Nonimmunologic hydrops fetalis: an etiopathogenetic approach through the postmortem study of 59 patients

Nonimmune hydrops fetalis in the liveborn: series of 32 autopsies

Nonimmune hydrops fetalis (NIHF) or generalized soft tissue edema and cavity effusions may be due to cardiovascular diseases, congenital infections, genitourinary malformations, thoracic masses, placental conditions, chromosomal abnormalities, and idiopathic. We report 32 cases of NIHF from among 429 neonates who underwent autopsies (incidence 7.45%). Sixteen cases (50%) had cardiovascular disease; all were due to low output cardiac failure; 7 had structural congenital heart disease. Three of the children with congenital heart disease also had chromosomal abnormalities: 2 had trisomy 18 and 1 had Noonan syndrome. Among myocardial conditions were five subjects with cardiomyopathies (1 of each of the following types): oncocytic, dilated, endocardial fibroelastosis, cardiac glycogenosis, and carnitine deficiency; 3 had myocarditis, and 1 had cardiac rhabdomyomas. Congenital infections were due to cytomegalovirus in 3 cases, bacteria in 2, and parvovirus in 1. The mechanism of NIHF in these cases might be a combination of decreased myocardial contractility due to myocarditis and fetal anemia. Genitourinary diseases were present in 5 newborns: Two had congenital nephrotic syndrome, 1 had VACTER association, 1 had prune-belly syndrome, and 1 had urogenital sinus malformation. Intrathoracic lesions were found in 2 babies (pulmonary sequestration and diaphragmatic hernia). One twin died of volume overload due to twin transfusion syndrome. Only 2 newborns were classified as idiopathic. Our study shows that cardiovascular diseases that lead to heart failure or impaired venous return are more common in the liveborn (50%), whereas congenital infections are more common in the stillborn with NIHF.

Detection of intrauterine viral infection using the polymerase chain reaction

Intrauterine viral infection commonly presents as nonimmune hydrops fetalis or intrauterine growth restriction. Cytomegalovirus (CMV) and parvovirus are commonly recognized causes of fetal infection using serology and cultures. We used the polymerase chain reaction (PCR) to evaluate the frequency of fetal viral infection and the associated clinical course and outcome. Specimens (amniotic fluid, fetal blood, pleural fluid, tissue) from 303 abnormal pregnancies at risk for viral infection and 154 controls were analyzed using primers for CMV, herpes simplex virus, parvovirus B19, adenovirus, enterovirus, Epstein-Barr virus, and respiratory syncytial virus. Viral genome was detected in 144/371 samples (39%) or 124/303 patients (41%), with adenovirus (n = 74 patients; 24%), CMV (n = 30 patients; 10%), and enterovirus (n = 22 patients; 7%) most common. Only 4/154 (2.6%), unaffected control patients' samples were PCR positive. We conclude that diagnosis of fetal viral infection by PCR is common in abnormal pregnancies. Adenovirus and enterovirus may cause fetal infection that have been previously unrecognized.

Immunohistochemical distribution of surfactant apoproteins in hypoplastic lungs of nonimmunologic hydrops fetalis

Forty-three patients with nonimmunologic hydrops fetalis (NIHF), including 32 patients (74%) with hypoplastic lung, were immunohistochemically examined for the expression of surfactant apolipoproteins (SPs), using anti-gamma G immunoglobulins against human SP-A with a molecular weight (MW) of 35 K and SP-B with a MW of 5 K compared with that in 59 patients in a control group and 45 patients with hypoplastic lung induced by causes other than NIHF. In the control group, SP-A was expressed in the lungs from 23 gestational weeks and became more numerous and intense in alveolar type II cells after 31 gestational weeks, whereas SP-B began to be expressed from 20 gestational weeks, and almost all patients showed a diffuse positivity after 26 gestational weeks. In the NIHF group, SP-A expression was generally weak, even after 31 gestation weeks. Moreover, most of the patients showing a weak expression of SP-A were also associated with hypoplastic lung and had a clinical history of persistent intrauterine pleural effusion of more than 2 weeks. Conversely, the immunoreactivity of SP-B was well preserved in NIHF cases either with or without hypoplastic lung. These results suggest that in the NIHF lung, there is a possible delay in the functional maturation or development of SP-A synthesis by alveolar type II cells, and this retardation of the functional maturation in type II cells also participates in the postnatal respiratory insufficiency in NIHF.

Non-immunological hydrops fetalis and intrapericardial teratoma: case report and review

A large intrapericardial teratoma was found at necropsy in a 38-week stillborn fetus, in which prenatal diagnosis of hydrops fetalis and an echogenic cardiac mass had been made. Clinical and pathological data are reported. In utero intrapericardial teratomata lead to different outcomes depending on whether fetal hydrops is associated. When generalized fetal hydrops is not present, the outcome is good, even in cases with large pericardial effusions. When generalized fetal hydrops occurs, it often results in a poor outcome. In our literature review, we have found eight perinatal deaths in nine similar cases reported.

Recurrent fatal hydrops fetalis associated with a nucleotide substitution in the erythrocyte beta-spectrin gene

We studied a kindred in which four third-trimester fetal losses occurred, associated with severe Coombs-negative hemolytic anemia and hydrops fetalis. Postmortem examination of two infants revealed extensive extramedullary erythropoiesis. Studies of erythrocytes and erythrocyte membranes from the parents revealed abnormal erythrocyte membrane mechanical stability as well as structural and functional abnormalities in spectrin, the principal structural protein of the erythrocyte membrane. Genetic studies identified a point mutation of the beta-spectrin gene, S2019P, in a region of beta spectrin that is critical for normal spectrin function. Both parents and two living children were heterozygous for this mutation; three infants dying of hydrops fetalis were homozygous for this mutation. In an in vitro assay using recombinant peptides, the mutant beta-spectrin peptide demonstrated a significant abnormality in its ability to interact with alpha spectrin. This is the first description of a molecular defect of the erythrocyte membrane associated with hydrops fetalis.

Non-immune hydrops fetalis and bilateral pulmonary hypoplasia in a newborn infant with extralobar pulmonary sequestration

Extralobar pulmonary sequestration was found in a newborn premature infant that presented with non-immune hydrops fetalis, massive bilateral hydrothorax and polyhydramnios in utero. The baby died of severe respiratory insufficiency 15 h after birth. Postmortem examination revealed distended lymphatic vessels in the sequestered lung tissue probably due to impeded lymph drainage. We suggest that not extralobar pulmonary sequestration itself but a subsequent massive unilateral hydrothorax due to severe obstruction of lymph drainage was the cause of the non-immune hydrops fetalis, pulmonary hypoplasia and polyhydramnios. If these symptoms are diagnosed before delivery, a search for extralobar pulmonary sequestration is indicated.

Umbilical pressure measurement in the evaluation of nonimmune hydrops fetalis

OBJECTIVE

Nonimmune hydrops fetalis continues to have a perinatal mortality rate > 50%. Although many abnormalities are associated with nonimmune hydrops fetalis, the direct mechanism by which the hydrops occurs is often obscure, even after delivery. There are at least three possible mechanisms for hydrops: heart failure (whether primary or a secondary effect of obstructed venous return), lymphatic malformation, and liver or peritoneal disease. The development of safe access to the fetal circulation by cordocentesis allows for the measurement of the umbilical venous pressure, which is closely related to the fetal central venous pressure. The premise that nonimmune hydrops fetalis of cardiac origin could be distinguished from that of noncardiac origin was examined by measuring the umbilical venous pressure.

STUDY DESIGN

Umbilical venous pressure was measured during indicated diagnostic cordocentesis in three groups of fetuses: 20 with nonimmune hydrops fetalis, four with a cardiac malformation but without nonimmune hydrops fetalis, and eight with immune hydrops (fetal hemolytic disease). In 16 of 20 fetuses with nonimmune hydrops fetalis the serum total protein and albumin concentrations were also measured.

RESULTS

Presumed inadequate cardiac output, as indicated by an elevated umbilical venous pressure, was the mechanism of nonimmune hydrops fetalis in 13 of 20 (65%). The pathologic condition included arrhythmia, cardiothoracic abnormalities, severe polycythemia and hyperviscosity, viral infection, and severe anemia. Successful antenatal treatment normalized the umbilical venous pressure. Nonimmune hydrops fetalis secondary to noncardiac mechanisms did not progress in severity and was not amenable to antenatal therapy. Hypoproteinemia and hypoalbuminemia were found in only six of 16 cases and were similarly distributed between cardiac and noncardiac mechanisms.

CONCLUSIONS

This is the first report where the measurement of umbilical venous pressure was applied to the evaluation of nonimmune hydrops fetalis. Cardiac dysfunction was the most common mechanism causing hydrops. The finding of a normal umbilical venous pressure greatly reduces the likelihood that the heart is the cause of the hydrops, even when there is a coexistent heart malformation. This immediate information allows the practitioner either to focus on therapeutic interventions that might lower the umbilical venous pressure or to look for noncardiac causes for the hydrops.

Genetically determined transient edema found in the WB/ReJ mouse strain in a teratogenic survey with acetazolamide

A continuing survey of the genetic variability of different mouse strains to acetazolamide teratogenesis demonstrated the WB/ReJ strain expresses a high frequency of induced subcutaneous edema in day 15 fetuses. In treated WB/ReJ fetuses, the probability of expression of edema is independent of the expression of forelimb ectrodactyly and, with the dosage regime, there is no significant increase in acetazolamide-induced resorption. It was surprising to find a high frequency of spontaneous edema on day 15 in untreated WB/ReJ fetuses. The spontaneous edema is a transient trait with maximum expression (56%) on day 14, and it is resolved by day 17 without apparent consequence to the survival of previously affected fetuses. There is no sex dimorphism in the liability to express the transient edema. Preliminary genetic crosses to investigate the spontaneous edema were made between WB/ReJ and the C57BL/6J strain, which historically had not be observed to express spontaneous edema. A low frequency of spontaneous edema was observed on day 14 in both C57BL/6J and the reciprocal F1 fetuses. The trait is not additive because there is dominance deviation of the BC1 fetuses in the direction of the F1 fetuses. The data were fitted to a threshold model suggesting that the developmental liability to express the difference in transient edema is determined by more than one gene, but the data can be interpreted by a minimum of two loci with duplicate epistasis. The observed differences in frequencies of edema suggest the genetic model can be tested with relatively few test crosses.