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Acute reversal of oligohydramnios-polyhydramnios sequence in monochorionic twins
GYNECOLOGY &OBSTETRICS International Journal of Gynecology & Obstetrics 55 (1996) 281-283
Case report
Acute reversal of oligohydramnios-polyhydramnios sequence in monochorionic twins B. Bromley*, Depatiments
of Obstetrics
& Gynecology
B.R. Benacerraf
and Radiology, Massachusetts General Hospital Harvard Medical School, Boston, MA, USA
and Brigham
& Women S Hospital,
Received 31 May 1996; revised 30 July 1996; accepted 5 August 1996
Abstract Two cases of monochorionic diamniotic twin gestation with severe oligohydramnios-polyhydramnios sequence (‘stuck’ twin) are described. In each of these cases there was a marked fluctuation in amniotic fluid volume and reversal of which twin was ‘stuck’. The definitive identification of the twins was evident due to a discordant fetal malformations in each twin pair. Copyright 0 1996 International Federation of Gynecology and Obstetrics. Keywords:
Twin-to-twin
transfusion;
Oligohydramnios;
1. Introduction
Oligohydramnios-polyhydramnios sequence, otherwise known as twin-to-twin transfusion syndrome, is a well known complication of monochorionic twinning. Poor perinatal outcome has been reported in 70-100% of affected fetuses diagnosed in the second trimester [1,2]. The pathophysisology of this phenomenon is poorly
a Corresponding author, Diagnostic Ultrasound Associates, 333 Longwood Avenue, Boston, MA 02115, USA. 0020.7292/96/$15.00 PII
SOO20-7292(96)
Copyright 0 1996 International 02771-3
Polyhydramnios
understood, although it may be due to arterial-venous anastomoses in the shared placenta. Since the flux of blood through the anastomoses is related to differences in pressure gradients, it is possible that changes in direction of blood flow can take place, resulting in fluctuations of the amniotic fluid volumes within each sac during the course of gestation. We report two cases of severe oligohydramnios-polyhydramnios sequence, each involving a ‘stuck’ twin (without any amniotic fluid) and its co-twin with severe polyhydramnios. In each of these two cases, the amniotic fluid volumes com-
Federation of Gynecology and Obstetrics
282
B. Bromley,
B.R. Benaceraf
/ International
Journal
pletely reversed, with the ‘stuck’ twin becoming the one within the polyhydramniotic sac and the twin previously within the polyhydramniotic sac becoming ‘stuck’. This was dramatically demonstrated by the presence of discordant minor fetal malformation in each twin pair, making it easy to definitively identify each twin. 2. Case 1 A 31-year-old patient was first diagnosed with monochorionic twins at 14 weeks’ gestation. At 15 weeks’ gestation, sonographic evaluation showed the classic appearance of severe oligohydramnios-polyhydramnios sequence with a ‘stuck’ twin, and a hvin within a sac with severe polyhydramnios [l]. In addition, the ‘stuck’ twin had a small, echogenic lung mass, consistent with a cystic adenomatoid malformation of the lung. Follow-up scans at 19, 22, and 25 weeks’ gestation revealed improvement in the amniotic fluid volume within each sac. However, when the patient returned at 26.5 weeks, a dramatic change in the ultrasound picture was noted. The previously seen ‘stuck twin with the lung mass now had severe polyhydramnios while its co-twin, which had previously had polyhydramnios, was now ‘stuck’, with no amniotic fluid present in its sac. The patient’s membranes spontaneously ruptured at 27 weeks, at which time an intrauterine fetal demise of each twin was noted. Two dead infants were delivered, weighing 1090 g and 900 g, respectively. The larger twin last seen as the twin within the polyhydramniotic sac had a small cystic adenomatoid malformation of the lung and diffuse visceral pallor on pathologic examination, consistent with the donor status in a twin-to-twin transfusion syndrome. The smaller twin, last been seen as the ‘stuck’ twin, had visceral congestion and mild-to-moderate cardiomegaly. Placental pathology revealed a monochorionic diamniotic placenta with deep artery-to-vein anastomoses. This case was previously included as part of another study which documented the natural history of oligohydramnios-polyhydramnios sequence in monochorionic twins [l]. The focus of that study, however, did not address acute complete reversal of the amniotic fluid volume.
of Gynecology
& Obstetrics
55 (1996) 281-283
3. Case 2 A 32-year-old patient was referred for an ultrasound because of presumed ‘twin-to-twin transfusion syndrome’ at 20 weeks’ gestation. At that time, the lower twin had severe polyhydramnios and the upper twin had severe oligohydramnios (‘stuck’). The structural survey on each twin was unremarkable with the exception of clubbed feet noted on the ‘stuck’ twin. At 21 weeks, after appropriate informed consent was obtained, the patient elected to undergo serial amniocenteses and 1200 cc of fluid were removed from the polyhydramniotic sac. One week later, the previously ‘stuck’ twin had only mildly decreased fluid, whereas the twin within the severely polyhydramniotic sac now had mild polyhydramnios. At 22.5 and 23.5 weeks, there was a normal amniotic fluid volume in each amniotic sac and the previously ‘stuck’ twin was again noted to have clubbed feet. Two weeks later (25.5 weeks), the previously ‘stuck’ twin had become associated with severe polyhydramnios and its clubbed feet were well recognized. The twin within the previously polyhydramniotic sac was now associated with severe oligohydramnios and was ‘stuck’. Another amniocentesis was done to remove 1200 ml of fluid from the newly polyhydramniotic sac. The procedure was repeated 4 days later, with the removal of 1400 ml of fluid; and again, 3 days later, with the removal of 1500 cc of fluid. At 27 weeks, the fetus with the clubbed feet still had moderate polyhydramnios; the co-twin had a normal volume of amniotic fluid. This latter fetus, however, appeared to have decreased myocardial contractility although no hydrops was identified. Three days later, the fetus with the clubbed feet again had severe polyhydramnios and now demonstrated absent diastolic flow on umbilical artery Doppler. The co-twin had a normal amount of amniotic fluid but minimal diastolic flow on umbilical artery Doppler. After extensive discussions with perinatologists and neonatologists concerning the morbidity and mortality associated with delivery at this gestational age, the family elected not to be delivered. Four days later, at 28 weeks, the twin within the polyhydramniotic sac died, and 1 day later the
B. Bromle~,
B.K. Benncetmf
/ It~temntionnlJottntnl
other twin succumbed. Perinatal autopsy revealed that the lower twin weighed 820 g and had pale skin and a thin umbilical cord consistent with donor status. The upper twin weighed 803 g and had a plethoric appearance. The umbilical cord was edematous consistent with being the recipient twin. This twin also had cardiomegaly and club feet as well as oligodactyly. In addition a ventriculoseptal defect, bicommisural pulmonic valve and atretic aortic valve were noted. Placental pathology revealed a mono chorionic diamniotic placenta with arterial-to-venous anastomoses, consistent with twin-to-twin transfusion syndrome. 4. Discussion The pathophysiology of oligohydramnios-polyhydramnios sequence (twin-to-twin transfusion syndrome) in monochorionic twins is not well understood. There have been previous reports of fluctuations in the amniotic fluid volumes within the amniotic sacs. Our previous study demonstrated fluctuations in the degree of polyhydramnios and oligohydramnios throughout gestation
of Gynrcology
& Obstetrics
55 (1994)
281-283
283
definitive in our diagnosis and not confuse the two fetuses. One case of reversed oligohydramnios-polyhydramnios sequence was spontaneous while the other occurred in the setting of serial amniocentesis therapy. The outcome in both cases was dismal, with the deaths of all four fetuses involved. This is in agreement with the experience of Gramellini who suggests that the remission of fetal hydrops in twin-to-twin transfusion syndrome may not be a reassuring prognostic index, since it may be an indication of revised twin-totwin transfusion syndrome in a hemodynamically unstable situation [5]. The small number of cases with acute and complete amniotic fluid volume reversal precludes making general management recommendations until further experience is available. The etiology and mechanism for this acute reversal remain unclear, but may result from the pressure differentials in the anastomotic sites in the placenta, allowing for the flow-shunting to be bi-directional. When the reversal of the oligohydramnios-polyhydramnios sequence in monochorionic twins is observed sonographically, the prognosis may be guarded.
Dl. The rapid change in the status of a twin involved in twin-to-twin transfusion syndrome is demonstrated by the result of performing selective feticide of one twin. Severe hydrops in the donor twin can rapidly develop, following selective feticide of the hydropic recipient [3]. Furthermore, Shapiro and Sharf report a case of ‘stuck’ twin phenomenon in which there was spontaneous resolution of hydrops in the recipient twin [4]. Gramellini et al. also report the spontaneous remission of hydrops in a case of severe twin-totwin transfusion syndrome and hypothesize that this occurred secondary to the hemodynamically unstable inter-twin balance, resulting in reversed shunting [51. Jou et al. report the occurrence of reversed twin-to-twin syndrome, but only after the intrauterine death of the donor [6]. Our cases represent a reversal in amniotic fluid volumes in monochorionic twins with oligohydramnios-polyhydramnios sequence occurring between two live twins. It was helpful that one fetus in each twin pair had an anatomic marker which clearly identified it, thus enabling us to be
References 111 Bromley
l21
[31
[41
[51
l61
B, Frigoletto Jr. FD, Estroff JA, Benacerraf BR. The natural history of oligohydramnios/polyhydramnios sequence in monochorionic diamniotic twins. Ultrasound Obstet Gynecol 1992; 2: 317-320. Patten RM, Mack LA, Harvey D, Cyr DR, Pretorius DH. Disparity of amniotic fluid volume and fetal size: problem of the ‘stuck’ twin - US studies. Radiology 1989; 172: 153-157. Mahone PR, Sherer DM, Abramowicz JS, Woods Jr JR. Twin-twin transfusion syndrome: rapid development of severe hydrops of the donor following selective feticide of the hydropic recipient. Am J Obstet Gynecol 1993; 169: 1666168. Shapiro I, Sharf M. Spontaneous Intrauterine Remission of Hydrops Fetalis in One Identical Twin: Sonographic Diagnosis. J Clin Ultrasound 1985; 13: 427-430. Gramellini D, Ludovici G, Paita Y, Merialdi A, Vadora B. Spontaneous remission of double pulsatile umbilical venous flow in twin-twin transfusion syndrome: a case report. Ultrasound Obstet Gynecol 1995; 5: 138-140. Jou HJ, Ng KY, Teng RJ, Hsich FJ. Doppler sonographic detection of reverse twin-twin transfusion after intrauterine death of the donor. J Ultrasound Med 1993; 5: 307-309.
Case report
Acute reversal of oligohydramnios-polyhydramnios sequence in monochorionic twins B. Bromley*, Depatiments
of Obstetrics
& Gynecology
B.R. Benacerraf
and Radiology, Massachusetts General Hospital Harvard Medical School, Boston, MA, USA
and Brigham
& Women S Hospital,
Received 31 May 1996; revised 30 July 1996; accepted 5 August 1996
Abstract Two cases of monochorionic diamniotic twin gestation with severe oligohydramnios-polyhydramnios sequence (‘stuck’ twin) are described. In each of these cases there was a marked fluctuation in amniotic fluid volume and reversal of which twin was ‘stuck’. The definitive identification of the twins was evident due to a discordant fetal malformations in each twin pair. Copyright 0 1996 International Federation of Gynecology and Obstetrics. Keywords:
Twin-to-twin
transfusion;
Oligohydramnios;
1. Introduction
Oligohydramnios-polyhydramnios sequence, otherwise known as twin-to-twin transfusion syndrome, is a well known complication of monochorionic twinning. Poor perinatal outcome has been reported in 70-100% of affected fetuses diagnosed in the second trimester [1,2]. The pathophysisology of this phenomenon is poorly
a Corresponding author, Diagnostic Ultrasound Associates, 333 Longwood Avenue, Boston, MA 02115, USA. 0020.7292/96/$15.00 PII
SOO20-7292(96)
Copyright 0 1996 International 02771-3
Polyhydramnios
understood, although it may be due to arterial-venous anastomoses in the shared placenta. Since the flux of blood through the anastomoses is related to differences in pressure gradients, it is possible that changes in direction of blood flow can take place, resulting in fluctuations of the amniotic fluid volumes within each sac during the course of gestation. We report two cases of severe oligohydramnios-polyhydramnios sequence, each involving a ‘stuck’ twin (without any amniotic fluid) and its co-twin with severe polyhydramnios. In each of these two cases, the amniotic fluid volumes com-
Federation of Gynecology and Obstetrics
282
B. Bromley,
B.R. Benaceraf
/ International
Journal
pletely reversed, with the ‘stuck’ twin becoming the one within the polyhydramniotic sac and the twin previously within the polyhydramniotic sac becoming ‘stuck’. This was dramatically demonstrated by the presence of discordant minor fetal malformation in each twin pair, making it easy to definitively identify each twin. 2. Case 1 A 31-year-old patient was first diagnosed with monochorionic twins at 14 weeks’ gestation. At 15 weeks’ gestation, sonographic evaluation showed the classic appearance of severe oligohydramnios-polyhydramnios sequence with a ‘stuck’ twin, and a hvin within a sac with severe polyhydramnios [l]. In addition, the ‘stuck’ twin had a small, echogenic lung mass, consistent with a cystic adenomatoid malformation of the lung. Follow-up scans at 19, 22, and 25 weeks’ gestation revealed improvement in the amniotic fluid volume within each sac. However, when the patient returned at 26.5 weeks, a dramatic change in the ultrasound picture was noted. The previously seen ‘stuck twin with the lung mass now had severe polyhydramnios while its co-twin, which had previously had polyhydramnios, was now ‘stuck’, with no amniotic fluid present in its sac. The patient’s membranes spontaneously ruptured at 27 weeks, at which time an intrauterine fetal demise of each twin was noted. Two dead infants were delivered, weighing 1090 g and 900 g, respectively. The larger twin last seen as the twin within the polyhydramniotic sac had a small cystic adenomatoid malformation of the lung and diffuse visceral pallor on pathologic examination, consistent with the donor status in a twin-to-twin transfusion syndrome. The smaller twin, last been seen as the ‘stuck’ twin, had visceral congestion and mild-to-moderate cardiomegaly. Placental pathology revealed a monochorionic diamniotic placenta with deep artery-to-vein anastomoses. This case was previously included as part of another study which documented the natural history of oligohydramnios-polyhydramnios sequence in monochorionic twins [l]. The focus of that study, however, did not address acute complete reversal of the amniotic fluid volume.
of Gynecology
& Obstetrics
55 (1996) 281-283
3. Case 2 A 32-year-old patient was referred for an ultrasound because of presumed ‘twin-to-twin transfusion syndrome’ at 20 weeks’ gestation. At that time, the lower twin had severe polyhydramnios and the upper twin had severe oligohydramnios (‘stuck’). The structural survey on each twin was unremarkable with the exception of clubbed feet noted on the ‘stuck’ twin. At 21 weeks, after appropriate informed consent was obtained, the patient elected to undergo serial amniocenteses and 1200 cc of fluid were removed from the polyhydramniotic sac. One week later, the previously ‘stuck’ twin had only mildly decreased fluid, whereas the twin within the severely polyhydramniotic sac now had mild polyhydramnios. At 22.5 and 23.5 weeks, there was a normal amniotic fluid volume in each amniotic sac and the previously ‘stuck’ twin was again noted to have clubbed feet. Two weeks later (25.5 weeks), the previously ‘stuck’ twin had become associated with severe polyhydramnios and its clubbed feet were well recognized. The twin within the previously polyhydramniotic sac was now associated with severe oligohydramnios and was ‘stuck’. Another amniocentesis was done to remove 1200 ml of fluid from the newly polyhydramniotic sac. The procedure was repeated 4 days later, with the removal of 1400 ml of fluid; and again, 3 days later, with the removal of 1500 cc of fluid. At 27 weeks, the fetus with the clubbed feet still had moderate polyhydramnios; the co-twin had a normal volume of amniotic fluid. This latter fetus, however, appeared to have decreased myocardial contractility although no hydrops was identified. Three days later, the fetus with the clubbed feet again had severe polyhydramnios and now demonstrated absent diastolic flow on umbilical artery Doppler. The co-twin had a normal amount of amniotic fluid but minimal diastolic flow on umbilical artery Doppler. After extensive discussions with perinatologists and neonatologists concerning the morbidity and mortality associated with delivery at this gestational age, the family elected not to be delivered. Four days later, at 28 weeks, the twin within the polyhydramniotic sac died, and 1 day later the
B. Bromle~,
B.K. Benncetmf
/ It~temntionnlJottntnl
other twin succumbed. Perinatal autopsy revealed that the lower twin weighed 820 g and had pale skin and a thin umbilical cord consistent with donor status. The upper twin weighed 803 g and had a plethoric appearance. The umbilical cord was edematous consistent with being the recipient twin. This twin also had cardiomegaly and club feet as well as oligodactyly. In addition a ventriculoseptal defect, bicommisural pulmonic valve and atretic aortic valve were noted. Placental pathology revealed a mono chorionic diamniotic placenta with arterial-to-venous anastomoses, consistent with twin-to-twin transfusion syndrome. 4. Discussion The pathophysiology of oligohydramnios-polyhydramnios sequence (twin-to-twin transfusion syndrome) in monochorionic twins is not well understood. There have been previous reports of fluctuations in the amniotic fluid volumes within the amniotic sacs. Our previous study demonstrated fluctuations in the degree of polyhydramnios and oligohydramnios throughout gestation
of Gynrcology
& Obstetrics
55 (1994)
281-283
283
definitive in our diagnosis and not confuse the two fetuses. One case of reversed oligohydramnios-polyhydramnios sequence was spontaneous while the other occurred in the setting of serial amniocentesis therapy. The outcome in both cases was dismal, with the deaths of all four fetuses involved. This is in agreement with the experience of Gramellini who suggests that the remission of fetal hydrops in twin-to-twin transfusion syndrome may not be a reassuring prognostic index, since it may be an indication of revised twin-totwin transfusion syndrome in a hemodynamically unstable situation [5]. The small number of cases with acute and complete amniotic fluid volume reversal precludes making general management recommendations until further experience is available. The etiology and mechanism for this acute reversal remain unclear, but may result from the pressure differentials in the anastomotic sites in the placenta, allowing for the flow-shunting to be bi-directional. When the reversal of the oligohydramnios-polyhydramnios sequence in monochorionic twins is observed sonographically, the prognosis may be guarded.
Dl. The rapid change in the status of a twin involved in twin-to-twin transfusion syndrome is demonstrated by the result of performing selective feticide of one twin. Severe hydrops in the donor twin can rapidly develop, following selective feticide of the hydropic recipient [3]. Furthermore, Shapiro and Sharf report a case of ‘stuck’ twin phenomenon in which there was spontaneous resolution of hydrops in the recipient twin [4]. Gramellini et al. also report the spontaneous remission of hydrops in a case of severe twin-totwin transfusion syndrome and hypothesize that this occurred secondary to the hemodynamically unstable inter-twin balance, resulting in reversed shunting [51. Jou et al. report the occurrence of reversed twin-to-twin syndrome, but only after the intrauterine death of the donor [6]. Our cases represent a reversal in amniotic fluid volumes in monochorionic twins with oligohydramnios-polyhydramnios sequence occurring between two live twins. It was helpful that one fetus in each twin pair had an anatomic marker which clearly identified it, thus enabling us to be
References 111 Bromley
l21
[31
[41
[51
l61
B, Frigoletto Jr. FD, Estroff JA, Benacerraf BR. The natural history of oligohydramnios/polyhydramnios sequence in monochorionic diamniotic twins. Ultrasound Obstet Gynecol 1992; 2: 317-320. Patten RM, Mack LA, Harvey D, Cyr DR, Pretorius DH. Disparity of amniotic fluid volume and fetal size: problem of the ‘stuck’ twin - US studies. Radiology 1989; 172: 153-157. Mahone PR, Sherer DM, Abramowicz JS, Woods Jr JR. Twin-twin transfusion syndrome: rapid development of severe hydrops of the donor following selective feticide of the hydropic recipient. Am J Obstet Gynecol 1993; 169: 1666168. Shapiro I, Sharf M. Spontaneous Intrauterine Remission of Hydrops Fetalis in One Identical Twin: Sonographic Diagnosis. J Clin Ultrasound 1985; 13: 427-430. Gramellini D, Ludovici G, Paita Y, Merialdi A, Vadora B. Spontaneous remission of double pulsatile umbilical venous flow in twin-twin transfusion syndrome: a case report. Ultrasound Obstet Gynecol 1995; 5: 138-140. Jou HJ, Ng KY, Teng RJ, Hsich FJ. Doppler sonographic detection of reverse twin-twin transfusion after intrauterine death of the donor. J Ultrasound Med 1993; 5: 307-309.