Right-Sided Diaphragmatic Eventration: A Rare Cause of Non-Immune Hydrops Fetalis

Abstract

We report 2 cases of non-immune hydrops fetalis (NIHF) in which autopsy findings revealed an association with right-sided congenital diaphragmatic eventration (CDE). Both patients born at 30 weeks of gestation presented with severe generalized skin oedema, pleural effusions and ascites. They both died shortly after birth of cardiorespiratory insufficiency due to lung hypoplasia and low output heart failure. The right thoracic cavity was filled with the membranous but intact right diaphragm covering the herniated visceral organs including parts of the liver, small bowel and colon surrounded by voluminous ascites. In similar fashion to the situation seen in congenital diaphragmatic hernia (CDH), the displaced visceral organs led to impaired lung growth resulting in important lung hypoplasia and obstructed venous return. Extravascular liquid accumulation was probably further aggravated by hypoproteinaemia secondary to liver dysfunction resulting from the venous congestion and cardiac failure. In summary, CDE is a rare condition resulting from impaired ingrowth of muscle fibres into the diaphragm during the first trimester. Prenatal differentiation of CDE from CDH is a real challenge. The association of CDE and NIHF has not been previously described.

Imaging findings in fetal diaphragmatic abnormalities

“…1). At 8-10 weeks of gestation, muscular fibers arising from the cervical myotomes grow in the lateral body wall and incorporate the intercostal muscles within the membranous diaphragm [12,14,15]. The internal layer of the body wall then forms the muscle of the peripheral diaphragm.…”

“…It is on the left in 80-90% of cases [11,13]. It results from a defect in the diaphragm caused by a malformation of the pleuro-peritoneal folds or from a failure of fusion between the pleuro-peritoneal folds and the transverse septum with the intercostal muscles [10, 11,15]. The anterior Morgagni hernia represents 12-15% of diaphragmatic defects in infancy and is caused by a defect in the fusion of the transverse septum to the lateral body wall, with the herniated organs passing between the sternal and the costal heads of the diaphragm (Fig.…”

“…It is caused by a focal defective musculature of the diaphragm, with absence or impaired development of the diaphragmatic muscle fibers in the involved region [12,15]. The absence of the muscle leads to a focal thinning of the diaphragm [11], which forms a pocket-like outpouching, allowing the displacement of the abdominal organs into the thorax.…”

“…c Anteroposterior chest and abdomen radiograph obtained a few minutes after birth shows the right intrathoracically located air-filled intestines and confirms the normal position of the stomach. The boy died at 2 days of age from severe respiratory insufficiency and pulmonary hypertension extensive eventrations are extremely difficult to differentiate from congenital hernias at prenatal imaging [13,15]. Right eventrations can produce non-immune hydrops fetalis, probably from the compression of the superior and inferior vena cava, with chronic impairment of the venous return and secondary low-output cardiac failure [14] (Fig.…”

“…Unilateral paralysis is almost impossible to differentiate from extensive congenital diaphragmatic eventration at prenatal exams, but elevation of the diaphragm by paralysis usually involves the entire hemidiaphragm, whereas in most cases of congenital diaphragmatic eventration only a portion of a hemidiaphragm is elevated [12][13][14][15]. Coronal US and MRI images might compare the position of the hemidiaphragms and show the elevation of the involved diaphragm.…”