What is the recommended management of acute non‑bloody diarrhea, including assessment of dehydration, fluid replacement, oral rehydration solution, diet, anti‑motility agents, antibiotics, zinc supplementation, and probiotics?

Management of Acute Non-Bloody Diarrhea

Oral rehydration solution (ORS) with 75-90 mEq/L sodium is the cornerstone of treatment for acute non-bloody diarrhea, and antibiotics should not be given in immunocompetent patients without recent international travel. 1

Assessment of Dehydration Severity

Categorize fluid deficit by clinical examination before initiating therapy:

• Mild dehydration (3-5% deficit): Slightly dry mucous membranes, increased thirst, normal mental status, and normal skin turgor 1
• Moderate dehydration (6-9% deficit): Dry mucous membranes, sunken eyes, loss of skin turgor with tenting when pinched, and reduced urine output 1
• Severe dehydration (≥10% deficit): Severe lethargy or altered consciousness, prolonged skin tenting (>2 seconds), cool and poorly perfused extremities, decreased capillary refill, and rapid deep breathing indicating acidosis 1

Prolonged skin retraction time, decreased perfusion, and rapid deep breathing are more reliable predictors than sunken fontanelle or absent tears. 1 Measure body weight to quantify deficit and monitor response. 1

Fluid Replacement Protocol

Mild Dehydration (3-5% deficit)

• Administer 50 mL/kg of ORS containing 50-90 mEq/L sodium over 2-4 hours 1
• Use small volumes initially (5 mL every 1-2 minutes with a teaspoon or syringe), then gradually increase as tolerated 1
• Reassess hydration status after 2-4 hours 1

Moderate Dehydration (6-9% deficit)

• Administer 100 mL/kg of ORS over 2-4 hours using the same small-volume technique 1
• For vomiting patients, give 5-10 mL every 1-2 minutes to avoid perpetuating emesis 1
• Nasogastric administration may be used if oral intake fails despite proper technique 1

Severe Dehydration (≥10% deficit)

• Immediate intravenous rehydration is mandatory 1
• Administer 20 mL/kg boluses of Ringer's lactate or normal saline until pulse, perfusion, and mental status normalize 1
• This may require two IV lines or alternate access (venous cutdown, femoral vein, intraosseous) 1
• Once consciousness returns, complete the remaining deficit with ORS 1

Replacement of Ongoing Losses

After initial rehydration, replace continuing losses:

• 10 mL/kg of ORS for each watery stool 1
• 2 mL/kg of ORS for each vomiting episode 1
• Continue maintenance fluids until diarrhea and vomiting resolve 1

Nutritional Management

Resume age-appropriate diet during or immediately after rehydration is completed—do not delay feeding. 1

• Breastfeeding must continue uninterrupted throughout the illness 1
• Bottle-fed infants should resume full-strength formula immediately upon rehydration 1
• Older children should eat starches, cereals, yogurt, fruits, and vegetables 1
• Avoid foods high in simple sugars and fats, which can worsen symptoms 1

Early feeding is safer and more effective than delayed feeding, promoting intestinal cell renewal and preventing nutritional deterioration. 1

Anti-Motility Agents

Loperamide and diphenoxylate-atropine are absolutely contraindicated in all children under 18 years of age. 1, 2

• In immunocompetent adults with acute watery diarrhea, loperamide may be given cautiously only after adequate hydration 1
• Never use antimotility agents when fever, bloody diarrhea, or inflammatory features are present, as they can precipitate toxic megacolon 2
• Antimotility drugs are not a substitute for fluid and electrolyte therapy 1

Antibiotic Therapy

Antibiotics are NOT indicated for typical acute watery diarrhea in immunocompetent patients without recent international travel. 1

Exceptions requiring empiric antibiotics:

• Immunocompromised patients or young infants who appear severely ill 1
• Clinical features of sepsis or suspected enteric fever 1
• Dysentery (bloody diarrhea) 1
• High fever with watery diarrhea persisting >5 days 1

When antibiotics are indicated, azithromycin is the preferred empiric agent for dysentery. 1 Never give antibiotics to patients with suspected STEC O157 or Shiga toxin-producing E. coli, as this increases the risk of hemolytic uremic syndrome. 1

Zinc Supplementation

Zinc supplementation (10-20 mg daily for 10-14 days) reduces diarrhea duration and severity in children 6 months to 5 years of age who reside in countries with high zinc deficiency prevalence or show signs of malnutrition. 3

• Zinc reduces the probability of continuing diarrhea by 15% in acute diarrhea and 24% in persistent diarrhea 3
• In persistent diarrhea, zinc reduces treatment failure or death by 42% 3
• Canadian and other well-nourished children eating a regular diet do not require zinc supplementation 4

The therapeutic benefit is greatest in malnourished children, those under 12 months, males, and those with low baseline plasma zinc. 3

Probiotics

Probiotic preparations may be offered to reduce symptom severity and duration in immunocompetent children with infectious diarrhea, though this is a weak recommendation. 1

Common Pitfalls to Avoid

• Do not use sports drinks, fruit juices, or soft drinks for rehydration—they lack adequate sodium and have excessive osmolality 1
• Do not allow a thirsty child to drink large volumes of ORS ad libitum—this worsens vomiting 1
• Do not delay rehydration while awaiting stool culture results—initiate ORS immediately 1
• Do not restrict diet during or after rehydration—early feeding improves outcomes 1
• Do not prescribe antibiotics empirically for uncomplicated watery diarrhea—this promotes resistance without benefit 1
• Do not treat asymptomatic contacts—provide infection-control counseling instead 1