Repro USMLE step 1 9-1 (1)

Question 1

This male patient presents with infertility, moderate hypertension, low levels of testosterone, and high levels of luteinizing hormone. This man likely has?

Answer 1

Klinefelter syndrome, a genetic disorder that occurs in 1/850 male subjects. Men with Klinefelter have testicular atrophy, feminine body shapes (often, but not always, presenting with gynecomastia), long extremities, and sparse body hair. This diagnosis is a common cause of hypogonadism found in an infertility work-up.

Question 2

This patient’s serum level of LH is high secondary to his underlying testicular atrophy. Resultant abnormal Leydig cell function leads to the decrease in serum testosterone, thus altering the normal feedback loop with the anterior pituitary that normally releases LH to stimulate testosterone synthesis in Leydig cells.

The genotype in Klinefelter syndrome is XXY As there are two X chromosomes in these men, a Barr body (inactivated X chromosome) can be seen on?

Answer 2

karyotyping and occasionally on microscopic examination at the cellular level.

Note that in rare situations, 46,XX men also can have Klinefelter syndrome; in this setting, the development of testes presumably is due to translocation of a small portion of chromosomal material containing the testis-determining factor to an X chromosome.

Question 3

An abdominal CT scan may reveal abnormalities in Turner syndrome (streak ovaries) or androgen insensitivity syndrome, and it could reveal atrophied testes in Klinefelter syndrome. However, karyotyping is more accurate for determining this syndrome.

Ciliary movement may be useful in diagnosing Kartegener syndrome, but the syndrome does not cause abnormal testosterone and LH levels, which are seen in this patient. Defective migration of GnRH cells and anosmia are classic symptoms of Kallman syndrome, which this man does not appear to have.

Sperm counts are commonly done in suspected male infertility, but the blood test findings point towards a diagnosis of?

Answer 3

Klinefelter, which is best diagnosed with karyotyping.

The smell test is used to diagnosis anosmia, which is a characteristic of Kallmann syndrome. Testosterone levels are low in these patients, but levels of gonadotropin-releasing hormones are also low (vs this patient’s high LH level).

Question 4

Klinefelter syndrome, which is caused by ?

Answer 4

the genotype XXY, results in a phenotypically male individual with testicular atrophy, gynecomastia, sparse body hair, and infertility. Karyotyping is performed to diagnose Klinefelter syndrome.

Question 5

The patient’s vaginal pruritis, white discharge, vaginal pH of 4.2, and recent history of broad-spectrum antibiotic use make a clinical vaginal infection with Candida albicans the most likely diagnosis. The use of antibiotics likely eliminated the majority of the normal vaginal flora, such as?

Answer 5

lactobacilli (gram-positive facultative anaerobes). A 10% potassium hydroxide preparation can reveal the characteristic budding yeast of C. albicans and pseudohyphae.

Question 6

Lactobacilli make up a majority of the normal flora of the vagina. The composition of the normal flora varies during the premenarchal, childbearing, and menopausal stages; but a key feature of the normal vaginal environment is a low pH (3.5–4.2), which inhibits growth of other, possibly pathogenic, organisms. This pH is likely maintained by the lactobacilli, and when numbers of these bacteria are reduced during the course of antibiotic treatment (eg, with tetracycline), the vaginal pH may relatively?

Answer 6

increase (4.0–4.5), making conditions favorable for the yeast C. albicans to grow. This patient has the symptoms of a yeast infection, and diagnosis is made by staining vaginal discharge with a 10% potassium hydroxide preparation on which pseudohyphae are seen.

Question 7

The presence of protozoa, such as Trichomonas vaginalis, would not be consistent with the lack of trophozoites on a wet mount. This patient’s symptoms are consistent with the overgrowth of, rather than the loss of, a dimorphic budding yeast (ie, C. albicans). Gram-positive cocci are not responsible for?

Answer 7

maintaining the protective low pH of the vagina, and obligate anaerobes are not present in the normal vaginal flora.

Question 8

Lactobacilli predominate in the normal vaginal flora and help protect against foreign organisms by maintaining a low pH of 3.5–4.2. Loss of lactobacilli as a result of antibiotic use can lead to overgrowth of?

Answer 8

C. albicans. C. albicans causes vulvovaginitis, which presents with vaginal pruritis and a white discharge.

Question 9

Because the fetus in this case lacks mesonephric, or Wolffian, ducts, any structures that develop from the mesonephric ducts would be absent. The prostate is the only genital structure listed that does not develop from the mesonephric ducts. The prostate develops?

Answer 9

from the urogenital sinus in response to dihydrotestosterone (DHT). The urogenital sinus also forms the prostatic urethra.
Most internal male genital structures develop in the mesonephric (Wolffian) ducts in response to testosterone. This can be remembered with the mnemonic BEEDS: trigone of the Bladder, Epididymis, Ejaculatory duct, Ductus deferens, Seminal vesicles. The external male genitalia (penis and scrotum), as well as the prostate, develop under the influence of DHT.

Question 10

In normal development the SRY gene is present on the Y chromosome and will produce testes-determining factor, leading to the development of the testes. Next during development, Sertoli cells will secrete anti-Müllerian factor. Anti-Müllerian factor inhibits the development of the paramesonephric ducts and prevents the female phenotype from forming, thus promoting the development of the mesonephric (Wolffian) duct structures. In this case, the developing fetus was found to have no mesonephric ducts, indicating that no male internal genitalia would form. The urachus develops from ?

Answer 10

the allantois, an embryologic derivative of the yolk sac. All other answers listed are part of male internal genitalia, including ejaculatory duct, epididymis, bladder, seminal vesicles, and vas deferens. As stated previously, these structures develop in the mesonephric (Wolffian) ducts.

Question 11

The prostate develops from?

Answer 11

the urogenital sinus. The mesonephric ducts develop into the male internal genital structures, which can be remembered with the mnemonic BEEDS: Bladder trigone, Epididymis, Ejaculatory duct, Ductus deferens, Seminal vesicles.

Question 12

This woman is in the secretory (also called luteal) phase of her menstrual cycle, which occurs after ovulation (approximately day 14 of a typical menstrual cycle) through the end of the cycle.

Progesterone increases after?

Answer 12

ovulation (as it is produced by the corpus luteum) and usually peaks around day 21–22. Progesterone is responsible for the increased endometrial production of glycogen and the differentiation and maintenance of the endometrium. The estrogen level is high just prior to ovulation (it induces the LH peak), but falls dramatically around the time of ovulation (when the follicle becomes the corpus luteum). After ovulation, the estrogen levels begin to rise again, returning to a relative peak during the luteal phase (around day 21). The high levels of estrogen and progesterone act in negative feedback during the luteal phase, inhibiting the release of FSH and LH; therefore during the secretory phase, progesterone and estrogen levels are high and FSH and LH levels are low due to negative feedback.

Question 13

Choice A represents a combination of hormone changes seen during the end of the menstrual cycle, when the corpus luteum degenerates. This woman is on day 19 of her cycle and, thus, still has a corpus luteum. Answer B is characteristic of the follicular phase of the menstrual cycle, during which estrogen increases slowly due to the maturation of the follicle(s) under the influence of FSH. This woman is in the secretory, or luteal, phase of her cycle, not follicular. Answer C predominates in the days prior to ovulation. Progesterone levels remain?

Answer 13

low and stable, due to the lack of a corpus luteum, which is responsible for the secretion of the hormone later in the cycle. Choice D is seen immediately following ovulation, when estrogen levels are decreasing (prior to increasing again during the luteal phase) and progesterone levels are increasing

Question 14

During the first half of the luteal phase (approximately days 14–21 of the menstrual cycle), estrogen and progesterone levels increase and exert a negative feedback on the secretion of FSH and LH, leading to?

Answer 14

low FSH and LH levels.

Question 15

Androgenic steroids are used to treat hypogonadism either due to failure of the hypothalamic-pituitary-gonadal axis (secondary hypogonadism) or due to Leydig cell dysfunction (primary hypogonadism). Patients should be warned that androgens cause?

Answer 15

premature closing of the epiphyseal plates by promoting calcium deposition in the bones.

Question 16

Androgenic steroids can cause polycythemia rather than anemia. This adverse effect is another risk factor for premature coronary artery disease and thrombosis.

Androgenic steroids play a large role in libido and sexual function. The use of this form of therapy is associated with increased libido. Inhibition of androgenic steroid synthesis, such as from 5α-reductase inhibitors, may cause decreased libido.

The use of androgenic steroids has been associated with?

Answer 16

decreased levels of serum HDL cholesterol levels, not increased. Furthermore, androgenic steroids have also been shown to increase LDL cholesterol levels. This change in lipid profile increases the possibility of atherosclerotic change and raises the risk of early coronary artery disease.

A serious adverse reaction to androgens is not leukocytosis but leukopenia due to decreased marrow production or decreased WBC survival.

Question 17

Undergoing treatment of hypogonadism carries risks and benefits. Some adverse reactions associated with androgen therapy include?

Answer 17

premature closure of the epiphyseal plates, leukopenia, decreased spermatogenesis, increased LDL cholesterol levels, and male pattern baldness.

Question 18

This pregnant patient with a significant smoking history presents with sudden onset abdominal pain, vaginal bleeding, fetal tachycardia, and a tender uterus. This is a common clinical picture of ?

Answer 18

abruptio placentae, the premature separation of the placenta from the uterine wall, that usually occurs during the third trimester of pregnancy. It manifests as painful vaginal bleeding that appears dark red due to the darker appearance of venous blood. This is in contrast to the bright red bleeding seen in placenta previa. As in this patient, initiation of contractions can also be seen in placental abruptions. Severe abruption may result in fetal death and disseminated intravascular coagulation. Risk factors include hypertension, trauma, smoking, and cocaine use during pregnancy.

Question 19

Placenta previa presents with painless vaginal bleeding, in contrast to this patient’s painful bleeding. Vasa previa can present with ?

Answer 19

painless vaginal bleeding, however it presents with fetal bradycardia (and the fetal heart rate here is 170/min). Umbilical cord prolapse does not present with any bleeding. While uterine rupture is associated with abdominal pain and vaginal bleeding, it occurs only during labor.

Question 20

Placental abruption should be suspected in ?

Answer 20

obstetric patients with painful vaginal bleeding in the third trimester, especially patients with risk factors of smoking, trauma, hypertension, or cocaine use.

Question 21

This patient’s presentation of abnormal menstrual bleeding in a woman who is likely post or perimenopausal is highly suggestive of endometrial carcinoma. The specimen from a hysterectomy demonstrates disorganized proliferative endometrium with glandular invasion of the myometrium (see left lower corner in the vignette image).
The primary risk factor for most endometrial carcinomas is?

Answer 21

increased estrogen exposure, which can result from nulliparity, late menopause, early menarche, and obesity. Obesity is thought to increase peripheral conversion of androgens to estrogens in adipose tissue. Overweight women have a 2-fold increase in risk of endometrial cancer compared to those of normal weight; obese women have a 3-fold increase in risk.

Weight loss would have been an effective risk-reducing measure in this patient.

Question 22

Other factors that would increase the risk of endometrial cancer are age, diabetes, history of endometrial hyperplasia, and a family history of bowel, bladder or uterine cancer (ie, Lynch syndrome).

The other answer choices would not be the most effective in preventing endometrial cancer. Late menopause would?

Answer 22

increase the patient’s risk of endometrial cancer but would not contribute as much as obesity. Drinking alcohol and genetics/family history do not increase the risk of endometrial cancer but are related to other cancers including breast cancer in women. Smoking has actually been shown to decrease the risk of endometrial cancer in women.

Question 23

Obesity is a significant risk factor for endometrial carcinoma. In addition, any condition that increases estrogen exposure increases the risk for ?

Answer 23

the development of endometrial hyperplasia or carcinoma.

Question 24

Mifepristone is a partial progesterone agonist that acts as a competitive antagonist in the presence of progesterone. Because progesterone is necessary to maintain a pregnancy, mifepristone’s interference with this hormone causes abortion of the embryo. A few days after mifepristone is administered?

Answer 24

misoprostol, a prostaglandin E agonist, is taken to stimulate uterine contraction and thus expel the embryotic contents from the uterus. Combining misoprostol with mifepristone increases the abortifacient effects of the regimen.

Question 25

Other options such as drugs that increase GnRH secretion, inhibit COX enzymes, or activate progesterone receptors, would not stimulate a medical abortion. The only option that would facilitate medical abortion would be an oxytocin receptor agonist, which stimulates uterine contractions; however, oxytocin agonists are less preferable in this context owing to?

Answer 25

increased side effects and decreased efficacy.

Question 26

In a medical abortion, the patient is first given mifepristone, a progesterone antagonist, to make the uterus an uninhabitable/unsustainable environment for the fetus. Misoprostol, a prostaglandin E1 agonist, is taken 24–48 hours later; this drug causes ?

Answer 26

uterine contraction and expulsion of the uterine contents.

Question 27

An 8-year-old white girl presents with abdominal pain. She has mild tenderness throughout the abdomen and is unable to localize the pain to any particular point. She also has prominent breast tissue. Menses started at 7 years of age. Imaging reveals a large intra-abdominal mass.

Answer 27

The symptoms listed are characteristic of hyperestrogenism.

Granulosa cell tumors are sex cord-stromal cell tumors that secrete estrogen, and thus often manifest with signs and symptoms of hyperestrogenism. In the adult form, which comprises 95% of cases, these signs and symptoms include endometrial hyperplasia or carcinoma, abnormal uterine bleeding, breast tenderness, postmenopausal bleeding, and menstrual irregularities. In the juvenile form, patients may present with precocious puberty due to excessive estrogen production. These tumors also may present as large, asymptomatic masses on abdominal or pelvic examination. They do have malignant potential. Histologically, they are indicated by the presence of Call-Exner bodies, which are characterized by fluid-filled cavities with a “rosette” appearance seen on microscopic exam (circles in image).

Question 28

Choriocarcinomas are highly malignant germ cell tumors. They are very rare as primary ovarian tumors and are more frequently of placental origin. Both gestational and ovarian choriocarcinomas produce human chorionic gonadotropin, which may cause isosexual precocity in young girls and irregular uterine bleeding. They tend to metastasize early via hematogenous routes to the lung, liver, brain, and bone. Ovarian types are highly unresponsive to therapy and generally result in death.

Dysgerminomas are?

Answer 28

malignant germ cell tumors, not sex cord-stromal cell tumors. They are relatively uncommon but account for about half of malignant germ cell tumors. Most arise in adolescents and young adults, who usually present with abdominal enlargement and pain. These tumors may produce placental alkaline phosphatase, lactate dehydrogenase, human chorionic gonadotropin, or estrogen, but most do not.

Question 29

Fibromas, the most common sex cord-stromal tumors of the ovary, are benign, solid tumors that occur primarily in postmenopausal women. They are not hormonally active. The triad of ovarian fibroma, ascites, and hydrothorax is termed Meigs’ syndrome.

Ovarian adenocarcinoma is a rare but often fatal neoplasm of the ovaries that would be extremely unlikely?

Answer 29

in a child this age.

Granulosa cell tumors are sex cord-stromal cell tumors that secrete estrogen, and thus often present with signs and symptoms of hyperestrogenism.

Question 30

The patient in the vignette suffered a perineal tear during delivery, and several hours later experienced fecal incontinence. She likely damaged her external anal sphincter. .

the perineal body is the site of convergence of several muscles of the urogenital diaphragm anterior to the anus: the bulbospongiosus, external anal sphincter, and perineal muscles. A severe perineal laceration in the midline may result in damage to the?

Answer 30

anal sphincter, leading to fecal incontinence. Perineal tears are common during vaginal deliveries, particularly in the setting of prolonged labor, babies large for gestational age, and in older mothers, as indicated in this vignette.

The coccygeus muscle is a muscle of the pelvic wall. Damage to the levator ani muscle or sphincter urethrae during parturition would result in urinary, not fecal, incontinence. The piriformis muscle lies in the gluteal region and is not commonly injured during childbirth.

Fecal incontinence can occur during vaginal delivery due to damage to the perineal body and the external anal sphincter.