What is the best treatment for acute diarrhea?

Treatment of Acute Diarrhea (Loose Stool)

The best treatment for loose stool is oral rehydration solution (ORS) containing 50-90 mEq/L sodium, combined with continued normal diet—this approach prevents dehydration while maintaining nutrition and is safer and more effective than intravenous therapy for most patients. 1, 2

Immediate Assessment of Hydration Status

Evaluate dehydration severity by checking for:

• Mild dehydration (3-5% deficit): Increased thirst, slightly dry mucous membranes 1, 2
• Moderate dehydration (6-9% deficit): Loss of skin turgor, dry mucous membranes, decreased urine output, prolonged capillary refill 1, 3
• Severe dehydration (≥10% deficit): Shock, altered mental status, cool extremities, rapid deep breathing—this is a medical emergency requiring immediate IV fluids 1

Obtain body weight as the most reliable indicator of fluid deficit 2

Rehydration Protocol Based on Severity

For Mild Dehydration (or No Dehydration)

• Administer ORS at 50 mL/kg over 2-4 hours 1, 2
• Use small volumes initially (one teaspoon every 1-2 minutes) via spoon, syringe, or medicine dropper, then gradually increase as tolerated 1
• Common pitfall: Allowing patients to drink large volumes rapidly from a cup increases vomiting—always give small, frequent amounts 1

For Moderate Dehydration

• Increase ORS to 100 mL/kg over 2-4 hours using the same gradual administration technique 1, 3
• Reassess hydration status after 2-4 hours; if still dehydrated, reestimate deficit and restart therapy 1, 3

For Severe Dehydration

• Initiate IV boluses of 20 mL/kg lactated Ringer's or normal saline until pulse, perfusion, and mental status normalize 1
• Once mental status improves, switch to ORS for remaining deficit replacement 1

Replace Ongoing Losses

Throughout treatment, replace continuing losses with:

• 10 mL/kg ORS for each watery stool 1, 2
• 2 mL/kg ORS for each vomiting episode 1, 2

This replacement continues until diarrhea and vomiting resolve 1

Nutritional Management

Continue normal diet immediately—do not practice "gut rest" as fasting reduces intestinal cell renewal and worsens outcomes 1

• For breastfed infants: Continue nursing on demand throughout illness 1, 3
• For bottle-fed infants: Use full-strength, lactose-free or lactose-reduced formulas immediately after rehydration 1, 3
• For older children and adults: Resume age-appropriate usual diet during or immediately after rehydration with easily digestible foods including starches, cereals, fruits, and vegetables 1, 2
• Avoid foods high in simple sugars and fats which worsen osmotic diarrhea 2

When to Consider Antibiotics

Empiric antibiotics are indicated when:

• Bloody diarrhea with high fever (suggests invasive bacterial infection) 1, 2
• Watery diarrhea persisting >5 days 2
• Clinical features of sepsis or suspected enteric fever 1
• Immunocompromised patients with severe illness 1

Do not use antibiotics for suspected STEC O157 or Shiga toxin-producing E. coli as this increases risk of hemolytic uremic syndrome 1

Role of Antimotility Agents

Loperamide should NOT be given to children <18 years of age due to risks of respiratory depression and cardiac adverse reactions 1, 4

For immunocompetent adults with watery (non-bloody) diarrhea:

• Loperamide may be considered only after adequate hydration and only if bloody diarrhea, C. difficile, and infectious colitis are ruled out 1, 4
• Avoid in elderly patients without excluding infectious causes, as complications can be serious 2

Critical Pitfalls to Avoid

• Do not delay ORS while awaiting diagnostic tests—start rehydration immediately 2
• Do not use antidiarrheal agents empirically without excluding infectious colitis, bloody diarrhea, or C. difficile 2, 4
• Do not allow rapid, large-volume drinking in vomiting patients—this worsens symptoms and leads to ORS failure 1
• Do not practice fasting or "gut rest"—continued feeding improves intestinal recovery 1
• Do not overlook medication-induced diarrhea—review all current medications including recent antibiotics and antacids 2

When Oral Rehydration Fails

Consider IV therapy or nasogastric ORS administration if:

• Patient cannot tolerate oral intake despite small-volume technique 1, 3
• Progression to severe dehydration or shock 1, 3
• Altered mental status or intestinal ileus 1
• True glucose malabsorption (dramatic increase in stool output with ORS administration, not just presence of reducing substances in stool) 1

Over 90% of patients with vomiting can be successfully rehydrated orally when proper small-volume technique is used 1