AUTHOR: DR. NAGAVENI. K., DNB RESIDENT CO-AUTHORS: DR. PRIYAN VOLTAIRE., DR. HARISENTHIL., DR. SAMJEE SMILE., DR. RAVICHANDRAN.V. INDIRA GANDHI GOVT. GENERAL HOSPITAL AND POST GRADUATE INSTITUTE. SCLEROSING ENCAPSULATING PERITONITIS – ROLE OF IMAGING

LEARNING OBJECTIVES There are various causes of intestinal obstruction. Imaging plays a key role in establishing preoperative diagnosis. Sclerosing encapsulating peritonitis is a rare benign cause of acute or sub-acute intestinal obstruction and has to be considered while evaluating causes for bowel obstruction.

Background Sclerosing encapsulating peritonitis is also called as Abdominal cocoon. In this the small bowel loops are partly or completely encased in a thick, fibrous membrane and hence the name. It is common in young adolescent girls from tropical or subtropical countries. It can be idiopathic or mainly secondary to chronic ambulatory peritoneal dialysis, peritoneo- venous or ventriculo peritoneal shunts, or treatment with practolol.

Rarely it can occur in people with chronic abdominal disorders like tuberculosis, sarcoidosis, malignancies etc., Abdominal distention, pain and vomiting are the common presenting features that may resolve spontaneously. The patient may have multiple such episodes.

CASE HISTORY A 36 yr old male presented with abdominal distention and pain for four days. he had similar episodes in the past 2 yrs. He had no history of previous surgical interventions or chronic infectious disorders. There was no family history of tuberculosis. Complete blood count, electrolytes and other routine laboratory investigations were within normal range.

IMAGING Abdominal Ultrasonography was done and dilated, aggregated small bowel loops with altered peristalsis were seen in abdomen. Mild inter-loop fluid was seen along with few enlarged mesenteric nodes. A supine radiograph of abdomen was taken which showed dilated bowel loops. A provisional diagnosis of sub acute intestinal obstruction was made. In view of aggregation of bowel loops with mesenteric nodes, subsequently Computed tomography[CT ] was done.

CT Abdomen Contrast enhanced CT abdomen showed dilated, aggregated bowel loops in the centre of abdomen surrounded by enhancing membrane forming sac and giving the appearance of a cocoon. Mild inter loop fluid and multiple mesenteric nodes were seen. In addition to this a small loculated pleural effusion was seen in the right posterior costo-phrenic angle. With this along with mesenteric nodes, tuberculous etiology was suspected.

Differential diagnosis include Internal hernias and congenital peritoneal encapsulation. Internal hernias show stretched, displaced, crowded, and engorged mesenteric vessels and no membrane like sac can be detected. Congenital peritoneal encapsulation, is characterized by a thin accessory peritoneal sac surrounding the small bowel found incidentally and is asymptomatic.

Sequential axial sections of CECT abdomen showing small bowel loops extending from left upper quadrant to the centre of abdomen inferiorly and are covered by enhancing membrane.

Axial and coronal reformatted images showing sac like membrane encasing the bowel loops.

Sagittal reformatted images showing clustered small bowel loops in a membrane.

Loculated effusion in right thorax

A diagnosis of abdominal cocoon secondary to Tuberculosis was made. Exploratory laporatomy was done and a thin fibrous sac seen encasing the bowel loops. The membrane was resected and sent for histo-pathological examination along with the drained fluid. Histo pathological examination showed epitheloid granulomas in the membrane.

a. Intra operative image showing the encapsulating membrane. b.HPE slide showing epitheloid granuloma. a b

CONCLUSION Abdominal cocoon is a rare but surgically treatable cause of intestinal obstruction. Imaging plays a key role in timely preoperative diagnosis and thus can help in preventing extensive resection of bowel. Though rare abdominal cocoon should be included in the differential diagnosis, while investigating for intestinal obstruction. In our country where tuberculosis is more prevalent, with appropriate clinical settings, Imaging helps to clinch the diagnosis.

REFERENCES Meryem Cereb Tombak, F. Demir Apaydın, Tahsin Colak etal. An Unusual Cause of Intestinal Obstruction: Abdominal Cocoon, AJR 2010; 194:W176–W178. Rajul rastogi. Saudi J Gastroenterol.Jul MustafaKemalDemir, MD. OkanAkinci, MD. EnderOnur, MD. NesetKoksal,MD. Sclerosing Encapsulating Peritonitis. Radiology: Volume 242: Number 3—March Wig JD, Gupta SK. Computed tomography in abdominal cocoon. J Clin Gastroenterol 1998;26:156– 157.

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