Prepared by Vivek Mishra, MD and Myron Kirshenbaum, MD from the Department of Radiology, Advocate Illinois Masonic Medical Center, Chicago, IL.

CASE SUMMARY

A 32-year-old man presented to the emergency department with complaints of mid-abdominal pain, bloating, decreased appetite, and no bowel movements for 2 days. He had stopped taking his medicine (Pancrease, McNeil Laboratories, Raritan, NJ) 5 months previously. Clinical examination revealed hypoactive bowel sounds and tenderness to deep palpation. Stool was heme-negative. His laboratory work was within normal limits with a normal white blood cell count and normal amylase and lipase.

DIAGNOSIS

Meconium ileus equivalent in adults

IMAGING FINDINGS

A radiograph of the abdomen, performed in the emergency department, revealed dilated small bowel loops suggestive of obstruction. A few foci of peritoneal calcification were also seen (Figure 1).

A computed tomography (CT) scan of the abdomen, performed after oral and intravenous contrast administration, revealed dilated small bowel loops with intraluminal bubbly fecal material seen in the distal ileum. Large bowel was unremarkable. The pancreas showed generalized fatty replacement, which is characteristic of cystic fibrosis. Peritoneal calcification was also seen (Figures 2, 3, and 4). A diagnosis of meconium ileus equivalent was made.

The Gastrografin (Bracco Diagnostics, Princeton, NJ) enema done in the radiology department did not show any obstructing lesion, with contrast refluxing into terminal ileum (Figure 5). The patient was given Gastrografin enemas every 4 hours for the first day, and every 12 hours on the second day. Patient was also given Golytely (Braintree Laboratories Inc., Braintree, MA) by mouth on both days. His abdominal pain gradually subsided and the patient had 6 to 7 bowel movements on the third day with relief of his symptoms. He was discharged on a pancreatic enzyme supplement.

DISCUSSION

Meconium ileus equivalent is a complication that is encountered with increasing frequency due to increased longevity of patients with cystic fibrosis (mucoviscidosis) as a result of improved treatment methods. Clinically it represents partial or complete intestinal obstruction. Some patients may experience acute complete obstruction, but most suffer from chronic partial obstruction, with recurring colicky abdominal pain and distension. The condition occurs only in cystic fibrosis patients who have exocrine pancreatic insufficiency. It has not been seen in other cystic fibrosis patients or other patients with exocrine pancreatic insufficiency. The frequency of these symptoms has been reported to be about 2.4% to 25%. ¹ Pathophysiologically, meconium ileus equivalent is caused by a combination of exocrine pancreatic insufficiency, increased transit time, and abnormal intestinal mucus and results from obstruction by putty-like fecal material in the terminal ileum and cecum. ^1-3

Microscopically it represents plugging of mucosal crypts with mucoid secretion, distension of goblet cells, and the presence of a thick layer of mucus, admixed with fecal material, adherent to the mucosal surface. ⁴

Plain films of the abdomen show a small bowel obstruction. A nodular pattern in the small bowel, with the nodules being larger than those seen in quiescent cystic fibrosis, has been reported. ⁵

On imaging, the CT scan may show features of cystic fibrosis, including fatty replacement of the pancreas, fatty infiltration of the liver, and partial or complete bowel obstruction with presence of bubbly fecal material in the terminal ileum and ascending colon. No other cause for mechanical obstruction may be evident. Other features of meconium ileus, such as peritoneal calcification, may also be seen.

The treatment is primarily nonsurgical. Specific treatment with N-acetyl cysteine, administered orally and/or as an enema, is recommended. Alternative treatment with water-soluble contrast medium, such as Gastrografin, administered orally or as an enema provides an easily available treatment as well as a means to perform a diagnostic study to rule out mechanical obstruction. It has a reported success rate of 81%, with 75% of patients treated as outpatients. ^6,7 This was the method employed in our case. It is important that the physician be familiar with the disease entity and available treatment methods. Nonoperative treatment is effective and the morbidity and mortality associated with surgery can be avoided.

CONCLUSION

Meconium ileus equivalent is an entity that is infrequently encountered, but will be seen more often with the increasing longevity of patients with cystic fibrosis. It is important to be aware of this disease, as nonoperative treatment is effective and the morbidity and mortality of surgery can be avoided.