Mirror Syndrome in Monochorionic Twin Pregnancy with Acardiac Fetus

Case reports in Obstetrics & Gynecology
13 Jan, 2019 ,

A 20-year-old patient, primigravida, with twin monochorionic pregnancy, with a weight gain of 6 kg in one week and increased blood pressure. During the ultrasound diagnostic investigation, placental edema and hydrops were identified in both fetuses, which, in association with maternal anasarca and pressure control, constitute the triad for mirror syndrome, also known as triple edema. In addition to being hydropic, one of the twins was an acardiac fetus, which is a rare combination of events. Gestation was terminated at 22 weeks and five days because of high maternal risk. The patient progressed with clinical and laboratory improvement. Our study is relevant in that it documents an extremely rare case and discusses relevant aspects of the symptoms and diagnosis of mirror syndrome. It also systematically reviews the condition.

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A 20-year-old woman, primigravida, with a gestational age of 22 weeks and three days was referred for high-risk prenatal care at the Department of Obstetrics, Paulista School of Medicine, Federal University of São Paulo, with a twin pregnancy, weight gain of 6 kg in the week prior, and increased blood pressure. Because 1 g/day of methyldopa was administered for two weeks before admission, she was asymptomatic at the time of admission, and she had a persistent blood pressure of 160/120 mmHg and edema in the lower limbs 4+/4+. She was referred for hospital admission.

During examination, an obstetric ultrasound revealed that both the fetuses were hydropic and one of the twins had complex disruptive phenomena, without characterization of the cephalic pole and signs suggestive of TRAP sequence. Laboratory analysis showed 12 g of proteinuria in urine, microcytic/hypochromic anemia, and normal hepatic and renal function. Mirror syndrome, also known as triple edema or Ballantyne's syndrome, was diagnosed because of the presence of hemodilution, uncontrolled blood pressure level, significant maternal edema, and fetal hydrops. Due to severe preeclampsia, magnesium sulfate was administered by the Zuspan regimen but was suspended because of the risk of hypermagnesemia following the patient's evolution with oliguria and acute pulmonary edema. Because of the maternal risk and reserved fetal prognosis, gestation was terminated at 22 weeks and five days after discussion with the patient and family.

Labor was induced by vaginal administration of misoprostol in accordance with the International Federation of Gynecology and Obstetrics (FIGO) protocol. Both the fetuses, birthed by vaginal delivery, were stillborn, with the first twin weighing 600 g, the acardiac twin weighing 375 g, and the placenta weighing 450 g. Postpartum recovery occurred in an Intensive Care Unit, with adequate blood pressure level after the administration of antihypertensives (hydralazine, methyldopa, and hydrochlorothiazide), with a significant reduction in edema, diuresis of 8000 ml within two days of furosemide therapy, and adequate control of serum potassium levels. The patient was scheduled for hospital discharge after improvement in laboratory test results and clinical symptoms upon the administration of a fourth antihypertensive, amlodipine, and puerperal follow-up for six days after gestational termination.