Imaging Findings in Dogs and Cats With Presumptive Sclerosing Encapsulating Peritonitis

Abstract

This retrospective case series describes imaging findings in seven dogs and two cats with a presumptive diagnosis of sclerosing encapsulating peritonitis (SEP) between 2014 and 2021. Peritoneal effusion was present in all animal patients. Sonographically, echogenic fluid with or without echogenic intraperitoneal septations, gathered or corrugated bowel loops, and abdominal lymphadenomegaly were suggesting an inflammatory process and the presence of adhesions. Gathering of the bowel with abdominal distension and/or signs of intestinal obstruction were major findings on radiographs. Abdominal fat stranding was an additional finding in animals undergoing a CT examination. Previous surgery, pregnancy, and the presence of a perforating foreign body were potential predisposing causes in 4/9 animals. Peritonitis was septic in 4/9 animals. As SEP is a rare condition but life threatening, this detailed description of imaging findings in a short case series can be useful for a presumptive diagnosis and surgical planning.

Stump pyometra in a spayed female dog secondary to tamoxifen

“…Clinical signs in dogs are nonspecific and may include anorexia, lethargy, intermittent vomiting, diarrhoea, abdominal distension, muscle wasting, and peritoneal effusion (Adamama‐Moraitou et al., 2004 ; Boothe et al., 1991 ; Hardie et al., 1994 ). While SEP may be suspected based on clinical signs and the presence of loculated peritoneal effusion, the diagnosis is confirmed by computed tomography (CT) findings similar to those reported in human studies, with the presence of free or loculated peritoneal fluid, encased bowel loops, and mesenteric fat stranding with extraluminal adhesions present (Berengere et al., 2022 ; Veiga‐Parga et al., 2015 ). Diagnosis may also be confirmed by exploratory laparotomy and biopsy of the characteristic thickened peritoneum and fibrous adhesions.…”

“…SEP is a rarely described disease in dogs and is characterised by excessive, progressive, and irreversible thickening, fibrosis, and adhesions of the visceral and parietal peritoneum (Bender & Ockner, 1983 ). Although cases have been reported in dogs (Adamama‐Moraitou et al., 2004 ; Berengere et al., 2022 ; Boothe et al., 1991 ; Etchepareborde et al., 2010 ; Hardie et al., 1994 ; Veiga‐Parga et al., 2015 ) and potential underlying factors have been identified, including foreign body ingestion, leishmaniasis, fiberglass ingestion, and bacterial peritonitis, little is known about the aetiology of the disease, and it has historically carried a poor prognosis in canines. In humans, underlying causes as well as an idiopathic form have been identified, and treatment is aimed at removal of the underlying cause, corticosteroids, tamoxifen, and surgical enterolysis, if indicated; still, mortality can reach 50% within a year of diagnosis (Danford et al., 2018 ).…”

Successful treatment of sclerosing encapsulating peritonitis in a cat using bioresorbable hyaluronate-carboxymethylcellulose membrane after surgical adhesiolysis and long-term prednisolone

“…1 –13 SEP has an extremely poor prognosis in cats despite aggressive surgical and medical treatment, and no report has described a cat with SEP in remission. 1,4,8,9 Of the seven cats in which this condition has been reported to date, one was euthanased at surgery because of the inability to dissect the adhesion, 9 two died or were euthanased within 7 days because of complications or lack of clinical improvement postoperatively, 8 three survived for 3–57 days postoperatively 4 and the remaining cat was alive 11 months after diagnosis, but no further follow-up was reported. 1 This is the first report of SEP in a cat with long-term survival of more than 3 years without recurrence after surgical adhesiolysis.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] Imaging findings of SEP in dogs and cats include plicated and/or corrugated small bowel loops with echogenic localised peritoneal effusion on abdominal ultrasound and fat stranding on CT. 8 SEP is definitively diagnosed by the characteristic gross thickening of the peritoneum that encloses some or all the small intestine in a cocoon of opaque tissue intraoperatively and by the histopathologic findings of fibroconnective tissue and inflammatory infiltrates. [1][2][3][4][5][6][7][8][9][10][11][12][13] SEP is extremely rare in feline medicine; only seven cases have been reported. 1,4,8,9 Although treatment protocols for SEP in cats have not yet been established, surgical adhesiolysis alone to relieve an intestinal obstruction or in combination with medical treatment to prevent recurrence have been attempted.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] SEP is extremely rare in feline medicine; only seven cases have been reported. 1,4,8,9 Although treatment protocols for SEP in cats have not yet been established, surgical adhesiolysis alone to relieve an intestinal obstruction or in combination with medical treatment to prevent recurrence have been attempted. However, the prognosis of SEP is poor; six of the seven previously reported cats died or were euthanased within 2 months postoperatively because of complications or lack of clinical improvement, and the remaining cat survived for 11 months.…”