What are the symptoms and treatment options for infectious diarrhea?

Infectious Diarrhea: Symptoms and Treatment

Clinical Presentation and Symptoms

Infectious diarrhea presents with distinct clinical patterns that guide management: acute watery diarrhea (most common, lasting 5-10 days), bloody diarrhea/dysentery (with fever, tenesmus, blood/pus in stool), or persistent diarrhea (≥14 days). 1, 2

Key symptoms to assess include:

• Stool characteristics: watery vs. bloody vs. mucoid, frequency, and volume 1
• Dehydration markers: thirst, tachycardia, orthostasis, decreased urination, lethargy, reduced skin turgor 1
• Systemic features: fever, abdominal pain, nausea, vomiting 1
• Dysenteric symptoms: fever, tenesmus, visible blood or pus in stool (suggests invasive pathogens like Shigella, Campylobacter, Salmonella) 1

Treatment Approach

Rehydration: The Cornerstone of Management

Oral rehydration solution (ORS) with reduced osmolarity is the first-line therapy for mild to moderate dehydration in all age groups, regardless of the infectious cause. 1, 3

Rehydration algorithm:

• Mild-moderate dehydration: Administer ORS orally until clinical dehydration corrects 1
• Moderate dehydration with poor oral tolerance: Consider nasogastric ORS administration in patients unable to drink adequately 1
• Severe dehydration, shock, or altered mental status: Initiate isotonic IV fluids (lactated Ringer's or normal saline) immediately 1
• Transition strategy: Continue IV fluids until pulse, perfusion, and mental status normalize, then complete rehydration with ORS 1
• Maintenance phase: Replace ongoing stool losses with ORS until diarrhea resolves 1

Nutritional Management

Continue age-appropriate feeding throughout the illness—do not withhold food. 1, 3

• Breastfed infants: Continue human milk feeding without interruption 1
• All patients: Resume normal diet during or immediately after rehydration 1
• Children 6 months-5 years in zinc-deficient regions: Administer oral zinc supplementation to reduce diarrhea duration 1, 3

Antimicrobial Therapy: When and What to Use

For most acute watery diarrhea without recent international travel, empiric antibiotics are NOT recommended. 1, 3

Indications for empiric antimicrobial therapy:

• Immunocompromised patients or ill-appearing young infants 1
• Fever ≥38.5°C with signs of sepsis 3
• Bloody diarrhea with presumptive shigellosis 3
• Recent international travelers with fever or severe illness 3
• Suspected enteric fever (treat empirically with broad-spectrum antibiotics after cultures) 1

Specific antimicrobial guidance:

• Ciprofloxacin is FDA-approved for infectious diarrhea caused by enterotoxigenic E. coli, Campylobacter jejuni, Shigella species, and Salmonella typhi 4
• Modify or discontinue antibiotics once a specific pathogen is identified 1
• CRITICAL CONTRAINDICATION: Avoid antibiotics in STEC O157 and Shiga toxin 2-producing E. coli infections due to increased risk of hemolytic uremic syndrome 1, 3

Adjunctive Therapies

Antimotility agents (loperamide):

• Absolutely contraindicated in children <18 years with acute diarrhea 1, 3
• May be used in immunocompetent adults with acute watery diarrhea 1
• Avoid in bloody diarrhea, fever, or suspected inflammatory diarrhea (risk of toxic megacolon) 1, 3

Antiemetics (ondansetron):

• May be given to children >4 years and adolescents to facilitate oral rehydration when vomiting is present 1, 3
• Use only after adequate hydration is initiated 1

Probiotics:

• May be offered to reduce symptom severity and duration in immunocompetent patients 1, 3

Critical Pitfalls to Avoid

Five dangerous errors in infectious diarrhea management:

1. Giving antimotility drugs to children or patients with bloody/febrile diarrhea (risk of toxic megacolon and prolonged infection) 1, 3

2. Using antibiotics for routine acute watery diarrhea (promotes resistance without benefit) 1, 3

3. Administering antibiotics for STEC infections (increases hemolytic uremic syndrome risk) 1, 3

4. Withholding food during illness (delays recovery and worsens nutritional status) 1, 3

5. Focusing on antibiotics while neglecting rehydration (dehydration kills, not the infection itself in most cases) 1, 3

Infection Control and Prevention

Hand hygiene is essential after toilet use, diaper changes, before/after food preparation, and after animal contact. 1, 3

• Healthcare settings require gloves, gowns, and appropriate hand hygiene (soap and water for certain pathogens like C. difficile) 1
• Asymptomatic contacts do not require treatment but must follow infection control measures 1
• Exception: Asymptomatic Salmonella Typhi carriers may be treated to reduce transmission 1, 3