What is the best approach to manage chronic constipation in an elderly patient with hypertension, asthma, Vitamin D deficiency, mild anemia, and a history of hemorrhoids and colonic polyps?

Management of Chronic Constipation in This Elderly Patient

Optimize the current laxative regimen by consolidating to polyethylene glycol (PEG) 17 g/day as first-line therapy, address the low mood with appropriate psychiatric evaluation, correct the vitamin D deficiency and mild anemia, ensure colonoscopy surveillance for the polyps, and implement structured non-pharmacological measures including scheduled toileting and increased mobility. 1

Immediate Medication Optimization

Simplify the polypharmacy laxative regimen to PEG 17 g/day as the primary agent. The patient is currently on multiple laxatives (cremalax, coenzyme gold, acoblis, ezego plus, constiheal), which represents unnecessary polypharmacy. PEG at 17 g/day offers the most efficacious and tolerable solution for elderly patients with an excellent safety profile, particularly important given this patient's cardiac comorbidity (hypertension on amlodipine). 2, 1

• Discontinue the current multiple laxative regimen and start PEG 17 g/day as monotherapy, as laxatives must be individualized based on cardiac and renal comorbidities to avoid drug interactions and adverse effects. 2

• Avoid magnesium-containing laxatives given the borderline low BUN (7.8) and mild hyponatremia (133.4), as saline laxatives carry risk of hypermagnesemia and electrolyte imbalances, particularly in elderly patients with potential renal issues. 2, 1

• Monitor for dehydration and electrolyte disturbances regularly, especially with the concurrent use of amlodipine, as there is risk of electrolyte imbalances when cardiac medications are combined with laxatives. 2

Critical Non-Pharmacological Interventions

Implement structured toileting habits immediately. Educate the patient to attempt defecation twice daily, 30 minutes after meals (when gastrocolic reflex is strongest), and strain no more than 5 minutes. 2, 1

• Ensure adequate toilet access, especially critical if mobility is limited due to age or the patient's low mood affecting motivation. 2, 1

• Increase fluid intake to at least 1.5 liters daily to optimize stool consistency and prevent dehydration, particularly important given the mild hyponatremia. 3

• Encourage physical activity within limitations, as even minimal movement stimulates bowel function and may improve the patient's mood. 3

• Provide dietetic support to manage any decreased food intake related to aging, chewing difficulties, or the patient's low mood, as these negatively influence stool volume and consistency. 2

Address Underlying Medical Issues

Correct the vitamin D deficiency (level 26). While not directly causing constipation, vitamin D deficiency contributes to overall frailty, muscle weakness, and potentially worsens mobility—all factors that exacerbate constipation in elderly patients. 4

Investigate and treat the mild anemia (Hb 11, MCV 83, MCH 25.9). This normocytic anemia with low MCH suggests possible iron deficiency or anemia of chronic disease. Given the colonoscopy findings of hemorrhoids and polyps, ensure adequate surveillance and rule out occult bleeding as a contributor. 4

Address the low mood and loneliness urgently. Depression is both a cause and consequence of constipation in elderly patients, and psychotropic medications used to treat depression can worsen constipation. 4 Consider:

• Psychiatric evaluation for appropriate antidepressant selection that minimizes constipation (avoid tricyclic antidepressants)
• Social work referral to address loneliness and isolation
• The patient's low mood may be contributing to decreased physical activity, poor dietary intake, and reduced motivation for self-care—all worsening constipation

Correct the mild hyponatremia (133.4). This may reflect poor oral intake, excessive fluid losses, or medication effects. Ensure adequate fluid intake while monitoring sodium levels, as dehydration worsens constipation. 2

Evaluate for Fecal Impaction

Perform digital rectal examination (DRE) to rule out fecal impaction, especially given the 3-year history of constipation despite multiple medications. 5, 4 If impaction is present:

• Manual disimpaction through digital fragmentation and extraction is first-line, followed by water or oil retention enemas. 5
• Avoid sodium phosphate enemas; use isotonic saline enemas instead due to lower risk of electrolyte disturbances in elderly patients. 2, 5
• After disimpaction, implement the PEG 17 g/day maintenance regimen to prevent recurrence. 5

Anorectal Manometry Results and Defecatory Disorders

The patient has undergone anorectal manometry (results not provided). If manometry reveals pelvic floor dysfunction or dyssynergic defecation, biofeedback therapy should be considered as it is effective for defecatory disorders, with satisfaction rates up to 76% and continence improvement in 55% of patients. 3, 6

Colonoscopy Surveillance

Ensure appropriate surveillance for the colonic polyps identified on colonoscopy, with repeat colonoscopy timing based on polyp histology and number per standard guidelines. The hemorrhoids should be managed conservatively unless causing significant bleeding or prolapse. 4

Medication Review for Constipating Effects

Review all current medications for constipating effects:

• Amlodipine (calcium channel blocker) can contribute to constipation, but given the patient's hypertension, do not discontinue without cardiology consultation
• Foracort (inhaled corticosteroid/long-acting beta-agonist) for asthma is unlikely to contribute significantly to constipation
• Consider whether any other medications not listed (particularly anticholinergics, opioids, or psychotropics) are being taken that could worsen constipation 4, 6

Common Pitfalls to Avoid

Do not use bulk-forming laxatives (psyllium, methylcellulose) in this patient, as they require high fluid intake and can cause mechanical obstruction in elderly patients with potentially limited mobility or fluid intake. 2, 1

Do not rely on docusate (stool softeners) alone, as it is ineffective for both prevention and treatment of constipation in elderly patients. 5, 3

Avoid liquid paraffin if the patient has any swallowing difficulties or becomes bed-bound, due to risk of aspiration lipoid pneumonia. 2, 1

Follow-Up and Monitoring

• Reassess in 2-4 weeks after initiating PEG and non-pharmacological measures
• Monitor electrolytes (sodium, potassium, magnesium) given the baseline hyponatremia and low BUN
• Track bowel movement frequency and consistency using a bowel diary
• Reassess mood and consider formal depression screening with geriatric depression scale
• If no improvement after adequate trial of PEG and lifestyle measures, consider referral to gastroenterology for further evaluation of slow transit constipation versus pelvic floor dysfunction 4, 6