What is the approach and management for a patient presenting with severe diarrhea?

Severe Diarrhea: Approach and Management

The immediate priority in severe diarrhea is aggressive rehydration with intravenous isotonic fluids (lactated Ringer's or normal saline) until pulse, perfusion, and mental status normalize, followed by transition to oral rehydration solution (ORS) to complete fluid replacement. 1

Initial Assessment and Stabilization

Assess hydration status immediately by evaluating pulse quality, perfusion, mental status, and vital signs. 1

Severe Dehydration (≥10% fluid deficit, shock, or near shock):

• Administer IV boluses of 20 mL/kg of lactated Ringer's or normal saline until pulse, perfusion, and mental status return to normal 1
• This may require two IV lines or alternate access sites (venous cutdown, femoral vein, intraosseous infusion) 1
• Continue IV rehydration until the patient awakens, has no aspiration risk, and has no evidence of ileus 1
• Once mental status normalizes, transition to ORS for remaining fluid deficit replacement 1

Moderate Dehydration (6-9% fluid deficit):

• Administer 100 mL/kg of ORS over 2-4 hours 1
• Nasogastric administration may be considered if oral intake is not tolerated 1, 2

Diagnostic Evaluation

Reserve diagnostic workup for specific high-risk scenarios rather than routine testing: 2, 3

• Severe dehydration or illness requiring hospitalization
• Persistent fever documented in medical setting
• Bloody or mucoid stools
• Immunocompromised patients
• Suspected nosocomial infection
• Signs of sepsis

When indicated, obtain: 1

• Complete blood count
• Electrolyte profile (particularly potassium, as hypokalemia is highly prevalent and often undertreated) 4
• Stool evaluation for blood, C. difficile, Salmonella, E. coli, Campylobacter

Antimicrobial Therapy: When to Treat

In most patients with acute watery diarrhea without recent international travel, empiric antimicrobial therapy is NOT recommended. 1, 2

Exceptions for Empiric Treatment:

For bloody diarrhea, empiric antibiotics are indicated ONLY in: 1

• Infants <3 months of age with suspected bacterial etiology
• Ill patients with fever documented in medical setting, abdominal pain, and bacillary dysentery (frequent scant bloody stools, fever, cramps, tenesmus) presumptively due to Shigella
• Recent international travelers with temperature ≥38.5°C and/or signs of sepsis
• Immunocompromised patients with severe illness and bloody diarrhea

Empiric antibiotic choices: 1

• Adults: Fluoroquinolone (ciprofloxacin) OR azithromycin, depending on local susceptibility patterns and travel history
• Children: Third-generation cephalosporin for infants <3 months or those with neurologic involvement; azithromycin based on local patterns and travel history

Critical Contraindication:

AVOID antimicrobials in STEC O157 and other STEC producing Shiga toxin 2 due to increased risk of hemolytic uremic syndrome 1, 2

Ongoing Fluid Replacement

Replace ongoing stool losses with ORS: 1

• 10 mL/kg for each watery or loose stool
• 2 mL/kg for each episode of emesis
• Continue until diarrhea and vomiting resolve

Nutritional Management

Continue breastfeeding throughout the diarrheal episode in infants 1, 2

Resume age-appropriate usual diet immediately after or during rehydration 1, 2

• Full-strength, lactose-free or lactose-reduced formulas for bottle-fed infants 1
• Older children: starches, cereals, yogurt, fruits, vegetables 1
• Avoid foods high in simple sugars and fats 1

Zinc supplementation (20 mg daily for 10-14 days) reduces diarrhea duration in children 6 months to 5 years in areas with high zinc deficiency prevalence 1, 2

Adjunctive Therapies: Use With Caution

Antimotility agents are NOT a substitute for fluid and electrolyte therapy and should only be considered after adequate hydration 1, 2

Loperamide:

• ABSOLUTE CONTRAINDICATIONS: 1, 2, 5
  • Children <18 years of age
  • Bloody diarrhea or fever
  • Suspected inflammatory diarrhea or toxic megacolon risk
• May be given to immunocompetent adults with acute watery diarrhea: 4 mg initially, then 2 mg after each loose stool (maximum 16 mg/day) 1, 2
• Use caution with CYP3A4 inhibitors, CYP2C8 inhibitors, or P-glycoprotein inhibitors due to increased cardiac risk 5

Antiemetics:

Ondansetron may be given to children >4 years and adolescents with vomiting to facilitate oral rehydration tolerance 1, 2

Probiotics:

May be offered to reduce symptom severity and duration in immunocompetent patients with infectious or antimicrobial-associated diarrhea 1, 2

Special Populations

Cancer Patients with Complicated Diarrhea:

Hospitalize and treat aggressively if: 1

• Sepsis, neutropenia, bleeding, or severe dehydration present
• Administer IV fluids, octreotide (100-150 mcg SC tid or 25-50 mcg/h IV), and empiric antibiotics (fluoroquinolone)
• Evaluate for neutropenic enterocolitis if neutropenic

Persistent Symptoms (≥14 days):

Reassess for: 1

• Noninfectious conditions (inflammatory bowel disease, irritable bowel syndrome, lactose intolerance)
• Fluid and electrolyte balance
• Nutritional status
• Optimal antimicrobial dose and duration if treating

Critical Pitfalls to Avoid

• Do NOT use commercial sports drinks, juices, or soft drinks for rehydration - inappropriate electrolyte composition 2, 6
• Do NOT treat asymptomatic contacts - advise infection control measures instead 1, 2
• Do NOT use antimotility agents in children or with bloody/febrile diarrhea - risk of complications 1, 2
• Do NOT give antibiotics for STEC infections - increases hemolytic uremic syndrome risk 1, 2
• Monitor potassium levels closely - hypokalemia is highly prevalent and frequently undertreated with standard WHO protocols 4