What is the treatment for infectious diarrhea?

Treatment for Infectious Diarrhea

The cornerstone of infectious diarrhea treatment is oral rehydration solution (ORS) for all patients with mild to moderate dehydration, with antimicrobials reserved only for specific high-risk situations including bloody diarrhea with presumptive shigellosis, immunocompromised patients, or travelers with fever ≥38.5°C. 1, 2

Rehydration: The Foundation of Treatment

Fluid replacement is the single most critical intervention and takes priority over all other therapies. 2

Assess Hydration Status First

• Check for orthostatic hypotension, decreased skin turgor, dry mucous membranes, altered mental status, and weakness to determine severity 3
• Severe dehydration manifests as shock, absent peripheral pulse, hypotension, or significantly altered mental status 2

Rehydration Strategy by Severity

For mild to moderate dehydration:

• Administer reduced osmolarity oral rehydration solution as first-line therapy 2
• Nasogastric ORS administration may be used if the patient cannot tolerate oral intake 2
• Continue ORS to replace ongoing stool losses until diarrhea resolves 1

For severe dehydration:

• Start isotonic intravenous fluids (lactated Ringer's or normal saline) immediately 2
• Continue IV fluids until pulse, perfusion, and mental status normalize 2
• Transition to ORS once stabilized to complete rehydration 2

Nutritional Management During Illness

Continue normal feeding throughout the diarrheal episode—withholding food is a common and harmful mistake. 2

• Continue breastfeeding in infants and children without interruption 1, 2
• Resume age-appropriate usual diet during or immediately after rehydration 1, 2
• In children 6 months to 5 years in zinc-deficient regions or with malnutrition, provide oral zinc supplementation (reduces duration by 10 hours on average) 2, 4

When to Use Antimicrobials

Empiric antimicrobials are NOT recommended for most acute watery diarrhea. 2 This is a critical point where overtreatment commonly occurs.

Specific Indications for Antimicrobial Therapy:

• Immunocompromised patients 2
• Infants <3 months with suspected bacterial etiology 2
• Fever, abdominal pain, and bloody diarrhea suggesting shigellosis 2
• Recent international travelers with fever ≥38.5°C or signs of sepsis 2
• Confirmed Salmonella Typhi infection 5

Antimicrobial Selection:

• Ciprofloxacin is FDA-approved for infectious diarrhea caused by enterotoxigenic E. coli, Campylobacter jejuni, Shigella species, and Salmonella typhi 5
• Modify or discontinue antimicrobials once a specific pathogen is identified 2

Critical Contraindication:

Never use antimicrobials for STEC O157 or other Shiga toxin 2-producing E. coli infections—this increases the risk of hemolytic uremic syndrome. 2

Adjunctive Symptomatic Therapies

Antimotility Agents (Loperamide)

Loperamide has strict age and clinical restrictions that must be followed to avoid serious complications. 1, 6

Absolute contraindications:

• Children <18 years of age (strong recommendation) 1, 2
• Any patient with bloody diarrhea or fever (risk of toxic megacolon) 1
• Suspected inflammatory diarrhea 1

May be used in:

• Immunocompetent adults with acute watery diarrhea only 1
• Dosing: 4 mg initially, then 2 mg after each unformed stool (maximum 16 mg/day) 3

Warning: Loperamide can cause serious cardiac arrhythmias including torsades de pointes and sudden death at higher than recommended doses 6

Antiemetics

• Ondansetron may be given to children >4 years and adolescents to facilitate oral rehydration when vomiting is present 1, 2
• Use only after adequate hydration is ensured 1

Probiotics: Modest Benefit with Good Safety Profile

• Probiotics may be offered to reduce symptom severity and duration (reduces diarrhea duration by approximately 25 hours) 4
• Greatest efficacy is in viral diarrhea, particularly rotavirus 4
• Contraindicated in critically ill or immunocompromised patients due to risk of bacteremia/fungemia 4
• Select well-studied strains with documented efficacy 4

Special Populations and Situations

Asymptomatic Carriers

• Generally do not require treatment if practicing good hand hygiene in low-risk settings 1
• Exception: Salmonella Typhi carriers may be treated empirically to reduce transmission 1, 2
• High-risk workers (healthcare, food service, childcare) should follow local public health guidance 1

Persistent Diarrhea (>14 days)

• Evaluate for non-infectious causes including inflammatory bowel disease and irritable bowel syndrome 2
• Consider stool studies if diarrhea persists beyond 48 hours despite treatment 3

Critical Pitfalls to Avoid

These are the most common errors that lead to complications:

1. Giving antimotility agents to children or patients with bloody/febrile diarrhea—this can cause toxic megacolon 1, 2
2. Using antimicrobials routinely for acute watery diarrhea—this promotes resistance without benefit 2
3. Neglecting rehydration while focusing on antimicrobials—dehydration kills, not the pathogen in most cases 2
4. Withholding food during illness—this worsens nutritional status without benefit 2
5. Treating STEC infections with antibiotics—this increases hemolytic uremic syndrome risk 2
6. Using probiotics in critically ill patients—risk of systemic infection 4

Prevention and Infection Control

• Hand hygiene after toilet use, diaper changes, before food preparation, and after animal contact is essential 1
• Ill patients should avoid swimming, water activities, and sexual contact while symptomatic 1
• Rotavirus vaccination should be administered to all infants without contraindication 1
• Use gloves, gowns, and appropriate hand hygiene (soap and water preferred over alcohol for certain pathogens like C. difficile) in healthcare settings 1