Acardius-myelacephalus: management of a misdiagnosed case of twin reversed arterial perfusion sequence with tense polyhydramnios

Abstract

Abstract Background: Twin reversed arterial perfusion (TRAP) sequence is the most severe form of twin to twin transfusion syndrome. Survival of the pump twin is threatened by extreme prematurity from polyhydramnios and cardiac failure, necessitating interventions. Rarely, interventions are indicated as a result of maternal life-threatening complications. The management of an acardiac-myelacephalus variant of TRAP sequence, complicated by severe maternal respiratory distress from tense polyhydramnios is presented in this report. Case presentation: A 29-year-old G3P2, Alive2 was referred to the Perinatal Unit on account of ultrasound diagnosed twin gestation with demise of one twin at an estimated gestational age (EGA) of 29 weeks. She was in severe respiratory distress with central cyanosis, and grossly distended abdomen. Ultrasonography revealed twin gestation with cardiac activity in only one twin and polyhydramnios. The second twin had no recognizable human body structure and retrograde umbilical arterial flow. TRAP sequence with tense polyhydramnios was diagnosed. The respiratory distress was relieved with serial reductive amniocentesis, and she was managed conservatively until an EGA of 34 weeks, when she delivered a live twin that weighed 2.05 kg, and an amorphous twin with a rudimentary limb that weighed 1.82 kg following spontaneous rupture of membranes. Monochorionic placentation was confirmed at delivery. The pump twin was discharged in a satisfactory state after a period of observation. Conclusion: TRAP sequence may be easily misdiagnosed due to its rarity, with adverse consequences. Accurate diagnosis of the condition, and the provision of basic facilities for in utero interventions when indicated are necessary for fetal salvage.