Utility of plain abdominal radiography in adult ED patients with suspected constipation

Background: Abdominal radiographs are often obtained in ED patients with suspected constipation, although their utility in adults is not well understood. We sought to compare ED management when an abdominal radiograph is and is not obtained.

Methods: We performed a retrospective chart review study of adult ED patients with a chief complaint of constipation from 2010 through 2016. Trained abstractors recorded radiologic tests ordered, treatments received, and final diagnosis. We determined the physician interpretation of the abdominal radiograph and its use in clinical decision making.

Results: Of 1142 eligible patients, 481 (42%) patients underwent abdominal radiography. Stool burden rated moderate or large was observed in 271 patients (46%). Sixteen patients (3%) were diagnosed with small bowel obstruction; 15/16 of these patients had high risk features such as old age, complex surgical history, history of small bowel obstruction, abdominal malignancy, or presented with vomiting or inability to pass flatus. Of the 197 patients with no or mild stool burden or normal radiograph, 109 (55%) were diagnosed with constipation and 89 (45%) received constipation treatment in the ED. Conversely, of the 271 patients with moderate or greater stool burden, 114 (42%) received no treatment for constipation in the ED and 104 (38%) were prescribed no discharge medications for constipation; 77 of these 271 patients (28%) were diagnosed with something other than constipation.

Conclusion: Plain abdominal radiography did not appear to significantly affect the ED management of patients presenting with constipation; it was common for patients to receive treatment that was in direct opposition to radiographic findings. Though a small number of patients had concerning diagnoses identified on plain radiography, the history and physical examination should have sufficiently excluded simple constipation, prompting an alternate diagnostic approach. Fecal loading on radiography does not preclude a more serious diagnosis. In conclusion, abdominal radiography appears to have low value in patients with constipation.