Encapsulating Peritoneal Sclerosis: Definition, Etiology, Diagnosis, and Treatment

Abstract

The utilization of the peritoneal cavity for dialysis creates the opportunity for alterations in the function and structure of the peritoneal membrane. The peritoneal membrane has proven, however, to be a remarkably resilient organ. Indeed, several studies have documented the functional stability of the membrane in short and midterm evaluations (1–5). One is reminded of the spectacular observations in a small number of patients examined at autopsy who had minimal structural changes despite recurrent infectious complications (6). These isolated observations illustrate the fact that the response of the peritoneal membrane to potentially modifying factors can be diverse, and generalizations on both the immunity to change or the proclivity to widespread change err in their extremism. Further, despite notable attempts at various time points in the history of peritoneal dialysis (PD) to examine the peritoneum of patients on PD (6–12), the scope of changes and the natural history of the peritoneal membrane during dialysis have not been fully elucidated. This is clearly due to the limitation of clinical material to examine and the possibly biased nature of samples that are examined. Further, the techniques of morphologic analysis have been gradually maturing; the targets of examination have also evolved. One structural modification of the peritoneum that has caused significant concern over the fate of dialysis patients is what has been labeled sclerosing encapsulating peritonitis. This entity is not unique to dialysis patients, it occurs in a variety of other clinical conditions discussed below. The multiplicity of suspected etiologies and the confusion over its pathophysiology are reflected in the variety of terms that have been used indiscriminately and interchangeably to describe this complication, such as peritoneal fibrosis, peritoneal sclerosis, sclerotic thickening of the peritoneal membrane, sclerotic obstructive peritonitis, calcific peritonitis, abdominal cocoon, and sclerosing peritonitis (13–34). The most common term used in the nephrology literature in recent years has been sclerosing encapsulating peritonitis, but the popularity of the term does not necessarily validate its continued use, as it is marred by its morphologic inaccuracy, particularly in its reference to an inflammatory component that is frequently absent in the developed syndrome (peritonitis). A more accurate description would be encapsulating peritoneal sclerosis (EPS), which is more descriptive of the morphologic changes.