Twin anemia-polycythemia sequence

Twin Anemia-Polycythemia Sequence

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Legs of twins affected by Twin Anemia-Polycythemia Sequence

Twin Anemia-Polycythemia Sequence (TAPS) is a rare condition that can occur in monochorionic twins, where the twins share a single placenta. It is characterized by a significant difference in the hemoglobin levels between the twins, leading to one twin becoming anemic and the other polycythemic.

Pathophysiology

TAPS is caused by very small vascular connections in the placenta, which allow blood to flow from one twin to the other. Unlike twin-to-twin transfusion syndrome (TTTS), which involves larger blood vessel connections, TAPS involves minuscule connections that result in a slow, chronic transfusion of blood from the donor twin to the recipient twin. This results in the donor twin developing anemia and the recipient twin developing polycythemia.

Diagnosis

TAPS is typically diagnosed through ultrasound and Doppler studies, which can detect differences in the blood flow velocities in the middle cerebral artery of the twins. The condition can also be diagnosed postnatally by measuring the hemoglobin levels of the twins.

Treatment

The management of TAPS depends on the severity of the condition and the gestational age at diagnosis. Options include close monitoring, intrauterine transfusion for the anemic twin, and early delivery if necessary. In some cases, laser surgery may be performed to close the small vascular connections in the placenta.

Prognosis

The prognosis for twins affected by TAPS varies. Early detection and treatment can improve outcomes, but the condition can lead to complications such as neurological damage or fetal demise if not managed appropriately.

Related pages

• Twin-to-twin transfusion syndrome
• Monochorionic twins
• Polycythemia
• Anemia