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Differential Diagnosis: Per Vaginum (PV) Bleeding in a 55-Year-Old Pregnant Patient (G3 P2 L1 A1)

Patient Profile at a Glance

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Causes: Organized by Trimester and Origin

I. OBSTETRIC CAUSES (Life-Threatening - Rule Out First)

1. Placenta Previa (Most likely cause of painless bleeding)

• Implantation of the placenta over or near the internal cervical os
• Classic presentation: Painless, bright red, fresh vaginal bleeding - often sudden
• Risk factors in this patient: advanced age, multiparity, prior abortion/curettage
• In ~20% of cases, mild uterine irritability may coexist
• Key rule: Never perform digital or speculum examination until placenta location confirmed by transvaginal ultrasound - can precipitate catastrophic hemorrhage
• Diagnosis: Transvaginal ultrasound (safe when done carefully)

"All patients with painless, second-trimester vaginal bleeding should be assumed to have placenta previa until proven otherwise." - Rosen's Emergency Medicine

2. Abruptio Placentae (Most common cause of painful bleeding)

• Premature separation of a normally implanted placenta from the uterine wall
• Complicates ~1% of pregnancies; incidence peaks 24-32 weeks
• Classic presentation: Dark blood, uterine tenderness, board-like rigidity, continuous pain; up to 20% may have no pain or visible bleeding (concealed hemorrhage)
• Risk factors in this patient: age >35, parity ≥3, hypertension/preeclampsia, prior abruption
• Severe abruption: tetanic contractions, maternal shock, DIC, fetal death
• Do NOT rely on ultrasound alone - fresh blood is isoechoic to placenta; US is specific but not sensitive
• Fetal distress monitoring (cardiotocography) has 100% NPV for adverse outcomes when reassuring

3. Vasa Previa

• Fetal blood vessels running over the internal os, unsupported by the placenta or umbilical cord
• Must be included in the differential of all third-trimester bleeding
• Critical: When vessels rupture, fetal blood is lost - fetal exsanguination risk is extreme
• Bleeding is characteristically fetal blood (painless, bright red); test with apt/Kleihauer-Betke test
• Antenatal diagnosis (color Doppler US) dramatically improves survival (97% vs 44% without diagnosis)
• Risk factors: velamentous cord insertion, low-lying placenta, bilobed placenta

4. Uterine Rupture

• Rare but catastrophic
• More likely in women with prior uterine surgery (prior C-section scar)
• Presents with sudden severe abdominal pain, cessation of contractions, fetal parts palpable outside uterus, maternal shock
• This patient's obstetric history (P2 - delivery mode unknown) may include prior C-section

5. Placenta Accreta Spectrum (PAS)

• Abnormal invasion of placental villi beyond the decidua basalis
• Risk factors: prior abortion, advanced maternal age, prior uterine surgery
• Can cause massive hemorrhage at delivery or even antepartum
• Screening: gray-scale + Doppler US, MRI if needed

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II. OTHER OBSTETRIC CAUSES

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III. NON-OBSTETRIC CAUSES

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Clinical Differentiation at a Glance

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Initial Management Priorities (Emergency)

1. Do NOT perform digital or speculum exam until placenta location confirmed by ultrasound
2. IV access x2, CBC, coagulation panel (PT, aPTT, fibrinogen, FDPs), type & cross-match
3. Transvaginal ultrasound - determine placental location, color Doppler for vasa previa
4. Cardiotocographic (electronic fetal) monitoring
5. Administer anti-D immunoglobulin (RhoGAM) if mother is Rh-negative
6. Urgent obstetric consultation
7. If DIC (from abruption): replace coagulation factors, fresh frozen plasma, cryoprecipitate

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Why Age 55 Matters

• Placenta previa (higher parity, prior uterine instrumentation)
• Abruptio placentae (higher rates of hypertension, preeclampsia)
• Chromosomal abnormalities in the fetus
• Placenta accreta spectrum
• Gestational hypertension leading to abruption

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