Urachal remnant small bowel obstruction: report of two adult cases.

Abstract: This report describes two separate cases of adult patients with intestinal obstruction caused by an urachal remnant. While reports of infected urachal cysts causing intra-abdominal pathology are not uncommon, intestinal obstruction caused by urachal remnants is exceedingly rare in the pediatric population and has never been described in adults. Both of these patients required surgical intervention with excision of the urachal remnant and subsequent resolution of the small bowel obstruction.

Key Words: intestinal obstruction, intra-abdominal pathology, small bowel, urachal remnant

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The urachus is a band of fibrous tissue extending from the apex of the bladder to the umbilicus. It is a remnant of an embryologic canal running from the fetal cloaca to the umbilicus. By 32 weeks, the urachus degenerates into a solid band of tissue called the median umbilical ligament. In 0.1 to 2.0% of the population, the urachus remains patent and may result in urine leaking from the umbilicus or infected urachal cysts. We have found that even in the face of normal regression, the urachal remnant may lead to complications. We report two patients with intestinal obstruction caused by an urachal remnant.

Case Reports

Patient 1

A 62-year-old male was transferred to the university hospital from an outside institution with a 5-day history of colicky, periumbilical abdominal pain. The patient also reported nausea, vomiting, and a lack of flatus or bowel movements for 5 days. He denied a history of previous abdominal operations, weight loss, or hematochezia but did report a history of similar episodes in the past that had resolved over several hours without intervention. Plain abdominal radiographs demonstrated dilated loops of small bowel with air fluid levels (Figure). A computed tomography scan also demonstrated dilated loops of small bowel, distal collapsed bowel, a transition point, some free fluid, and no free air. The patient was taken to the operating room for a diagnostic laparoscopy. On visualization of the peritoneal cavity, there were no adhesions. One markedly dilated loop of small bowel was seen, which appeared dusky. The decision was made to convert from a laparoscopic to an open procedure, and a midline incision was made. The dusky loop of bowel was kinked by a band of tissue from the umbilicus to the urinary bladder. The band was excised and the bowel was immediately released. After several minutes, the bowel color returned to normal and resection was deemed unnecessary. Pathologic examination of the resected band of tissue revealed an urachal remnant.

Patient 2

A 42-year-old male who had been complaining of colicky right-sided abdominal pain was admitted to the Veterans Administration Hospital. He also reported nausea and a lack of flatus or bowel movements for 3 days. He was otherwise healthy and denied any previous abdominal operations, hernias, or weight loss. He had similar episodes of pain over the past 2 years that had resolved spontaneously. Abdominal plain films revealed some dilated loops of bowel. Computed tomography scan revealed several loops of dilated small bowel; however, no definite transition point, free fluid, or free air was identified. The patient's abdominal pain progressively worsened, and he was taken to the operating room for exploratory laparotomy. On exploration, no adhesions were found, but the jejunum was quite distended. An obstructed loop of jejunum was herniated over a band of tissue from the umbilicus to the dome of the bladder. The band was excised, releasing the jejunum, which then decompressed distally. There was no evidence of ischemia. Histologic evaluation revealed an urachal remnant.

Before surgery, urachal remnants were not considered among the possible causes of bowel obstruction in either case. Exploration was required for both diagnostic and therapeutic purposes. Complete excision of the remnant was effective in both cases.

Discussion

The urachus is a cord or band of fibrous tissue extending from the bladder to the umbilicus. It is an embryonic canal that develops from the allantois and the ventral part of the cloaca. The allantois is an embryonic diverticulum, which gives rise to the blood vessels of the umbilical cord. The cloaca is the terminal portion of the embryonic hindgut, which will divide into the bladder, rectum, and genital primordia. By the third month of gestation, the allantois involutes and the urachus elongates as the fetal bladder descends from the abdomen to the pelvis. During the neonatal period, this connection is usually sealed; however, patency results in an urachal remnant. Urachal remnants have been reported to result in pathology, the most common being acute infection.

Urachal anomalies are classified into four groups, based on which portion remains patent--patent urachus, umbilical urachal sinus, vesicourachal diverticulum, and urachal cyst. Most reported cases of urachal complications have involved an infected urachal cyst. The anatomic position of the urachus becomes important when considering the presentation of patients with urachal disease. The urachus and umbilical arteries are in the space of Retzius, which is an extraperitoneal fascial plane. This makes an urachal remnant an unlikely cause of intra-abdominal pathology, particularly intestinal obstruction. However, neglected infections of urachal remnants have been reported to cause intra-abdominal pathology.

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Conclusion

Intestinal obstruction resulting from an infected urachal cyst has been described. (1-3) However, a small bowel obstruction due to a noninfected, normally regressed urachal remnant has not been reported in adults. Colonic obstruction has been described by a mesourachus. (4) A mesourachus is a well-defined mesentery, which connects the anterior abdominal wall to the intestinal mesentery of the posterior abdomen. An urachal remnant is found within the mesourachus. Similarly, small intestinal obstruction by urachal remnants resembling a mesourachus have been described only twice in children. Bleichert-Toft and Mielsen (2) described a 6-cm tubular structure passing from the mesentery to the bladder, causing small intestinal obstruction in a 15-year-old male. Similarly, a 7-year-old female was found to have a band extending from her bladder to her umbilicus, which was trapping omentum and cecum. (5) To the best of our knowledge, an urachal remnant has not been previously reported as a cause of small intestinal obstruction in an adult. (6)

References

1. Bleichert-Toft M, Axelsson C. Urachal lesion associated with calculus formation causing intestinal obstruction. Scand J Urol Nephrol 1977;11:77-79.

2. Bleichert-Toft M, Mielsen OV. Disease of the urachus simulating intra-abdominal disorders. Am J Surg 1971;122:123-128.

3. Ward T, Saltzman E, Chiang S. Infected urachal remnants in the adult: case report and review. Clin Infect Dis 1993;16:26-29.

4. Dammert W, Currarino G. Mesourachus and colon obstruction. J Ped Surg 1983;18:308-310.

5. Haupt GJ, Keitel HK. Intestinal obstruction in a child with a peritonealized urachal treatment. J Pediatr 1960;57:741-743.

6. Cameron J, et al. Current Surgical Therapy. Seventh edition. Mosby Publishing, 2001, pp 122-128.

Khashayar Vaziri, MD, Todd A. Ponsky, MD, Jon C. White, MD, and Bruce A. Orkin, MD

From the Departments of Surgery at George Washington University and the Veteran's Administration Hospital, Washington, DC.

Correspondence to Dr. Bruce A. Orkin, Division of Colon and Rectal Surgery, 2150 Pennsylvania Avenue, NW, Suite 6B-414, Washington, DC 20037. Email: [e-mail]

Accepted November 22, 2004.

RELATED ARTICLE: Key Points

* In the face of normal regression, urachal remnants can cause significant intra-abdominal pathology in adults.

* This report describes two adult cases of small bowel intestinal obstruction caused by normally regressed urachal remnants.

* Proper identification of an urachal remnant as the cause of small bowel intestinal obstruction and appropriate management is important in the treatment of this disease.