|Year : 2013 | Volume
| Issue : 3 | Page : 222-224
Non-immune hydrops fetalis incidentally found on routine obstetric sonography: A case report
Sajid Ansari, Kaleem Ahmad, Kanchan Dhungel, Mukesh K Gupta
Department of Radiodiagnosis, B. P. Koirala Institute of Health Sciences, Dharan, Nepal
|Date of Web Publication||19-Feb-2014|
Department of Radiodiagnosis, B. P. Koirala Institute of Health Sciences, H-2733, BPKIHS, Dharan
Source of Support: None, Conflict of Interest: None
Non-immune hydrops fetalis is an uncommon but serious disorder associated with an overall poor prognosis, characterized by abnormal fluid accumulation in two or more fetal serous compartments, together with generalized soft tissue edema. Sonographic detection of hydrops fetalis is usually straightforward, and detailed prenatal diagnostic investigations allow identification of disorders which may be amenable to treatment and avoidance of inappropriate fetal interventions in cases associated with a poor outcome. We present a case of non-immune hydrops fetalis incidentally detected on routine obstetric sonography in a 32-year-old, third gravida woman. She had past history of hydrops fetalis in her first pregnancy, but the second baby was still alive. She had undergone cesarean section and the baby died after a few minutes. Past history and investigations excluded the immune cause of hydrops fetalis, therefore making it most likely the non-immune type.
Keywords: Hydrops fetalis, Non-immune, Sonography
|How to cite this article:|
Ansari S, Ahmad K, Dhungel K, Gupta MK. Non-immune hydrops fetalis incidentally found on routine obstetric sonography: A case report. J Med Soc 2013;27:222-4
|How to cite this URL:|
Ansari S, Ahmad K, Dhungel K, Gupta MK. Non-immune hydrops fetalis incidentally found on routine obstetric sonography: A case report. J Med Soc [serial online] 2013 [cited 2020 Oct 29];27:222-4. Available from: https://www.jmedsoc.org/text.asp?2013/27/3/222/127399
| Introduction|| |
Hydrops fetalis literally means edema of the fetus and is classified into immune and non-immune types based on the presence or absence of Rhesus isoimmunization and histologic evidence of erythroblastosis.  Non-immune hydrops fetalis (NIHF) is a serious condition with almost 90% mortality characterized by abnormal fluid accumulation in two or more fetal serous compartments, together with generalized soft tissue edema. It accounts for 3% of perinatal morbidity in the Western countries and up to 25% of perinatal mortality in Southeast Asia, mainly due to Barts hydrops. , Its incidence ranges from 1 in 600 to 1 in 4000 pregnancies. 
| Case Report|| |
A 32-year-old, third gravida woman presented at 28 weeks of pregnancy with labor pain for 14 h. The mother had no antenatal care and had been suffering from respiratory distress at later months of her present pregnancy. According to mother's statement, her first baby was hydrops and was alive for about 2 min, and her second baby was apparently healthy and still alive. Mother's blood group was B negative and preoperative Rh antibody was undetectable in mother's blood. Mother's blood sugar was 7 mmol/l. Venereal Disease Research Laboratory (VDRL) test of both parents was nonreactive. There was no relevant history of maternal infection in any pregnancy and no history of abortion. Mother took no antenatal care, and no Rh anti-D prophylaxis and no Rh positive blood transfusion in the previous pregnancies.
Ultrasonography revealed single fetus in longitudinal lie and breech presentation, scalp edema [Figure 1] and subcutaneous tissue edema, hydrothorax, massive ascites [Figure 2] and [Figure 3], and polyhydramnios, but without gross congenital anomaly. On general examination, the mother was moderately anemic and normotensive with no edema, jaundice, or cyanosis. Per abdominal examination of the mother prior to delivery showed hugely enlarged abdomen, and presentation and lie of the fetus could not be delineated. Emergency cesarean section was done for prolonged labor. At birth, the neonate had generalized edema, color was pale, heart rate was 130/min, and respiratory rate was 20/min, irregular, and gasping. Immediately after birth, the neonate was actively resuscitated with bag and mask ventilation, but expired at about 6 min of life.
|Figure 1 : Fetal USG image (transverse view) showing scalp edema (arrow)|
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|Figure 2 : Fetal USG image (transverse view) showing ascites with abdominal wall edema|
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|Figure 3 : Fetal USG image (longitudinal view) showing ascites (arrow) and pleural effusion (arrowhead)|
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Cord blood was submitted for blood group, Rh typing and direct Coombs' test. Cord blood hemoglobin was 5 g/dl and the blood group was AB positive. Features detected by antenatal ultrasound scan, post-delivery physical findings, and very low cord blood hemoglobin on investigation suggested that the neonate was hydrops. Since history and investigations did not illustrate the immune cause of hydrops fetalis, the pathogenesis of hydrops fetalis in this neonate was most probably of the non-immune type and may be idiopathic. So, it is hard for this mother for optimum management and prevention of hydrops fetalis in subsequent pregnancies.
| Discussion|| |
About 10-20% of hydrops fetalis cases are idiopathic. ,, In addition to idiopathic causes, the majority of cases are due to: cardiovascular pathologies (35%), chromosomal anomalies (20%), anemia (15%), malformation syndromes (15%), infections (10%), liver diseases (5%), and miscellaneous causes (5%). ,,, However, as a general rule, NIHF presenting before 24 weeks is usually due to chromosomal aberrations, while hydrops presenting after this is usually due to structural anomalies (such as cardiac and pulmonary). 
Cardiac structural and functional anomalies are a common cause of NIHF. Genetic syndromes, apart from inherited hemoglobinopathies, and inborn errors of metabolism are rare. Severe fetal anemia accounts for a significant proportion of cases of NIHF as a result of homozygous α-thalassemia (Hb Barts). , It is postulated that fetal anemia is the underlying mechanism of hydrops seen in monozygous twin-to-twin transfusion, although uteroplacental insufficiency of the donor twin leading to preferential shunting of blood away to the recipient twin has been suggested as another reason. ,,
Malformation syndromes can involve any of the major systems including pulmonary, renal-urologic, gastrointestinal, neurologic, and skeletal. Some of the examples are congenital cystic adenomatoid malformation of the lung (CCAM), extralobar bronchopulmonary sequestration, congenital diaphragmatic hernia (CDH), esophageal atresia, midgut volvulus, meconium peritonitis, duodenal diverticulum, intestinal duplication, malrotation, imperforate anus, hypoplastic kidneys, polycystic kidneys, renal vein thrombosis, bladder outlet obstruction, and dysplastic kidneys.  Skeletal dysplasias may be associated with thoracic compression and impairment of venous return, resulting in hydrops.  Intrauterine infection includes toxoplasmosis, rubella, cytomegalovirus, herpes simplex, syphilis (collectively known as "TORCHS"), coxsackie virus, and parvovirus B19. 
Physical examination has little role in the assessment of cause of hydrops, but the presence of twins, uterus larger or smaller than dates, poly or oligohydramnios, or other evidence of intercurrent viral illness, herpetic lesions, or chancres should alert the clinician and prompt further investigations and to look for hydrops.
On ultrasound, it is characterized by generalized edema with skin thickness greater than 0.5 mm, together with excessive fluid accumulation in two or more serous cavities such as pleural, pericardial, or peritoneal. ,, In the presence of single serous cavity involvement, the addition of an abnormally thick placenta (>6 cm) is needed to diagnose hydrops.  However, if only one serous cavity is found to be involved without any other supporting signs, it should not be labeled as hydrops.  In this case, only the involved area is specified, such as isolated ascites or pleural effusion.  In some cases of NIHF with this isolated finding, it may further progress to hydrops.
A careful history from both parents should be obtained about possible maternal complications associated with hydrops, such as symptoms of threatened preterm labor, reduced fetal movements, and/or symptoms of impending eclampsia. 
Maternal blood work should include:  blood group typing, Coombs' testing for antibodies, full blood count, hemoglobin electrophoresis and glucose-6-phosphate dehydrogenase deficiency screening, α-fetoprotein, liver function tests, renal function tests, autoimmune screening including lupus anticoagulant and anti-Ro, oral glucose tolerance test, TORCH IgG and IgM viral titers, syphilis serology test, and parvovirus B19 IgG and IgM titers.
Twinning can easily be excluded, and fetal well-being and growth should also be assessed during ultrasound through biometry, biophysical profile assessment, Doppler studies, and measurement of amniotic fluid index.  Doppler flow studies of the umbilical and fetal circulation can be done weekly from 24 weeks, and biometric growth scans can be carried out every 2 weekly (but not more frequent than that) which could also improve the chances for structural malformations to be detected.  Cardiotocography and biophysical profiles can be done daily from 28 weeks onward, which means that the mother would need admission and may need to stay in for weeks.
In general, cardiac and pulmonary structural malformations and chromosomal anomalies are associated with a poor prognosis; hence, counseling should include the option of termination of pregnancy.  Cesarean section has not been shown to improve neonatal outcome, but it does allow for a planned resuscitation by the neonatal team and may avoid the problem of soft tissue dystocia in grossly hydropic fetuses. ,, Postpartum hemorrhage can be prevented by administration of a bolus of intravenous oxytocin at the end of second stage, followed by a maintenance oxytocin drip after delivery of the placenta. 
Fetal therapy is useful in only about 20-30% of fetuses with NIHF.  For fetal anemia, intravascular transfusion at the time of a cordocentesis allows both diagnosis and therapy. A hematocrit of less than 30% is an indication for transfusion.  Antenatal surgical interventions include: Needle aspiration, feto-amniotic shunting, open fetal surgery, and fetal endoscopic surgery. All fetuses or neonates who die from hydrops should be sent for postmortem examination. Autopsy will identify a definite cause in the majority of cases, which would facilitate genetic counseling and allow prediction of recurrence. It is rare for idiopathic NIHF to recur, but recurrences can and do occur. 
| Conclusions|| |
This case has been reported to create awareness among radiologists and clinicians about this uncommon and serious disorder with an overall poor prognosis. The ultrasonographic detection of hydrops fetalis is usually straightforward, but its etiology may be elusive depending on the vigor with which the diagnosis is pursued. Detailed past history and prenatal diagnostic investigations allow identification of disorders which may be amenable to treatment and avoidance of inappropriate invasive fetal interventions in cases associated with a poor outcome.
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[Figure 1], [Figure 2], [Figure 3]