How to manage diarrhea, classified as Bristol Stool Scale (BSFS) types 6 and 7, in critically ill patients in the Intensive Care Unit (ICU)?

Management of Diarrhea (Bristol Stool Scale Types 6-7) in ICU Patients

In critically ill ICU patients with diarrhea (BSFS types 6-7), prioritize identifying and treating Clostridioides difficile infection, maintain enteral nutrition unless contraindicated, ensure aggressive fluid and electrolyte replacement, and avoid antimotility agents in the absence of a clear non-infectious etiology.

Initial Assessment and Risk Stratification

Immediate Evaluation

• Assess for C. difficile infection in any ICU patient with diarrhea who received antibiotics or chemotherapy within 60 days, as this is the most common infectious cause of fever and diarrhea in the ICU 1
• Obtain stool testing for C. difficile toxin A or B in all patients with new-onset diarrhea (≥3 loose stools per day) occurring ≥72 hours after ICU admission 2
• Evaluate for complications: fever, abdominal pain/cramping, distension, ileus, leukocytosis, sepsis, dehydration, and electrolyte disturbances 1
• Do not routinely send stool cultures for other bacterial pathogens (Salmonella, Shigella, Campylobacter) unless the patient was admitted with diarrhea, is HIV-positive, or is part of an outbreak investigation, as these are rarely ICU-acquired 1

Hydration Status Assessment

• Examine skin turgor, mucous membranes, mental status, pulse, and perfusion 1
• Check for orthostatic symptoms (dizziness upon standing) 1
• Obtain complete blood count and electrolyte profile to assess for dehydration severity and electrolyte disturbances 1

Fluid and Electrolyte Management

Severe Dehydration or Shock

• Administer isotonic IV fluids (lactated Ringer's or normal saline) immediately until pulse, perfusion, and mental status normalize 1
• Continue IV rehydration until the patient awakens, has no aspiration risk, and has no evidence of ileus 1

Mild to Moderate Dehydration

• Initiate reduced osmolarity oral rehydration solution (ORS) as first-line therapy for patients who can tolerate oral intake 1
• Consider nasogastric administration of ORS in patients with moderate dehydration who cannot tolerate oral intake 1
• Replace ongoing losses: administer 10 mL/kg ORS for each watery stool 3

Enteral Nutrition Management

Continue enteral nutrition in patients with diarrhea unless there are specific contraindications (ileus, bowel obstruction, severe hemodynamic instability) 1, 4. The evidence shows:

• Enteral nutrition per se is not independently a diarrhea risk factor; rather, it is the combination of EN covering >60% of energy target with antibiotics or antifungal drugs that increases diarrhea incidence 5
• Do not routinely monitor gastric residual volumes, but measure them in patients with feeding intolerance or high aspiration risk 1
• Use prokinetic agents (metoclopramide, erythromycin) in patients with feeding intolerance 1
• Consider post-pyloric feeding tube placement in patients with feeding intolerance or high aspiration risk 1

Dietary Modifications

• Stop all lactose-containing products, alcohol, and high-osmolar supplements 1
• Advance to age-appropriate diet as tolerated, including starches, cereals, fruits, and vegetables 1

Antimicrobial Management

C. difficile Infection Treatment

• If C. difficile is confirmed, initiate metronidazole or vancomycin immediately; the median delay to treatment should be ≤1 day 2
• Consider pseudomembranous colitis, which occurs in approximately 51% of ICU-acquired CDI cases 2
• Obtain sigmoidoscopy/colonoscopy if pseudomembranous colitis is suspected, though only 71% of severe cases and 23% of mild cases show pseudomembranes 1

Empiric Antibiotic Therapy

• In complicated cases with fever, sepsis, neutropenia, or severe dehydration, administer empiric fluoroquinolone antibiotics while awaiting stool studies 1
• Modify or discontinue antimicrobial therapy once a clinically plausible organism is identified 1

Pharmacological Interventions

Antimotility Agents

Loperamide is contraindicated in multiple scenarios and should be used with extreme caution in ICU patients 1, 6:

• Absolutely contraindicated in patients <18 years of age due to risks of respiratory depression and serious cardiac adverse reactions 6
• Avoid in suspected or proven inflammatory diarrhea, diarrhea with fever, or conditions where toxic megacolon may result 1
• Avoid in elderly patients taking QT-prolonging drugs (Class IA or III antiarrhythmics) 6
• If used in immunocompetent adults with confirmed non-infectious watery diarrhea: initial dose 4 mg, then 2 mg after each unformed stool (maximum 16 mg/day) 6

Octreotide for Severe Cases

• In complicated cases with severe dehydration or grade 3-4 diarrhea failing loperamide, initiate octreotide at 100-150 mcg SC three times daily or IV (25-50 mcg/hour), with dose escalation up to 500 mcg until diarrhea is controlled 1
• This is particularly important as loperamide is less effective in grade 3-4 diarrhea 1

Antiemetics

• Consider ondansetron to facilitate tolerance of oral rehydration in patients with associated vomiting 1

Risk Factor Modification

Modifiable Risk Factors

The strongest risk factors for ICU-acquired diarrhea include 5, 7:

• Antibiotics (relative risk 3.64) 5
• Antifungal drugs (relative risk 2.79) 5
• Enteral nutrition covering >60% of energy target (relative risk 1.75) 5
• Laxative use 7
• Moderate-high protein content enteral feeds 7

Interventions to Reduce Diarrhea Burden

• Review and discontinue unnecessary antibiotics and antifungal agents 5
• Reassess laxative necessity 7
• Consider adjusting enteral nutrition protein content if diarrhea is persistent and non-infectious 7

Monitoring and Complications

Ongoing Assessment

• Monitor for consequences of diarrhea: hypovolemia, electrolyte disturbances, malnutrition, skin lesions, and contamination of wounds 4
• Consider fecal management device insertion for patients with persistent diarrhea to prevent skin breakdown and contamination 7
• Continue intervention until the patient has been diarrhea-free for 24 hours 1

Prognostic Considerations

• Diarrhea prevalence in ICU patients ranges from 14-60.4% depending on definition used 4, 8, 7
• ICU-acquired CDI, if treated early, is not independently associated with increased mortality (case-fatality rate 21.5% vs 25.3% in diarrheic controls without CDI) 2
• Diarrhea increases ICU and hospital length of stay but does not independently increase mortality when adjusted for illness severity 7, 2

Common Pitfalls to Avoid

• Do not withhold or delay enteral nutrition in patients with diarrhea unless there is ileus, obstruction, or severe hemodynamic instability 1, 4
• Do not use antimotility agents empirically without excluding infectious causes, particularly C. difficile 1
• Do not routinely send stool cultures for bacterial pathogens in ICU-acquired diarrhea unless specific epidemiological factors are present 1
• Do not delay C. difficile testing in any patient with new diarrhea and recent antibiotic exposure 1, 2
• Do not use probiotics as they have no effect on the incidence or duration of diarrhea in ICU patients 8