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USMLE Step 1 High‐Yield Reproductive Topics
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Reproductive
High Yield USMLE Step 1 Notes
Welcome to the Reproductive High-Yield Notes for Step 1.
These are the most commonly tested topics on the exam—ideal for quick review in your last 2 weeks before the exam, when you’re short on time, or when you’re just starting out and want to focus on what is high yield. Created and peer-reviewed by physicians who scored 260+ on Step 1 in a Q&A style to reinforce active learning.
How to use this file
- Read the question ➔ cover the answer ➔ self-quiz before revealing.
- Review the NOTES ➔ they include high-yield details you don’t want to miss.
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Table of Contents
Embryonic development
1. A 6-day-old blastocyst is preparing to implant in the endometrium. What hormone begins to rise at this time to maintain the corpus luteum?
➔ hCG (human chorionic gonadotropin)
- Note: hCG is secreted by the syncytiotrophoblast starting around day 6 post-fertilization, right as the blastocyst implants. It maintains the corpus luteum, which produces progesterone.
- Week 1: hCG secretion from syncytiotrophoblast begins around implantation. It maintains corpus luteum
- Week 2: Formation of bilaminar disc: epiblast + hypoblast.
- Week 3: Gastrulation → Formation of trilaminar disc: ectoderm, mesoderm, endoderm.
○ Notochord induces ectoderm → neural plate (neurulation via SHH signaling). It gives nucleus pulposus.
2. A newborn has a congenital absence of the anterior pituitary and hypopigmented patches. Which embryological layer is responsible for these affected structures?
➔ Ectoderm
- Note: Ectoderm (External layer)
- Surface: Epidermis, Rathke pouch (anterior pituitary), lens of eye, oral sensory epithelium.
- Neural tube: CNS neurons, oligodendrocytes, astrocytes, ependymal cells, retina.
- Neural crest: PNS ganglia, adrenal medulla, melanocytes, Schwann cells, aorticopulmonary septum “endocardial cushion.
3. A patient with abdominal trauma in the left upper quadrant. The organ most likely damaged originates from which embryologic origin?
➔ Mesoderm “spleen rupture”
- Note: Mesoderm (Middle layer)
- Muscle, bone, cardiovascular system, spleen, kidneys, Microglial cells, and reproductive organs.
Endoderm (Internal layer) - “Enternal layer” → Gut tube epithelium, lungs, liver, pancreas, thyroid, bladder.
4. A pregnant woman is treated with ACE inhibitors during the first trimester. What fetal complication is most likely to develop?
➔ Oligohydramnios
- Note: ACE inhibitors (teratogens) → Renal agenesis → ↓ fetal urine → oligohydramnios.
- Antiepileptics “phenytoin” or folate antagonists “Methotrexate” : Neural tube defects.
- Vitamin A: craniofacial dysmorphism. Do pregnancy test and give contraceptives.
- Warfarin: bone and cartilage abnormalities. Use heparin instead.
5. A newborn has a smooth philtrum, thin upper lip, and small head circumference. What prenatal exposure is the most likely cause?
➔ Alcohol (Fetal Alcohol Syndrome)
- Note: Fetal alcohol syndrome → smooth philtrum, thin vermillion, microcephaly.
- Maternal Diabetes: cardiac defects “VSD or transposition of great vessels”, neonatal hypoglycemia, macrosomia
- Smoking or Cocaine: low birth weight, preterm fetal growth restriction, and sudden infant death.
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6. A fetus is found to have excessive amniotic fluid and an absent stomach bubble on ultrasound. What is the most likely cause of the polyhydramnios?
➔ Esophageal atresia
- Note: Polyhydramnios (excessive amniotic fluid): Causes include fetal malformations (e.g., esophageal/duodenal atresia, anencephaly → inability to swallow), maternal diabetes, fetal anemia, and multifetal gestation.
7. A newborn has flat facies, limb deformities, and underdeveloped lungs. What condition during pregnancy most likely caused this?
➔ Oligohydramnios
- Note: Oligohydramnios (too little amniotic fluid): Causes include placental insufficiency, bilateral renal agenesis, posterior urethral valves (males) → inability to excrete urine.
- Severe cases may cause Potter sequence (lung hypoplasia, limb deformities, facial anomalies).
8. A 2-day-old newborn presents with tremors, high-pitched crying, irritability, and seizures. His mother has a history of opioid use. What is the most likely diagnosis?
➔ Neonatal abstinence syndrome
- Note: Opioid withdrawal in newborns → High-pitched cry, irritability, tremors, tachypnea, seizures.
- Treatment: Morphine, methadone, buprenorphine.
9. A newborn has meconium-stained discharge from the umbilicus. What is the most likely underlying embryological defect?
➔ Patent vitelline duct (Omphalomesenteric duct)
- Note: Patent vitelline duct: Total failure to obliterate → meconium discharge from umbilicus.
- Meckel diverticulum: Slight failure → outpouching of the ileum, may contain gastric or pancreatic tissue → melena, hematochezia, abdominal pain.
- If clear fluid discharges from the umbilicus ”urine” → patent urachus “allantois remnant”, failure to obliterate.
10. A newborn has micrognathia, cleft palate, and ear anomalies. These features suggest a defect in which pharyngeal arches?
➔ 1st and 2nd pharyngeal arches
- Note: 1st arch: Maxilla, Maxillary process, mandible, mandibular process, malleus, incus, muscles of mastication, and mandibular nerve.
- 2nd arch: Stapes, styloid, stylohyoid muscle, lesser hyoid, muscles of facial expression, facial nerve.
- 6th arch: recurrent laryngeal nerve, laryngeal muscles except cricothyroid.
- 4th arch: superior laryngeal nerve, cricothyroid, and pharyngeal muscles.
11. A boy with DiGeorge syndrome has hypocalcemia and recurrent infections. Which pharyngeal pouches failed to develop?
➔ 3rd and 4th pouches
- Note: 3rd pouch: Thymus + inferior parathyroids
- 4th pouch: Superior parathyroids
- DiGeorge = 22q11.2 deletion; Leads to T-cell deficiency (↓ thymus) and hypocalcemia (↓ PTH).
12. In a healthy male newborn, which embryological structure is suppressed due to Müllerian-inhibiting substance?
➔ Paramesonephric (Müllerian) duct
- Note: Male Development
- SRY gene on Y chromosome → Testis-determining factor → Testes development.
- Sertoli cells: Secrete Müllerian-inhibiting substance (MIS) → suppress paramesonephric duct development.
- Leydig cells: Secrete androgens → stimulate mesonephric duct development.
Female Development: Default pathway. - The male duct degenerates into “Mesonephric (Wolffian)” and the female duct develops into “paramesonephric (Müllerian)”.
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Congenital Sex Disorders
13. A 16-year-old girl with primary amenorrhea. Virilization + clitoromegaly during puberty. Which disorder?
➔ 5α-reductase deficiency
- Note: Genetically male (46, XY) with ambiguous genitalia until puberty
- At puberty, ↑ Testosterone → Virilization, growth of external genitalia
- Normal Testosterone & Estrogen, Normal or ↑ LH
14. A 16-year-old girl with primary amenorrhea. Breast are normal for age, but no uterus and scant pubic hair. What is the diagnosis?
➔ Androgen insensitivity syndrome
- Note: Defective androgen receptor (46, XY):
- Phenotypically female, but 46-XY karyotype
- Scant pubic/axillary hair, rudimentary vagina, no uterus/fallopian tubes
- Normal testes (often in labia majora, removed to prevent malignancy)
- ↑ Testosterone, estrogen, LH
15. A tall, infertile man with small firm testes and gynecomastia. What is the most likely diagnosis?
➔ Klinefelter syndrome (47,XXY)
- Note: Small testes, infertility (azoospermia), Tall stature with long limbs, Gynecomastia
- ↓ seminiferous tubules → ↓ inhibin B → ↑ FSH.
- ↓ Leydig cell function → ↓ Testosterone → ↑ LH.
16. A 15-year-old girl with short stature and primary amenorrhea is found to have coarctation of the aorta. What condition does she have?
➔ Turner syndrome (45, XO)/ mosaic karyotype ((45, XO)+ (46, XX))
- Note: Short stature (GH therapy helps), cystic hygroma, lymphedema, and horseshoe kidney.
- Ovarian dysgenesis (“streak ovary”) → Primary amenorrhea → ↓E, ↑LH, ↑ FSH.
- Bicuspid aortic valve, coarctation of the aorta, osteoporosis risk.
17. A newborn XX female has ambiguous genitalia, and her mother had acne and hirsutism during pregnancy. What enzyme deficiency is responsible?
➔ Aromatase deficiency
- Note: Virilization of female infant & mother
- Ambiguous genitalia in XX female
- Maternal hirsutism is a keyword.
18. A boy with delayed puberty and no sense of smell. What is the diagnosis?
➔ Kallmann syndrome
- Note: Failure of GnRH neuron migration → Hypogonadotropic hypogonadism (↓ GnRH, FSH, LH, testosterone) → Delayed puberty, infertility
- Anosmia (absent olfactory bulbs)
Pregnancy
19. A pregnant woman has decreased BUN and mild glucosuria on labs. What’s the next step?
➔ Reassurance (physiologic change)
Physiological Changes in Pregnancy
| System | Changes |
|---|---|
| Respiratory | Mild respiratory alkalosis |
| Cardiovascular | ↑ Cardiac output, ↑ Heart rate (late pregnancy), peripheral edema |
| Gastrointestinal | Constipation, GERD, Gallstones |
| Skin | Melasma, linea nigra, striae gravidarum, varicose veins, palmar erythema |
| Endocrine | ↑ Insulin resistance due to Human Placental Lactogen, ↑ TBG, ↑ Cortisol, ↑ SHBG |
| Hematologic | Dilutional anemia, hypercoagulability, ↑ Micronutrient needs |
| Renal | ↑ GFR, ↓ BUN & Creatinine, Mild glucosuria/proteinuria |
| Musculoskeletal | Lordosis, joint laxity |
20. A pregnant woman is in labor. She develops sudden abdominal pain and loss of fetal station. History of prior C-section. What is the most likely diagnosis?
➔ Uterine rupture
- Note: Uterine Rupture
- Painful vaginal bleeding, loss of fetal station.
- Risk: Prior C-section, or fibroma removal
- Treatment: Immediate surgery
21. A woman continues to bleed heavily after delivery. The uterine fundus is boggy. What is the most likely cause of this postpartum hemorrhage?
➔ Uterine atony
- Note: Postpartum Hemorrhage
High yield Etiologies: - Tone (atony): Most common, the uterus is boggy. Treat with massage and oxytocin.
- Trauma: Common in operative vaginal delivery. Laceration of cervix or vagina. Repair the laceration.
- Retained Tissue: previous uterine surgery. Boggy uterus + placenta missing some parts.
○ Treatment: manual extraction or Dilation & curettage.
22. A woman with positive hCG presents with unilateral abdominal pain and no intrauterine pregnancy on ultrasound. What is the diagnosis?
➔ Ectopic pregnancy
- Note: Implantation outside the uterus (the fallopian tube is most common)
- Amenorrhea, vaginal bleeding, positive pregnancy test, and lower abdominal pain
- ↑ hCG but no intrauterine pregnancy on ultrasound
23. A pregnant woman develops high blood pressure and proteinuria at 28 weeks. What is the most likely diagnosis?
➔ Preeclampsia
- Note: Gestational Hypertension
- BP >140/90 after 20 weeks with no proteinuria
- Treatment: α-Methyldopa, Labetalol, Hydralazine, Nifedipine
Preeclampsia - New-onset HTN + Proteinuria/End-organ damage after 20 weeks
- Treatment: Aspirin (prophylaxis), IV Magnesium (seizure prevention), Delivery
Eclampsia - Preeclampsia + Seizures
- Treatment: Immediate delivery, IV Magnesium sulfate
24. A pregnant woman has anemia, elevated liver enzymes, and thrombocytopenia. What is the diagnosis?
➔ HELLP syndrome
- Note: HELLP Syndrome (A severe form of preeclampsia)
○ Hemolysis, Elevated Liver enzymes, Low Platelets
○ Treatment: Immediate delivery.
25. After delivery, a woman begins breastfeeding. Which hormone is responsible for milk production, and what causes its activation?
➔ Prolactin; disinhibited by drop in estrogen and progesterone
- Note: After delivery, ↓ estrogen & progesterone → disinhibit prolactin → Lactation.
- Prolactin: Induces & maintains milk production.
- Oxytocin: Milk letdown & uterine contractions.
- Breastfeeding benefits:
○ ↓ Risk of infections, asthma, allergies, diabetes, and obesity.
○ Maternal benefits: ↓ Breast & ovarian cancer risk, bonding.
Breast
26. A 29-year-old woman reports bilateral breast lumps and tenderness that worsen before each menstruation. What is the most likely diagnosis?
➔ Fibrocystic changes
- Note: Presents with premenstrual breast pain or lumps, often bilateral and multifocal.
- The KEY is menstruation + bilateral. Symptoms get better when the menstruation is over.
27. A breastfeeding mother develops a painful, red, swollen breast with fever. What is the most likely diagnosis?
➔ Lactational mastitis
- Note: Common during breastfeeding, S. aureus is the most common pathogen.
- Treat with antibiotics and continue breastfeeding.
28. A 36-year-old woman presents with bloody nipple discharge but no palpable mass. What is the most likely diagnosis?
➔ Intraductal papilloma
- Note: Intraductal Papilloma:
- Small, fibroepithelial tumor within lactiferous ducts.
- The keyword is bloody nipple discharge.
29. A 24-year-old woman presents with a small, well-circumscribed, mobile breast mass that gets tender before her period. What is the most likely diagnosis?
➔ Fibroadenoma (Key: Single breast lesion + Worsens with menstruation)
- Note: Fibroadenoma:
- Small, well-defined, mobile mass.
- Estrogen-sensitive: Increases in size/tenderness (pregnancy, before menstruation).
- No cancer risk.
30. A 58-year-old woman presents with a firm, irregular breast mass and nipple retraction. What is the most likely diagnosis?
➔ Invasive breast carcinoma
- Note: Breast Cancer
- Postmenopausal Women.
- Axillary lymph node metastasis = most important prognostic factor.
- Risk factors:
○ ↑ Estrogen exposure (nulliparity, late first pregnancy, obesity).
○ Family history (BRCA1/BRCA2 mutations). - Note: BRCA mutations are seen in both breast and ovarian cancer. If we see a BRCA mutation in a patient with ovarian cancer, we look for breast cancer via imaging (and the other way around).
31. A 58-year-old woman with estrogen receptor-positive breast cancer is started on a drug. Now she reports hot flashes. What is the drug?
➔ Tamoxifen
- Note: Tamoxifen → Estrogen antagonist at breast, agonist at uterus & bone
- Treats ER+ breast cancer and gynecomastia prevention in prostate cancer
- ↑ Risk of endometrial cancer, thrombosis.
- Raloxifene is only used to prevent Osteoporosis. Can increase thrombosis risk but no endometrial cancer.
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Ovary
32. An ovarian mass in a young woman contains hair and teeth on ultrasound. What is the most likely diagnosis?
➔ Mature teratoma
- Note: If tumor contains hair or teeth → Mature teratoma (dermoid cyst)
- High risk of ovarian torsion, carcinoma, and hyperthyroidism if contains thyroid tissue.
33. A young woman presents with an ovarian mass. Histology shows large cells with clear cytoplasm and “fried egg” appearance. What is the diagnosis?
➔ Dysgerminoma
- Note: Ovarian tumors:
- If “fried egg” cells are present, ↑ hCG, ↑ LDH → Dysgerminoma
- If Schiller-Duval bodies are present, ↑ AFP → Yolk Sak Tumor
- If associated with precocious puberty, endometrial hyperplasia → Granulosa Cell
- If associated with hirsutism or virilization → Sertoli-Leydig
- If biopsy shows psammoma bodies → serous carcinoma
34. A 24-year-old woman presents with sudden, severe unilateral lower abdominal pain, nausea, and vomiting. Pelvic exam reveals adnexal tenderness. Doppler ultrasound shows decreased blood flow to the ovary. What is the most likely diagnosis?
➔ Ovarian torsion
- Note: Due to twisting of ovarian vessels, due to an ovarian mass as teratoma
- Surgical emergency → detorsion or oophorectomy
- Ultrasound: enlarged ovary ± absent or reduced blood flow.
35. A woman presents with sharp, one-sided pelvic pain midway through her cycle. What is the most likely cause?
➔ Mittelschmerz (ovulatory pain)
- Note: Mittelschmerz (“middle hurts”):
- Mid-cycle ovulatory pain due to peritoneal irritation from follicular rupture.
- Unilateral, mild, can mimic appendicitis.
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Uterus
36. A 38-year-old woman with heavy menstrual bleeding and pelvic pain. The uterus is uniformly enlarged and tender. What is the most likely diagnosis?
➔ Adenomyosis (keyword is uniformly enlarged uterus)
- Note: Adenomyosis
- Endometrial glands in the myometrium
- Uniformly enlarged, “boggy” tender uterus
- Dysmenorrhea, menorrhagia
37. A 34-year-old woman with infertility and chronic pelvic pain. The exam reveals a fixed, retroverted uterus. What is the most likely diagnosis?
➔ Endometriosis (keyword is immobile cervix or uterus)
- Note: Keyword: Immobile Cervix and Uterus (Adhesion), nodularity of pelvic ligaments, or chocolate cyst in the ovary.
- Pelvic pain, dyspareunia, and infertility
38. A woman has an irregularly enlarged uterus and complains of heavy menstrual bleeding. Imaging shows multiple well-defined uterine masses. What is the most likely diagnosis?
➔ Leiomyoma (fibroid, keyword is irregularly enlarged)
- Note: Benign smooth muscle tumor, estrogen-sensitive (Regresses after menopause)
- Enlarged irregular uterus with multiple well-demarcated masses (NOT uniform)
39. A 60-year-old obese woman with postmenopausal bleeding. Biopsy reveals endometrial carcinoma. What is the main risk factor?
➔ Unopposed estrogen exposure
- Note: We see unopposed estrogen exposure in obesity, PCOS, nulliparity, and hormone replacement therapy.
- Estrogen plus progesterone → ↑ Breast cancer risk.
40. During a total abdominal hysterectomy, a surgeon carefully ligates a structure that carries the uterine artery near the cervix. What ligament is this?
➔ Cardinal ligament
- Note: Cardinal ligament: It connects the cervix to the pelvic wall. It carries uterine vessels and has a risk of injury during hysterectomy
- Infundibulopelvic ligament (suspensory ligament of ovary):
It connects the ovary to the pelvic wall. It carries ovarian vessels, ligated during oophorectomy.
- Ureter runs close to both, might be injured during oophorectomy and hysterectomy → “water under the bridge”
Ureter under uterine artery (cardinal lig)
Ureter near ovarian vessels (IP lig)
Other Gynecological Disorders
41. A 28-year-old woman has regular 28-day cycles. LH surge occurs on day 14. Which hormone peaks just before the LH surge, and which hormone dominates the luteal phase?
➔ Estrogen peaks before LH surge; progesterone dominates the luteal phase
- Note: Estrogen rises in late follicular phase → triggers LH surge → ovulation. FSH stimulates follicle growth; LH triggers ovulation.
- Progesterone rises after ovulation (from corpus luteum) → stabilizes endometrium. hCG (from syncytiotrophoblast) maintains corpus luteum in early pregnancy.
- If no fertilization: corpus luteum degenerates → ↓ progesterone → menstruation
42. A 22-year-old woman with amenorrhea and a BMI of 16. What is the most likely diagnosis? And what are the levels of FSH, LH, and estrogen?
➔ Functional hypothalamic amenorrhea (↓ FSH, ↓ LH, ↓ Estrogen)
- Note: Functional Hypothalamic Amenorrhea (CENTRAL)
- ↓ GnRH secretion due to stress, eating disorders, or excessive exercise
- ↓ Leptin → ↓ LH, ↓ FSH, ↓ Estrogen
Keyword: BMI < 18.5 + amenorrhea
43. A 52-year-old woman has 13 months of amenorrhea and elevated FSH. What is the diagnosis?
➔ Menopause
- Note: ↑↑ FSH after age 45 is specific for menopause. ↑LH, ↑GnRH.
- Associated with: Osteoporosis, Coronary artery disease.
- Hormone replacement therapy:
○ Estrogen alone → ↑ Endometrial cancer risk. Add progesterone to prevent hyperplasia.
○ Estrogen plus progesterone → ↑ Breast cancer risk. - Amenorrhea (or menstruation irregularity) + ↑ FSH + age < 45 → primary ovarian insufficiency.
44. A 32-year-old woman has secondary amenorrhea. Labs show elevated FSH and LH, but low estrogen. What is the most likely diagnosis?
➔ Primary ovarian insufficiency
- Note: Primary Ovarian Insufficiency (POI)
- Early menopause (<40 years old)
- ↑ LH, ↑ FSH, ↓ Estrogen
- Causes: Turner syndrome, Fragile X syndrome, autoimmune
45. A 28-year-old woman with a painful swelling near her vaginal opening. Exam shows a tender, fluctuant mass at the posterior introitus. What is the most likely diagnosis?
➔ Bartholin’s abscess
- Note: Bartholin Cyst (just bulging) & Abscess (Painful)
- Blockage of the Bartholin gland duct → Fluid accumulation
- May lead to abscess due to obstruction & inflammation
- Occurs in reproductive-age females
46. A 52-year-old woman with abnormal vaginal bleeding. Biopsy reveals clear cell adenocarcinoma. What is the most important risk factor?
➔ In utero exposure to diethylstilbestrol (DES)
- Note: Clear Cell Adenocarcinoma of vagina
- Arises from vaginal adenosis (persistence of columnar epithelium in proximal vagina).
- Linked to in-utero diethylstilbestrol (DES) exposure.
- Squamous cell carcinoma of either the vulva, vagina, or the cervix are mostly due to HPV. Multiple sexual partners is the most significant risk factor.
47. A 41-year-old woman undergoes a cervical biopsy. Histology shows atypical squamous cells with hyperchromatic nuclei extending beyond the basement membrane. What is the most likely diagnosis?
➔ Invasive cervical cancer
- Note: In cervical intraepithelial neoplasia (CIN):
- CIN 1 or CIN 2: Atypical squamous cells involve a partial thickness of the cervical epithelium.
- CIN 3: Atypical cells extend through the full thickness of the epithelium without invading the basement membrane.
- Invasive cervical cancer: Atypical cells breach the basement membrane and invade the underlying stroma. Can invade the ureter causing hydronephrosis.
48. A 26-year-old woman presents with hirsutism, irregular periods, and obesity. Labs show increased LH:FSH ratio. What is the most likely diagnosis?
➔ Polycystic ovary syndrome (PCOS)
- Note: PCOS (Polycystic Ovary Syndrome)
- ↑ LH : FSH, ↑ androgens, ↑ E, insulin resistance
- Hirsutism, obesity, oligomenorrhea, and infertility
- ↑ Risk of endometrial cancer (unopposed estrogen)
49. A 29-year-old woman with PCOS is trying to conceive. Which medication can induce ovulation?
➔ Clomiphene
- Note: Clomiphene → Blocks negative feedback on GnRH → ↑ LH & FSH. (induces ovulation).
Weight loss and spironolactone are supportive.
Adverse effects include; hot flushes, and multiple gestations.
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Male Genital Disorders
50. A male patient has low testosterone, low LH, and low FSH. Testes are small but present. Which testicular cells normally produce testosterone, and which hormone stimulates them?
➔ Leydig cells produce testosterone; stimulated by LH
- Note: Leydig cells: Make testosterone → under LH stimulation.
- Sertoli cells: Support spermatogenesis → stimulated by FSH.
- It also secrete inhibin B (↓ FSH) and ABP (androgen-binding protein) to trap testosterone in seminiferous tubules.
- Most serum testosterone is bound to SHBG (sex hormone–binding globulin). Only free testosterone is biologically active.
51. A male patient has infertility due to immotile sperm, chronic sinus infections, and situs inversus. What is the most likely diagnosis?
➔ Primary ciliary dyskinesia (Kartagener syndrome)
- Note: Ciliary dyskinesia (Kartagener syndrome) → Impaired sperm motility → Infertility.
- Cystic fibrosis → Absent vas deferens → Infertility, but normal sperm motility.
52. A 1-year-old boy has an undescended right testicle. What is he at increased risk for?
➔ ↑ Risk of germ cell tumors (Diagnosis: Cryptorchidism)
- Note: Cryptorchidism:
- Failure of the testicle to descend → impaired spermatogenesis → infertility.
- ↑ Risk of germ cell tumors (even with orchiopexy).
- Most resolve spontaneously; if not, orchiopexy before 2 years ol
53. A teenage boy presents with sudden, severe scrotal pain. Exam shows a high-riding testicle and absent cremasteric reflex. What is the diagnosis?
➔ Testicular torsion
- Note: Testicular Torsion:
- Acute, severe pain, high-riding testis, absent cremasteric reflex (keyword).
- Treatment: Surgery within 6 hours.
54. A 27-year-old man has a painless scrotal mass described as a “bag of worms.” What is the most likely diagnosis?
➔ Varicocele
- Note: Varicocele:
- Dilated pampiniform plexus → “bag of worms”. More common on the left side.
- Infertility risk due to high temperature.
- Can be idiopathic or secondary to renal vein occlusion by thrombi or cancer.
55. A 3-month-old male presents with a painless scrotal swelling that transilluminates on exam. The swelling increases in size when the baby cries. What is the most likely diagnosis?
➔ Communicating hydrocele
- Note: Caused by patent processus vaginalis → Fluid from peritoneal cavity flows into scrotum
- Transilluminates, unlike hernias with bowel. Often resolves by 1–2 years
56. A 3-year-old boy has an enlarged testicle. Tumor markers show elevated AFP. What is the most likely diagnosis?
➔ Yolk sac tumor
- Note: 95% of Testicular Tumors are germ cell tumors:
- Seminoma (Most common, “fried egg” cells, ↑ PLAP).
- Yolk Sac Tumor (Schiller-Duval bodies, ↑ AFP, most common in children).
- Choriocarcinoma (↑ hCG, fast hematogenous metastases).
- Leydig cell tumor: precocious puberty.
- Note: If nothing is mentioned about the tumor, it is probably a seminoma as it is the most common one.
57. A 65-year-old man presents with urinary hesitancy, weak stream, and nocturia. What is the most likely diagnosis?
➔ Benign prostatic hyperplasia (BPH)
- Note: Benign Prostatic Hyperplasia (BPH):
- Hyperplasia (not hypertrophy) of the transition zone → urethral compression. Smooth on rectal exam.
- Symptoms: ↑ frequency, nocturia, hesitancy, weak stream, dysuria.
- Treatment:
○ α1-antagonists (tamsulosin, terazosin) → relax smooth muscle. Risk of orthostatic hypotension.
○ 5α-reductase inhibitors (finasteride) → ↓ DHT production. (Also used for male-pattern baldness)
58. A 72-year-old man complains of low back pain. Labs show elevated PSA. Imaging reveals osteoblastic lesions in the spine. What is the most likely diagnosis?
➔ Prostatic adenocarcinoma
- Note: Prostatic Adenocarcinoma
- Arises from the posterior/peripheral zone of the prostate. Nodular on rectal exam.
- Metastases to bone (especially spine via vertebral venous plexus) → low back pain.
59. A 52-year-old man with prostate cancer starts a GnRH analog that initially increases testosterone before suppressing it. What drug is he likely taking?
➔ Leuprolide
- Note: Leuprolide, Goserelin (GnRH analog):
- At first, they stimulate the GnRH receptors, but continuous use downregulates GnRH receptors.
- For Fibroids, endometriosis, prostate cancer, and precocious puberty.
60. A 60-year-old man uses sildenafil for erectile dysfunction. What is the mechanism by which this medication promotes erection?
➔ Inhibits PDE-5, increases cGMP
- Note: Erection = Parasympathetic, Emission = Sympathetic, Ejaculation = Somatic.
- Mnemonic: “S2, 3, 4 keep the penis off the floor.”
- PDE-5 inhibitors (e.g., sildenafil) → ↓ cGMP breakdown → Prolonged erection.
- If used with nitrates → ↑↑↑ cGMP → Severe Vasodilation → ↓↓↓ Blood Pressure.
61. A trauma patient has rising BUN and fluid seen intraperitoneally on imaging. Which organ is most likely injured?
➔ Bladder dome (superior bladder wall)
- Note: Bladder injury:
○ Superior bladder wall (dome) injury → Rupture → Intraperitoneal urine leakage (↑ BUN, creatinine).
○ Anterior bladder wall or neck injury → Pelvic fracture → Extraperitoneal urine accumulation (retropubic space). - Renal injury: Hematuria, flank pain (caused by direct trauma or rib fractures).
62. A man presents after a motorcycle accident with blood at the urethral meatus and a high-riding prostate on exam. What injury is most likely?
➔ Posterior urethral injury
- Note: Anterior Urethral Injury → Bulbar urethra disruption → Scrotal and penile hematoma
- Posterior Urethral Injury → Pelvic fracture → Urine leakage into retropubic space, high-riding prostate
- Blood at the meatus → urethral injury. Catheterization is contraindicated in urethral injuries!
🏁 Final Thoughts
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Version 1.0 May 2025. No part of this document may be reproduced or distributed without written permission. For personal study only. Medical information herein is for educational purposes and does not constitute clinical advice. Always confirm with current guidelines and your institution’s policies.
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