How to manage constipation in a patient with a stoma?

Constipation Management in Patients with a Stoma

For patients with a colostomy experiencing constipation, begin with dietary modifications including increased fiber and fluid intake, and if unsuccessful after 3 months, add first-line pharmacological therapy with osmotic laxatives (polyethylene glycol) or bulk-forming agents (psyllium), followed by stimulant laxatives (senna, bisacodyl) if needed. 1, 2

Initial Assessment and Exclusion of Structural Causes

Before treating constipation medically, you must exclude morphological stoma changes that require surgical intervention 2, 3:

• Parastomal hernia (the most common structural cause, accounting for 72-84% of surgical cases) 3
• Stomal stenosis (narrowing of the stoma opening) 3
• Stomal retraction or collapse 3
• Stomal prolapse 3
• Recurrent disease in remaining bowel 4
• Intra-abdominal sepsis or enteritis 4

Approximately 15% of patients with stoma-related constipation will require surgical referral for these morphological changes 2. Physical examination of the stoma and imaging when indicated should be performed before initiating conservative management 2, 3.

Type of Stoma Matters

Constipation management differs fundamentally based on stoma type 5:

• Colostomy patients: Constipation is common and managed similarly to patients without stomas, using dietary modifications and laxatives 1, 2
• Ileostomy patients: The primary concern is typically high output and dehydration, NOT constipation. These patients require fluid restriction and sodium replacement 5, 4
• Jejunostomy patients: Almost never experience constipation; high output is the predominant issue 5

First-Line Treatment: Dietary Modifications (3-Month Trial)

Dietary changes alone resolve constipation in 56-60% of colostomy patients 1, 2:

• Increase dietary fiber intake through fruits, vegetables, whole grains, and legumes 5, 1, 2
• Increase fluid intake to 2-2.5 liters daily 5, 1, 2
• Add salt to meals at the table and during cooking to maintain sodium balance 5
• Evaluate response after 3 months before escalating to pharmacological therapy 1, 2

Critical caveat: For ileostomy patients, high fiber intake can paradoxically increase loose stools, flatulence, and bloating, so fiber should be limited in this population 5.

Second-Line Treatment: Pharmacological Management

When dietary modifications fail after 3 months, add medications in a stepwise fashion 2, 6:

First-Line Pharmacological Options

Osmotic laxatives (preferred based on strong evidence) 5, 7, 8:

• Polyethylene glycol (PEG): 17 grams dissolved in 8 oz water once to twice daily 7, 8
• Lactulose: Standard dosing 5, 7
• Magnesium hydroxide: 30-60 mL daily (use cautiously in renal impairment) 5, 8

Bulk-forming agents 2, 6:

• Psyllium (Normacol Plus): Effective in colostomy patients 2, 6
• Note: Bulk laxatives are contraindicated in opioid-induced constipation and should be avoided in non-ambulatory patients with low fluid intake 5, 7

Probiotics may be added as adjunctive therapy 2

Second-Line Pharmacological Options (If First-Line Fails)

Stimulant laxatives 5, 7, 9:

• Senna: 2-3 tablets twice to three times daily, titrated to effect (up to 8-12 tablets daily maximum) 8, 9
• Bisacodyl: 10-15 mg orally 2-3 times daily or as rectal suppository 8
• Sodium picosulfate: Alternative stimulant option 5

Goal of treatment: Achieve one non-forced bowel movement every 1-2 days 7, 8

Evidence-Based Treatment Protocol

A randomized controlled trial demonstrated that a standardized laxative protocol significantly reduces fecal loading compared to ad hoc laxative use (1 episode vs 7 episodes, P = 0.05) 6:

1. First-line: Bulk-forming agent (sterculia and frangula bark) plus stool softener (liquid paraffin) 6
2. Second-line: Iso-osmotic polyethylene glycol (Movicol) if first-line fails 6
3. Monitor for fecal loading and adjust accordingly 6

Rectal Interventions

Suppositories and enemas are preferred first-line therapy when digital rectal examination identifies a full rectum or fecal impaction 5, 7:

• Glycerine suppositories 7
• Bisacodyl suppositories 7, 8
• Small-volume enemas if oral treatment fails 7

Contraindications to enemas: Neutropenia, thrombocytopenia, paralytic ileus, intestinal obstruction, recent colorectal/gynecological surgery, recent anal/rectal trauma, severe colitis, toxic megacolon, undiagnosed abdominal pain, or recent pelvic radiotherapy 5.

Medications to Avoid

Docusate (stool softener) should NOT be used 7:

• Explicitly not recommended by NCCN guidelines due to lack of efficacy evidence 7
• Listed under "laxatives generally not recommended" by ESMO 7
• Inadequate experimental evidence supporting its use 7

Liquid paraffin should be avoided in bed-bound patients and those with swallowing disorders due to risk of aspiration lipoid pneumonia 5.

Special Considerations for Opioid-Induced Constipation

If the patient is on opioid therapy 5, 7:

• Prophylactic laxatives should be prescribed at the time opioids are initiated 5, 7
• Osmotic or stimulant laxatives are preferred over bulk-forming agents 5, 7
• Consider peripherally acting μ-opioid receptor antagonists (PAMORAs) such as methylnaltrexone for refractory cases 5, 7
• Patients do not develop tolerance to opioid-induced constipation, so ongoing prophylactic treatment is necessary 8

Common Pitfalls to Avoid

• Do not confuse ileostomy management with colostomy management: Ileostomy patients need fluid restriction and sodium replacement, NOT increased fluids and fiber 5
• Do not encourage hypotonic fluid intake (water, tea, coffee) in ileostomy patients, as this paradoxically increases stomal sodium losses and worsens dehydration 5, 4
• Do not use bulk laxatives for opioid-induced constipation as they are ineffective and may worsen symptoms 5, 7
• Do not attribute symptoms to IBS until comprehensive investigation has excluded organic causes, especially in patients who did not have IBS before surgery 5
• Do not rely solely on stool softeners (docusate) without addressing bowel motility or water content 7
• Always exclude structural stoma complications before assuming functional constipation 2, 3

Monitoring and Follow-Up

• Assess response to dietary modifications at 3 months 1, 2
• If pharmacological therapy is initiated, reassess after 2-4 days and titrate as needed 8
• Monitor for signs of fecal impaction, which may require digital disimpaction 5
• In refractory cases with severely impaired quality of life, discuss stoma revision or alternative surgical options 5