Sclerosing Peritonitis (Encapsulating Peritoneal Sclerosis)

What is sclerosing peritonitis?

The peritoneum is a thin, smooth membrane that lines the abdominal wall and covers the bowel. In peritoneal dialysis (PD), it acts as the filter, with dialysis fluid running in and out of the abdomen through a catheter.

Over years, exposure to glucose-based dialysis fluid, repeated infections and inflammation can thicken and scar the membrane. In a small number of people, the scarring becomes a thick, fibrous, sometimes calcified layer that sticks the loops of small intestine together and wraps them like a cocoon. The bowel can no longer move food along normally, causing intermittent or complete obstruction.

Who gets it

Peritoneal dialysis

PD is by far the most common cause. The risk rises sharply with time on PD:

Other factors include repeated or severe bacterial or fungal peritonitis, high glucose dialysis fluids, a "fast transporter" membrane, younger age at starting PD, and stopping PD (EPS often appears in the months after switching to hemodialysis or after a kidney transplant). Modern dialysis fluids and better infection control may be lowering the risk.

Other causes

• abdominal tuberculosis
• the beta-blocker practolol (now withdrawn)
• abdominal surgery, ventriculoperitoneal or peritoneovenous shunts
• liver transplant, cirrhosis and some cancers
• Idiopathic abdominal cocoon: a rare form with no clear cause, reported mainly in young women in tropical and subtropical regions

Symptoms

Symptoms often build over months:

• recurring bouts of cramping abdominal pain
• nausea, vomiting and bloating after eating
• constipation, alternating with diarrhea in some cases
• loss of appetite, early fullness and weight loss
• a doughy or firm mass feeling in the abdomen
• bloodstained dialysis effluent or ascites
• declining fluid removal on PD
• malnutrition: muscle wasting, low albumin, fatigue

Acute episodes of bowel obstruction can need hospital admission.

How it is diagnosed

EPS combines symptoms of bowel obstruction with typical imaging findings.

• CT scan of the abdomen: the key test. It shows a thickened, enhancing or calcified peritoneum, fluid pockets, and loops of small bowel clumped together in the center of the abdomen.
• Blood tests: inflammation markers (CRP), albumin and nutritional markers.
• Ultrasound or MRI may help in some cases.
• Surgery: sometimes the diagnosis is confirmed only during an operation, when a white, fibrous membrane is found around the bowel.

Other causes of obstruction such as adhesions from surgery, hernias and tumors need to be excluded. A chronic peritonitis from ongoing infection can look similar and is treated differently.

Treatment

Care is best provided at a kidney center experienced with EPS, with a dietitian and specialist surgeon.

Stopping peritoneal dialysis

Most patients switch to hemodialysis. Whether to stop PD in everyone on long-term PD to prevent EPS is debated.

Nutrition

Because the bowel cannot handle food well, many patients need a liquid diet, small frequent meals, or parenteral nutrition (nutrients given into a vein). Correcting malnutrition is essential before and after surgery.

Medicines

• Corticosteroids, especially in the early, inflammatory stage.
• Tamoxifen, which has anti-fibrotic effects, used in some centers.
• Immunosuppressants such as mTOR inhibitors after kidney transplant have been tried.

Evidence for these medicines comes from case series rather than large trials.

Surgery

Enterolysis (peritonectomy and enterolysis) removes the fibrous membrane and frees the bowel loops without cutting them. It is a long, delicate operation with good results in experienced centers, where many patients return to eating normally. Bowel resection is avoided where possible because of the risk of leaks.

Outlook

EPS has a high mortality, historically around 25% to 50% within a year of diagnosis, mainly from malnutrition, bowel obstruction, perforation and infection. Earlier diagnosis, specialist surgery and nutrition support have improved survival considerably. The idiopathic abdominal cocoon form generally has a good outcome after surgery.

Prevention

• Use the lowest glucose dialysis fluids that achieve adequate dialysis, with glucose-sparing solutions such as icodextrin where appropriate.
• Prevent and promptly treat peritonitis with careful exchange technique and exit site care.
• Review the plan regularly in people approaching 5 or more years on PD.

Frequently asked questions

What is encapsulating peritoneal sclerosis?

It is a rare condition in which the abdominal lining becomes thick and scarred and wraps the small bowel in a fibrous cocoon, causing repeated blockages. It mostly develops in people who have had peritoneal dialysis for many years.

What are the symptoms of sclerosing peritonitis?

Typical symptoms are recurring cramping abdominal pain, nausea and vomiting, bloating, poor appetite and weight loss. People on peritoneal dialysis may notice bloodstained fluid or less fluid being removed. Severe episodes cause complete bowel obstruction.

Can sclerosing peritonitis be cured?

Surgery to strip away the fibrous membrane can free the bowel and allow many patients to eat normally again, especially in specialist centers. Medicines and nutrition support help others. It remains a serious condition, but outcomes have improved with earlier diagnosis.

Does sclerosing peritonitis only happen with dialysis?

No, although long-term peritoneal dialysis is the most common cause. It can also follow abdominal tuberculosis, certain shunts, liver transplant and some medicines. A rare form called idiopathic abdominal cocoon has no known cause.

Can EPS develop after stopping peritoneal dialysis?

Yes. Many cases appear after PD has stopped, often in the first year or two after switching to hemodialysis or having a kidney transplant. Symptoms of bowel blockage or weight loss during that time should be reported to your kidney team.