A Bochdalek hernia (plural: hernias or herniae) is a form of congenital diaphragmatic hernia. They occur posteriorly and are due to a defect in the posterior attachment of the diaphragm when there is a failure of pleuroperitoneal membrane closure in utero. Retroperitoneal structures may prolapse through the defect, e.g. retroperitoneal fat or left kidney.
Large hernias typically present in infancy, are usually said to be most frequently left-sided, presumably owing to the protective effects of the liver, although recently this has been disputed, at least in adults 1. The left opening of the posterior diaphragm closes later in fetal life than the right which may also contribute to the asymmetric occurrence. Complications are usually due to pulmonary hypoplasia.
In adults, incidentally-discovered posterior diaphragmatic hernias are rare (0.17% of patients having an abdominal CT). Of these, right-sided hernias are more common (68%), and more frequent in females. The great majority are small, with only 27% containing abdominal organs such as bowel, spleen or liver.
On conventional radiographs, the hernia may appear as a lung base soft-tissue opacity lesion seen posteriorly on lateral images.
CT usually demonstrates fat above the diaphragm and is extremely beneficial in revealing organ entrapment. Coronal and sagittal reformatted images show the defect to best advantage.
- Bochdalek herniae may mimic diaphragmatic rupture from trauma, but you would expect to find other supportive signs of chest and/or abdominal trauma
BBBBB is a simple mnemonic to recall the features of Bochdalek hernias.
- 1. Mullins ME, Stein J, Saini SS et-al. Prevalence of incidental Bochdalek's hernia in a large adult population. AJR Am J Roentgenol. 2001;177 (2): 363-6. AJR Am J Roentgenol (full text) - Pubmed citation
- 2. Temizöz O, Gençhellaç H, Yekeler E et-al. Prevalence and MDCT characteristics of asymptomatic Bochdalek hernia in adult population. Diagn Interv Radiol. 2010;16 (1): 52-5. doi:10.4261/1305-3825.DIR.2750-09.1 - Pubmed citation
- 3. Hamid KS, Rai SS, Rodriguez JA. Symptomatic Bochdalek hernia in an adult. JSLS. 2010;14 (2): 279-81. doi:10.4293/108680810X12785289144719 - Free text at pubmed - Pubmed citation