How should I treat an 80-year-old patient presenting with diarrhea?

Treatment of Diarrhea in an 80-Year-Old Patient

In an 80-year-old patient with diarrhea, immediately assess for severe fecal impaction with digital rectal examination and test for Clostridioides difficile infection, as these are critical diagnoses that require specific management and carry high morbidity in this age group. 1, 2

Initial Diagnostic Approach

Mandatory First Steps

• Perform digital rectal examination to detect fecal impaction, which paradoxically presents as diarrhea (overflow diarrhea) and is common in elderly patients 1, 2
• Test stool for C. difficile in all elderly patients with diarrhea, regardless of antibiotic history, as infection markedly raises morbidity and mortality 1, 3
• Assess vital signs four times daily to detect early deterioration, particularly signs of hypovolemic shock (tachycardia, tachypnea, cool extremities, oliguria) 1, 2
• Obtain laboratory tests: complete blood count, renal function, electrolytes (especially potassium), albumin, and C-reactive protein 1, 2

Key Clinical Distinctions

• Abnormal vital signs or altered mental status indicate critical illness requiring immediate aggressive management 2
• Confusion during diarrheal illness is more common in geriatric patients and may represent delirium from dehydration or sepsis 2
• Abdominal distension has a positive likelihood ratio of 16.8 for severe impaction but may develop progressively 2

Management Based on Etiology

If Fecal Impaction is Present (Stercoral Colitis)

Conservative Management:

• Manual disimpaction via digital fragmentation when rectal impaction is confirmed 1
• Isotonic saline enemas are preferred in elderly patients to minimize electrolyte disturbances 1
• Osmotic laxatives (polyethylene glycol ~17 g/day, lactulose, magnesium salts) are effective and well-tolerated 1
• Avoid bulk-forming agents (psyllium) in non-ambulatory patients with limited fluid intake due to obstruction risk 1
• Avoid liquid paraffin in bed-bound patients due to aspiration risk 1

Supportive Care:

• Aggressive IV fluid resuscitation to correct dehydration and optimize colonic perfusion 1
• Potassium supplementation of at least 60 mmol/day 1
• Monitor daily with plain abdominal radiographs if colonic dilatation suspected; transverse colon diameter >5.5 cm signals imminent perforation 1

Surgical Indications:

• Immediate surgical consultation for peritonitis or clinical deterioration despite optimal conservative therapy 1
• Hartmann's procedure (resection with exteriorization) is preferred over primary anastomosis due to high anastomotic failure risk 1

If C. difficile Infection is Confirmed

• Oral vancomycin 125 mg four times daily for 10 days is the treatment of choice 1, 4, 3
• Metronidazole may be used as alternative but vancomycin is preferred in elderly patients 3
• Monitor renal function during and after treatment, as elderly patients (>65 years) are at increased risk of vancomycin-induced nephrotoxicity 4
• Elderly patients may take longer to respond to therapy; do not discontinue prematurely 4
• Recurrence occurs in 7-20% of patients; treat first recurrences the same as initial cases 3

If Inflammatory Bowel Disease is Suspected

For elderly patients with new-onset IBD presenting with diarrhea:

• Aminosalicylates (mesalamine) are first-line for mild-to-moderate disease due to lack of systemic immunosuppression 5
• Budesonide-MMX is preferred over systemic corticosteroids for left-sided disease to reduce systemic exposure 5
• Never use systemic corticosteroids for maintenance; they are ineffective and highly toxic in elderly patients 6, 5

For moderate-to-severe disease requiring advanced therapy, prioritize gut-selective agents:

1. Vedolizumab (first choice) - gut-selective mechanism reduces systemic immunosuppression and infection risk 6, 5
2. Ustekinumab (second choice) - similar gut-selective profile with favorable safety 6, 5
3. Anti-TNF agents - only after confirming ability to adhere to infusion/injection schedules 6, 5
4. Tofacitinib - use 5 mg twice daily for maintenance; avoid 10 mg twice daily due to increased venous thromboembolism risk in patients with cardiac risk factors 6, 5

If Acute Infectious Diarrhea (Non-C. difficile)

Most cases are self-limiting and require only supportive care:

• Oral rehydration is the cornerstone of treatment 7, 8
• Loperamide can be used for symptomatic relief in acute watery diarrhea: initial dose 4 mg followed by 2 mg after each unformed stool, maximum 16 mg/day 9, 8
• Use loperamide with caution in elderly patients taking drugs that prolong QT interval (Class IA or III antiarrhythmics) 9
• Empiric antibiotics are rarely warranted except in sepsis or inflammatory diarrhea with bloody stools 8
• Molecular stool studies are preferred over traditional cultures when testing is indicated 8

Critical Pitfalls to Avoid

• Do not assume all diarrhea in elderly patients is infectious; fecal impaction with overflow diarrhea is extremely common and requires opposite management 1, 2
• Do not delay C. difficile testing while awaiting other stool culture results in severe presentations 1
• Do not stop NSAIDs gradually; discontinue immediately as they precipitate or worsen ischemic colonic changes 1
• Do not abruptly discontinue essential cardiac medications without cardiology consultation, as this may impair colonic perfusion 1, 5
• Do not use antidiarrheal agents if fecal impaction or C. difficile infection is suspected, as they can worsen outcomes 1
• Do not assume conservative management will succeed in severe presentations; obtain early surgical consultation for peritonitis or clinical deterioration 1, 5

Medication Safety in Elderly Patients

• Assess hepatic function before loperamide use, as systemic exposure may be increased due to reduced metabolism 9
• Monitor renal function during vancomycin treatment, especially in patients >65 years with normal baseline function 4
• Implement thromboprophylaxis with subcutaneous low-molecular-weight heparin during acute episodes of severe diarrhea 1