Answer: To clarify medical terms, signs are features that one observes (e.g. cloudy drained dialysate) versus symptoms, which a patient feels (e.g. pain).

Peritonitis is almost always caused by microorganisms, such as bacteria or fungi, in the peritoneal cavity, which is normally sterile. When these organisms multiply, they provoke an inflammatory reaction by the cells of the peritoneum. This reaction is a self-defense against the invading organisms. Part of that reaction is a dilation of the blood vessels to bring blood cells to the site of the infection. Also, some of these blood cells move into the peritoneal fluid, causing it to look cloudy. These are the infection-fighting white blood cells. Also accompanying the cells are proteins and other infection-fighting molecules directed against the organisms. This protein can make the dialysate clot somewhat into fibrin strands or clumps of what looks like slime or jelly.

Some peritoneal dialysis patients use automated means of performing exchanges (e.g. cyclers) and the exchange of fluid is so rapid that some of these phenomenons are not observed. Essentially, the rapid exchanges dilute out the inflammatory signs, but they are still occurring, even if they are less obvious.

It is believed that these reactions begin within hours of a contamination, when the organisms get into the peritoneal cavity. While a delay of several hours may be seen, it probably will not be several days. Some symptoms and signs may be mild or not observed for a while, but most reactions to contamination begin within hours of the precipitating event.

Almost all occurrences of peritonitis are accompanied by abdominal pain. This may start in a particular area but generally becomes more widespread within hours. This consists of deep pain, made worse by movement or touching. Other symptoms include loss of appetite, often progressing to nausea and occasionally to vomiting. Diarrhea is unusual, but not rare, and some patients even experience constipation. Fever and chills may occur occasionally, but probably not in most cases.

It is imperative that the contents of the peritoneal cavity be visually inspected for cloudiness when these symptoms occur and persist for an hour or so. The combination of abdominal pain and cloudy peritoneal dialysate is almost diagnostic of peritonitis. If rapid cycles are being performed, then the fluid may not have time to become cloudy. The exchanges should be slowed so that the fluid can reside in the abdomen for at least an hour. If you are between exchanges, you should perform an exchange immediately if the abdominal pain has persisted for an hour. So even if the next exchange is not due, it must be moved forward so that you can observe the drained dialysate for cloudiness. Your dialysis training program must instruct you as to what specifically to do next.

Exit site infections predispose to peritonitis. Therefore, patients with exit site infections must be particularly vigilant for peritonitis, which leads to the next question.

Answer provided by Tom Golper, MD. Dr. Golper is a Professor of Medicine at the Vanderbilt University Medical Center, Division of Nephrology and a member of the AAKP Board of Directors. He is also a member of the AAKP Medical Advisory Board.

The Dear Doctor column provides readers with an opportunity to submit renal related health questions to healthcare professionals who specialize in the area of concern. The answers are not to be construed as a diagnosis and therefore, altercations in current healthcare should not occur until the patient's physician is consulted.

This article originally appeared in July 2001 aakpRENALIFE, Vol. 17, No. 1.

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