What are the causes and management options for chronic constipation in an elderly female?

Causes of Chronic Constipation in Elderly Females

Chronic constipation in elderly females results primarily from age-related degenerative changes in the enteric nervous system, compounded by medications (especially opioids and psychotropics), reduced mobility, inadequate fluid intake, and comorbid conditions including hypothyroidism and hypercalcemia. 1

Primary Age-Related Mechanisms

• Degenerative enteric nervous system changes occur with aging, causing disrupted colonic motility, diminished rectal distension perception, and rectal sphincter dysfunction 1
• Prevalence ranges from 24-50% in community-dwelling elderly, escalating to 74% laxative use in nursing home residents 1
• Female sex is an independent risk factor, with elderly women experiencing more severe constipation than men 2, 3

Medication-Induced Causes

• Opioid analgesics are the most critical medication cause, producing constipation without tolerance development over time 4
• Psychotropic medications commonly prescribed in institutionalized elderly patients cause chronic constipation 1
• 5-HT3 receptor antagonist antiemetics slow colonic transit and increase fluid absorption 4
• Polypharmacy in general increases constipation risk through multiple mechanisms 5

Secondary Medical Causes

• Metabolic disturbances: Hypercalcemia, hypokalemia, uremia, and hypothyroidism must be checked when clinically suspected 1, 4
• Structural causes: Abdominal/pelvic masses, radiation fibrosis, and colorectal pathology 4
• Neurological conditions: Diabetes, dementia, stroke, and Parkinson's disease contribute through autonomic dysfunction 6

Lifestyle and Functional Factors

• Physical inactivity and reduced mobility are major contributors in elderly populations 5, 2
• Inadequate fluid intake (below 1.5 liters daily) and low-fiber diet worsen stool consistency 1, 6
• Lack of toilet privacy and poor access to toilets, especially with decreased mobility, perpetuate the problem 7, 4
• Decreased food intake from anorexia of aging and chewing difficulties reduces stool volume and consistency 1

Assessment Approach

Obtain a complete medication list and withdraw inappropriate medications as the first intervention. 1

Essential History Elements

• Social situation: Living alone versus with family versus nursing home residence 1
• Previous episodes: 30-40% report prior constipation episodes 1
• Medication review: Focus on opioids, anticholinergics, psychotropics, calcium supplements 1
• Dietary intake: Assess fiber, fluid consumption, and overall caloric intake 1

Physical Examination

• Abdominal examination for distension, masses, and tenderness 1
• Digital rectal examination (DRE) is mandatory to assess for fecal impaction, rectal masses, and sphincter tone 1
• Perineal inspection for structural abnormalities 1

Laboratory Investigations

• Corrected calcium levels and thyroid function should be checked when clinically suspected 1
• Electrolytes and renal function are necessary given dehydration risk in elderly patients 1
• Routine investigations are not necessary in uncomplicated cases 1

Imaging

• Plain abdominal X-ray may image fecal loading extent and exclude bowel obstruction, though limited as a standalone tool 1
• More extensive investigation is warranted for severe symptoms, sudden bowel habit changes, blood in stool, or unintended weight loss 1, 2

Management Algorithm

Step 1: Non-Pharmacological Measures (Always First)

• Ensure toilet access, especially critical for patients with decreased mobility 1, 7
• Optimize toileting habits: Attempt defecation twice daily, 30 minutes after meals (when gastrocolic reflex is strongest), straining no more than 5 minutes 1, 7, 6
• Increase fluid intake to at least 1.5 liters daily 1
• Increase physical activity within patient limitations, even bed-to-chair transfers 1
• Provide dietetic support to manage decreased food intake and chewing difficulties 1

Step 2: First-Line Pharmacological Treatment

Polyethylene glycol (PEG) 17 g/day is the first-line laxative due to superior efficacy and excellent safety profile in elderly patients. 1, 7

• PEG offers the best balance of effectiveness and tolerability in this population 1, 7
• Osmotic laxatives (lactulose) or stimulant laxatives (senna, bisacodyl, sodium picosulfate) are alternatives if PEG is not tolerated 1, 7

Step 3: Individualize Based on Comorbidities

• Laxative selection must account for cardiac and renal comorbidities, drug interactions, and adverse effects 1, 7
• Regular monitoring is essential in patients with chronic kidney or heart failure on diuretics or cardiac glycosides (risk of dehydration and electrolyte imbalances) 1

Critical Contraindications and Pitfalls

• Avoid bulk laxatives (psyllium) in non-ambulatory patients with low fluid intake due to mechanical obstruction risk 1, 7
• Avoid liquid paraffin in bed-bound patients and those with swallowing disorders due to aspiration lipoid pneumonia risk 1, 7
• Use magnesium-containing laxatives cautiously in renal impairment due to hypermagnesemia risk 1, 7
• Isotonic saline enemas are preferable to sodium phosphate enemas in elderly patients due to better safety profile 1, 7

Step 4: Rectal Measures When Indicated

• Suppositories and enemas are first-line when DRE identifies full rectum or fecal impaction 1
• For swallowing difficulties or repeated fecal impaction, rectal measures may be the preferred treatment route 1, 7
• Digital disimpaction followed by enema or suppository is necessary for fecal impaction 1

Step 5: Specialist Referral

• Refer for further evaluation if symptoms persist despite optimal conservative therapy, or if alarm features present (rectal bleeding, unintended weight loss, iron deficiency anemia, acute onset in older adults) 2, 8
• Physiologic testing (anorectal manometry, colonic transit studies, defecography) may be needed to identify pelvic floor dysfunction or slow transit constipation 5, 3