USMLE USMLE Certifications USMLE-STEP-3 Questions & Answers

• Question 381:

  A 17-year-old female presents with delayed puberty. Her mother reports her daughter has never menstruated. On examination, the patient is 59 in. (4 ft 11 in.) tall and is shown in Figure. Which of the following tests is most likely to confirm the diagnosis?

  

  A. karyotype

  B. follicle-stimulating hormone (FSH)

  C. luteinizing hormone (LH)

  D. cranial magnetic resonance imaging (MRI)

  E. growth hormone (GH)

  Correct Answer: A Section: (none)

  Explanation:

  Numerous causes lead to delayed puberty. Common features of Turner syndrome include short stature, sexual infantilism, "shield" chest, "webbed" neck, high arched palate, increased carrying angle of the arms (cubitus valgus), short fourth metacarpal, and streak gonads. The diagnosis of Turner syndrome requires the presence of typical phenotypic features and the complete or partial absence of a second X chromosome. Diagnosis should be considered in individuals with primary or secondary amenorrhea and in adult women with unexplained infertility, particularly when such individuals also are short in stature. Although the FSH would be elevated in Turner syndrome, it would not differentiate among the many causes of ovarian failure. In childhood, GH therapy is standard to prevent short stature as an adult. Estrogen replacement therapy usually is required, but starting too early can compromise adult height. Estrogen usually is started from age 12 to 15 years

• Question 382:

  A23-year-old female presents to her obstetrician gynecologist (OB/GYN) complaining of inability to conceive. She has regular menstrual cycles, and her husband's semen analysis is normal. She undergoes a hysterosalpingogram that shows evidence of bilateral distal tubal obstruction. Which of the following is the most likely cause of acquired tubal damage?

  A. appendicitis

  B. pelvic inflammatory disease (PID)

  C. salpingitis isthmica nodosa (SIN)

  D. Asherman's syndrome

  E. ruptured ovarian cyst

  Correct Answer: B Section: (none)

  Explanation:

  PID is the most common cause of Fallopian tube damage. It is a polymicrobial infection that originates from upward spread of infecting organisms through the cervix and into the uterus, Fallopian tubes, or peritoneal cavity. The two most common pathogens are Neisseria gonorrhea and Chlamydia trachomatis; however, microorganisms that comprise the vaginal flora (e.g., anaerobes, Gardnerella vaginalis, Haemophilus influenzae, enteric gram-negative rods, and Streptococcus agalactiae) also have been associated with PID. Symptoms of PID include lower abdominal pain, dyspareunia, fever, back pain, and vomiting, as well as symptoms of lower genital tract infection such as abnormal vaginal discharge or bleeding, itching, and odor. In some women, symptoms are mild or even absent. Risk factors for PID include the presence of a sexually transmitted infection, a previous episode of PID, sexual intercourse at an early age, high number of sexual partners, and alcohol use. Empiric treatment of PID should be initiated in sexually active young women and other women at risk for STDs if they are experiencing pelvic or lower abdominal pain, if no cause for the illness other than PID can be identified, and if one or more of the following minimum criteria are present on pelvic examination: cervical motion tenderness OR uterine tenderness OR adnexal tenderness. Other common causes of acquired tubal damage include endometriosis, previous pelvic surgery, and a ruptured appendix.

• Question 383:

  A 31-year-old female presents to her physician complaining of rapid onset of hirsutism, deepening of the voice, irregular menses, clitoral enlargement, and acne. Which of the following is the most likely cause of this clinical presentation?

  A. polycystic ovary syndrome (PCOS)

  B. Cushing syndrome

  C. type II diabetes mellitus

  D. androgen secreting tumor

  E. congenital adrenal hyperplasia

  Correct Answer: D Section: (none)

  Explanation:

  Androgen excess syndromes are common and usually characterized by one or more of the following problems: hirsutism, acne, weight gain, or irregular menses. PCOS is the most common disorder of androgen excess. Other syndromes that often result in signs and symptoms of androgen excess in adults include Cushing syndrome and late-onset congenital adrenal hyperplasia. The classic presentation of a patient with an androgen-secreting tumor of the ovary or adrenal gland involves the rapid onset of symptoms. Late-onset congenital adrenal hyperplasia and an androgen-secreting tumor are the only disorders of androgen excess usually resulting in clitoromegaly.

• Question 384:

  Following tubal ligation what percentage of pregnancies are ectopic?

  A. 1%

  B. 5%

  C. 30%

  D. 50%

  E. 75%

  Correct Answer: C Section: (none)

  Explanation: Following tubal ligation pregnancy occurs about 1% of the time. This depends on the method used and the expertise of the surgeon. In general, 30% of pregnancies following tubal ligation are ectopic. A patient who presents with a positive pregnancy test following tubal ligation should be considered an "ectopic until proven otherwise."

• Question 385:

  A23 year old female presents to the emergency department (ED) with "abdominal cramping" nausea, and vaginal bleeding. Ahuman chorionic gonadotropin (hCG) level returns 5150 mIU/mL. A vaginal probe ultrasound is performed and notes no evidence of an intrauterine pregnancy, normal appearing ovaries, a mild amount of fluid in the cul-de-sac, and no evidence of ectopic gestation.

  The ED physician can exclude which diagnosis from the differential?

  A. spontaneous abortion

  B. ectopic pregnancy

  C. singleton intrauterine pregnancy

  D. ruptured ovarian cyst (corpus luteum)

  E. molar pregnancy

  Correct Answer: C Section: (none)

  Explanation: Differentiating between an ectopic pregnancy, an early intrauterine pregnancy, or a miscarriage is a common dilemma for the ED physician. Transabdominal ultrasound (TAUS) requires a -hCG level of 6500 mIU/mL before an intrauterine gestation can be confidently visualized. Transvaginal ultrasound (TVUS) is the most accurate means of confirming intrauterine pregnancy and gestational age during the early first trimester. TVUS can help detect signs of intrauterine pregnancy approximately 1 week earlier than TAUS because it has a lower discriminatory zone (-hCG level between 1000 and 1500 mIU/mL). ATAUS that does not detect an intrauterine gestational sac with a -hCG level higher than 6500 mIU/mL or a TVUS examination that does not detect an intrauterine gestational sac when the -hCG level is higher than 1500 mIU/mL suggests an ectopic pregnancy. The literature provides a wide range of sensitivities and specificities for transvaginal ultrasonography in the detection of ectopic pregnancy. Sensitivities range from 69 to 99%, and specificities range from 84 to 99.6%.

• Question 386:

  Which of the following are currently recommended for all children for every well-child visit?

  A. serum lead levels

  B. hematocrit

  C. PPD

  D. full physical examination

  E. urinalysis

  Correct Answer: D Section: (none)

  Explanation:

  While all of the screenings listed may be appropriate for children with varying symptoms, only a full physical examination is recommended by the American Academy of Pediatrics for ALL well-child visits.

• Question 387:

  An 18-month-old boy is taken to his family doctor for evaluation of easy bruising and decrease range of motion of the right knee. On examination, he had multiple large ecchymoses, mostly in the lower extremities, and a right knee hemarthrosis. He has not had surgery or family history of a bleeding disorder. Initial blood tests reveal a prolonged activated partial thromboplastin time (aPTT) with a normal PT and platelet count.

  What further tests should be ordered to make a diagnosis in this boy?

  A. factor VII

  B. factors II, VII, IX, and X

  C. bleeding time

  D. factors XI, IX, VIII

  E. factor I and II

  Correct Answer: D Section: (none)

  Explanation:

  The PTT represents the time for clot formation after adding calcium, phospholipids, and kaolin to citrated blood. It is prolonged by heparin, direct thrombin inhibitors, a deficiency or inhibitor for factors in the intrinsic and common pathway (i.e., factors II, V, VIII, IX, X, XI, XII) as well as lupus anticoagulant, vitamin K deficiency, or severe liver disease. The PT represents the time for clot formation after the addition of thromboplastin (tissue factor) and calcium to citrated blood. It is prolonged with deficiencies of the extrinsic and common pathway factors II, V, VII, X, or fibrinogen; liver disease; vitamin K deficiency and Warfarin use.

• Question 388:

  A 4-year-old boy is brought to the emergency room by his mother after the child spontaneously admitted to swallowing part of a toy. The child is unable to describe what he ate further, although he appears to be in no distress. His vital signs are normal and his respiratory and abdominal examinations are unremarkable. The child is hungry and is demanding to eat something. ACXR reveals what appears to be a watch battery ("button battery") in the patient's esophagus. What is the best course of action in this situation?

  A. admit the child to the hospital and allow him to eat

  B. admit the child to the hospital but keep him in a fasting state

  C. induce vomiting

  D. emergency endoscopy

  E. discharge the patient with instructions to look in his stools for the battery to confirm passage

  Correct Answer: D Section: (none)

  Explanation:

  The child has ingested a button battery which has lodged in the esophagus. This constitutes a medical emergency and immediate emergency endoscopy is warranted. Button batteries can cause severe esophageal injury and tissue necrosis via electrical current discharge as well as burns from alkali chemicals contained within the battery itself. Severe burns and perforation can occur within hours. Admission for observation is inadequate, and vomiting should not be induced as this could promote aspiration of the battery or gastric contents. Emergency surgery should be reserved for patients in whom endoscopy fails. The patient cannot be discharged with a button battery in the esophagus.

• Question 389:

  A concerned mother brings in her 18-monthold infant girl. The baby's developmental milestones have been normal. The mother states that there is a "funny glint" in her baby's eyes. She also states that sometimes the infant's eyes look crossed. Which of these supports the diagnosis of a serious life-threatening disease?

  A. Baby reaches for small objects.

  B. Baby fusses when each eye is covered.

  C. Bright red reflex in one eye, a white reflex in the other.

  D. Baby rubs both eyes.

  E. Baby holds objects close to inspect them.

  Correct Answer: C Section: (none)

  Explanation:

  Leukocoria, a white pupillary reflex, can be caused by several conditions. The most serious, and potentially life threatening, is retinoblastoma. Retinoblastoma is a malignant neoplasm of the retina that may appear as a white mass extending into the vitreous, a mass lesion underlying a retinal detachment or as a diffusely spreading lesion. Retinoblastomas may be unilateral, bilateral, or multifocal. The diagnosis is usually made between 1 and 2 years of age. Other causes of leukocoria may include retinopathy of prematurity, congenital cataracts, toxocarisis (a nematode infection), or Coats disease (a retinal vascular abnormality). The treatment of retinoblastoma may involve surgery, chemotherapy, or other modalities such as cryotherapy and photocoagulation.

• Question 390:

  A 10-year-old boy presents to your clinic with right knee pain for 2 weeks. He is physically active at school and plays soccer and basketball. He describes pain in his knees when he runs or jumps. He denies any recent trauma. His physical examination is normal except for mild edema and tenderness over the right tibial tubercle. What is the most likely diagnosis?

  A. slipped capital femoral epiphysis

  B. Osgood-Schlatter disease

  C. patellar tendonitis

  D. iliotibial band friction syndrome

  E. septic joint

  Correct Answer: B Section: (none)

  Explanation:

  Osgood-Schlatter disease is a repetitive stress injury to the inferior end of the patellar tendon at its insertion into the tibial tubercle. These patients are usually young, athletic males between the ages 10 and 15 years. The diagnosis is made when a young male presents with knee pain that increases with exercise without a history of trauma. Treatment consists of rest, activity restriction, and anti-inflammatory agents. Slipped capital femoral epiphysis occurs most commonly in African American obese adolescent males. It refers to a slipping of the epiphysis off the metaphysis. The "slipping" is caused by weakening of the perichondral ring of the growth plate, which allows the epiphysis and metaphysis to gradually or acutely displace from each other. This results in pain in the groin, thigh, or knee as well as a limp. Treatment is primarily operative internal fixation. Patellar tendonitis is caused by injury to the patellar tendon. Most of these patients have tenderness in the inferior portion of the patella and complain of chronic anterior knee pain. Iliotibial band friction syndrome causes lateral knee pain in runners.