What is the treatment for acute diarrhea?

Treatment of Acute Diarrhea

The cornerstone of acute diarrhea management is oral rehydration therapy (ORT) with reduced-osmolarity oral rehydration solution (ORS) as first-line treatment for mild to moderate dehydration, while reserving intravenous fluids for severe dehydration or shock, and antimicrobial therapy should be avoided in most cases of watery diarrhea unless specific high-risk conditions exist. 1

Initial Assessment

Assess dehydration severity clinically to guide treatment intensity:

• Mild dehydration (3-5% fluid deficit): Increased thirst, slightly dry mucous membranes 1
• Moderate dehydration (6-9% fluid deficit): Loss of skin turgor, skin tenting when pinched, dry mucous membranes 1, 2
• Severe dehydration (≥10% fluid deficit): Severe lethargy or altered consciousness, prolonged skin tenting (>2 seconds), cool and poorly perfused extremities, decreased capillary refill, rapid deep breathing indicating acidosis 1

Most reliable clinical indicators are rapid deep breathing, prolonged skin retraction time, and decreased perfusion—more predictive than sunken fontanelle or absent tears 1. Weigh the patient to establish baseline for monitoring 2.

Stool examination should confirm abnormal consistency and identify blood or mucus, which indicates invasive/dysenteric diarrhea requiring different management 1.

Rehydration Protocol Based on Severity

Mild Dehydration (3-5% deficit)

Administer 50 mL/kg of ORS containing 50-90 mEq/L sodium over 2-4 hours 1, 2:

• Start with small volumes (one teaspoon) using a teaspoon, syringe, or medicine dropper 1, 2
• Gradually increase amount as tolerated 1
• Reassess hydration status after 2-4 hours 1, 2
• If rehydrated, progress to maintenance phase; if still dehydrated, reestimate deficit and restart rehydration 1, 2

Moderate Dehydration (6-9% deficit)

Administer 100 mL/kg of ORS over 2-4 hours using the same gradual approach 1, 2. This higher volume accounts for the greater fluid deficit while maintaining the same sodium concentration and administration technique 2.

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

This constitutes a medical emergency requiring immediate intravenous rehydration 1:

• Administer boluses of 20 mL/kg of Ringer's lactate or normal saline 1
• Continue IV fluids until pulse, perfusion, and mental status normalize 1
• Once patient awakens with no aspiration risk and no ileus, transition remaining deficit replacement to ORS 1

Critical caveat: For patients with vomiting, do not allow ad libitum drinking from cup or bottle—this common mistake worsens vomiting 1. Instead, administer small volumes (5-10 mL) every 1-2 minutes via spoon or syringe, gradually increasing as tolerated 1. Greater than 90% of vomiting patients can be successfully rehydrated orally with this technique 1.

Maintenance Phase and Ongoing Loss Replacement

Once rehydration is achieved:

Replace ongoing losses with ORS until diarrhea and vomiting resolve 1:

• 10 mL/kg of ORS for each diarrheal stool 2
• 2 mL/kg of ORS for each vomiting episode 2
• For infants <10 kg: provide 60-120 mL ORS per diarrheal stool or vomiting episode, up to approximately 500 mL/day 2

Nutritional Management

Continue breastfeeding on demand throughout the diarrheal episode 1, 2. This is critical and should never be interrupted 1.

Resume age-appropriate usual diet immediately after rehydration is completed 1. For bottle-fed infants, administer full-strength formula (lactose-free or lactose-reduced formulations are acceptable) 2. Early refeeding improves outcomes and does not prolong diarrhea 1.

When Antimicrobials Are NOT Indicated

In most patients with acute watery diarrhea without recent international travel, empiric antimicrobial therapy is not recommended 1. This is a strong recommendation because:

• Most acute watery diarrhea is viral and self-limited 1
• Antibiotics provide no benefit for viral causes 3
• For STEC O157 and other STEC producing Shiga toxin 2, antimicrobials should be avoided as they increase risk of hemolytic uremic syndrome 1

When Antimicrobials ARE Indicated

Consider empiric antimicrobial therapy only in these specific situations:

• Dysentery (bloody diarrhea): Likely bacterial (especially Shigella) requiring antibiotics 1, 3
• Immunocompromised patients or young infants who are ill-appearing 1
• Clinical features of sepsis with suspected enteric fever: Treat empirically with broad-spectrum therapy after cultures, then narrow based on susceptibilities 1

Asymptomatic contacts should never receive empiric or preventive antimicrobial therapy 1.

Ancillary Medications

Antimotility agents (e.g., loperamide) can be considered once the patient is rehydrated 1, but with important restrictions:

• Contraindicated in children <2 years of age due to risks of respiratory depression and serious cardiac adverse reactions including cardiac arrest 4
• Avoid in bloody diarrhea or when inhibition of peristalsis could cause complications (ileus, toxic megacolon) 4
• Avoid doses higher than recommended due to risk of QT prolongation, Torsades de Pointes, and sudden death 4
• Avoid in combination with QT-prolonging drugs or in patients with cardiac risk factors 4

Loperamide is FDA-approved for symptomatic relief in patients ≥2 years of age but does not address the underlying cause or prevent dehydration 4.

Laboratory Testing

Stool cultures are indicated for dysentery (bloody diarrhea) but not needed for typical acute watery diarrhea in immunocompetent patients 1. Serum electrolytes should be measured only when clinical signs suggest abnormal sodium or potassium concentrations 1. Most cases do not require laboratory investigations 5, 6.

Common Pitfalls to Avoid

• Do not withhold ORT due to high stool output: Even patients purging >10 mL/kg/hour can usually be managed with adequate oral replacement 1
• Do not use medications, inappropriate home remedies, or withhold feeding 1
• Do not confuse presence of reducing substances in stool with glucose malabsorption: This is common in diarrhea and does not indicate ORT failure unless accompanied by dramatic increase in stool output with ORS administration 1
• Do not use standard ORS for hypernatremic dehydration: These patients require different management with slower correction rates 7