Congenital diaphragmatic hernia--does the side of the defect influence the incidence of associated malformations?

Patients with congenital diaphragmatic hernia (CDH) frequently have associated anomalies. Experiments in the nitrofen CDH model have shown differential embryonic cell death patterns in rodents suggesting unique mechanisms in the formation of right-sided (RCDH) or left-sided (LCDH) diaphragmatic hernia. These findings provide insight into the pathogenesis of CDH and may aid our understanding on the spectrum of associated anomalies commonly observed in humans. This study therefore set out to test the hypothesis that the side of the diaphragmatic defect in humans is related to the incidence and severity of coexistent organ malformations.

The medical and autopsy records of 301 CDH patients presenting to two institutions over a 23-year period were examined to analyze these factors.

One hundred patients (33%) were found to have one or more associated anomalies. The incidence of multiple-RCDH (10%) versus LCDH (7.3%) and cardiac anomalies-RCDH (10%) versus LCDH (8.5%) was similar in both groups of patients. However, the hypoplastic heart syndrome was a unique feature in 5 of 22 patients (23%) with LCDH who had cardiac abnormalities. This cardiac anomaly may be related developmentally to LCDH.

The cellular mechanisms underlying the genesis of this spectrum of abnormalities in humans and the nitrofen CDH model warrant further study to elucidate factors governing embryonic cell fate and phenotype expression.