What is the best course of treatment for a 22-year-old patient with constipation (no bowel movement for 2 days), soft and non-tender abdomen, and positive bowel sounds?

Management of Acute Constipation in a Young Adult

For a 22-year-old with 2 days of no bowel movement, soft abdomen, and positive bowel sounds, start with increased dietary fiber, adequate hydration, and physical activity; if no improvement within 24-48 hours, initiate polyethylene glycol (PEG) 17g in 8 oz water once or twice daily as first-line pharmacologic therapy. 1, 2

Initial Assessment

This clinical presentation requires minimal workup given the benign examination findings:

• Rule out fecal impaction through digital rectal examination, though this is unlikely given the soft, non-tender abdomen 2
• No imaging is needed at this stage with only 2 days of constipation and reassuring physical findings 2
• Assess for secondary causes: Review medications (anticholinergics, opioids, antacids), recent dietary changes, and activity level 3, 1

The positive bowel sounds and soft abdomen effectively rule out bowel obstruction, making this a straightforward case of acute constipation 2.

First-Line Non-Pharmacologic Management

Dietary and lifestyle modifications should be initiated immediately:

• Increase dietary fiber through fiber-rich foods as the foundation of treatment 1
• Ensure adequate fluid intake to support fiber effectiveness and prevent worsening constipation 1, 2
• Encourage regular physical activity within the patient's normal routine 1
• Establish regular bathroom habits, particularly after meals when the gastrocolic reflex is strongest 1

Pharmacologic Treatment if No Response in 24-48 Hours

Polyethylene glycol (PEG) is the preferred first-line laxative:

• PEG 17g in 8 oz water once or twice daily has an excellent safety profile and is effective for increasing spontaneous bowel movements 2, 4
• Alternative option: Bisacodyl 10-15 mg daily as a stimulant laxative if PEG is unavailable or not tolerated 2
• Goal: One non-forced bowel movement every 1-2 days 3, 2

The evidence strongly supports osmotic laxatives like PEG over stimulant laxatives as initial therapy due to better tolerability and safety profile 2, 5.

If Constipation Persists Beyond 3-5 Days

Escalate treatment systematically:

• Increase bisacodyl to 10-15 mg two to three times daily if already started 2
• Add or switch to lactulose as an alternative osmotic laxative 1, 2
• Consider magnesium hydroxide or magnesium citrate in patients with normal renal function 3, 2
• Re-assess for impaction if no response after 5-7 days of treatment 3, 2

Important Caveats

Avoid bulk-forming laxatives (psyllium) initially in this acute setting, as they require adequate fluid intake and may worsen symptoms if the patient is not well-hydrated 2. While psyllium has good evidence for chronic constipation management 1, it is not ideal for acute constipation in young patients.

Stool softeners alone (docusate) are ineffective and should not be used as monotherapy 3. If used at all, they should be combined with a stimulant laxative, though evidence suggests the combination offers no advantage over stimulant alone 3.

Monitor for warning signs that would require further evaluation: severe abdominal pain, vomiting, rectal bleeding, or failure to respond to treatment within one week 4. These could indicate a more serious underlying condition requiring imaging and specialist referral 3.

Treatment Goal

Achieve at least 3 bowel movements per week without straining as the therapeutic endpoint 1. For this young patient with acute constipation and benign exam findings, response to simple interventions should occur within 3-5 days 1, 2.