What is the appropriate assessment and management for a patient presenting with a 1-week history of constipation?

Assessment for 1-Week Constipation

For a patient presenting with 1-week constipation, begin with a focused history targeting alarm features, perform a digital rectal examination with simulated evacuation maneuvers, obtain only a complete blood count, and initiate empiric fiber supplementation and over-the-counter laxatives—reserving colonoscopy and specialized testing for those with red flags or treatment failure. 1

Initial History: Target These Specific Elements

The history must identify the predominant symptom pattern to guide diagnosis:

• Bowel pattern specifics: Date of last bowel movement, baseline frequency, current stool consistency (hard vs soft), and any recent changes 1
• Defecation mechanics: Prolonged excessive straining with soft stools or inability to pass enema fluid strongly suggests defecatory disorders rather than slow transit 2
• Need for manual assistance: Digital evacuation or perineal/vaginal pressure to evacuate is an even stronger indicator of pelvic floor dysfunction 2, 3
• Associated symptoms: Abdominal pain, bloating unrelated to defecation suggests underlying irritable bowel syndrome 2

Critical Red Flags Requiring Urgent Evaluation

• Blood in stools 1
• Unintentional weight loss 1
• Anemia 1
• Abrupt onset of constipation (especially if age >50) 1

Medication and Lifestyle Review

• Constipating medications: Opioids, anticholinergics, calcium channel blockers—discontinue if feasible before further testing 1, 3
• Dietary habits: Fiber and fluid intake 1
• Physical activity level relative to baseline 1
• Environmental barriers: Privacy for defecation, assistance needed, bed-bound status 1

Physical Examination: Specific Maneuvers Required

A cursory digital rectal examination is inadequate—the examination must include functional assessment 1:

Digital Rectal Examination Components

• Observe perineal descent during simulated evacuation and elevation during squeeze in left lateral position 1
• Assess resting sphincter tone and augmentation during voluntary squeeze 1, 3
• Evaluate puborectalis muscle contraction during squeeze (acute tenderness suggests levator ani syndrome) 1, 3
• Instruct patient to "expel my finger" to assess integrated expulsionary forces 1, 3
• Check for impacted feces, masses, hemorrhoids, stenosis 1, 3

Abdominal and Perineal Inspection

• Abdominal examination: Distension, masses, liver enlargement, tenderness, bowel sounds 1, 3
• Perineal inspection: Skin tags, fissures, prolapse, perianal ulceration, patulous opening during simulated defecation (suggests neurogenic constipation) 1

Critical caveat: A normal digital rectal examination does NOT exclude defecatory disorders 1, 3

Laboratory Testing: Minimal Approach

In the absence of alarm symptoms, only a complete blood count is necessary 1, 2:

• CBC only for all patients without red flags 1, 3
• Metabolic tests NOT recommended routinely: Glucose, calcium, thyroid-stimulating hormone have low diagnostic utility and cost-effectiveness unless other clinical features warrant them 1, 2
• If clinically suspected: Check corrected calcium (hypercalcemia) and thyroid function (hypothyroidism) only when other symptoms suggest these diagnoses 1, 3

Structural Evaluation: When to Perform Colonoscopy

Colonoscopy should NOT be performed unless 1:

• Alarm features present (blood in stools, anemia, weight loss) 1, 2
• Age >50 years without previous colorectal cancer screening 1
• Abrupt onset of constipation 1

For patients meeting these criteria, colonoscopy provides direct visualization and biopsy capability 3. Alternatives include CT colonography or flexible sigmoidoscopy with barium enema 1.

Initial Management: Empiric Trial Required Before Specialized Testing

All patients must undergo a 1-2 week trial before proceeding to specialized testing 1, 4:

First-Line Interventions

• Fiber supplementation: Increase dietary fiber intake 1
• Over-the-counter laxatives: Osmotic laxatives (polyethylene glycol preferred) or stimulant laxatives (bisacodyl, senna) 1, 4
• Lifestyle modifications: Adequate fluid intake, regular physical activity 1

The American Gastroenterological Association explicitly recommends against proceeding to specialized testing before attempting fiber and laxatives 4.

When to Refer or Escalate

Indications for Specialized Testing

Proceed to anorectal manometry and colonic transit studies only if 1, 4:

• Failure to respond to fiber and over-the-counter laxatives after 1-2 weeks 1, 4
• History suggests defecatory disorder: Prolonged straining with soft stools, need for digital evacuation, inability to pass enema fluid 2, 4
• Abnormal digital rectal examination suggesting pelvic floor dysfunction 1, 3

Testing Sequence

1. Anorectal testing first (manometry, balloon expulsion test) to identify defecatory disorders 2, 4
2. Colonic transit study only if anorectal tests normal or symptoms persist despite treatment of identified defecatory disorder 1, 2, 4

Common Pitfalls to Avoid

• Do not rely solely on digital rectal examination to exclude defecatory disorders—normal exam does not rule them out 1, 3
• Do not order metabolic panels routinely—increases costs without proven benefit 1, 3
• Do not skip structural evaluation in patients with alarm symptoms, age >50 without screening, or abrupt onset 1, 3
• Do not proceed to specialized testing before empiric fiber/laxative trial 4

Provisional Diagnosis After Initial Evaluation

At this stage, tentatively classify as 1:

• Normal transit constipation (infrequency alone, normal exam) or irritable bowel syndrome (if pain/bloating present) 2
• Slow transit constipation (infrequency, normal anorectal function) 2
• Defecatory disorder (straining with soft stools, abnormal exam findings) 2
• Secondary constipation (medication-induced, metabolic, structural) 1