USMLE USMLE Certifications USMLE-STEP-3 Questions & Answers

• Question 291:

  A 16-year-old nulligravid high school student is on your afternoon office schedule for a "talk visit." She was seen last year by one of your colleagues for an initial GYN evaluation. She is healthy and has no medical problems. Today she tells you that she and her new boyfriend had intercourse the night before, and the condom they were using broke.

  Your initial course of action should include which of the following?

  A. placing an IUD

  B. requesting that her parents be told of the situation

  C. an examination and offer of sexually transmitted infections testing

  D. performing a new obstetric workup

  E. empirically treating her with ceftriaxone and doxycycline

  Correct Answer: C Section: (none)

  Explanation:

  Discussing the potential implications of her sexual activity is warranted, both in terms of potential pregnancy and risk of acquiring sexually transmitted infections. Making assumptions about her decision making (choices B and D) would breach the ethical principles of autonomy and confidentiality. In August 2006, the FDA approved emergency oral contraception (Plan B) to be available over the counter for women ages 18 and older. Younger women must have a prescription from a health care provider. Plan B contains 0.75 mg of levonorgestrel in two doses taken 12 hours apart. It is to be used within 72 hours of unprotected intercourse. The mechanisms of action include delay in ovulation, insufficient corpus luteum function, and interference with sperm transport. It is not an abortifacient. A physician is not obligated to provide treatments which conflict with his or her own personal belief system. Nonetheless, using ethical principles of autonomy, beneficience, nonmaleficence, veracity, and justice, physicians should discuss patients' requests for treatments in an attempt to reach common ground. If that is not possible, the physician should provide an alternative resource to address a patient's request.

• Question 292:

  A healthy 38-year-old G4P3003 presents for amniocentesis. The karyotype returns as shown in the Figure You counsel the patient that which of the following was likely her biggest risk factor for the development of this karyotype?

  

  A. cigarette smoking

  B. lack of folic acid supplementation

  C. maternal age at conception

  D. family history

  E. alcohol consumption

  Correct Answer: C Section: (none)

  Explanation:

  Down syndrome is a trisomy of chromosome 21. It is the most common nonlethal trisomy. Patau syndrome is trisomy 13 and Edwards syndrome is trisomy 18. Turner syndrome is 45 X, a monosomy. Klinefelter syndrome is the presence of an extra X chromosome in a male resulting in 47 X-X-Y. Down syndrome is the most commonly recognized genetic cause of mental retardation. The risk of trisomy 21 is directly related to maternal age as a result of maternal nondisjunction. The risk of having a child with Down syndrome increases in a gradual, linear fashion until about age 30 and increases exponentially thereafter. Women who will be 35 years or older at the time of delivery should be offered chorionic villus sampling or secondtrimester amniocentesis. Women younger than 35 years should be offered maternal serum screening at 1618 weeks of gestation. The maternal serum markers used to screen for trisomy 21 are alpha-fetoprotein, unconjugated estriol, and hCG. The use of ultrasound to estimate gestational age improves the sensitivity and specificity of maternal serum screening

• Question 293:

  A healthy 38-year-old G4P3003 presents for amniocentesis. The karyotype returns as shown in the Figure. What is the diagnosis?

  

  A. Down syndrome

  B. Patau syndrome

  C. Edwards syndrome

  D. Turner syndrome

  E. Klinefelter syndrome

  Correct Answer: A Section: (none)

  Explanation:

  Down syndrome is a trisomy of chromosome 21. It is the most common nonlethal trisomy. Patau syndrome is trisomy 13 and Edwards syndrome is trisomy 18. Turner syndrome is 45 X, a monosomy. Klinefelter syndrome is the presence of an extra X chromosome in a male resulting in 47 X-X-Y. Down syndrome is the most commonly recognized genetic cause of mental retardation. The risk of trisomy 21 is directly related to maternal age as a result of maternal nondisjunction. The risk of having a child with Down syndrome increases in a gradual, linear fashion until about age 30 and increases exponentially thereafter. Women who will be 35 years or older at the time of delivery should be offered chorionic villus sampling or secondtrimester amniocentesis. Women younger than 35 years should be offered maternal serum screening at 1618 weeks of gestation. The maternal serum markers used to screen for trisomy 21 are alpha-fetoprotein, unconjugated estriol, and hCG. The use of ultrasound to estimate gestational age improves the sensitivity and specificity of maternal serum screening.

• Question 294:

  Preconception counseling is an important component of health care encounters with reproductive age women. As a general recommendation, women of childbearing age should be advised to consume what dose of folic acid for prevention of neural tube defects?

  A. 0.1 mg

  B. 0.4 mg

  C. 1mg

  D. 4mg

  E. folic acid has only been shown to prevent the recurrence of neural tube defects in women who have previously had an affected child

  Correct Answer: B Section: (none)

  Explanation:

  In randomized-controlled trials, the daily administration of 0.4 mg of folic acid in the periconception period was shown to prevent the first occurrence of open neural tube defects by approximately 70% as compared to placebo. For women who have previously had a fetus with an open neural defect, the recommended dose for prevention of recurrence is 4 mg and has been shown to have approximately 70% effectiveness in preventing recurrence.

• Question 295:

  You are called by the labor and delivery nurse to evaluate the fetal monitoring strip of a patient. She is a 24year-old G1 female at 40 weeks' gestation that went into spontaneous labor earlier today. She is currently

  on IV oxytocin (Pitocin). You review the fetal monitoring strip shown in figure below.

  

  What is the most appropriate management at this point?

  A. reduction in the dose of oxytocin

  B. place the woman on oxygen 10 L via facemask

  C. reposition the patient from her back to her left side

  D. acetaminophen to reduce maternal temperature

  E. reassurance and continuation of current care

  Correct Answer: E Section: (none)

  Explanation:

  The fetal monitoring strip in these questions shows the presence of early decelerations. Early decelerations are characterized by a gradual decrease in the fetal heart rate and gradual return to the baseline in association with a contraction. The onset and recovery of the heart rate are coincident with the onset and recovery of the contraction. These are thought to be due to vagal stimulation due to fetal head compression. They are not associated with fetal hypoxia or acidosis and no intervention, other than continued careful labor monitoring, is indicated. Variable decelerations are caused by umbilical cord compression. They are characterized by the abrupt decrease in heart rate. The onset of the deceleration frequently varies in successive contractions, and they generally last less than 2 minutes. Late decelerations are gradual decreases in heart rate that begin at or after the peak of the contraction and return to baseline after the contraction has ended. It is often the first fetal heart rate abnormality seen in uteroplacentalinduced hypoxia. Any process that causes maternal hypotension, excessive uterine activity, or placental dysfunction can induce late decelerations. Fetal tachycardia is defined as a baseline fetal heart rate of >160 bpm and is considered severe if the rate is >180 bpm. The most common cause of this is maternal fever, but it can also be due to fetal compromise, arrhythmias, or certain medications. Hyperstimulation is a nonreassuring heart rate pattern caused by the presence of frequent uterine contractions. This occurs most commonly in labors that are being augmented with oxytocin. The initial management includes reduction in the dose, or discontinuation, of the oxytocin

• Question 296:

  You are called by the labor and delivery nurse to evaluate the fetal monitoring strip of a patient. She is a 24year-old G1 female at 40 weeks' gestation that went into spontaneous labor earlier today. She is currently on IV oxytocin (Pitocin). You review the fetal monitoring strip shown in figure below.

  

  

  What physiologic process causes this to occur?

  A. uteroplacental insufficiency

  B. umbilical cord compression

  C. compression of the fetal head

  D. maternal fever

  E. fetal acidosis caused by too frequent uterine contractions

  Correct Answer: C Section: (none)

  Explanation:

  The fetal monitoring strip in these questions shows the presence of early decelerations. Early decelerations are characterized by a gradual decrease in the fetal heart rate and gradual return to the baseline in association with a contraction. The onset and recovery of the heart rate are coincident with the onset and recovery of the contraction. These are thought to be due to vagal stimulation due to fetal head compression. They are not associated with fetal hypoxia or acidosis and no intervention, other than continued careful labor monitoring, is indicated. Variable decelerations are caused by umbilical cord compression. They are characterized by the abrupt decrease in heart rate. The onset of the deceleration frequently varies in successive contractions, and they generally last less than 2 minutes. Late decelerations are gradual decreases in heart rate that begin at or after the peak of the contraction and return to baseline after the contraction has ended. It is often the first fetal heart rate abnormality seen in uteroplacentalinduced hypoxia. Any process that causes maternal hypotension, excessive uterine activity, or placental dysfunction can induce late decelerations. Fetal tachycardia is defined as a baseline fetal heart rate of >160 bpm and is considered severe if the rate is >180 bpm. The most common cause of this is maternal fever, but it can also be due to fetal compromise, arrhythmias, or certain medications. Hyperstimulation is a nonreassuring heart rate pattern caused by the presence of frequent uterine contractions. This occurs most commonly in labors that are being augmented with oxytocin. The initial management includes reduction in the dose, or discontinuation, of the oxytocin

• Question 297:

  You are called by the labor and delivery nurse to evaluate the fetal monitoring strip of a patient. She is a 24

  

  year-old G1 female at 40 weeks' gestation that went into spontaneous labor earlier today. She is currently on IV oxytocin (Pitocin). You review the fetal monitoring strip shown in figure below.

  What fetal heart rate condition does this monitor strip reveal?

  A. late decelerations

  B. early decelerations

  C. variable decelerations

  D. hyperstimulation

  E. fetal tachycardia

  Correct Answer: B Section: (none)

  Explanation:

  The fetal monitoring strip in these questions shows the presence of early decelerations. Early decelerations are characterized by a gradual decrease in the fetal heart rate and gradual return to the baseline in association with a contraction. The onset and recovery of the heart rate are coincident with the onset and recovery of the contraction. These are thought to be due to vagal stimulation due to fetal head compression. They are not associated with fetal hypoxia or acidosis and no intervention, other than continued careful labor monitoring, is indicated. Variable decelerations are caused by umbilical cord compression. They are characterized by the abrupt decrease in heart rate. The onset of the deceleration frequently varies in successive contractions, and they generally last less than 2 minutes. Late decelerations are gradual decreases in heart rate that begin at or after the peak of the contraction and return to baseline after the contraction has ended. It is often the first fetal heart rate abnormality seen in uteroplacentalinduced hypoxia. Any process that causes maternal hypotension, excessive uterine activity, or placental dysfunction can induce late decelerations. Fetal tachycardia is defined as a baseline fetal heart rate of >160 bpm and is considered severe if the rate is >180 bpm. The most common cause of this is maternal fever, but it can also be due to fetal compromise, arrhythmias, or certain medications. Hyperstimulation is a nonreassuring heart rate pattern caused by the presence of frequent uterine contractions. This occurs most commonly in labors that are being augmented with oxytocin. The initial management includes reduction in the dose, or discontinuation, of the oxytocin:

• Question 298:

  A thin, 37-year-old patient undergoes a total abdominal hysterectomy and bilateral salpingooophorectomy for chronic menometrorrhagia. The procedure lasts 2 hours. ABalfour retractor is utilized intraoperatively to assist with exposure. On the morning of postoperative day 2, the patient stands to get out of bed and collapses on the floor, her right lower extremity is unable to support her weight. You are called to examine her. Your neurologic examination suggests an absence of deep tendon reflex in the right lower extremity, absence of cutaneous sensation to the anterior and medial thigh, and an inability to flex at the hip and extend at the knee. Which of the following is the most likely etiology for this presentation postoperatively?

  A. DVT

  B. intraoperative compression injury of the femoral nerve

  C. intraoperative stroke

  D. intraoperative transection of the sciatic nerve

  E. undiagnosed diabetes

  Correct Answer: B Section: (none)

  Explanation:

  The femoral nerve is the most commonly injured nerve at the time of gynecologic surgical procedures. The nerve can be injured at the time of laparotomy through the inappropriate placement of lateral retractor blades with fixed or selfretaining retractors. The retractor blades, when placed too deeply within the lateral pelvis, have the potential to directly compress the psoas muscle and thereby, the femoral nerve within the psoas muscle. The more prolonged the nerve compression, the more pronounced and long lasting the injury postoperatively. The femoral nerve can also be injured at the time of vaginal surgery as a result of inappropriate lithotomy positioning, with extreme hip flexion and maximal knee extension most commonly associated with injury. The femoral nerve is a component of the lumbosacral nerve plexus and provides both motor as well as sensory function. Injury to the femoral nerve will present with diminished or absent deep tendon reflexes, inability to straight leg raise, hip flex, or knee extend. There may also be a loss of cutaneous sensation over the anterior thigh as well as the medial aspect of the thigh and calf.

  DVT will generally present with asymmetric lower extremity swelling postoperatively, but without associated motor or sensory neurologic deficits. An undetected cerebrovascular accident intraoperatively will generally present with more widespread central deficits than the focal lower extremity deficit seen in this example. Injury to the sciatic nerve will present with a different constellation of neurologic deficits, including inability to extend at the hip, flex at the knee, ankle dorsiflex, and evert. Undiagnosed diabetes can present with a variety of neurologic sequelae including peripheral neuropathy, nephropathy, and retinopathy. Rarely will undiagnosed diabetic neuropathy present with such a focal deficit as seen in this case scenario.

• Question 299:

  A65-year-old female presents with ascites, multiple peritoneal implants, and a large abdominopelvic mass. At laparotomy, she is found to have omental disease, splenic metastases, retroperitoneal lymphadenopathy, and bilateral pelvic masses with rectosigmoid involvement posteriorly and bladder involvement anteriorly. The appropriate surgical management for this patient would be which of the following?

  A. bilateral salpingo-oophorectomy, followed by postoperative chemotherapy

  B. total abdominal hysterectomy and bilateral salpingo-oophorectomy, followed by postoperative chemotherapy

  C. complete omentectomy, retroperitoneal lymphadenectomy, total abdominal hysterectomy, and bilateral salpingooophorectomy, followed by postoperative chemotherapy

  D. peritoneal stripping, splenectomy, complete omentectomy, retroperitoneal lymphadenectomy, total abdominal hysterectomy, and bilateral salpingo-oophorectomy, followed by postoperative chemotherapy

  E. rectosigmoid resection with reanastomosis, peritoneal stripping, splenectomy, complete omentectomy, retroperitoneal lymphadenectomy, total abdominal hysterectomy, and bilateral salpingooophorectomy, followed by postoperative chemotherapy

  Correct Answer: E Section: (none)

  Explanation:

  Despite decades of effort aimed at improving methods of early detection and diagnosis, the majority of cases of cancer of the ovary are not diagnosed until the disease has spread beyond the ovary. The surgical management of epithelial ovarian cancer consists of attempts at maximal surgical cytoreduction at the time of surgical exploration. The surgical goal is to remove all disease, such that at the completion of the debulking procedure no visible remaining disease is present. In order to accomplish this goal, extensive surgical procedures are often required in those patients presenting with advanced stage disease. Griffiths et al. reviewed the theoretical basis for cytoreductive surgery. Complete removal of bulky ovarian tumor masses improves patient survival when compared to inadequate or incomplete surgical cytoreduction, in three specific ways:

  1.

  Maximal surgical debulking enables the resection of hypoxic tumor sanctuaries in which viable tumor cells have the ability to escape exposure to adequate concentrations of chemotherapy postoperatively.

  2.

  Maximal surgical debulking enables the resection of large tumor masses containing chemoresistant tumor clones that do not respond well to any form of postoperative chemotherapy.

  3.

  Maximal surgical debulking enables the resection of large tumor masses, thereby reducing the tumor burden to such an extent that all remaining cells in the G0 resting state will now return to the actively dividing cell cycle, where they are more amenable to chemotherapeutic damage and ultimate cell kill. Numerous investigators (Griffiths, Munnell, Delclos and Quinlan, Hoskins, Eisenkop) have consistently confirmed the biggest single prognosticator predicting how well a patient will respond, and how long they will live, following treatment for ovarian cancer is the volume of disease remaining following their initial surgical debulking. Patients left with residual deposits of disease >2 cm in diameter are considered suboptimally debulked and do no better than patients who have no surgical debulking procedure performed. Optimal surgical cytoreduction, on the other hand, is defined as no residual deposit of disease remaining greater than 1 cm in maximal dimension. The smaller the residual disease remaining (no deposit >.5 cm, no deposit >.25 cm, and so on), the longer the overall survival of the patient, with those left with no visible remaining disease having the longest overall survival of all as a rule. Given the immense amount of retrospective data supporting the importance of optimal surgical debulking in the patient's overall outcome and survival, all attempts must be made at the time of initial surgical cytoreduction to obtain an optimal debulking, preferably one with no visible remaining disease at completion

• Question 300:

  A 37-year-old female presented to your office with an ultrasound report suggestive of bilateral ovarian masses. You take her to the operating room for an exploratory laparotomy and note the left ovary to be replaced by an 8 9 cm neoplastic process. The right ovary appears to have a small 2 x 2 cm cystic process, similar in appearance to the left ovary, involving only a small portion of the right ovary. After obtaining pelvic and upper abdominal washings, you remove the left ovary and then perform a cystectomy on the right ovary, removing all visible disease without rupture. The frozen section on both resected specimens reveals a serous tumor of low malignant potential (LMP). The best procedure for the patient at this point is which of the following?

  A. termination of the procedure; await final pathology report on the resected specimens

  B. total abdominal hysterectomy and right salpingo-oophorectomy

  C. omentectomy and peritoneal biopsies

  D. omentectomy, peritoneal biopsies, selected pelvic and peritoneal lymph node sampling

  E. terminate procedure and prescribe postoperative chemotherapy

  Correct Answer: D Section: (none)

  Explanation:

  Borderline tumors of the ovary, or tumors of low malignant potential (LMP), represent approximately 15% of all epithelial ovarian tumors. The average age at diagnosis is 40 years of age, 1520 years earlier than is the average age at diagnosis for the invasive ovarian counterpart. Roughly 50% of all borderline tumors are serous. Because most borderline serous tumors occur in women of reproductive age and are classified as stage I at the time of diagnosis, treatment is usually conservative. Most patients can be managed with cystectomy or oophorectomy alone; in fact, cystectomy is the treatment of choice in the presence of bilateral borderline ovarian cystic tumors, or when only one ovary remains and fertility is desired. If the patient is perimenopausal, postmenopausal, or has no desire for fertility, hysterectomy with bilateral salpingo-oophorectomy is recommended. When the diagnosis of borderline tumor is made on the basis of an intraoperative frozen section evaluation, a complete staging procedure is still recommended in the event the final pathology report reveals an invasive cancer. The staging information will be critical in that setting in order to determine the stage of disease present and the need for chemotherapy postoperatively. Surgical staging should include pelvic and abdominal cytology, random peritoneal biopsies (right hemidiaphragm, paracolic gutters, ovarian fossa bilaterally, cul-de-sac, and bladder flap), partial omentectomy, and lymph node sampling.