What is the diagnosis and treatment for an elderly female patient with a history of hypothyroidism, hypertension, hyperlipidemia, and glaucoma, taking amlodipine, Hygroton (chlorthalidone), Dorzolamide, Timolol, Levothyroxine, and Lovastatin, presenting with rectal pain, constipation, and partial digital disimpaction, without abdominal pain or fever?

Diagnosis and Treatment of Fecal Impaction in an Elderly Female

This patient has fecal impaction, confirmed by partial digital disimpaction, and requires immediate manual disimpaction followed by enemas/suppositories, then initiation of a maintenance bowel regimen with polyethylene glycol (PEG) to prevent recurrence. 1

Diagnosis

Fecal impaction is the diagnosis based on:

• Rectal pain with constipation 2, 3
• Ability to partially disimpact digitally (confirms distal rectal impaction) 1
• Absence of fever and abdominal pain (suggests no perforation or peritonitis) 1

Contributing Factors in This Patient

• Advanced age - elderly patients have 24-50% prevalence of constipation 1
• Multiple constipating medications: 1
  • Chlorthalidone (Hygroton) - diuretic causing dehydration
  • Timolol - beta-blocker with anticholinergic effects
  • Lovastatin - can cause constipation
• Hypothyroidism - even if treated, may contribute to decreased bowel motility 1
• Likely decreased mobility given age and multiple comorbidities 1

Immediate Treatment Algorithm

Step 1: Complete Disimpaction

Manual digital disimpaction should be performed first, with premedication using an analgesic ± anxiolytic for patient comfort 1. This involves digital fragmentation and extraction of the stool 1.

Step 2: Rectal Measures

Following partial manual disimpaction, administer: 1

• Water or oil retention enema to facilitate passage of remaining stool through the anal canal 1
• Glycerine suppository as an alternative or adjunct 1
• Isotonic saline enemas are preferable in elderly patients due to lower risk of adverse effects compared to sodium phosphate enemas 1

Important contraindications to check (none appear present in this patient): 1

• Neutropenia or thrombocytopenia
• Recent colorectal/gynecological surgery
• Recent anal or rectal trauma
• Severe colitis or abdominal infection
• Paralytic ileus or complete obstruction

Step 3: Oral Laxative Therapy

Once the distal colon is partially emptied: 1

• Administer PEG (polyethylene glycol) 17g/day orally - this is the preferred agent for elderly patients with an excellent safety profile 1
• PEG solutions containing electrolytes help soften and wash out remaining proximal stool 1

Maintenance Bowel Regimen to Prevent Recurrence

A structured maintenance program is essential as this patient has multiple ongoing risk factors: 1

First-Line Maintenance

• Continue PEG 17g daily - safest option given her cardiac (hypertension) and potential renal considerations with diuretic use 1
• Avoid magnesium-based laxatives (magnesium hydroxide, magnesium citrate) due to risk of hypermagnesemia, especially with potential renal impairment from diuretic use 1

Alternative/Additional Options if PEG Insufficient

• Stimulant laxatives: Senna, bisacodyl 10-15mg daily, or sodium picosulfate 1, 4
• Lactulose 30-60mL twice daily as an osmotic alternative 1
• Avoid bulk-forming agents (psyllium, fiber supplements) in this patient given likely reduced mobility and fluid intake - risk of mechanical obstruction 1

Non-Pharmacologic Interventions

Critical for elderly patients: 1

• Ensure toilet access and privacy - especially important if mobility limited 1
• Optimize toileting schedule: attempt defecation twice daily, 30 minutes after meals, strain no more than 5 minutes 1
• Increase fluid intake within limits of cardiac status 1
• Maximize mobility even if just bed-to-chair transfers 1
• Small footstool to assist with positioning and gravity during defecation 1

Medication Review and Monitoring

Critical Medication Adjustments

• Review necessity of chlorthalidone - diuretics significantly contribute to constipation through dehydration 1
• Monitor for electrolyte imbalances given combination of diuretic therapy and laxative use 1
• Ensure adequate levothyroxine dosing - hypothyroidism contributes to constipation 1

Monitoring Parameters

• Regular assessment of kidney and heart function when using diuretics with laxatives - risk of dehydration and electrolyte disturbances 1
• Goal: 1 non-forced bowel movement every 1-2 days 1

Colorectal Evaluation

Post-treatment colonic evaluation is indicated after fecal impaction resolves: 2

• Flexible sigmoidoscopy, colonoscopy, or barium enema
• To rule out underlying structural causes (stricture, mass, obstruction)
• Particularly important given age and need for colorectal surgery consultation

Common Pitfalls to Avoid

• Do not use liquid paraffin - risk of aspiration lipoid pneumonia in elderly, especially if any swallowing difficulties 1
• Avoid aggressive use of stimulant laxatives alone without addressing underlying causes - can cause pain and cramps in elderly 1
• Do not overlook medication-induced constipation - multiple drugs in this patient's regimen contribute 1
• Never assume absence of ischemia based on lack of fever/peritonitis - bowel ischemia can be present without hyperlactatemia, though unlikely given successful partial disimpaction 1