Non-immune fetal hydrops of metabolic origin: a case report and a review of the literature

Abstract

AbstractAimTo propose a diagnostic algorithm for non-immune fetal hydrops (NIFH) of metabolic origin based on a review of the literature and on the workup of a clinical case.BackgroundThe etiology of NIFH is complex and remains unexplained in 15%–25% of patients. The appropriate work up beyond an initial approach is still not well defined but it should include screening for metabolic conditions. Inborn errors of metabolism comprise a heterogeneous group of autosomal recessive rare inherited disorders, among which lysosomal storage disorder is the most common subtype.Case descriptionWe report a case of a 30-year-old pregnant, primiparous woman, referred to a tertiary hospital at 22 weeks of gestation because of a fetal hydrops. The second trimester obstetric ultrasound showed a hydrothorax and a large subcutaneous edema. At 30 weeks of gestation, the fetal health status deteriorated and a massive hepatomegaly was detected. The metabolic study of the amniotic fluid supernatant suggested a lysosomal disease. The ominous prognosis of the condition motivated the parents to opt for a termination of pregnancy. The autopsy study confirmed the existence of a metabolic disease.ConclusionThe incidence of inborn errors of metabolism may be significantly higher in NIHF than reported previously. Consequently, an extensive investigation for the etiology of NIHF including the screening for metabolic disorders seems to be crucial for a definitive diagnosis.Clinical relevanceDespite the lack of treatment options for the majority of these disorders, it is of great importance to follow an established workup, in order to identify the index case as soon as possible, as pregnancy management decisions and prenatal counselling in future pregnancies will depend on a more precise diagnosis.