Diagnostic Approach to Constipation

Clinical Assessment

The American College of Physicians recommends that the diagnosis of constipation is fundamentally clinical and does not require routine imaging, with a thorough clinical assessment including history, physical examination with digital rectal examination (DRE), and patient-reported outcome measures guiding diagnosis and management 1, 3
Physical examination should include abdominal examination with auscultation, perineal inspection, and digital rectal examination to assess for hemorrhoids, sphincter tone, tenderness, obstruction/stenosis, impacted feces, and tumor masses 4

The American Gastroenterological Association suggests that investigations are not routinely necessary for constipation, but may be warranted in cases of severe symptoms, sudden changes in bowel movement number and consistency, blood in stool, or suspected metabolic causes 1, 3, 5
The sensitivity of plain abdominal x-ray for detecting obstruction is only 74-84% and specificity is 50-72%, making it a limited diagnostic tool 6
CT scan is superior to plain radiography for diagnosing bowel obstruction, with a sensitivity of 93-96% and specificity of 93-100% 6

The European Society of Gastrointestinal Endoscopy recommends starting with a thorough clinical assessment, including history, abdominal examination, perineal inspection, and DRE 1, 3, 5
Imaging should be reserved for specific indications, such as suspected obstruction or severe symptoms with unclear etiology, and CT scan should be used instead of plain x-ray 6, 7
Treatment should be initiated based on clinical findings, not imaging, with osmotic laxatives or stimulant laxatives used as first-line treatment 5, 8