What are the diagnostic criteria for constipation in adults?

Diagnostic Criteria for Constipation in Adults

Constipation in adults is diagnosed when a patient presents with at least two of the following symptoms for at least 12 weeks in the previous 12 months (not necessarily consecutive): straining during bowel movements, lumpy or hard stool, sensation of incomplete evacuation, sensation of anorectal blockage or obstruction, manual evacuation procedures to remove stool, or fewer than 3 bowel movements per week. 1, 2, 3

Core Diagnostic Criteria (Rome III/IV Criteria)

The standard clinical definition requires any two of the following six symptoms present for at least 12 weeks within the preceding 12 months: 1, 2, 3

• Straining during bowel movements 1, 2, 3
• Lumpy or hard stool (Bristol Stool Form Scale Types 1-2) 1, 2, 3
• Sensation of incomplete evacuation 1, 2, 3
• Sensation of anorectal blockage or obstruction 1, 2, 3
• Manual evacuation procedures to remove stool (digital disimpaction or pelvic floor support) 1, 2, 3
• Fewer than 3 bowel movements per week 1, 2, 3

Critical Clinical Considerations

Constipation is a symptom, not a disease, and the experience is highly subjective. 1, 3 Two essential aspects must be considered beyond the Rome criteria: 1

• Measurable objective symptoms: Individual stool characteristics and frequency of defecation 1
• Patient perception: Level of discomfort and ease of defecation 1

Important pitfall: Reduced stool frequency correlates poorly with delayed colonic transit—patients with daily bowel movements may still experience constipation if other criteria are met. 2

Distinguishing Clinical Patterns

Pattern Recognition for Subtype Classification

Infrequency alone (without excessive straining) suggests normal transit constipation or slow transit constipation. 4

Prolonged excessive straining with soft stools or inability to pass enema fluid strongly indicates a defecatory disorder. 4

Need for perineal/vaginal pressure or digital evacuation is an even stronger indicator of defecatory disorders. 4

Abdominal pain, bloating, and malaise unrelated to defecation suggests underlying irritable bowel syndrome with constipation rather than functional constipation. 4

Special Diagnostic Entity: Opioid-Induced Constipation

Opioid-induced constipation is defined as constipation triggered or worsened by opioid analgesics and represents a distinct diagnostic entity per Rome IV criteria. 1, 3, 4 The clinical presentation is similar to other functional gastrointestinal disorders but requires specific management approaches. 1

Alarm Features Requiring Urgent Evaluation

The following red flags mandate prompt investigation and potentially colonoscopy, regardless of whether Rome criteria are met: 4

• Blood in stools 4
• Anemia 4
• Unintentional weight loss 4
• Sudden onset of constipation (especially in older patients) 4

Minimal Required Testing

In the absence of alarm symptoms, only a complete blood cell count is necessary. 4

Metabolic tests (glucose, calcium, thyroid-stimulating hormone) should not be performed unless other clinical features warrant them. 4

Colonoscopy should not be performed unless alarm features are present or age-appropriate colon cancer screening has not been completed. 4

Physical Examination Requirements

A digital rectal examination must be performed to assess: 4

• Resting tone of internal sphincter and augmentation during squeezing effort 4
• Pelvic floor motion during simulated evacuation 4
• Puborectalis muscle contraction during squeeze 4
• Acute localized tenderness along puborectalis (levator ani syndrome) 4