NBME OBGYN Form 4 - Answers & Explanations
Updated: Nov 16, 2019
1) Increasing her current anticonvulsant medication
• This patients phenytoin concentration is low - the dose should be increased
• Pregnancy → ↑ proteins that bind phenytoin → ↓ phenytoin concentration
• The benefits of treating with phenytoin outweigh the risks, as seizures in mom are dangerous for the baby; additionally, the majority of infants born to women who take phenytoin during pregnancy will not develop fetal hydantoin syndrome
• There is evidence that children exposed to multiple anticonvulsants may be at greater risk for birth defects
2) Hemoglobin electrophoresis
• This patient has microcytic anemia (MCV <80)
• Serum ferritin and iron are normal = no iron deficiency
• Hemoglobin electrophoresis should be used to check for other causes of microcytic anemia (eg, thalassemia)
3) Cervicitis • This patient is afebrile with postcoital bleeding from a new partner • Acute cervicitis commonly presents with postcoital bleeding, mucopurulent discharge, and a friable cervix
4) Normal labor
• Dilation of cervix + painful contractions = labor
• Closed cervix + painless contractions = Braxton-Hicks contractions
• Cervical insufficiency (incompetence) = painless dilation of cervix that can lead to 2nd trimester pregnancy loss
5) Cystic teratoma • Dermoid cysts are seen on U/S as a partially calcified mass (teeth) with multiple thin echogenic bands (hair) • Torsion (twisting of ovary around the infundibulopelvic and utero-ovarian ligaments) → acute-onset severe pain
6) Placement of an IUD
• IUDs are the most effective contraceptives options (~99% efficacy) • This patient is non-compliant with her HTN meds - this makes oral contraceptives (taken daily) and Depo-Provera (injections every 3 months) a poor choice
7) Intraductal papilloma • MCC of unilateral bloody nipple discharge
• No assocaited mass or LAD
8) BMI
• Low body weight, especially < 128lbs (58kg) → ↓ peak bone density → ↑ risk of fracture
• If the patient had suffered a previous fracture (not family history), then that would be the greatest risk factor for an osteoporotic fracture
9) Hysterectomy • Endometrial cancer tx: hysterectomy • Endometrial hyperplasia tx: hysterectomy or progestin
10) Uterine synechiae • Uterine synechiae = Asherman’s syndrome
• D&C → trauma to basal layer of endometrium → intrauterine scars → failure to respond to estrogen
11) Amenorrhea
• Suction and sharp curettage → denuded basal layer of endometrium → Asherman’s syndrome → 2° amenorrhea
• Diagnosis and treatment = hysteroscopy (lyse adhesions)
12) Down syndrome • Down syndrome (trisomy 21) is associated with Duodenal atresia (→ duodenal bubble)
13) Atelectasis • 5 W’s of post-op fever
• Wind (atelectasis) = Post-op day (POD) 1-2 • Water (UTI) = POD 3-5 • Walking (DVT) = POD 4-6 • Wound (infection of surgical wound) = POD 5-7 • Wonder (anything) = POD 7+
• Abdominal surgery (c-section) → pain on deep inspiration → shallow breathing → underutilization of lung bases → atelectasis
14) Vasa previa • Fetal bradycardia is an important distinguishing feature of vasa previa; occurs because hemorrhage is of fetal origin (vs. maternal origin in placenta previa)
15) Uteroplacental insufficiency • Uteroplacental insufficiency → Late decelerations (nadir of deceleration occurs after peak of contraction)
16) Vesicovaginal fistula • Pelvic surgery or irradiation → ↑ risk of vesicovaginal fistula
• Characterized by continuous, painless urine leakage form vagina (→ moist vaginal mucosa)
• Dx: Dye test, cystourethroscopy
17) Stress incontinence
• ↓ urethral sphincter tone and/or urethral hypermobility → stress incontinence → leakage of urine with ↑ abdominal pressure (eg, coughing, lifting, sneezing)
• Tx: Pelvic floor exercises, pessary
18) Placental dysfunction
• Fetal complications of maternal HTN include fetal growth restriction, oligohydramnios, and preterm delivery
• This patient has been receiving prenatal care since 8 weeks gestation - rules out incorrect gestational age
19) Amnioinfusion
• Maternal repositioning (eg, left lateral decubitus) is first-line intervention for variable decelerations as it may reduce cord compression and subsequently improve fetal placental blood flow
• Amnioinfusion is a possible second-line intervention - artificially creates more amniotic fluid which can reduce umbilical cord compression and decrease variable decelerations
20) Chlamydia trachomatis infection
• Chlamydia → cervicitis → Inflamed, friable cervix
• Tx: Azithromycin and Ceftriaxone
21) 50% • Sickle cell is autosomal recessive
• Mom has it (aa), Dad is carrier (Aa)
22) Colonoscopy • Adults 50-75 years old should be screened for colorectal cancer with a colonoscopy q10y, Sigmoidoscopy q5y, or an FOBT yearly
23) Varicella-zoster immune globulin therapy
• Post-exposure prophylaxis for infants = human varicella-zoster immune globulin therapy
• Tx of disseminated infection in infants = IV acyclovir x 10 days
24) Arrest of active phase
• Recent ACOG guidelines state active phase starts at 6 cm (in an attempt to reduce the number of patients getting unnecessary c-sections)
• Prior guidelines set active stage at 4 cm (this question is outdated)
25) Pulmonary embolus • Sudden-onset pleuritic chest pain • Normal ECG helps rule out acute coronary syndrome
26) Fetal growth restriction • Preeclampsia arrow underdevelopment of spiral arteries → ↑ vascular resistance → utero-placental insufficiency → asymmetric fetal growth restriction
27) Detrusor hyperreflexia
• MS affecting UMNs → loss of inhibitory control over bladder → urge incontinence
• If this patients MS had affected LMNs → hypotonic bladder → overflow incontinence
• Low postvoid residual volume (< 150mL in women, < 50mL in men) rules out overflow incontinence
• Urgency incontinence sxs: sudden urge to urinate (urinary urgency)
• Urgency incontinence tx: antimuscarinic drugs
28) Pyelonephritis • Asx bacteriuria left untreated → pyelonephritis (→ ⊕ CVA tenderness) • Microorganisms may release cytokines and prostaglandins → uterine contractions
29) Prostaglandin production • During menses, endometrium → ↑ prostaglandins → uterine contractions and endometrial sloughing • ↑ endometrial prostaglandin production → uterine hypercontractility & hypertonicity → ischemia arrow primary dysmenorrhea
30) Oxytocin administration
• Too much oxytocin administration → uterine tachysystole (insufficient uterine relaxation between contractions) → spiral artery constriction → ↓ placental blood flow → fetal hypoxia → late deceleration
• Uterine tachysystole = contractions occurring ≤2 minutes apart or >5 contractions in 10 minutes
• Tx: maternal repositioning, tocolysis, discontinue uterotonic agents (eg, oxytocin)
31) Arrange for an immediate psychiatric evaluation • This patient has suicidal ideations and requires immediate in-patient management
• SSRIs take 4-6 weeks to kick in
32) Fetal sleep state • Fetal sleep is the MCC of a nonreactive nonstress test (eg, no accelerations)
• Fetal sleep cycle can last up to 40 minutes
33) Increased cervical cell vulnerability to infections
• Young women have ↑ columnar epithelium lining their cervix → ↑ susceptibility to Gonorrhea and Chlamydia infections
• Overtime this columnar epithelium is replaced with squamous epithelium → ↑ microbial resistance
• ↑ progesterone → thickening of cervical mucus plug → ↓ risk of infection
34) Previous cesarean delivery • Prior placenta previa and previous C-section (or other uterine surgeries) are the biggest risk factor for placenta previa; Multiparity and advanced maternal age are also risk factors
35) Vaginal metronidazole gel • Bacterial vaginosis → Thin grayish discharge, Clue cells, pH >4.5
• Tx: Metronidazole or Clindamycin
36) Condylomata acuminata
• HPV 6, 11 → Condylomata acuminata
• HPV 16 and 18 are high risk strains
• Time frame of her partners syphilis (recently treated) helps rule out condyloma lata (2° syphilis), as it would not have progressed that quickly
37) Uteroplacental artery
• From mother to fetus: uteroplacental artery → placenta → umbilical vein
• Mothers blood doesn’t cross the placenta, therefore thrombosis must occur before the placenta
38) Recommendation for use of a lubricant
• Breastfeeding (↑ prolactin) → ↓ GnRH → ↓ LH, ↓ FSH → ↓ estrogen → vaginal dryness (atrophy)
• This short-term dyspareunia can be managed with lube
39) Ask the patient to convene a meeting of the church elders to discuss cesarean delivery
• This patient has decision-making capacity and can not be subjected to treatment against her will, regardless of the effect on the fetus
40) Testosterone • Lab findings of PCOS: ↑ testosterone, ↑ estrogen, imbalance of LH/FSH (often ≥2:1 ratio of LH:FSH)
41) Duplex venous ultrasonography • Leg swelling and ⊕ Homan sign (calf pain with dorsiflexion) = DVT
• U/S is used for DVT, Dopler is used for arterial insufficiency
42) Transvaginal incision and drainage • This adolescent girl likely has an imperforate hymen - amenorrhea and cyclic lower abdominal pain with an anterior central mass (hematocolpos)
43) Pedunculated submucous leiomyoma uteri • Submucosal fibroids arise under the endometrial lining and protrude into the uterine cavity → heavy and prolonged bleeding • They can prolapse through the cervical os → cervical dissension → labor-like pain
44) Carpal tunnel syndrome • More common during the 3rd trimester of pregnancy due to accumulation of fluid in carpal tunnel; usually resolves following delivery
45) Vaginal foreign body
• Should be managed by irrigation with warmed fluid (after application of a topical anesthetic in the vaginal introitus) or removal with a swab
• Speculum examination should not be performed in prepubertal girls
• Sexual abuse often leads to UTI → dysuria (which this patient does not have). Additionally, the physical exam shows no abnormalities (no signs of abuse).
46) Septic abortion
• Description of “unintended” pregnancy and the presence of cervical laceration implies there was an abortion, possibly with a non-sterile technique → infection
• Presents with fever, ↑ WBCs, abdominal pain, purulent foul smelling vaginal discharge
47) Endometriosis • Presents with chronic pelvic pain, dysmenorrhea, deep dyspareunia, and dyschezia • Physical examination reveals uterosacral ligament nodules and immobile uterus
48) Ruptured corpus luteum cyst • Sudden onset lower abdominal pain + free fluid in posterior cul-de-sac (culdocentesis) + absence of a mass
49) Breast • Progestin replacement is protective against endometrial hyperplasia
50) Ultrasonography • Most likely fetal malposition (eg, transverse lie) → U/S to confirm
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