Repro USMLE step 1 9-6 (10)

Question 1

This 18-year-old patient presenting with amenorrhea for 6 months has an elevated BMI (31), elevated testosterone, and increased LH:FSH ratio which strongly suggests polycystic ovarian syndrome (PCOS). This disease often has onset during the late teenage years to early 20s. Patients will often also report hirsutism and deepening voice. Ultrasound typically shows multiple cysts in the ovaries; however, the presence of cysts is not necessary to make the diagnosis. PCOS is a hyperandrogenic state in which high levels of testosterone cause most of the clinical signs. The small anovulatory follicular cysts secrete large amounts of estrogen as well, at levels high enough to have positive feedback on luteinizing hormone (LH) release. However, the high estrogen levels inhibit follicle-stimulating hormone (FSH) release. None of the follicles that develop in these ovaries are mature, so LH is unable to induce ovulation. Therefore in PCOS, a patient would have elevated testosterone, estrogen, and LH levels, with low FSH levels. Also key would be an elevated LH:FSH ratio, which is also seen in PCOS.

Complications include type 2 diabetes and metabolic syndrome; thus, physicians need to test?

Answer 1

Glucose levels to monitor for insulin resistance and associated complications.

Question 2

The other answer choices would not be affected in PCOS. ß-Human chorionic gonadotropin would indicate pregnancy but LH and FSH are typically low in pregnancy. Cancer antigen 125 would be useful for monitoring ovarian cancer treatment but ovarian cancer would be highly unlikely in this patient due to her age. Increased prolactin levels are associated with?

Answer 2

prolactinomas, which typically present with other symptoms including galactorrhea and neurological symptoms (eg, headache, visual disturbances). Prolactin does not cross-interact with testosterone so the physical changes seen in PCOS would not be seen. Changes in thyroid-stimulating hormone, triiodothyronine, and thyroxine levels are associated with thyroid issues, most likely hypothyroidism, would present with additional symptoms beyond amenorrhea alone.

Question 3

The elevated LH:FSH ratio and presentation of the patient (irregular periods, hair growth on the chin and lip, and deepening of the voice) are common presentations of?

Answer 3

Polycystic ovarian syndrome. These patients are at risk for insulin resistance and metabolic syndrome.

Question 4

This patient presents with a uterus larger than expected for gestational age, a ß-hCG level elevated to >100,000 mU/mL, and an ultrasound revealing a “bag of grapes” or “snowstorm” appearance but no fetal parts. For a normal singleton pregnancy at 10 weeks, the ß-hCG level can range from 25,700–288,000 mIU/mL; however, a single gestation should be seen in the uterus, which is not the case for this patient.
This patient’s presentation suggests the presence of?

Answer 4

a complete or classic mole, which consists of an exclusively paternally derived pregnancy without any fetal parts, and associated with a uterine size that is significantly large for length of gestation and a highly elevated ß-hCG level. This patient’s ultrasound shows the uterus to be distended by a heterogeneously echogenic mass with multiple hypoechoic foci (“bag of grapes” appearance). In contrast, an ultrasound of a partial mole might show fetal parts.

Question 5

Complete moles are diploid, and both sets of chromosomes are paternally derived. Complete moles most commonly occur when an enucleated ovum is fertilized by a single sperm, which then duplicates. Partial moles result from polyploid fertilization with an extra set of paternally derived chromosomes. Both types of moles can present with?

Answer 5

Vaginal bleeding, pelvic pain, increased ß-hCG, and uterine enlargement. However, when a complete mole is present, these signs are observed earlier, and symptoms are more severe.

Question 6

The description 69,XXY; extra paternal set applies to a partial mole, which results from polyploid fertilization with an extra set of paternally derived chromosomes. Partial moles usually present with signs of fetal loss rather than an enlarged uterus and increased ß-hCG. The description 69,XXX; extra maternal set would not apply to either a partial or complete mole because all molar pregnancies have an extra set of paternal chromosomes. The karyotype 45;XO is characteristic of ?.

Answer 6

Tuner syndrome, which does not present with visible uterine abnormalities. A complete mole can have a karyotype of 46,XX but would not have a set of maternal chromosomes

Question 7

A complete, or classic, mole presents with a significantly large uterine size for the duration of the pregnancy and a high β-hCG level. Its karyotype is ?

Answer 7

46 XX or 46 XY
and all chsomes are paternally derived.
Color400PreMole NOSUterine

Question 8

This couple is having difficulty conceiving, even when intercourse is scheduled around the woman’s ovulation time. The woman appears to have no issues related to fertility based on the results of her physical and ultrasound examinations. However, the man’s semen analysis shows a lack of motility. Impaired motility presents a problem for couples trying to conceive, since the sperm need to travel to the egg to fertilize it.
Spermatogenesis takes place in the seminiferous tubules, from which spermatids are transferred to and stored in the epididymis. Sperm are passed from the epididymis into the vas deferens, where they move via the ejaculatory duct into the urethra and out of ?

Answer 8

the penis during ejaculation.
Sperm formation takes approximately 70 days from the spermatocyte stage, and the transport of sperm through the epididymis to the ejaculatory ducts requires about 14 days. Some maturation of sperm occurs during passage through the epididymis, as evidenced by enhancement of motility, but the final maturation (or capacitation) of sperm may take place in the female urogenital tract after ejaculation.

A helpful mnemonic for remembering the journey of sperm is “SEVE(N) UP” (Seminiferous tubules, Epididymis, Vas deferens, Ejaculatory duct, [Nothing,] Urethra, Penis).

Sperm acquire motility in the epididymis, which is lined with a layer of pseudostratified columnar epithelium with stereocilia.

Question 9

The epididymis has columnar epithelium, but it does not have true cilia.
Pseudostratified columnar epithelium with cilia lines the vas deferens.
Simple cuboidal cell epithelium with?

Answer 9

luminal flagella lines the rete testes.

Tall, simple columnar epithelium refers to Sertoli cells, which are located in the seminiferous tubules.

Question 10

Sperm acquire motility in the epididymis, which is lined with?

Answer 10

a layer of pseudostratified columnar epithelium with stereocilia.

Question 11

This patient presents with a septated ovarian mass on ultrasound and an elevated β-human chorionic gonadotropin level. A biopsy specimen obtained during laparotomy reveals uniform cells among stroma, containing lymphocytes. Together, these findings support the diagnosis of dysgerminoma. Dysgerminomas are malignant germ cell tumors that typically present in young women as abdominal pain.

Histologic examination reveals an abundance of large vesicular cells with clear cytoplasm and central nuclei. The ovaries drain first to?

Answer 11

the para-aortic lymph nodes because the lymph vessels run with the ovarian vessels to the posterior abdominal wall, and thus these nodes are the most likely site of early metastasis. In men, it is important to remember that during embryonic development the testes begin high up in the abdomen. The blood supply for the testes from the testicular vessels follows the testes into the scrotal sacs. For this reason, they also drain first to the para-aortic lymph nodes. The table provided here lists lymph nodes and their corresponding areas of drainage.

Question 12

The deep inguinal lymph nodes relay drainage from the superficial inguinal lymph nodes to the external iliac lymph nodes. The bladder drains mostly into?

Answer 12

the external iliac nodes. The deep inguinal lymph nodes would be a very unlikely site of early metastasis from the ovaries.

Question 13

The colon distal to the posterior third of the transverse colon drains to the inferior mesenteric lymph nodes, which are a common site of early colorectal cancer metastasis; they do not receive any lymph drainage from the ovaries.

The internal iliac lymph nodes receive drainage from the prostate, body and cervix of the uterus, proximal vagina, and corpus cavernosum. The ovaries have a separate lymph drainage from the rest of the female reproductive anatomy and do not drain into?

Answer 13

the internal iliac lymph nodes.

The buttocks, lower extremities, parts of the abdominal wall, and the perineum all drain to the superficial inguinal lymph nodes, which in turn drain to the deep inguinal lymph nodes. From there, lymph drains to the external iliac lymph nodes. Spread of ovarian malignancy occurs primarily through lymph drainage, not by direct invasion of surrounding tissue. Although direct invasion might cause metastasis in the superficial lymph nodes, the ovaries drain to a different set of lymph nodes.

Question 14

The ovaries drain first to the para-aortic lymph nodes, and these nodes are the most likely site of early metastasis in a patient with ovarian cancer. The testes originate in the abdomen during embryonic development and also drain to?

Answer 14

the para-aortic lymph nodes.

Question 15

Irregular squamous epithelial cells with nuclear enlargement and perinuclear halos extending from the basal layer of the squamocolumnar junction is descriptive of koilocytes that occur as a result of infection by human papillomavirus (HPV). Most HPV infections are asymptomatic and resolve spontaneously. Some infections can persist and result in warts or precancerous lesions. Cervical cancer is almost always diagnosed in addition to HPV infection. HPV types 16 and 18 currently cause nearly 70% of cervical cancer cases, and both preventative vaccines that are currently in use protect against these types. Cervical cancers are most often squamous cell carcinomas and arise from disordered epithelial growth, classified as cervical intraepithelial neoplasia 1, 2, or 3, depending on the extent of epithelial involvement. Pap smears have reduced the mortality of these cancers because they identify the precursor dysplastic lesions before the tissues become identifiably cancerous.

Risk factors for developing cervical cancer include?

Answer 15

Early

Sexua activity, multiple sex partners, smoking, and low socioeconomic status.

Question 16

Nulliparity is a risk factor for breast cancer and endometrial cancer. Cervical cancer is not sensitive to estrogen and thus nulliparity has no impact on cervical cancer. Early menarche is a risk factor for endometrial cancer and has no impact on cervical cancer. Genital warts are caused by?

Answer 16

types of HPV that are not carcinogenic. Family history is a risk factor for many cancers with a genetic factor. The primary cause of cervical cancer is HPV, thus having a family history imparts little or no additional risk.

Question 17

Early onset of sexual activity is a major risk factor for cervical cancer. Other risk factors include ?

Answer 17

multiple sex partners, smoking, and low socioeconomic status. Pap smears can identify cervical dysplasia (koilocytes) beginning at the transformation zone.

Question 18

Uterine fibroids are benign smooth-muscle tumors of the uterus. Most are asymptomatic, but some women experience painful or heavy periods. Etiology is unclear, but risk factors include obesity, family history, polycystic ovary syndrome, nulliparity, and African descent. This patient elects to receive a hysterectomy while preserving her ovaries. Disruption of blood flow to the ovary during surgery can result in severe damage.

The suspensory ligaments (also known as the infundibulopelvic ligaments) contain the ovarian arteries and veins. They are responsible for direct blood supply to the ovaries. Thus, severing the ?

Answer 18

suspensory ligament would severely disrupt blood flow to the ovaries.

The uterine arteries contained in the cardinal ligament provide collateral blood flow to the ovaries. But severing this ligament should not significantly decrease blood flow to the ovary if the ovarian arteries remain intact. Severing the fallopian tubes would disrupt normal fertilization but would not significantly affect blood flow to the ovary. The round ligament contains no important structures and is not a source of blood for the ovary. The ovarian ligament does not contain any blood vessels.

Question 19

Ovarian vessels run within?

Answer 19

the suspensory ligaments and are responsible for the direct supply of blood to the ovaries.

Question 20

Amenorrhea, scant pubic hair, stage 2 Tanner breasts, and underdeveloped reproductive structures seen in this 16-year-old girl signify that reproductive abnormalities must have occurred during fetal development. Mutations of the SRY (sex-determining region) gene on the Y chromosome, which encodes a transcription factor called testis-determining factor, can result in this presentation. This gene induces a pattern of gene expression that ultimately results in development of?

Answer 20

the testes from indifferent gonads. The testes secrete both testosterone and Müllerian inhibitory factor, triggering a sequence of changes that give rise to a male phenotype. Without a functional SRY gene (which can be seen in the setting of a nonsense mutation, as in this patient), this process is derailed. This means that the fetus will progress along the default pathway of sexual development, that of a female. The mesonephric (Wolffian) ducts will regress spontaneously, and the paramesonephric ducts will develop as they normally do in females. Such individuals will be born with a female phenotype, and they may not have any symptoms until puberty, at which point they often present with primary amenorrhea.

Question 21

The development of internal male genitalia from the mesonephric duct, development of the urogenital sinus into the prostate gland, and the involution of the paramesonephric ducts are all downstream events that affect either Sertoli or Leydig cells found in the testes, but not both types of cells. Leydig cells are involved in ?

Answer 21

the initiation and progression of male reproductive development, whereas Sertoli cells are involved in female reproductive development regression. Only the SRY gene affects both Sertoli and Leydig cells because it is an upstream gene, and this is illustrated by the unique presentation in this patient who has female reproductive structures present and male reproductive structures absent even though her genetic analysis reveals XY chromosomes.

Question 22

The SRY gene encodes testis-determining factor, which induces?

Answer 22

the gene expression responsible for testicular development. Individuals with mutated SRY genes will present with the female phenotype.

Question 23

The patient presents with a painful, exudative, genital ulcerative lesion, indicating a possible sexually transmitted infection. The differential diagnosis of a genital ulcer in a sexually active patient should include primary syphilis, genital herpes, lymphogranuloma venereum, and chancroid. Genital herpes is characterized by small, vesicular lesions on the external genitalia. These may start with itching/burning and be followed by moderate pain but are not typically associated with fever. Syphilis and lymphogranuloma venereum may both present with ulcers, but they are usually painless. Additionally, the results of the Venereal Disease Research Laboratory and rapid plasma reagin tests and the findings on dark-field microscopy are negative for syphilis. The characteristic lesion along with the fever and bilateral swollen lymph nodes suggest a diagnosis of chancroid.
Chancroid is a bacterial infection caused by ?

Answer 23

Haemophilus ducreyi, which manifests typically as a painful genital ulcer with associated inguinal lymphadenopathy. It is typically treated with an intramuscular injection of ceftriaxone or oral azithromycin.

Question 24

Acyclovir is an antiviral agent used to treat herpes infections.
Foscarnet is an antiviral agent used to treat cytomegalovirus and acyclovir-resistant herpes simplex virus.
Ribavirin is an antiviral agent used to treat?

Answer 24

respiratory syncytial virus.

Vancomycin is a bactericidal antibiotic used to treat infections caused by multidrug-resistant gram-positive organisms.

Question 25

Chancroid is caused by Haemophilus ducreyi and develops as a painful ulcer accompanied by?

Answer 25

exudates and inguinal lymphadenopathy. Intramuscular ceftriaxone is a recommended treatment.

Question 26

This patient is likely suffering from benign prostatic hyperplasia (BPH), an enlargement of the prostate gland that affects one-third of men > 50 years old. BPH involves proliferation of the stromal and epithelial elements within the periurethral and transition zones of the prostate. It is believed that as these elements enlarge, the capsule surrounding the gland prevents it from expanding and results in compression of the urethra.

In addition, obstruction gradually leads to bladder dysfunction, which is believed to contribute significantly to symptoms, including increased urinary frequency and urgency, nocturia, difficulty initiating a stream, a weak stream, and incomplete bladder emptying. Smooth muscle proliferation within the prostate and tension in the stroma, urethra, and bladder neck all contribute to symptoms.
Because tension is mediated by a1-adrenergic receptors, the first-line treatment is a selective α1-receptor blocker, such as?

Answer 26

Tamsulosin. In fact, the α1a subtype of receptors is the most concentrated in the bladder neck and prostate, and tamsulosin is a partially selective α1a-blocker.

Question 27

Oxybutinin and mirabegron are medications used in the treatment of overactive bladder, but would not be the first choice for treating BPH as they could make urinary retention worse. Phenoxybenzamine was originally studied as?

Answer 27

a treatment for BPH; however, it was replaced by more selective α1-adrenergic blockers. Sildenafil is a phosphodiesterase type 5 inhibitor, which shows some efficacy in treating BPH, but is not FDA-approved for this indication.

Question 28

The first-line treatment for benign prostatic hyperplasia (BPH) is a selective α1-receptor blocker such as ?

Answer 28

tamsulosin.

Question 29

This asymptomatic woman who is engaging in unprotected sex has a partner who is experiencing pain on urination and a purulent discharge from his urethra. Judging from this woman’s negative Chlamydia trachomatis swab, in conjunction with her partner’s symptoms, the partner is likely infected with Neisseria gonorrhoeae (N. gonorrhoeae). Nucleic acid amplification is now the first-line test for gonorrhea diagnosis.Culture on Thayer-Martin agar has long been considered the gold standard and is still used to evaluate antibiotic-resistant infections.

Thayer-Martin agar is a chocolate agar plate suffused with?

Answer 29

vancomycin, trimethoprim, colistin, and nystatin (VTCN)—all antibiotics that suppress the growth of endogenous flora while supporting the growth of N. gonorrhoeae . Vancomycin is an inhibitor of cell wall peptidoglycan synthesis that binds to the D-ala-D-ala part of cell wall precursors. Its purpose in the Thayer-Martin agar is to prevent the growth of gram-positive organisms such as Staphylococcus aureus.

Question 30

The majority of people (up to 60% of men and 70% of women) infected with N. gonorrhoeae are asymptomatic. However, women with asymptomatic infections are at the same risk for pelvic inflammatory disease and other complications as symptomatic women. As a result, this patient, who likely has an asymptomatic infection since she has engaged in unprotected sexual activity with her symptomatic partner, should be treated. Chlamydia often co-infects with gonorrhea, so antibiotic therapy should include ?

Answer 30

coverage for both organisms. Preferred treatment includes a one-time dose of intramuscular ceftriaxone for gonorrhea and a one-time dose of oral azithromycin for Chlamydia.

Question 31

None of the other drugs named are found in Thayar-Martin agar. Doxycycline, which prevents bacterial protein synthesis from binding to the 30S ribosomal subunit, is used to treat pneumonia and other respiratory tract infections, as well as certain skin, genital (including chlamydia), intestine, and urinary system infections. Azithromycin, a macrolide antibiotic, acts by binding to the 50S ribosomal subunit; among the indications for this drug are acute bacterial exacerbations of chronic obstructive pulmonary disease, bacterial sinusitis, and otitis media, as well as other respiratory and skin infections. Penicillin prevents bacterial cell wall synthesis by binding transpeptidases, which cross-links peptidoglycan in the cell wall. It is indicated for?

Answer 31

the treatment of a range of infections; however, owing to the development of penicillin resistance in many common pathogens, including N. gonorrhoeae, its efficacy has become more limited. Among other indications, the CDC recommends use of ceftriaxone in combination with a second antibiotic as treatment for N. gonorrhoeae. Ceftriaxone is a 3rd-generation cephalosporin antibiotic that prevents bacterial cell wall synthesis by binding transpeptidases, which cross-links peptidoglycan in the cell wall.

Question 32

Men with urethritis due to Neisseria gonorrhoeae often present with dysuria and purulent urethral discharge; women with the same type of infection are usually asymptomatic. Thayer-Martin agar, which contains ?

Answer 32

vancomycin, trimethoprim, colistin, and nystatin, is the most appropriate medium for culture and diagnosis of N. gonorrhoeae infection.