toxic to oocytes, their effect will be to prevent conception or cause an early spontaneous abortion. The developing conceptus is not exposed to maternal toxins or teratogens until after implantation and establishment of a blood supply from mother to fetus. Even after implantation, the fetus is relatively resistant to teratogens for about 1 week. Organogenesis is complete by the end of the first trimester. Congenital abnormalities are, therefore, unlikely in the second and third trimesters.

• Question 579:

  A 37-year-old pregnant woman has a genetic amniocentesis at 16 weeks' gestation. Aconcurrent ultrasound shows normal fetal anatomy. Her prenatal course has been unremarkable. Her prenatal laboratory tests include a B-negative blood type, a negative rubella antibody titer, a negative hepatitis B surface antigen, and a hematocrit of 31%. Which of the following is the most appropriate management for this woman?

  A. rubella immunization at the time of the amniocentesis

  B. a serologic test for the presence of hepatitis B surface antibody

  C. a follow-up ultrasound in 1 week to assess for intra-amniotic bleeding

  D. administration of Rh immune globulin at the time of the amniocentesis

  E. chorionic villus biopsy at the time of the amniocentesis

  Correct Answer: D

  Rh immune globulin should always be administered to an Rh-negative pregnant woman who sustains any trauma or has any type of invasive procedure, such as an amniocentesis. Detectable fetomaternal hemorrhage occurs in 6% of women having an amniocentesis and 1% of Rh-negative women will develop Rh isoimmunization after amniocentesis (without Rh immune globulin). The immune globulin reduces the risk of subsequent Rh sensitization during the pregnancy, which could result in severe erythroblastosis fetalis. Although chorionic villus biopsy might be an alternative to amniocentesis, it is done earlier in pregnancy, and occasionally must be followed by an amniocentesis after 14 weeks' gestation because of the possibility that maternal decidua was analyzed. Rubella immunization should be given after delivery to avoid the theoretical risk of a congenital rubella syndrome from the administration of the live vaccine. The presence of hepatitis B surface antibody suggests immunity to hepatitis B but is unrelated to amniocentesis. Intra-amniotic bleeding is a complication of amniocentesis but occurs at thetime of the procedure. The amniotic fluid will appear bloody

• Question 580:

  A48-year-old G5P5 woman has genuine stress incontinence (GSI). Kegel exercises have not helped, and her incontinence is gradually worsening. Her urethrovesical junction (UVJ) is prolapsed into the vagina, and her urethral closure pressure is normal. Which of the following procedures will most likely cure her incontinence?

  A. retropubic urethropexy

  B. anterior colporrhaphy

  C. suburethral sling procedure

  D. needle suspension of paraurethral tissue

  E. paraurethral collagen injections

  Correct Answer: A

  In a patient with GSI, a retropubic approach offers the best long-term cure of the incontinence. The Burch procedure and the Marshall- Marchetti-Krantz procedure are the most common retropubic procedures. With an anterior colporrhaphy, plication sutures are placed at the UVJ in an effort to support and elevate it. Long-term results are not as good as a retropubic urethropexy or a suburethral sling. Asuburethral sling procedure is used when urethral closing pressure is low, less than 20 cmH2O. A needle suspension procedure is most often done when there is associated genital prolapse with potential incontinence. Collagen injections at the UVJ have been attempted to obstruct the urethra partially. Incontinent patients who may benefit the most from collagen injections are those with intrinsic sphincter deficiency and a fixed bladder neck.