What is the best course of action for a patient with abdominal distention and pain after 10 days without a bowel movement, admitted to 23-hour observation?

Immediate Management of Severe Constipation with Bowel Obstruction Risk

This patient requires urgent evaluation to rule out mechanical bowel obstruction or fecal impaction before initiating any laxative therapy, followed by aggressive bowel decompression if obstruction is excluded. 1, 2

Initial Assessment and Diagnostic Workup

Rule out mechanical obstruction immediately - this is the critical first step that determines all subsequent management:

• Obtain plain abdominal radiographs to assess for bowel obstruction, looking for dilated bowel loops, air-fluid levels, and absence of rectal gas 1
• Perform digital rectal examination to check for fecal impaction, which commonly presents with overflow diarrhea around the impaction 1
• Assess for peritoneal signs on physical examination - absence of peritonitis does not exclude bowel ischemia 1
• Order basic laboratory studies including complete blood count, electrolytes, renal function, and lactate to evaluate for ischemia and metabolic derangements 1

Key clinical red flags suggesting obstruction rather than simple constipation:

• Colicky abdominal pain with high-pitched or absent bowel sounds 1, 3
• Progressive vomiting (bilious or feculent) 1, 4
• Complete absence of flatus and bowel movements 1
• Visible peristalsis on examination 1

Management Algorithm

If Obstruction is Ruled Out:

Immediate interventions for severe fecal impaction (10 days without bowel movement):

1. Manual disimpaction following premedication with analgesic ± anxiolytic 1
2. Glycerin suppository ± mineral oil retention enema 1
3. Tap water enema until clear if impaction persists 1

Aggressive laxative regimen once impaction is cleared:

• Stimulant laxative: Bisacodyl 10-15 mg daily to three times daily, with goal of one non-forced bowel movement every 1-2 days 1
• Osmotic laxative: Polyethylene glycol (PEG) 17 grams (one heaping tablespoon) with 8 oz water twice daily 1
• Alternative osmotic agents if PEG ineffective: Lactulose 30-60 mL 2-4 times daily, sorbitol 30 mL every 2 hours × 3 then as needed, or magnesium citrate 8 oz daily 1

Avoid stool softeners alone - docusate has not shown benefit and should not be used as monotherapy 1

If Obstruction is Present:

Conservative management initially:

• NPO (nothing by mouth) with nasogastric tube decompression 5, 4
• Intravenous fluid resuscitation and electrolyte replacement 4
• Serial abdominal examinations 4

Obtain CT scan with IV contrast if diagnosis uncertain or to evaluate for complications - CT has positive likelihood ratio of 3.6 for diagnosing small bowel obstruction and can identify ischemia, though sensitivity for ischemia is limited (30-52%) 1, 3

Surgical consultation immediately if any signs of:

• Peritonitis or perforation 4
• Bowel ischemia (elevated lactate, peritoneal signs) 1
• Closed-loop obstruction 1
• Failed conservative management after 48-72 hours 4

Critical Medication Considerations

Assess and discontinue constipating medications:

• Opioids are the most common culprit - chronic opioid use causes constipation without development of tolerance 1
• Anticholinergics, calcium channel blockers, iron supplements 1

If patient is on chronic opioids and obstruction is excluded:

• Consider peripherally-acting mu-opioid receptor antagonists (methylnaltrexone, naloxegol, or naldemedine) as rescue therapy when constipation is clearly opioid-related 1
• These agents are contraindicated in mechanical bowel obstruction 1

Monitoring and Reassessment

• Reassess for obstruction or impaction if constipation persists despite aggressive laxative therapy 1
• Check for hypercalcemia as a metabolic cause of severe constipation 1
• Goal: Achieve one non-forced bowel movement every 1-2 days 1

Common Pitfalls to Avoid

• Never initiate polyethylene glycol or other laxatives without first ruling out bowel obstruction - this can cause perforation 2
• Do not use supplemental fiber (psyllium) in severe constipation - it is ineffective and may worsen obstruction 1
• Avoid rectal suppositories or enemas if patient has neutropenia or thrombocytopenia 1
• Limit sodium phosphate enemas to maximum once daily in patients with renal dysfunction due to electrolyte abnormalities 1