NBME OBGYN Form 3 - Answers & Explanations
Updated: Feb 25, 2020
1) Ectopic pregnancy
• ↑ β-hCH + abdominal pain + no gestational sac = ectopic pregnancy
• Ectopic pregnancies have a lower β-hCG than expected and don’t double every 24 hours
• This patient has a pseudo-gestational sac (present in ~10% of ectopic pregnancies)
2) Antenatal testing • Antenatal testing will explain why there is polyhydramnios
• Amniocentesis → ↑ risk of PROM
3) No longer indicated • Total abdominal hysterectomy (TAH) in a patient with no prior history of cervical dysplasia (further pap testing not needed because the TAH was due to a benign cause)
• Total abdominal hysterectomy includes removal of the cervix → stop pap testing (no cervix, no cancer) • A partial/supracervical hysterectomy would entail removal of the uterus with preservation fo the cervix
4) Placement of a copper IUD • Hormonal contraception should be avoided in women with current or past history of breast cancer
5) Insulin
• Maternal hyperglycemia → ↑ fetal insulin production → ↓ surfactant synthesis → ARDS (hyaline membranes)
• Cortisol & thyroxine → ↑ surfactant synthesis
6) Granulosa cell tumor
• Granulosa cells convert testosterone to estradiol via aromatase
• Malignant proliferation → ↑ estradiol levels → postmenopausal thickened endometrium
7) Injury to the fifth and sixth cervical roots • Erb-Duchenne palsy → pronated forearm, adducted, internally rotated shoulder • Klumpke palsy (injury to lower trunk, C8-T1) → total claw hand, Horner syndrome
• Spontaneously resolves within 3 months
8) Secretory endometrium • Progesterone, which is normally secreted by the corpus lute during ovulatory cycles, causes differentiation of the proliferative endometrium into secretory endometrium; withdrawal causes menstruation
9) Clomiphene
• Clomiphene treats infertility due to anovulation
• Clomiphene blocks estrogen receptors at the hypothalamus, inhibiting negative feedback mechanism and restoring pulsatile release of GnRH
• Clomiphene is associated with twins and ovarian hyper-stimulation
10) Parvovirus B19 infection • Polyhydramnios, ascites, and skin thickening are consistent with hydrops fetalis
(cardiac inability to keep up with the anemia induced by Parvo)
• Work in a preschool → obtain infection from children
11) Cocaine use • Cocaine → placental abruption
• Cocaine is a more significant risk factor than amphetamine or tobacco use
12) Estrogen deficiency • This patient has urge incontinence, a urinary sxs of atrophic vaginitis (menopause)
13) Normal development • Weight and height is normal, amenorrhea < 6 months
14) Intrahepatic cholestasis • Typically presents in the 3rd trimester with pruritis that is worse on hands/feet
• Dx: ↑ total bile acids (> 10) • Tx: Ursodeoxycholic acid + delivery at 37 weeks gestation
15) Incompetent cervix • Breech position “in the vagina” (not uterus) = fetus is descending, likely due to an incompetent cervix • No contractions rule out all labor options
16) Voiding immediately after coitus • Early postcoital voiding reduces risk of UTI
17) Karyotype analysis • Absent thelarche + ↑ FSH = primary hypogonadism, likely due to Turner syndrome
18) Cervical stenosis
• 2° dysmenorrhea or amenorrhea s/p cervical procedure = development of surgical stenosis (eg, this patients “small, scarred cervical os”)
• Unable to expel sloughed off layer → build up & possible retrograde menstruation → ↑ risk of endometriosis
19) Uterine rupture • Previous cesarean section + fetal parts above the fundus
20) Cyclic progesterone therapy • This adolescent has irregular menstrual bleeding due to anovulatory cycles • Progesterone, which is normally secreted by the corpus lute during ovulatory cycles, causes differentiation of the proliferative endometrium into secretory endometrium; withdrawal causes menstruation
21) Galactocele • Mobile, well-circumscribed, non-tender mass with no fever
• Mastitis = tenderness + erythema + fever • Abscess = tenderness + erythema + fever + fluctuant mass
22) Ultrasonography of the pelvis
• With 6cm dilation, presenting fetal part should be palpable
• U/S should be used to check for CPD (cephalopelvic disproportion), transverse fetal lie, etc.
• Performing an amniotomy prior to head engagement can cause cord prolapse
23) Premature labor • ~60% of twin are delivered preterm; ~90% of triplets are delivered preterm
24) Bartholin duct abscess
• Common in women age ≤ 30
• Bartholin ducts are located B/L at the posterior vaginal introitus and have ducts that drain into the vulvar vestibule at the 4 and 8 o’clock positions to provide vulvuvaginal lubrication
• Tx (symptomatic): I&D followed by a Word catheter placement
• Tx (asymptomatic): observation - spontaneous drainage and resolution may occur
25) Maternal fever • Fetal tachycardia (>160/min) is commonly associated with maternal fever • Cardiotocography (CTG) shows fetal tachycardia with minimal to moderate variability
26) Herpes simplex virus 1 • HSV and H. ducreyi are the two most common causes of tender genital lesions • Clusters of small round lesions and remnants of vesicle clusters are visible • This patient has had “increasing stress during the past month” = herpes outbreak
27) Measurement of urinary ketones
• Hyperemesis gravidarum (HG) is differentiated from typical vomiting of pregnancy by the presence of ketones on urinalysis or lab abnormalities (eg, hypokalemia, hypochloremic metabolic alkalosis)
• Tx: admission to hospital, antiemetics + IVF
28) Squamous cell carcinoma • Squamous cell carcinoma is the most common type of cervical carcinoma (~80%)
• Smoking and HPV 16, 18, 31, and 33 are the most significant risk factors • Usually presents in women > 60
29) Fibrocystic changes of the breast • Fibrocystic change = multiple, tender • Fibroadenoma = single, non-tender mass
30) Endometrial biopsy
• This obese patient (BMI 37) is having heavy menstrual flow, likely from ↑ estrogen (aromatase conversion in excess adipose tissue)
• Any woman ≥ 45 with abnormal uterine bleeding (AUB) → endometrial biopsy
• Any woman ≥ 35 with atypical glandular cells on Pap → endometrial biopsy
31) Parvovirus B19 • Polyhydramnios, ascites, and skin thickening are consistent with hydrops fetalis (cardiac inability to keep up with the anemia induced by Parvo)
32) Amniotic fluid embolism • Present with rapid onset of hypoxemic respiratory failure, severe hypotension, and DIC during labor or the immediate postpartum period • Tissue factor in amniotic fluid activates the coagulation cascade
33) Folic acid deficiency • No prenatal care in an alcoholic with macrocytic anemia • B12 deficiency would have neurological sxs • Pregnancy → ↑ plasma volume → dilution of WBC and platelet concentrations
34) Polymicrobial infection
• Fetal tachycardia + maternal fever + prolonged rupture of membranes = Chorioamnionitis
• Ampicillin & gentamicin are the correct antibiotics, but they were only given 8 hours ago and have not had enough time to impact maternal fever
• Septic pelvic thrombophlebitis is a diagnosis of exclusion which requires persistent fever unresponsive to antibiotics and a ⊖ infectivity workup
35) Alendronate now
• Bisphosphonates are the drug of choice for prevention and treatment of steroid induced osteoporosis
• SLE is a relative contraindication for estrogen use due to ↑ risk of VTE/stroke
• Additionally, this woman is premenopausal and has normal ovarian function (she has enough estrogen)
• Raloxifene is not given to premenopausal women
36) Urethrocele
• ⊕ Q-tip test = stress incontinence; >30° of movement = urethral hypermobility
• Well supported anterior and posterior vaginal wall rules out cystocele and rectocele
37) Imperforate hymen • This adolescent girl likely has an imperforate hymen - amenorrhea and cyclic lower abdominal pain with an anterior central mass (hematocolpos)
38) Pregnancy test • Ruling out pregnancy is the most appropriate next step in diagnosis
39) Surgical exploration
• Fever + leukocytosis + right-sided abdominal pain → appendicitis
• Appendix perforation → fluid in paracolic gutter (which could potentially cause peritonitis/sepsis)
40) Administer a prostaglandin • Late- and post-term pregnancies are commonly complicated by oligo-hydramnios
• Aging placentas may have decreased fetal perfusion, which causes decreased renal perfusion and urinary output
• The presence of oligohydramnios is an indication for delivery • Cervix is not favorable yet, so ripen cervix with prostaglandin
41) Necrotizing fasciitis
• Bartholinitis (cellulitis) is a painful complication of Bartholin cysts, and more commonly, Bartholin abscesses
• Necrotizing fasciitis of the perineum (Fournier’s gangrene) is a severe complication of Bartholinitis associated with diabetics
42) Hydatidiform mole • Hydatidiform mole → ↑↑↑ β-hCG → ovarian hyper-stimulation → theca lutein cysts (resolve with decreasing β-hCG levels)
43) Indirect antiglobulin (Coombs) test
• Rh ⊖ mother in her 2nd pregnancy
• Indirect Coombs test detects presence of unbound antibodies in the serum (direct Coombs test detects antibodies attached directly to the RBC surface)
• Kleihauer-Betke test is used to check the dose of RhoD
44) Doppler ultrasonography of the umbilical artery • This baby has asymmetrical FGR • Doppler U/S of the umbilical artery can show absent or reverse flow, and determines the risk of IUFD
45) Cone biopsy of the cervix • This patients SCJ cannot be visualized meaning inadequate colposcopy result
• Non-pregnant women > 25 with CIN3 should be managed with LEEP or Cone biopsy of the cervix
• Pregnant patients should be managed with colposcopy + biopsy to confirm CIN3 (need to be sure before making a pregnant patient incompetent or stenosed)
46) Follicle-stimulating hormone
• ↑↑ FSH is specific for menopause (loss of negative feedback on FSH due to ↓ estrogen)
• Hypothyroidism can’t account for night sweats, anxiety, etc.
47) Test for Chlamydia trachomatis • All sexually active females < 25 should be offered annual Chlamydia and Gonorrhea screening
48) Autoimmune ovarian failure
• This patient has primary ovarian insufficiency, hypergonadotrophic hypogonadism (↑ FSH & ↓ Estrogen), in the setting of autoimmune disease
49) Ultrasonography • U/S is the next best step to exclude the possibility of incorrect dating • ↑ MSAFP is seen in multiple gestations, placental abruption, fetal abnormalities, or error in the date of gestation
50) Candida albicans • Candida vaginitis presents with a normal pH (3.8 - 4.5) ± thick ‘cottage cheese’ discharge • Risk factors: recent corticosteroid or antibiotic use, pregnancy, diabetes
Found a mistake or have a suggestion? Let us know here