What is the recommended management for a patient with persistent acute diarrhea lasting 10 days?

Management of 10-Day Diarrhea

For diarrhea lasting 10 days in an immunocompetent patient, obtain stool testing for bacterial pathogens (Salmonella, Shigella, Campylobacter, STEC) and parasites (especially Giardia), while prioritizing oral rehydration and avoiding empiric antibiotics unless specific high-risk features are present. 1

Initial Assessment Priorities

Hydration Status Evaluation

• Assess for dehydration immediately by examining mucous membrane moisture, skin turgor, mental status, capillary refill, urine output, tachycardia, and orthostatic vital signs. 1
• Severe dehydration (≥10% fluid deficit) with shock or near-shock requires immediate IV boluses of 20 mL/kg Ringer's lactate or normal saline until perfusion normalizes. 1
• Mild-to-moderate dehydration should be treated with oral rehydration solution (ORS) at 50-100 mL/kg over 2-4 hours, replacing ongoing losses with 10 mL/kg per watery stool. 1, 2

Key Clinical Features to Document

• Presence or absence of fever (temperature ≥38.5°C), bloody or mucoid stools, severe abdominal cramping, and tenesmus—these features distinguish invasive bacterial pathogens from viral or toxigenic causes. 1
• Recent antibiotic exposure within 8-12 weeks raises suspicion for Clostridioides difficile infection, even in community-acquired cases. 3, 4
• Travel history, day-care or long-term care facility exposure, food service work, immunocompromise, and recent hospitalization all warrant stool testing. 1

Diagnostic Testing at 10 Days

Indications for Stool Studies

At 10 days duration, stool testing is indicated because diarrhea persisting ≥7 days increases the likelihood of bacterial or parasitic etiology over self-limited viral illness. 1, 3

Order the following tests: 1

• Bacterial culture or PCR for Salmonella, Shigella, Campylobacter, and Yersinia
• Shiga toxin assay or PCR for STEC (including O157 and non-O157 serotypes)
• Ova and parasite examination or antigen testing for Giardia and Cryptosporidium
• C. difficile toxin testing if recent antibiotic use or healthcare exposure

When to Obtain Blood Cultures

• Obtain blood cultures if fever with signs of sepsis, infants <3 months of age, immunocompromise, hemolytic anemia, or travel to enteric fever-endemic areas. 1

Empiric Antibiotic Therapy: When to Treat Before Results

Do NOT Give Empiric Antibiotics If:

Empiric antibiotics are NOT recommended for watery, non-bloody diarrhea in immunocompetent adults without fever or severe illness—most cases are viral or toxigenic and self-limited. 1, 2, 5

DO Give Empiric Antibiotics If:

Consider empiric treatment ONLY in these specific scenarios: 1, 2

• Infants <3 months with suspected bacterial infection
• Fever, abdominal pain, and bloody diarrhea suggesting bacillary dysentery (Shigella)
• Recent international travel with fever ≥38.5°C or signs of sepsis
• Immunocompromised patients with severe illness

First-line empiric regimen for adults: azithromycin 500-1000 mg single dose, or ciprofloxacin 500-750 mg single dose (depending on local resistance patterns and travel history). 1, 5

For children: azithromycin or third-generation cephalosporin (for infants <3 months). 1

Empiric Treatment for Suspected Giardiasis

If stool testing is negative or unavailable and diarrhea persists 10-14 days with suggestive exposure history (travel, untreated water), empiric treatment for giardiasis is reasonable. 1

Antimotility Agents

Loperamide may reduce stool frequency in watery diarrhea but AVOID if bloody stools, high fever, or suspected invasive/inflammatory pathogen (risk of toxic megacolon or prolonged pathogen shedding). 2, 6, 7

Dietary Management

• Continue normal diet as tolerated; breast-fed infants should continue nursing on demand. 1
• For bottle-fed infants, use full-strength lactose-free or lactose-reduced formula immediately after rehydration; lactose-containing formula can be used under supervision. 1
• Older children and adults should eat starches, cereals, yogurt, fruits, and vegetables; avoid foods high in simple sugars and fats. 1

Reassessment Timeline and Non-Infectious Causes

At 14 Days (Persistent Diarrhea)

If symptoms persist beyond 14 days, expand testing to include parasites (Giardia, Cryptosporidium, Cyclospora) and consider non-infectious etiologies such as inflammatory bowel disease, microscopic colitis, or lactose intolerance. 1, 3, 2, 8

At 30 Days (Chronic Diarrhea)

Beyond 30 days, non-infectious causes become more likely: inflammatory bowel disease, irritable bowel syndrome, celiac disease, or medication-induced diarrhea. 1, 3

Common Pitfalls to Avoid

• Do NOT prescribe antibiotics for suspected STEC O157 or Shiga toxin 2-producing strains—this increases risk of hemolytic uremic syndrome. 1
• Do NOT overlook medication history: magnesium-containing agents, NSAIDs, antihypertensives, and antibiotics commonly cause diarrhea. 3
• Do NOT assume viral etiology at 10 days—viral gastroenteritis (norovirus, rotavirus) typically resolves within 2-7 days in immunocompetent adults. 3, 4
• Do NOT delay rehydration while awaiting test results—fluid and electrolyte replacement is the cornerstone of management regardless of etiology. 1, 2

Follow-Up and Return to Activities

• Follow-up stool testing after symptom resolution is NOT routinely needed for case management, except when required by local health authorities for food handlers, healthcare workers, or day-care attendees. 1
• Reassess fluid status, nutritional status, and antimicrobial therapy duration in patients with persistent symptoms. 1, 2