Repro USMLE step 1 9-1 (3)

Question 1

The patient presents with sudden vaginal bleeding and painful abdominal cramps at 32 weeks’ gestation without trauma. She has low blood pressure and rapid heart rate indicating a bleed. The fetus is in distress within a hypertonic uterus. The patient’s history of smoking and cocaine use also point to a diagnosis of abruptio placentae, or placental abruption.

Placental abruption is the partial or complete premature separation of placenta from the uterine wall. Risk factors include smoking and cocaine use as seen in this patient, as well as trauma, hypertension, and preeclampsia. Patients present with sudden painful bleeding in the third trimester, as seen in the vignette. Complications are life threatening and include?

Answer 1

DIC from tissue factor entering maternal circulation, maternal shock, and fetal distress or death.

Question 2

Postpartum hemorrhage and Sheehan syndrome are associated with placenta accreta/increta/percreta, where the maternal portion of the placenta, the desidua basalis, has abnormal attachment and separation after delivery. This condition would be visible on ultrasound, unlike what is seen in this patient. Preeclampsia is a condition of new-onset hypertension with?

Answer 2

either proteinuria or end-organ dysfunction after the 20th week of gestation. Abruptio placentae can be a complication of preeclampsia, but not a cause. This patient’s condition also does not include infertility as a complication.

Question 3

Bleeding in the third trimester that is bright or dark red and associated with painful abdominal cramps suggests placental abruption. Placental abruption is the partial or complete premature separation of placenta form the uterine wall. Risk factors include smoking, cocaine use, trauma, hypertension, and preeclampsia. Complications include?

Answer 3

DIC, maternal shock, and fetal distress.

Question 4

This patient’s genotype and the presence of male internal genitalia are suggestive of a genotypic male who was born with ambiguous genitalia due to?

Answer 4

a congenital 5a-reductase deficiency.

Question 5

5a-Reductase converts testosterone to dihydrotestosterone (DHT), the potent androgen required for the development of male external genitalia in utero. Individuals with a congenital 5a-reductase deficiency are born with male internal genitalia (including testes) but ambiguous or female-appearing external genitalia, such that most are raised as girls. When they reach puberty, however, increasing testosterone levels cause ?

Answer 5

masculinization of the external genitalia, resulting in the “penis-at-12” phenomenon. 5a-Reductase deficiency thus causes an increased testosterone/DHT ratio; luteinizing hormone levels can be normal or elevated in patients with 5a-reductase deficiency.

Question 6

17a-Hydroxylase deficiency leads to decreased sex hormone and cortisol levels with elevated mineralocorticoid levels. Tyrosinase deficiency presents with characteristics of albinism. Nicotinamide adenine dinucleotid phosphate oxidase deficiency is ?

Answer 6

characteristic of immune disorders. 21-Hydroxylase deficiency and aromatase deficiency present with male characteristics at birth.

Question 7

5α-Reductase converts testosterone to DHT, which plays a critical role in male sexual development. Congenital 5α-reductase deficiency results in?

Answer 7

male internal genitalia (including testes) but ambiguous or female-appearing external genitalia. However, at puberty, increased testosterone levels cause masculinization of the external genitalia.

Question 8

This patient presents with reduced libido, erectile dysfunction, and fatigue a few weeks after starting a new treatment for tinea cruris. He is also found to have reduced body hair and testicular volume, as well as gynecomastia. These signs and symptoms suggest testosterone deficiency. Diminished testosterone secretion in adults leads to decreases in libido, sexual hair, muscle mass, testicular volume, and energy. Ketoconazole, an antifungal drug used to treat tinea infections, directly inhibits?

Answer 8

testosterone biosynthesis, resulting in testosterone deficiency.

Leydig cells produce testosterone and are the only major cell type found in the interstitium surrounding the seminiferous tubules. Testosterone secreted by these cells is responsible for the maintenance of the seminiferous epithelium, and thus for spermatogenesis, as well as for the development of secondary sexual characteristics in males.

Question 9

Although cells of the zona reticularis produce small amounts of testosterone, it is unlikely that reduced functioning would cause a large enough decrease in testosterone levels to cause the symptoms seen in this patient. Sertoli cells support and nourish developing sperm. Reduced function of Sertoli cells would result in ?

Answer 9

infertility due to impaired sperm production and decreased inhibin secretion, resulting in high follicle-stimulating hormone levels. Dysfunction of both spermatids and spermatozoa would also result in infertility, as opposed to symptoms of reduced libido and erectile dysfunction.

Question 10

Antifungal drugs, such as ketoconazole, have been shown to interfere with testosterone synthesis in the Leydig cells of the testes, resulting in?

Answer 10

decreased testosterone levels. Leydig cells are the major producers of testosterone in males. A low testosterone level results in decreased libido, body hair, muscle mass, testicular volume, and energy.

Question 11

This patient, who is currently undergoing chemotherapy, presents with vaginal burning, itching, and inflammation and the presence of a thick white discharge in the vagina. Gram staining of the discharge shows constrictions between rod-like cells along with globular buds, confirming a diagnosis of ?

Answer 11

Candida albicans vulvovaginitis.

C. albicans is a pathogenic yeast found in the vulva and vagina, which commonly causes opportunistic infections. Risk factors include immunosuppression, diabetes mellitus, antibiotic use, and contraceptive device use. Diagnosis can be made with microscopic observation of C. albicans on a wet mount or with Gram staining. The microscopic image provided shows constrictions (“pseudohyphae”) between rod-like C. albicans cells along with globular buds, which represent newly formed fungal cells that are still growing.

Question 12

It is likely that Candida vulvovaginitis developed because this patient is undergoing chemotherapy, which results in a state of immunosuppression. Significantly, C. albicans can also cause ?

Answer 12

esophagitis in immunocompromised patients.

In particular, it is known to cause esophagitis in patients with HIV whose CD4+ cell count has dropped below 100/mm3.

Chronic lung disease resembling tuberculosis is suggestive of the presence of Histoplasma, not Candida, organisms. Lesions in lung cavities may be caused by Aspergillus fumigatus, but not Candida. Meningoencephalitis is a manifestation of Cryptococcus neoformans infection in immunocompromised individuals; it is not a known manifestation of Candida infection. Migrating synovitis is caused by infection with Neisseria gonorrhoeae, not Candida.

Question 13

C. albicans is a yeast and common opportunistic pathogen. Vaginal itching with a whitish, curd-like discharge is suggestive of ?

Answer 13

C. albicans vulvovaginitis. Candida infection can also cause esophagitis in immunocompromised patients

Question 14

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?

Answer 14

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.

Question 15

Because tension is mediated by a1-adrenergic receptors, the first-line treatment is a selective α1-receptor blocker such as?

Answer 15

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 16

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 a treatment for BPH; however, it was replaced by more selective α1-adrenergic blockers. Sildenafil is a?

Answer 16

phosphodiesterase type 5 inhibitor, which shows some efficacy in treating BPH, but is not FDA-approved for this indication.

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

Question 17

The patient with hypertension, proteinuria, and signs of end-organ damage (headache and blurry vision) likely has preeclampsia, and magnesium toxicity has resulted from her treatment. Preeclampsia is treated with magnesium to lower blood pressure and prevent seizures (progression to eclampsia). Magnesium sulfate is the drug of choice for?

Answer 17

preventing seizures in women with preeclampsia during labor and is given in very high doses. Loss of deep tendon reflexes (hyporeflexia) is one of the first signs of toxicity (magnesium level = 4.0–5.0 mmol/L), along with central nervous system depression (drowsiness) and flushing. Respiratory depression, coma, and eventually cardiac arrest can occur at higher magnesium levels.

Question 18

Hypermagnesemia does not cause hyperactivity, hypertension, or involuntary movements. Magnesium also does not cause a rash, although many antiseizure agents, such as carbamazepine and phenytoin, carry the risk of Stevens-Johnson syndrome, which is characterized by?

Answer 18

bullae formation with a fever. Note that any drug allergy can cause a rash. Phenytoin can cause nystagmus, and it is used to treat epilepsy, not to prevent eclampsia.

Question 19

Magnesium is used to treat preeclampsia, which presents with hypertension and proteinuria in the last 10 weeks of pregnancy. Magnesium toxicity results in?

Answer 19

loss of deep tendon reflexes, sinoatrial and atrioventricular node blockade, drowsiness, respiratory depression, and ultimately cardiac arrest.

Question 20

This asymptomatic patient with a history of sexual activity at an early age, infrequent use of protection, and multiple partners is found to have high-grade dysplasia on a Pap smear and laboratory findings. The causative agent of cervical dysplasia and cancer is the human papillomavirus (HPV).
The E6 and E7 HPV gene products downregulate p53 and pRb, respectively, allowing?

Answer 20

the cell to cycle out of control, despite any damage to cellular DNA. Tumor suppressors, such as p53 and hypophosphorylated RB, normally inhibit G1-to-S progression; mutations in these genes result in unrestrained cell division. Cervical intraepithelial neoplasia (CIN) can progress in three stages:

CIN 1 occurs when dysplasia involves lower third of epithelium or less,
CIN 2 occurs when dysplasia involves lower third to lower two-thirds of the epithelium
CIN 3 occurs when dysplasia extends above lower two-thirds of epithelium, if full thickess involvement then can be called carcinoma in situ.
If dysplasia is present in the full epithelium, the patient has carcinoma in situ.

Question 21

Blood vessel growth factors are not targeted by the HPV virus and the oncogenes from the HPV virus do not directly activate DNA replication. Oncoproteins such as the HPV gene products are unlikely to inhibit ?

Answer 21

the mitogenic signal transduction, and the HPV virus does not affect the activation of the RNA-dependent DNA polymerization.

Question 22

The human papillomavirus causes cervical dysplasia and and in some cases, cancer by?

Answer 22

allowing the cell to cycle out of control, despite any damage to cellular DNA.

Question 23

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 23

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.

Question 24

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?

Answer 24

para-aortic lymph nodes.

The following lymph nodes are less likely to be the site of metastasis from the ovaries: deep inguinal, inferior mesenteric, internal iliac, and superficial inguinal lymph nodes.

Question 25

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 the?

Answer 25

para-aortic lymph nodes.

Question 26

n this scenario, the principles of beneficence and autonomy are in conflict. Although a C-section is medically indicated, if the patient has decision-making capacity, then she is free to refuse care, even if that decision is ultimately not in her (or her unborn child’s) best interest. There is nothing to suggest the patient does not have decision-making capacity, and she has provided clear and consistent expression of her choice. However, it is important to practice evidence-based, safe medicine at all times and to explain to the patient the risks and benefits of each action. Therefore, the physician should attempt?

Answer 26

to understand the patient’s reservations, correct any misunderstandings, and ensure that she understands the consequences of her choice. At this point, if the patient has decision making capacity, she can refuse the surgery.

Question 27

The American College of Obstetricians and Gynecologists (ACOG) has said: “Pregnancy does not obviate or limit the requirement to obtain informed consent. Intervention on behalf of the fetus must be undertaken through the body and within the context of the life of the pregnant woman, and therefore her consent for medical treatment is required, regardless of the treatment indication.” Furthermore, it advises physicians to ?

Answer 27

counsel and educate their patient in the case, “in which a mother refuses a diagnostic or surgical procedure, and thus endangers her fetus, or in which a mother’s lifestyle or health practices endanger her fetus.”

Question 28

Allowing the patient to have a natural childbirth is not the correct option at this time, because the physician first needs to further assess the mother’s decision-making capacity. Explaining to the husband that his wife is putting herself and the baby at risk is not the correct choice because this does not solve the problem, and the physician should first try and understand the patient’s refusal. Proceeding with a C-section only if death is imminent is not correct because the?

Answer 28

patient has explicitly denied the C-section both before and during labor, despite the risks to the fetus and herself. Obtaining a court order to proceed with a C-section is premature and therefore is not correct. The patient should first be assessed for decision-making capacity, and if she is found to have decision-making capacity she has the right to refuse treatment.

Question 29

Patients have a right to refuse treatment if they are deemed to have decision-making capacity. This right still applies to mothers who may go against medical advice and put themselves and/or their unborn fetus at risk. In these situations, the best option is?

Answer 29

to try and understand why the patient has reservations and ensure she understands the consequences of her choice.