Twin Reverse Arterial Perfusion Sequence

Arcadius Acepalus with Externalsed Intestines

Abstract

Background: Twin reversed-arterial perfusion sequence (TRAPS) is a unique

complication of monozygotic monochorionic multiple gestation and the cause not known  

with certainty. In TRAPS, one twin develops normally (‘pump twin’), whereas the other develops without normal heart (acardiac twin).

The ‘pump twin’ supplies blood to the acardiac twin and for itself via a retrograde blood flow through the umbilical artery. An acardius is therefore a parasitic twin since it receives its entire blood supply from the pump twin.

Acardius acephalus, as a form of acardiac twin is a rare abnormality occurring in multifetal pregnancy particularly monozygous monochorionic twin gestation, and even rarer is the occurrence of externalized intestines with an associated omphalocele. It is usually associated with many structural malformations incompatible with intrauterine and extrauterine survival. Reports on acardius acephalus fetal anomaly are scanty. We report a case of acardius acephalus with co-existing omphalocele and externalized intestines in an undiagnosed twin delivered by caesarean section to a 34-year-old multipara who presented with reduced fetal movements.

Objective: To report an acardius acephalic twin with omphalocele and externalized intestines as the second of an undiagnosed twin pregnancy delivered to a multipara by caesarean and review of important literature.

Method: A case report of multipara who presented with reduced fetal movements and was diagnosed to have twin gestation with an acardiac twin and managed at the maternity unit of the Federal Medical Centre Gusau, Zamfara State in which relevant history, physical examination and radiological investigation were evaluated. The case was documented, and local and international literature search conducted and reviewed.

Conclusion: Acardius acephalus may have additional malformations in the other organs. The current case, the second in our centre, shows yet other striking gross and severe malformations characterizing acardius acephalus.  

Key words: Acardiac, acephalus, omphalocele, externalized intestines, twin reverse arterial perfusion sequence (TRAPS)