Examkin

Question

Difficulty: HardObstetric Complications

Match the following specific ultrasonographic and clinical findings in monochorionic twin gestations with their most accurate diagnosis.

  • Monochorionic diamniotic gestation at 2222 weeks showing a deepest vertical pocket of 1.51.5 cm in one sac and 9.59.5 cm in the other, with normal MCA-PSV.Twin-twin transfusion syndrome (TTTS)
  • Monochorionic diamniotic gestation at 2424 weeks showing normal and equal amniotic fluid volumes, but significant discordance in middle cerebral artery peak systolic velocity (>1.5> 1.5 MoM in one, <1.0< 1.0 MoM in the other).Twin anemia-polycythemia sequence (TAPS)
  • Monochorionic gestation at 1616 weeks demonstrating one structurally normal fetus and an anomalous mass lacking a functioning heart, with retrograde blood flow.Twin reversed arterial perfusion (TRAP) sequence
  • Monochorionic monoamniotic gestation at 2020 weeks demonstrating closely approximated fetal insertions and intertwined umbilical vessels on color Doppler.Umbilical cord entanglement

Answer

The presentations map respectively to Twin-twin transfusion syndrome, Twin anemia-polycythemia sequence, Twin reversed arterial perfusion sequence, and Umbilical cord entanglement.
Each specific complication of monochorionic twinning has unique sonographic criteria: TTTS relies on fluid discordance (oligohydramnios/polyhydramnios), TAPS relies on MCA-PSV discordance indicating anemia/polycythemia, TRAP involves an acardiac anomalous twin with retrograde flow, and cord entanglement is a direct physical complication in monoamniotic gestations.

Step-by-Step Solution

1
Analyze the first presentation (fluid discordance without anemia/polycythemia markers).
Identified as Twin-twin transfusion syndrome (TTTS).
The defining diagnostic criterion for TTTS is oligohydramnios (DVP <2< 2 cm) in the donor twin and polyhydramnios (DVP >8> 8 cm) in the recipient twin.
2
Analyze the second presentation (MCA-PSV discordance without fluid discordance).
Identified as Twin anemia-polycythemia sequence (TAPS).
TAPS is characterized by significant hematologic discordance, measured via MCA-PSV, without the severe amniotic fluid imbalances of TTTS.
3
Analyze the third presentation (acardiac mass with retrograde flow).
Identified as Twin reversed arterial perfusion (TRAP) sequence.
TRAP uniquely features a lack of a functional heart in one twin, relying entirely on the other twin for perfusion via retrograde flow.
4
Analyze the fourth presentation (intertwined umbilical vessels in a monoamniotic sac).
Identified as Umbilical cord entanglement.
Monochorionic monoamniotic twins lack an intertwining membrane, leading to a high risk of cord entanglement, easily seen on Doppler.

Key Concept

Complications of Monochorionic Twin Gestations
Estimated Time:1m 30s
Rate this question

Topics

Obstetric Complications

More questions from this topic