Biochemical analysis of ascites fluid as an aid to etiological diagnosis: a series of 100 cases of nonimmune fetal ascites

Etiology and Outcome of Isolated Fetal Ascites: A Systematic Review

OBJECTIVE

To describe the etiology of isolated fetal ascites and associated perinatal outcomes, and to assess the progression of isolated fetal ascites to fetal hydrops.

DATA SOURCES

PubMed, Cochrane Library, Scopus, and ClinicalTrials.gov databases were searched using the following keywords: "fetus" OR "foetal" OR "fetal" OR "foetus" AND "ascites" from inception to February 2020. The search was limited to the English language.

METHODS OF STUDY SELECTION

A total of 1,983 articles were identified through the search strategy. All studies containing five or more cases of isolated fetal ascites were included.

TABULATION, INTEGRATION, AND RESULTS

Eleven studies, involving 315 cases of isolated fetal ascites, were eligible for inclusion in this systematic review. All included studies were evaluated using the tool for evaluating the methodologic quality of case reports and case series described by Murad et al. Data were summarized using narrative review and descriptive statistics. Two-tailed Fisher exact P values calculated from hypergeometric distribution were used to compare outcome by etiology. CIs were calculated with Clopper-Pearson exact binomial interval. The etiologies of isolated fetal ascites are genitourinary (24%), gastrointestinal (20%), viral or bacterial infections (9%), cardiac (9%), genetic disorders not otherwise categorized (8%), chylous ascites (6%), metabolic storage disorders (3%), other structural disorders (4%), other causes (4%) and idiopathic (13%). Survival is most favorable for cases of isolated fetal ascites as a result of chylous (100%), idiopathic (90%), gastrointestinal (77%) and genitourinary (77%) etiologies. Survival is least favorable for fetuses with isolated fetal ascites as a result of structural disorders (25%), cardiac etiology (32%) and metabolic storage disorders (33.3%). When pregnancy terminations were excluded, survival rates were similar between fetuses diagnosed at or after 24 weeks of gestation compared with those diagnosed at less than 24 weeks (74% vs 61%, P=.06). Progression of fetal ascites to fetal hydrops occurred in 6.6% (95% CI 3.6-9.6%) (17/259) of cases when pregnancies that were terminated were excluded.

CONCLUSION

Isolated fetal ascites has a diverse etiology. Outcome is related to the etiology of isolated fetal ascites. In the majority of cases, fetal ascites does not progress to fetal hydrops.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42020213930.

Finding vacuolated lymphocytes in fetal effusions improves the prenatal diagnosis of lysosomal storage diseases

OBJECTIVES

There are many causes of fetal effusions, including the rare lysosomal storage diseases (LSDs). Vacuolated lymphocytes (VLs) are found in the blood of infants with LSDs, and their presence in fetal effusion could increase the risk of underlying LSD.

METHODS

Between 2006 and 2018, all fetal effusions samples from 43 fetal multidisciplinary centers were referred to a single laboratory. Cells were counted, and, if observed, VLs were categorized and counted. Screening for LSDs was performed by metabolite analyses on amniotic fluid supernatant. The diagnosis of an LSD was confirmed by measuring the activity of the corresponding enzyme and/or mutation analysis.

RESULTS

Our laboratory received 614 ascitic fluids and 280 pleural fluids sampled between 22 and 33 weeks of gestation. The final diagnosis was LSD in 16 cases (1.8%). VLs were reported in all these 16 cases, in a mix of lymphocytes with and without vacuoles. Vacuoles in VLs varied in size and number. In most cases, VLs were easy to recognize, with numerous, large, round, well-defined vacuoles, but in three cases of LSDs, VLs were atypical.

CONCLUSION

The finding of VLs in fetal effusions is an inexpensive first-line test that may help to prioritize biochemical and genetic tests for LSDs.

Prenatal sonographic diagnosis of isolated fetal ascites in cri-du-chat (5p-) syndrome: A case report

Isolated fetal ascites and cri-du-chat syndrome (CdCS; OMIM #123450) are two very rare conditions that, to our best knowledge, have never been reported together. Here, we describe a case of isolated fetal ascites detected in the first trimester ultrasound, with no other remarkable signs. After an extensive work-up (fetal ultrasound, serologies, Coombs test, and NIPT), an amniocentesis was performed and revealed an abnormal karyotype of 46,XX,del(5)(p15.2), characteristic of CdCS. We hypothesize that isolated fetal ascites has to be considered an antenatal ultrasonographic marker for CdCS, a finding that should be confirmed in further cases.

Isolated ascites in a newborn with 'apple peel' jejunal atresia

Isolated fetal ascites was diagnosed at 20 weeks in a primiparous woman with no significant medical history. Progressive fetal ascites worsened after 28 weeks and resulted in fetal hydroceles. Delivery was by caesarian section at 33 weeks, preceded by reduction of fetal ascites under ultrasound guidance. Following delivery, the baby required further reduction of abdominal fluid and endotracheal intubation to provide respiratory support. An extensive set of investigations, including metabolic and genetic screening, was performed; all results were negative. On day two of life, the baby developed bilious aspirates and an abdominal radiograph suggested intestinal obstruction. At laparotomy, an 'apple peel' jejunal atresia, abnormal mesentery with precarious blood supply and a proximal perforation were identified and the perforation 'sewn over'. The postoperative course was unremarkable, with Monogen feeds tolerated three weeks later. The baby continued to thrive at one year, tolerating increasing amount of long-chain fatty acids in diet.

Antenatal manifestations of inborn errors of metabolism: biological diagnosis

Inborn errors of metabolism (IEMs) that present with abnormal imaging findings in the second half of pregnancy are mainly lysosomal storage disorders (LSDs), cholesterol synthesis disorders (CSDs), glycogen storage disorder type IV (GSD IV), peroxisomal disorders, mitochondrial fatty acid oxidation defects (FAODs), organic acidurias, aminoacidopathies, congenital disorders of glycosylation (CDGs), and transaldolase deficiency. Their biological investigation requires fetal material. The supernatant of amniotic fluid (AF) is useful for the analysis of mucopolysaccharides, oligosaccharides, sialic acid, lysosphingolipids and some enzyme activities for LSDs, 7- and 8-dehydrocholesterol, desmosterol and lathosterol for CSDs, acylcarnitines for FAODs, organic acids for organic acidurias, and polyols for transaldolase deficiency. Cultured AF or fetal cells allow the measurement of enzyme activities for most IEMs, whole-cell assays, or metabolite measurements. The cultured cells or tissue samples taken after fetal death can be used for metabolic profiling, enzyme activities, and DNA extraction. Fetal blood can also be helpful. The identification of vacuolated cells orients toward an LSD, and plasma is useful for diagnosing peroxisomal disorders, FAODs, CSDs, some LSDs, and possibly CDGs and aminoacidopathies. We investigated AF of 1700 pregnancies after exclusion of frequent etiologies of nonimmune hydrops fetalis and identified 108 fetuses affected with LSDs (6.3 %), 29 of them with mucopolysaccharidosis type VII (MPS VII), and six with GSD IV (0.3 %). In the AF of 873 pregnancies, investigated because of intrauterine growth restriction and/or abnormal genitalia, we diagnosed 32 fetuses affected with Smith-Lemli-Opitz syndrome (3.7 %).