|Year : 2017 | Volume
| Issue : 2 | Page : 98-102
Twin-Twin Transfusion Syndrome-Ultrasonographic Evaluation-A Case Report
Nupur Arora, Mukta Mital, Prashant K Gupta, Nidhi Tyagi
Department of Radio-diagnosis, Imaging & Interventional Radiology, N.S.C.B. Subharti Medical College, Swami Vivekananda Subharti University, Subhartipuram, U.P., India
|Date of Web Publication||28-Jun-2017|
Prashant K Gupta
108, Chanakyapuri, Shastri Nagar, Meerut-250 004, U.P.
Source of Support: None, Conflict of Interest: None
Twin–twin transfusion syndrome is a rare, serious condition that can occur in pregnancies when identical twins share a placenta and allow blood to flow unevenly between the babies leading to high rate of perinatal morbidity. Its prevalence is approximately 1 to 3 per 10,000 births. Its diagnosis is made prenatally by ultrasound and great advances have been made in its identification.
Keywords: Transfusion, twin, ultrasound
|How to cite this article:|
Arora N, Mital M, Gupta PK, Tyagi N. Twin-Twin Transfusion Syndrome-Ultrasonographic Evaluation-A Case Report. MAMC J Med Sci 2017;3:98-102
|How to cite this URL:|
Arora N, Mital M, Gupta PK, Tyagi N. Twin-Twin Transfusion Syndrome-Ultrasonographic Evaluation-A Case Report. MAMC J Med Sci [serial online] 2017 [cited 2017 Nov 21];3:98-102. Available from: http://www.mamcjms.in/text.asp?2017/3/2/98/209023
| Introduction|| |
Twin–twin transfusion syndrome is a congenital entity unique to monochorionic diamniotic twin pregnancies, characterized by an imbalanced blood exchange between twins circulation, which occurs through interplacental anatomises and may cause fetal compromise varying from growth discordance to death of both fetuses.
TTTS complicates about 15% of monochorial twin gestations and is responsible for 17% of the perinatal mortality in multiple pregnancies.
In TTTS, blood begins to flow unevenly with one fetal twin receiving too much blood (recipient) and other receiving little (donor).When two fetuses share same placenta, vascular anastomoses develop between their circulations. These anastomoses can be of three types: vein to vein, artery to artery, and artery to vein. The donor twin becomes hypovolemic owing to blood loss. Hypoxia develops because of placental insufficiency, which is also responsible for intrauterine growth restriction. Poor renal perfusion leads to oligohydromnios. Hypervolemia with increased renal perfusion leads to polyhydromnios in the sac of recipient.
Ultrasound criteria for the diagnosis of TTTS include monochorionic placentation with visualization of a separating membrane, fetuses of the same sex, mid-pregnancy polyhydramnions-oligohdramnios sequence (polyhydrommnios at the recipient’s sac and oligohydromnios at the donor’s sac), in the absence of other causes of abnormal amniotic fluid volume, and marked growth discordance. Significance weight discordance is considered a difference between the twin’s size equal or greater than 20%.
| Doppler Findings|| |
| Case History|| |
A 25-year-old woman was referred for routine antenatal ultraso-sonography (USG) in the second trimester of pregnancy with predominant complaints of excessive abdominal distension and dyspnea. USG revealed monochorionic diamniotic twin live intrauterine pregnancy with a single placenta and discordant fetal growth with fetus A corresponding to 26 wk 4 days gestation, weight approximately 991 g, showing edema of subcutaneous planes [Figure 1], pleural effusion [Figure 2], ascitis and a large urinary bladder [Figure 3], and increased liquor volume [Figure 4], whereas fetus B corresponding to 22 wk, weight approximately 506 g, with no edema [Figure 5], reduced liquor volume [Figure 6], and bladder not visible [Figure 7]. In addition, Doppler ultrasound revealed elevated umbilical artery resistance with absent diastolic flow in both twins [Figure 8]. On the basis of this, a diagnosis of TTTS was made with twin A as recipient and B as donor. The patient went into spontaneous labor and delivered fetuses of same gender with a single placenta. Both the babies were admitted in NICU; however, the parents refused further treatment due to poor socioeconomic status and went home against medical advice.
|Figure 8: Doppler ultrasound revealed elevated umbilical artery resistance with absent diastolic flow in both twins|
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| USG Findings of Both Twins|| |
| Discussion|| |
TTTS occurs in multiple gestation and involves chronic flow of blood from one twin to its co-twin the prevalence of TTTS is approximately 1 to 3 per 10,000 births. The syndrome usually occurs in monochorionic twins who themselves have a very high rate of complications, including severely preterm delivery, fetal growth restriction, fetal death, and TTTS. TTTS leads to high rate of perinatal morbidity due to its poorly understood etiology and difficulty in diagnosing and treatment. Early diagnosis during antenatal USG is important in reducing the morbidity and mortality rates. The morbidity rate of TTTS is high, ranging from 40 to 70%.
Vascular connections in the placenta between both twins are necessary for TTTS to develop. The progressive nature of twin–twin transfusion in utero is thought to be due to one twin (the donor) who slowly pumps blood to the other (the recipient) through the placental vascular anastomoses Vascular anastomoses are in virtually 100% of monochorionic twin pregnancies, whereas twin–twin transfusion occurs in 5 to 10% of monochorionic pregnancies., The reason for the occurrence of TTTS in only a small proportion of the monochorionic twin pregnancies with vascular anastomosis is unknown.
The intraplacental anastomosis is usually situated in a single, shared cotyledon of the common placenta and is usually arteriovenous but maybe arterial–aretrial.,
TTTS is a diagnosis made prenatally by ultrasound and great advances have been made in its identification. The diagnosis of TTTS requires two criteria: (1) the presence of a MCDA pregnancy and (2) the presence of oligohydramnios (defined as a maximal vertical pocket of <2 cm) in one sac, and of polyhydramnios (a maximal vertical pocket of >8 cm) in the other sac.
Other features that help in diagnosis include—marked difference in the size of fetuses of same gender, difference in size of umbilical cord, a single placenta, evidence of fluid buildup in the skin of either fetus, and findings of congestive heart failure in the recipient twin.
Mothers with TTTS may experience sensation of rapid growth of the womb, a uterus that measures large for dates, abdominal pain, tightness, contractions, sudden increase in body weight, swellings in hands, and legs in early pregnancy.
Complications of TTTS are premature labor either due to ruptured membranes or induction, respiratory, digestive, heart, or brain defects in the recipient twin because of excess fluid, donor twin developing anemia, and fetal demise/death.
| Staging of Twin–Twin Transfusion Syndrome|| |
Stage 1: Bladder in donor twin is still visible
Stage 2: Bladder in donor twin is no longer visible, but no critically abnormal findings are observed on Doppler
Stage 3: Doppler studies are critically abnormal
Stage 4: Hydrops is present
Stage 5: Demise of one or both twins occurs.
| Treatment Options|| |
Careful antenatal assessment by ultrasound and tocolysis for preterm labor are the cornerstones of conservative management and generally used as adjuncts to other invasive treatments. Frequent antenatal assessment may form the basis of an iatrogenic decision for delivery and is often associated with prevention of death in utero. The various options available are amnioreduction, fetoscopic laser occlusion of chorioangiopagus placental vessels, septostomy, removal of one twin at hysterectomy, and percutaneous ultrasound guided cord ligation.
| Reduction Amniocentesis|| |
The most common procedure to treat TTTS is reduction amniocentesis. This procedure involves draining the amniotic fluid from around the recipient twin. This procedure may improve circulation in the donor twin especially if the anastomosis is superficial in the placenta and the TTTS is in a lower stage. This procedure may need to be performed multiple times during the pregnancy.
Amniocentesis involves removal of excessive amniotic fluid from the sac of recipient twin using a needle that is passed through maternal abdomen. Proceedure is usually completed within 30 min or less. The procedure is generally not thought to be effective for more advanced stages of TTTS-stage 3 and 4.
| Laser Ablation of the Placental Anastomotic Vessels|| |
In more advanced stage of TTTS (stage 2 and higher), laser ablation of the communicating vessels on the placenta between the twin fetuses can be a curative treatment.
This is mostly reserved for more severe cases, especially those which do not respond to amnioreduction. In pregnancies treated with fetoscopic procedures, the overall survival is 75% with 85% having at least one fetus survival.
Septostomy–It is creation of a hole in the membrane between the babies sacs using a needle. This causes fluid to move from amniotic sac with excessive fluid into the sac with absent or low fluid.
| Conclusion|| |
TTTS is a rare, serious condition that can occur in pregnancies when identical twins share a placenta and allow blood to flow unevenly between the babies leading to high rate of perinatal morbidity. Early diagnosis of TTTS during antenatal USG is important to reduce perinatal morbidity.
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Conflicts of interest
There are no conflict of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]