What is the management for fecal impaction?

Management of Fecal Impaction

The first-line treatment for fecal impaction is manual disimpaction through digital fragmentation and extraction of stool, followed immediately by enemas (water or oil retention), and then implementation of a maintenance bowel regimen to prevent recurrence. 1

Initial Assessment and Diagnosis

Before proceeding with treatment, confirm the diagnosis and rule out contraindications:

• Perform digital rectal examination (DRE) to identify the large mass of dry, hard stool in the rectum 2
• Be aware that DRE may be non-diagnostic if impaction occurs in the proximal rectum or sigmoid colon—in these cases, imaging with plain abdominal X-ray or CT is needed 1, 2
• Rule out absolute contraindications including suspected perforation, bleeding, neutropenia (WBC < 0.5), thrombocytopenia, paralytic ileus, intestinal obstruction, recent colorectal/gynecological surgery, recent anal/rectal trauma, severe colitis, toxic megacolon, undiagnosed abdominal pain, or recent pelvic radiotherapy 1

Treatment Algorithm

For Distal Fecal Impaction (Rectal):

Step 1: Pre-medication

• Administer analgesia and/or anxiolytic before the procedure to prevent vagal stimulation, which can cause bradycardia and hemodynamic instability 2, 3

Step 2: Manual Disimpaction

• Perform digital fragmentation and extraction of the stool 1
• Position patient in left lateral decubitus or lithotomy position 2

Step 3: Enema Administration

• Follow immediately with water or oil retention enema to facilitate passage of remaining stool 1, 2
• Options include warm oil retention enema (mineral oil/arachis oil), hypertonic sodium phosphate enema, docusate sodium enema, or bisacodyl enema 2
• Glycerol suppositories may also be used as a rectal stimulant 2

For Proximal Fecal Impaction (Sigmoid/Proximal Colon):

• In the absence of complete bowel obstruction, administer oral or nasogastric polyethylene glycol (PEG) solutions containing electrolytes to soften or wash out stool 1, 2
• This lavage approach is used when the impaction is too high to reach manually 1

Critical Post-Disimpaction Management

Implement a maintenance bowel regimen immediately after successful disimpaction—this is essential as recurrence is extremely common without preventive measures 1, 3:

Preferred Laxative Options:

• Osmotic laxatives: PEG (17 g/day), lactulose, or magnesium salts 1, 3
• Stimulant laxatives: senna, cascara, bisacodyl (10-15 mg daily to TID), or sodium picosulfate 1, 3
• Goal: 1 non-forced bowel movement every 1-2 days 3

Laxatives to Avoid:

• Do NOT use bulk laxatives such as psyllium, especially in patients with opioid-induced constipation or limited mobility, as they increase the risk of obstruction 1, 2

Special Population Considerations

Elderly Patients:

• PEG (17 g/day) offers the best efficacy and tolerability with a good safety profile for elderly patients 1, 2, 3
• Ensure access to toilets, especially for patients with decreased mobility 1, 2
• Educate patients to attempt defecation at least twice daily, usually 30 minutes after meals, and to strain no more than 5 minutes 1, 3
• Avoid liquid paraffin in bed-bound patients and those with swallowing disorders due to risk of aspiration lipoid pneumonia 1
• Use magnesium salts cautiously due to risk of hypermagnesemia, particularly in renal impairment 1

Opioid-Induced Constipation:

• All patients on opioids should receive prophylactic laxatives (osmotic or stimulant preferred) 1, 3
• For unresolved opioid-induced constipation, consider peripheral opioid antagonists such as methylnaltrexone or naloxegol 1, 3

Common Pitfalls and How to Avoid Them

• Never skip pre-medication before manual disimpaction—vagal stimulation during rectal manipulation can cause bradycardic arrest and death 2, 3
• Never use enemas in neutropenic patients—the risk of sepsis is prohibitive 1, 3
• Don't assume a negative DRE rules out impaction—proximal impactions require imaging for diagnosis 1, 2, 3
• Don't forget to implement maintenance therapy immediately—recurrence is extremely common without preventive measures 1, 3, 4
• Increase daily water and fiber intake to 30 g/day if patient has adequate fluid intake and physical activity 2, 3, 4
• Limit medications that decrease colonic motility 2, 4

When to Consider Surgical Intervention

• Surgical resection is reserved for peritonitis resulting from bowel perforation, stercoral ulceration with perforation, or when medical therapies fail in severe cases 5, 4