Key words : Intestinal obstruction, Pediatrics, Renal transplantation

Introduction
Encapsulated peritoneal sclerosis (EPS) is a clinical syndrome with persistent or recurrent symptoms of intestinal obstruction due to adhesions of the diffusely thickened peritoneal membrane.¹ It is a rare complication of long-term peritoneal dialysis that has a high rate morbidity and mortality. The prevalence of EPS in adults has been shown to range from 0.7% to 2.8%, with a similar rate of 2% in children.² The risk of EPS is high in children who have undergone peritoneal dialysis for extended periods of time, have frequent peritonitis, and have ultrafiltration failure.³

Case Report
An 18-year-old girl was admitted to the hospital. When she was 8 years old, she had presented with complaints of weakness, nausea-vomiting, and failure to thrive and was diagnosed with renal failure with serum creatinine level of 10.98 mg/dL. A kidney biopsy showed glomerular and microvascular changes compatible with thrombotic microangiopathy and global glomerulosclerosis. The patient was started on peritoneal dialysis at age of 8 years.

The patient, who was followed up in the peritoneal dialysis program for 7 years, had bacterial peritonitis 4 times during this period and had continued peritoneal dialysis with high-concentration fluids due to insufficient ultrafiltrate. At the age of 15 years, bacterial peritonitis developed for the fifth time with Escherichia coli. Peritoneal dialysis was discontinued, and a hemodialysis program was started at 3 days per week. While in the hemodialysis program, the patient developed progressive abdominal distension within a few weeks. Intestinal obstruction was not observed in ultrasonography performed due to vomiting and abdominal distention, but intense acid was observed in the abdomen. Excretory paracentesis was performed twice. Significant leukocytes were seen in the peritoneal fluid, but there was no growth in fluid cultures.

Abdominal tomography showed loculated peritoneal fluid extending from the liver to the pelvis, pushing the bowel loops and stomach posteriorly. In addition, peritoneal thickening that became nodular in places on the peritoneal face was remarkable (Table 1). With these findings, the patient was diagnosed with EPS. Symptoms regressed in the patient, and the abdominal circumference decreased from 68 to 59 cm after treatment with steroid and tamoxifen.

Two months after treatment of EPS was started, the patient received a kidney transplant from an HLA fully matched deceased donor. She received antithymocyte globulin for induction immunosuppression. Corticosteroids, tacrolimus, and mycophenolate mofetil were commenced as maintenance therapy. Tamoxifen, which had been used for 10 months, was discontinued due to an increase in uterine wall thickness.

Three years after transplant, the patient presented with complaints of vomiting, abdominal pain, and abdominal distension. Laboratory examination revealed that her creatinine level had increased up to 5.02 mg/dL, with tacrolimus level quite high at 18.8 ng/mL. Tacrolimus was interrupted, and close drug-level monitoring was performed. In the follow-up, tacrolimus was started again, with drug levels of between 4 and 6 ng/mL.

In abdominal tomography, the liver was pushed posteriorly. The patient had a 12 × 25 × 31-cm peritoneal fluid extending from the subdiaphragmatic area to the pelvis and superior to the bladder; compatible with EPS, this observation was accompanied by increased peritoneal thickness and millimetric calcifications. In addition, dilatation was observed in which the intestinal loops were pushed posteriorly secondary to the loculated fluid, and there were air-fluid levels in the small intestine loops (Table 2). Excretory paracentesis was performed. After pulse steroid treatment for 3 days, 16 mg/day methylprednisone and 10 mg/day tamoxifen were started. During patient follow-up, signs and symptoms regressed. Serum creatinine level also decreased to the basal value of 0.63 mg/dL.

Discussion
Encapsulated peritoneal sclerosis is a rare clinical syndrome characterized by an acquired, inflammatory fibrocollagenous membrane encasing the abdominal contents, including the small intestine, stomach, and liver, resulting in signs and symptoms of abdominal obstruction like distention, pain, and nausea or vomiting.⁴ It may even occur after patients have switched to hemodialysis or after kidney transplant like in our patient.⁵

Long-term peritoneal dialysis, recurrent bacterial peritonitis, and use of high-concentration fluid due to ultrafiltrate deficiency are the major risk factors for development of EPS.³ Kidney transplant and the use of calcineurin inhibitors after transplant can increase the risk.⁶ Our patient had all of these risk factors. Exposure to possible chemicals such as chlorhexidine and genetic factors have also been shown to be among other risk factors for development of EPS.⁷ Signs of new-onset ultrafiltration failure and intestinal obstruction may be seen in the patients with EPS.⁸ A massively fibrotic and calcified peritoneum enclosing the intestine and parietal wall can be detected in radiologic evaluations, as shown in our patient.⁸

Corticosteroids and tamoxifen are the main components of treatment. Due to the difficulty of the surgical procedure and the risk of causing serious complications, patients are primarily followed up with medical treatment. In a case series of 26 patients who underwent perionectomy and enterolysis, minor complications were seen in 2 patients (7.6%) and major complications occurred in 11 patients (42.3%). Three patients (11.5%) died within the first year after surgery.⁹ Therefore, an excretory paracentesis may be necessary in some patients. Azathioprine, mycophenolate mofetil, or mechanistic target of rapamycin inhibitors, which can reduce inflammation, fibrin deposition, and collagen synthesis can be used in selected patients.¹ Despite all of these medications and interventions, mortality rates have remained at 25% to 55% in adults and 14% in children.¹⁰

In conclusion, factors such as long-term use of peritoneal dialysis, a history of bacterial peritonitis, and use of high-concentration dialysate may cause EPS, with possibility of symptoms recurring even after transplant. Thus, it is important to recognize that EPS may even cause graft loss due to the various complications that it can cause.

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