Abdominal cocoon in an adolescent male patient

Introduction

Abdominal cocoon, first described by Foe et al. in 1978, is a rare clinical condition that primarily affects adolescent females. ¹ However, cases affecting children and older patients belonging to both genders have been reported. It commonly affects residents of tropical and subtropical regions and its aetiology is not fully known.

The condition commonly presents with features of recurrent acute or subacute intestinal obstruction. Diagnosis is often incidental at laparatomy. Treatment of choice for this condition is surgery and majority of the patients have good postoperative prognosis. We report on an adolescent male patient who presented with features of acute intestinal obstruction due to abdominal cocoon.

Case history

In May 2007, a 14-year-old male patient presented to the accident and emergency room of our hospital with colicky abdominal pains, abdominal distension, vomiting and constipation of 72 hours' duration. He was referred from a private clinic where he had spent 24 hours. He had not experienced similar episodes in the past and had not lost weight. There was no history of abdominal surgery and he had no underlying medical problems.

On examination, the patient was in distress, dehydrated, but was neither febrile nor pale. Blood pressure was 100/70 mmHg, pulse rate was 88 beats/min, respiratory rate was 26 cycles/min and temperature was 37°C. His abdomen was distended; mildly tender and visible peristalsis was present in the upper half. Liver and spleen were not palpably enlarged and there were no palpable intra-abdominal masses. Bowel sounds were normoactive and the rectum was empty on examination.

Laboratory investigations showed haemoglobin levels of 15 g/dL and normal serum electrolyte and urea levels. Plain abdominal x-rays revealed multiple air-fluid levels in the erect film and dilated small bowel loops in the supine film. There was no evidence of free air in the peritoneal cavity.

A provisional clinical diagnosis of acute mechanical intestinal obstruction was made and the patient had an exploratory laparotomy through a midline incision. Findings upon entering the abdominal cavity were that of dilated proximal small intestines encased in a dense whitish membrane (Figure 1). Inter-loop adhesions were also present and the membrane extended to the surface of the liver as well. The large intestines were not affected. The encasing membrane and the inter-loop adhesions were easily separated by blunt and sharp dissections which freed the whole length of the small bowel. Incident appendicectomy was done before closure of the abdomen. The postoperative period was unremarkable and he was discharged from the hospital on the tenth postoperative day. Histopathological examination of the membrane showed fibrous tissue with chronic non-specific inflammatory reaction. The patient is doing well almost two years after surgery.

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Figure 1

Intraoperative photograph showing encased small bowel loops

Discussion

Intestinal obstruction is a common surgical emergency and bowel adhesions are among the frequently encountered aetiological factors. This paper reports a rare type of adhesion in an adolescent male, which is an uncommon age and gender combination for this entity.

Abdominal cocoon is an unusual cause of small intestinal obstruction. Less than a hundred cases have so far been reported in the English literature. The cause of obstruction in these patients was a membrane encasing the small intestine in the manner of a cocoon. ¹ The majority of the patients were young adolescent females, although a few cases were seen in older females, males and children. The exact aetiology is unknown; however, retrograde menstrual flow was postulated as a possible cause. The characteristic membrane is dense, whitish and encases the small bowel partially or completely. Mesothelial and inflammatory cells, fibroblasts and cytokines are believed to play a role in the pathogenesis of peritoneal fibrosis and neoangiogenesis seen in this condition. ²

Similar conditions which are often interchangeably referred to as ‘abdominal cocoon’ are peritoneal encapsulation (PE) and sclerosing encapsulating peritonitis (SEP). PE is a very rare condition and was first described by Cleland in 1868. ³ It is a congenital condition resulting from abnormal return of the midgut loop to the abdominal cavity during early development. It is characterized by the presence of an accessory peritoneal sac which covers the small intestine. The sac is derived from the original dorsal mesentery which normally forms the transverse mesocolon. SEP, on the other hand, is a rare complication of chronic ambulatory peritoneal dialysis. This condition is also characterized by a thick grayish white fibrous membrane covering the small intestine. It is a more serious condition with high mortality. Other causes of SEP include beta-blockers (practolol), recurrent peritonitis, peritoneovenous shunting, sarcoidosis and systemic lupus erythematosis. ⁴

Abdominal cocoon usually presents with clinical features of subacute or acute intestinal obstruction. Although recurrent attacks of small bowel obstruction with weight loss, nausea, anorexia and at times a palpable abdominal mass may raise suspicion of this condition, diagnosis is mostly incidental at laparotomy. Preoperative imaging findings are largely non-specific. However, the presence of a ‘cauliflower sign’, which is a serpentine configuration of dilated small bowel loops in a U-shaped cluster, and delayed transit in a small intestine contrast study are believed to be helpful. ⁵ Useful CT and MRI findings include sacculated, dilated bowel loops and soft tissue capsule encircling the bowel loops. ^6,7 Surgical excision of the thick membrane and freeing of the encased small intestine lead to complete long-term recovery. The bowel is usually viable and resection is not required. Recurrence of abdominal cocoon has not been reported. Incident appendicectomy is recommended because the appendix may be difficult to locate if the patient develops acute appendicitis and requires surgery.