USMLE Step 2 — Lesson 1
OBSTETRIC Highlights USMLE Step 2 Elmar P. Sakala, MD, MPH Discrepant Fundal Size Case #1 · A 20 y/o woman comes to the out-pt prenatal clinic for a new OB visit. · She is 30 wks gest by LMP. · Fundal measurement is 24 cm. Fundus smaller than dates Differential Diagnosis Fundus smaller than dates Think of 3 uterine compartments: o Fetal: fetal demise, IUGR o Amniotic fluid: oligohydramnios o Placental: molar preg Diagnosis Fundus smaller than dates Obtain OB ULTRASOUND: o Fetal: cardiac motion, fetal biometry (BPD, HC, AC, FL) o Amniotic fluid: 4-quad AFI <5 cm o Placental: texture, appearance Etiology Intrauterine Growth Restriction SYMMETRIC IUGR: o BPD, HC, AC, FL are less than expected due to growth potential: e.g. aneuploidy, 1st trimester infection ASYMMETRIC IUGR: o AC is less than expected due to nutritional supply e.g. hypertension, preeclampsia Etiology Oligohydramnios · Premature membrane rupture · Urinary tract anomaly · Placental insufficiency · Meds: indomethacin, ACE inhibitors Management Fundus smaller than dates · Details are specific to the problem identified. Case #2 · A 20 y/o woman comes to the out-pt prenatal clinic for a new OB visit. · She is 30 wks gest by LMP. · Fundal measurement is 35 cm. Fundus larger than dates Differential Diagnosis Fundus larger than dates Think of 4 compartments: o Fetal: multiple fetuses, macrosomia o Amniotic fluid: polyhydramnios o Placental: molar preg, fetal hydrops, infection o Uterine: leiomyomas Diagnosis Fundus larger than dates Obtain OB ULTRASOUND: o Fetal: # of fetuses; fetal biometry (BPD, HC, AC, FL) shows macrosomia o Amniotic fluid: 4-quad AFI >25 cm o Placental: texture, appearance o Uterus: leiomyomas Etiology Polyhydramnios · Fetal GI tract: TE fistula, duod atresia · Fetal NTD: spina bifida, anencephaly · Fetal hydrops: immune, nonimmune · Diabetes mellitus: poor glucose control Management Fundus larger than dates · Details are specific to the problem identified.
USMLE Step 2 — Lesson 2
FIRST Trimester Bleeding Case #3 · A 25 y/o woman comes to the out-pt prenatal clinic for a return OB visit. · She has had vaginal bleeding with no cramping. · She is 12 wks gest by LMP. Differential Diagnosis First trimester bleeding · Threatened abortion · Missed abortion · Inevitable abortion · Incomplete abortion · Completed abortion · Molar pregnancy · Ectopic pregnancy Diagnosis First trimester bleeding SYMPTOMS o Bleeding? Passed tissue? Contractions? Diagnosis First trimester bleeding SYMPTOMS: o Bleeding? Passed tissue? Contractions? PELVIC EXAMINATION o Cervical lesion? Internal cervical os dilated? Diagnosis First trimester bleeding SYMPTOMS: o Bleeding? Passed tissue? Contractions? PELVIC EXAMINATION o Cervical lesion? Internal cervical os dilated? ULTRASOUND: o Gest sac? Embryo? Cardiac motion? Diagnosis & Management THREATENED abortion Characteristics: o Bleeding: minimal o Cramping: none or minimal o Internal cervical os: closed o Ultrasound: normal findings Management: o Conservative management Diagnosis & Management MISSED abortion Characteristics: o Bleeding: none o Cramping: none o Internal cervical os: closed o Ultrasound: non-viable pregnancy Management: o Scheduled D&C, RhoGAM if Rh- Diagnosis & Management INEVITABLE abortion Characteristics: o Bleeding: YES o Cramping: YES o Internal cervical os: dilated o Tissue passed: none o Ultrasound: POC remains in uterus Management: o Emergency D&C, RhoGAM if Rh- Diagnosis & Management INCOMPLETE abortion Characteristics: o Bleeding: YES o Cramping: YES o Internal cervical os: dilated o Tissue passed: YES o Ultrasound: POC remains in uterus Management: o Emergency D&C, RhoGAM if Rh- Diagnosis & Management COMPLETED abortion Characteristics: o Bleeding: Minimal o Cramping: Minimal o Internal cervical os: dilated o Tissue passed: YES o Ultrasound: Normal uterus stripe Management: o Observation; serial quantitative b-hCG (to r/o ectopic) Diagnosis & Management SEPTIC abortion Characteristics: o History: Non-sterile uterine instrumentation o Bleeding: Minimal o Cervical os: purulent discharge o Uterus: tender o Vital Signs: Fever, tachycardia Management: o Admit; cultures; IV gent & clindamycin; gentle D&C SECOND Trimester Loss Case #4 · A 25 y/o woman (G2 P1Ab1) at 18 wks gest presents to the hospital maternity unit with pelvic pressure but NO contractions. · On exam membranes are bulging to the introitus. Second trimester loss Differential Diagnosis Second trimester loss o Incompetent cervix o Mullerian anomaly o Submucus leiomyoma Diagnosis & Management Incompetent Cervix Characteristics: o Painless cervical dilation. o Non-viable gest age. o Delivery of immature normal fetus that dies. Management: o Cervical cerclage (emerg now if possible; scheduled at 14 wks next pregnancy) Cervical CERCLAGE Diagnosis & Management Mullerian anomaly History: · Regular contractions with cervical dilation. · Non-viable gestational age. · Delivery of immature normal fetus that dies. Diagnosis: Hysteroscopy or HSG Management: Hysteroscope resection if thin uterine septum; laparotomy if thick septum Diagnosis & Management Submucus leiomyoma History: · 2nd trim demise occurs without explanation. · Non-viable gestational age. · Delivery of stillborn normal fetus. Diagnosis: Hysteroscopy or HSG · Management: Hysteroscope resection. THIRD Trimester Bleeding Case #5 · A 25 y/o G2 P1Ab1 woman presents to the hospital maternity unit with painful vaginal bleeding. · She is 30 wks gest by LMP. · Fetal heart tones are present. THIRD trimester bleeding Differential Diagnosis THIRD trimester bleeding · Abruptio placenta · Placenta previa · Vasa previa · Uterine rupture Diagnosis & Management Abruptio Placenta Findings: o PAINFUL vag bleeding with uterus not relaxing between UCs. o Assoc with PIH, cocaine, trauma, DIC Sono: Normally implanted placenta Management: o Depends on gest age, status of Mom & fetus. Normal
Placental
Implantation
- Fundal
- Anterior
- Posterior
Overt ABRUPTIO Placenta
ConcealedABRUPTIOPlacenta
Diagnosis & Management Placenta previa Findings: o PAINLESS vaginal bleeding. o Assoc with prev PP, twins,multiparity, AMA Sono: placenta in lower uterine segment Types: Low-lying, partial, complete Management: o Depends on gest age, status of Mom & fetus. LowLyingPlacentaPrevia
Partial Placenta Previa
Total Central Placenta Previa
Diagnosis & Management Vasa previa Findings: o PAINLESS vaginal bleeding. o Assoc with twins,accessory placental lobe o Bleeding is fetal blood! Triad: AROM, vag bleeding, fetal bradycardia Management: o Immediate cesarean on diagnosis! VASA Previa
TEST TAKING WORKSHOPBarbara J. Irwin, BSN, RN Diagnosis & Management Uterine rupture Findings: o PAINFUL vaginal bleeding with UCs. o Assoc: prev classical CS, XS oxytocin, trauma. o Non-reassuring fetal monitor pattern. Types: Complete, incomplete Management: o Immediate cesarean delivery on diagnosis!
USMLE Step 2 — Lesson 3
Postdates Pregnancy Case #6 · A 24 y/o multigravida comes to the out-pt office for a return OB visit. · She is now 42½ wks gest by LMP. Her first prenatal visit was 6 weeks ago. · Her fundal height measures 41 cm. · FHT are 145 beats/min. BP is 125/75. POSTDATES pregnancy Level of Question Difficulty· Recall Recognition · Comprehension · Application · Analysis Diagnosis POSTDATES pregnancy · >42 weeks amenorrhea(assuming ovulation occurred on day 14) · >294 days amenorrhea(assuming ovulation occurred on day 14) · >280 days postconception(time of conception is known) Diagnosis POSTDATES pregnancy · Based on Amenorrhea 6-12% (false) · Based on Conception 3-5% (true) Hazards POSTDATES pregnancy PERINATAL MORTALITY 3-fold Fetus in Postdates Preg? Key question: Placental Function? 75% Maintained
MACROSOMIA Syndrome
Difficult Labor & Delivery
Forceps, Vacuum Shoulder Dystocia Birth trauma Cesarean Section
25% Deteriorates
DYSMATURITY Syndrome
Placental Insufficiency
Acidosis Meconium aspiration Oxygen deprivation Cesarean Section
POSTDATES pregnancy First Question to ask: How much confidence do you have in the GESTATIONAL AGE? Confirming gest age POSTDATES pregnancy · Menstrual history sure; planned preg; normal cycle; no Ocs · Clinical landmarks uterine size & FHT<12 wk; quickening · Sonogram dating CRL <12 wk (+ or - 5d); BPD 12-18 wk (+ or - 7d) Differential Diagnoses POSTDATES pregnancy · Dates sure o cervix favorable· Dates sure o cervix Unfavorable· Dates unsure POSTDATES Management Dates FIRM - Cx FAVORABLE · 1 Induce labor: AROM, oxytocin · Intrapartum EFM looking for: o VARIABLE decels umbilical cord compression o LATE decels placental insufficiency POSTDATES Management What about MECONIUM? · Incidence: 4 times more common · Mechanism: bowel function or acidosis POSTDATES Management What about MECONIUM? Management: · Amnioinfusion · Suction pharynx · Tracheal aspiration POSTDATES Management Dates FIRM - Cx Unfavorable · 1 Induce labor: prostaglandin E2 · Await spont labor looking for: o NSTs reactive 2/week o AFIs > 5-8 cm 2/week POSTDATES Management Dates UNSURE · Await spont labor looking for: NSTs reactive 2/week AFIs > 5-8 cm 2/week Hypertension in Pregnancy HYPERTENSION in Preg Effect of normal physiologic changes of pregnancy Case #7 · A 21 y/o primigravida at 32 wks gest comes for a routine OB visit. · Her BP sitting is 155/95; repeat reading was 145/90. · Urine dipstick protein is 3+. · No previous history of HTN. Hypertension in Pregnancy Differential Diagnosis Hypertension in Pregnancy o Mild preeclampsia o Severe preeclampsia o Eclampsia o HELLP syndrome o Chronic HTN MILD preeclampsia SEVERE preeclampsia ECLAMPSIA Can be RAPID progression! Preeclampsia should be renamed: Diffuse VASOSPASTIC Disease of Pregnancy AGGRESSIVE Management GUIDELINES: · MAINTAIN BP diastolic 90-100 mm Hg · Prevent CONVULSIONS with MgSO4 · Initiate DELIVERY rapidly Diagnosis & Management MILD Preeclampsia Findings: · HTN > 140/90; proteinuria 1-2+; edema. · Hemoconcent ( H&H, uric acid, BUN, creat) · No Symptoms (HA, epig pain, visual D). · No Signs (DIC, cyan, oliguria, pulm edema). Management: · Conservative – in hospital if < 36 wks gest · Aggressive – if > 36 wks gest, IV MgS04 Diagnosis & Management SEVERE Preeclampsia Findings: · HTN > 160/110; proteinuria 3-4+; edema · Any Symptoms (HA, epig pain, visual D). · Any Signs (DIC, cyanosis, oliguria, pulmon edema). Management: · Conservative – in ICU if 26-33 wks gest if only HTN & proteinuria present; hydralazine; MgS04; steroids. · Aggressive – if <26 or >33 wks, or symptoms/signs; MgS04; steroid. Diagnosis & Management ECLAMPSIAFindings: · HTN > 140/90; proteinuria; edema · New onset of generalized convulsions. · May occur ante/intra/postpartum. Management: · Conservative – NEVER. · Aggressive – as soon as diagnosis is made; hydralazine; IV MgS04; steroids. Diagnosis & Management HELLP syndromeFindings: · Hemolysis, Elev Liver enyz, Low Platelets. · Other findings of preeclampsia. · May occur ante/intra/postpartum. Management: · Conservative – NEVER. · Aggressive – as soon as diagnosis is made; hydralazine; IV MgS04; steroids. Diagnosis & Management CHRONIC hypertensionFindings: · Pre-existent HTN or HTN prior to 20 wks that persists past 6 wks PP. · Proteinuria is variable. Management: · Conservative – Aldomet is drug of choice · Aggressive – if superimposed preeclampsia; hydralazine; MgS04, steroids Aggressive in-patient: · Mild PIH : > 37 wks · Severe PIH < 26 wks · Severe PIH > 34 wks · Severe PIH maternal jeopardy · Severe PIH fetal jeopardy · Chr HTN with PIH.. any GA · Eclampsia………… any GA · HELLP…………….. any GA Glucose Intolerance in Pregnancy Case #8 · A 36 y/o multigravid at 28 wks gest.
· · 1 hr 50 g glucose is 165 mg/dl.
· · 3 hr 100 g OGTT is F-90; 1hr- 190 ; 2-hr 165 ; 3-hr 145 .
· · Urine dipstick glucose is 3+.
· · · DIABETES in Pregnancy Differential Diagnosis DIABETES in Pregnancy · Gestational diabetes · Type 1 diabetes mellitus · Type 2 diabetes mellitus Diagnosis GESTATIONAL diabetes Findings: o 2 of 4 values abnormal on 3 hr 100 g OGTT. o Onset > 20 wks gestation (if true GDM) o Onset any time during pregnancy. o Due to hPL, placental insulinase, cortisol. o No in fetal anomalies (if true GDM). o Resolves after delivery (if true GDM). Diagnosis TYPE 1 diabetes mellitus Findings: o Onset prior to pregnancy. o Due to islet cell destruction. o Plasma insulin level is . o Fetal anomalies may be . o Unable to achieve nonPG euglycemia without insulin. Diagnosis TYPE 2 diabetes mellitus Findings: o Onset prior to pregnancy. o Due to insulin resistance. o Plasma insulin level is . o Fetal anomalies may be . o Is able to achieve nonPG euglycemia without insulin. EUGLYCEMIA management All Preg Glucose Intolerance · Diet: ADA diet ( complex CHO). · Educ: Mom re glucose control. · Exercise: Regular, consistent · Targets: FBS 60-90; 1 hr PP <140 · Insulin: NPH & Reg human insulin if euglycemia not achieved with diet; split dose of 2/3 AM & 1/3 PM. Anomaly detection Type 1 & 2 Diabetes Mellitus Most common anomalies· NTD defects · CHD defects · Sacral agenesis Anomaly detection Type 1 & 2 Diabetes Mellitus 13-14 wk Sono anencephaly 16-18 wk MSAFP NTD 18-22 wk Focused sono other anomalies 22-24 wk Fetal echo cardiac anomalies ( if first trimester Hb A1C) Anomaly PREVENTION Type 1 & 2 Diabetes Mellitus · PreconceptionEUGLYCEMIA · PreconceptionFOLIC ACID 4 mg po /day
USMLE Step 2 — Lesson 4: Medical Complications of Pregnancy
CARDIAC Disease in Pregnancy Cardiac Disease in Preg Effect of normal physiologic changes of pregnancy Physiology of Pregnancy Cardiac Formula for Cardiac OUTPUT? (Volume of blood pumped by heart in 1 minute) Physiology of Pregnancy Cardiac Formula for Cardiac OUTPUT? (Volume of blood pumped by heart in 1 minute)HR x SV (Heart Rate x Stroke Volume) Physiology of Pregnancy Cardiac IF HR & SV THENCardiac Output Case #9 · A 40 y/o multigravida at 18 wks gest comes to the out-pt clinic. · History of rheumatic fever. · SOB with mild activity. · Pulse: 110/min; parasternal heave;Gr 4/6 pandiastolic murmur. Cardiac Disease in Preg Significant Diagnoses Cardiac Disease in Preg · Mitral stenosis · Eisenmenger’s syndrome · Marfan’s syndrome · Tetralogy of Fallot Diagnosis & Management Mitral STENOSIS Findings: · Most common acquired heart disease. · Problem: narrow valve diastolic filling. · Results: LA Atrial fib, SBE, emboli. CARDIAC Cycle: Diastole/Systole CARDIAC Cycle: Diastole/Systole CARDIAC Cycle: Diastole/Systole Factors worsening MITRAL STENOSIS?· heart rate · blood volume · heart rate · blood volume Normal changes of PREGNANCY? Factors worseningMITRAL STENOSIS: heart rate blood volume Normal changes of PREGNANCY: MITRALSTENOSIS: Do not go welltogether Normal changes of PREGNANCY: Diagnosis & Management Mitral STENOSISFindings: o Most common acquired heart disease. o Problem: narrow valve diastolic filling. o Results: LA Atrial fib, SBE, emboli. Management: o Watch decompensation: PND, syncope, JVD. o Avoid fluid overload: Na+ diet, diuretics. o Avoid tachycardia: anemia, exercise, sedation. o Vag delivery; invasive monitoring; SBE prophylax Cardiac Disease in Preg STENOTIClesions are toleratedPOORLY.
USMLE Step 2 — Lesson 5: Management of Labor
Abnormal Labor ABNORMAL LABOR STAGES of NORMAL LABOR Case 12 · A 32 y/o multigravida at 39 wks gest in the maternity unit has UCs every 3-4 minutes. · Her cervix is 1-2 cm dilated and has been the same for the past 16 hours. · Fetal monitor strip is reassuring.ABNORMAL labor Significant Diagnoses ABNORMAL labor · Prolonged latent phase · Prolonged active phase · Active phase arrest · Arrest of descent Diagnosis & Management Prolonged LATENT phase Findings: · Cervical dilation < 3 cm with UCs present. · No labor progress >14 hrs in multipara. · No labor progress >20 hrs in primipara Cause: · Injudicious analgesia, hypo/hypertonic UCs. Management: · Therapeutic rest or sedation; avoid cesarean. Causes of ACTIVE phase problems: · PELVIS · Passenger · Powers PROBLEMS with MATERNAL BONY PELVIS How much can you change PROBLEMS with MATERNAL BONY PELVIS? How much can you change PROBLEMS with MATERNAL BONY PELVIS? NONE! Causes of ACTIVE phase problems: · Pelvis · PASSENGER · Powers PROBLEMS with IN-UTERO FETAL ORIENTATION Nomenclature forIN-UTERO FETAL ORIENTATION · Fetal LIE · Fetal PRESENTATION · Fetal POSITION · Fetal ATTITUDE · STATION Terms to remember: Orientation of Fetus In-utero Fetal LIE Relationship between long axis of the fetus & long axis of mother Most common:LONGITUDINAL Terms to remember: Orientation of Fetus In-utero PRESENTATION Portion of fetus overlying the pelvic inlet Most common: CEPHALIC Terms to remember: Orientation of Fetus In-utero POSITION Relationship between a reference point on the presenting fetal part & maternal bony pelvis Most common: OCCIPUT ANTERIOR Terms to remember: Orientation of Fetus In-utero ATTITUDE Degree of flexion or extension of fetal head Most common: VERTEX Terms to remember: Orientation of Fetus In-utero STATION Degree of descent of the presenting part through birth canal (Expressed in cm above or below maternal ischial spine) How much can you change PROBLEMS with IN-UTERO FETAL ORIENTATION? How much can you change PROBLEMS with IN-UTERO FETAL ORIENTATION? Very little! Causes of ACTIVE phase problems: · Pelvis · Passenger · POWERS PROBLEMS with INADEQUATE UTERINE CONTRACTIONS Assessment of POWERS Criteria for ADEQUACY of UTERINE CONTRACTIONS · DURATION - 45-60 seconds · FREQUENCY - every 2-3 minutes · INTENSITY - > 50 mm Hg How much can you change PROBLEMS with INADEQUATE CONTRACTIONS? How much can you change PROBLEMS with INADEQUATE CONTRACTIONS? Considerable! Causes of ACTIVE phase problems: · Pelvis · Passenger · POWERS Causes of ACTIVE phase problems: · Pelvis · Passenger · POWERS <- The only parameter that can be modified Only CORRECTABLE Cause of ACTIVE phase problems:Inadequate POWERSIV OXYTOCIN Diagnosis & Management ACTIVE phase ARREST Findings: · Cervical dilation > 3 cm with UCs present. · NO Labor progress in multipara. · NO Labor progress in primipara Cause: · Pelvic, Passenger, Powers. Management: · IV oxytocin (if inadequate UCs) or cesarean. Diagnosis & Management Prolonged ACTIVE phase Findings: · Cervical dilation > 3 cm with UCs present. · Labor progress <1.5 cm/hr in multipara. · Labor progress <1.2 cm/hr in primipara Cause: · Pelvic, Passenger, Powers. Management: · IV oxytocin (if inadequate UCs) or cesarean. Diagnosis & Management ARREST of DESCENT Findings: · Cervical dilation is 10 cm or “complete”. · Delivery not take place in spite of adequate maternal pushing efforts. · Duration > 30 min in multip or >60 min in primip. Cause: · Pelvic, Passenger, Powers. Management: · IV oxytocin, vacuum extractor, forceps or CS. Intrapartum Fetal Monitoring Case 13 · A 27 y/o primigravida at 41 wks gest is in labor in the maternity unit. · She is 5 cm dilated, 100% effaced with UCs every 2-3 minutes. · The EFM shows a baseline FHR of 140/min with decels: sudden drops of 40 beats/min lasting 15 seconds with rapid return. ABNORMAL fetal monitor Differential Diagnoses ABNORMAL fetal monitor · Early decelerations · Variable decelerations · Late decelerations Diagnosis & Management EARLY deceleration Findings: · Onset of the deceleration is simultaneous with the onset of the contraction. · End of the decelerations is simultaneous with the end of the contraction. · Deceleration is a mirror image of the contraction. Cause: · Vagal stimulation; fetal head compression. Management: · Observation – no clinical significance. Diagnosis & Management VARIABLE deceleration Findings: · Onset of the deceleration is variable with the onset of the contraction. · End of the decelerations is variable with the end of the contraction. · Sudden drops with rapid return to baseline. Cause: · Vagal stimulation; Umbil cord compression. Management: · Observation if mild-mod; worrisome if severe. Diagnosis & Management LATE deceleration Findings: · Onset of the deceleration is late in relation to the onset of the contraction. · End of the decelerations is late in relation to the end of the contraction. · Gradual drops with gradual return to baseline. Cause: · Uteroplacental insufficiency. Management: · All are worrisome! Generic Interventions ABNORMAL fetal monitor · Decrease uterine activity · Correct hypotension · Change maternal position · Administer high flow O2 · Vag exam r/o prolapsed cord We have covered The HIGHLIGHTS of ObstetricsUSMLE Step 2This brings us to The END of the SESSIONBEST WISHES on the EXAM!
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