What are the guidelines for using oral rehydration solution (ORS) in hospitalized adults with diarrhea?

Guidelines for ORS Use in Hospitalized Adults with Diarrhea

Oral rehydration solution (ORS) is recommended as first-line therapy for hospitalized adults with mild to moderate dehydration from acute diarrhea, with intravenous fluids reserved only for severe dehydration, shock, altered mental status, or ORS failure. 1

Rehydration Protocol for Hospitalized Adults

Initial Assessment and ORS Administration

For mild to moderate dehydration (characterized by decreased skin turgor, dry mucous membranes, sunken eyes, decreased urine output):

• Administer 2-4 liters of reduced osmolarity ORS over 3-4 hours 1
• Use low-osmolarity formulations (<250 mmol/L) such as Pedialyte Liters, CeraLyte, or Enfalac Lytren 1, 2
• Do not use apple juice, Gatorade, or commercial soft drinks for rehydration 1, 2

Ongoing Loss Replacement

After initial rehydration, replace continuing losses:

• Ad libitum ORS up to ~2 L/day for adults 1
• Continue replacement as long as diarrhea or vomiting persists 1

When to Switch to IV Fluids

Immediately transition to intravenous isotonic crystalloid (lactated Ringer's or normal saline) if any of the following develop: 1, 2

• Severe dehydration (≥10% fluid deficit with altered mental status, shock, poor perfusion)
• Inability to tolerate oral intake despite nasogastric administration
• Ileus
• Failure of ORS therapy after adequate trial

Administer IV boluses of up to 20 mL/kg body weight until pulse, perfusion, and mental status normalize, then transition back to ORS for maintenance 1

Special Considerations for Hospitalized Patients

Nasogastric ORS Administration

Consider nasogastric tube administration in adults with moderate dehydration who cannot tolerate oral intake but have normal mental status 1, 3

Ketonemia

In patients with ketonemia, an initial course of intravenous hydration may be needed to enable tolerance of oral rehydration 1

Electrolyte Abnormalities

• Low-osmolarity ORS is safe in both hypernatremia and hyponatremia (except when edema is present) 1
• The risk of symptomatic hyponatremia with reduced osmolarity ORS is minimal (0.05% incidence) and actually lower than with older formulations 4

Nutritional Management During Hospitalization

• Resume age-appropriate diet immediately during or after rehydration—do not withhold food 3, 2, 5
• Early realimentation prevents malnutrition and may reduce stool output 3

Antimicrobial Decisions

Do not prescribe empiric antibiotics for typical acute watery diarrhea without red flags 3, 2, 5

Consider antibiotics only if:

• Fever ≥38.5°C with clinical signs of sepsis 3, 5
• Bloody diarrhea with severe illness 3, 2
• Immunocompromised state with severe symptoms 3, 2

Never use antibiotics if STEC (Shiga toxin-producing E. coli) infection is suspected, as this increases hemolytic uremic syndrome risk by up to 50% 2, 5

Adjunctive Therapies

Probiotics

• May be offered to reduce symptom severity and duration (reduces diarrhea by approximately 25 hours) 3, 2
• Use only in immunocompetent patients 3

Antimotility Agents

Loperamide is contraindicated if: 3, 2, 5

• Patient has bloody diarrhea or fever
• Inflammatory diarrhea is suspected
• STEC infection is possible

Common Pitfalls to Avoid

• Do not default to IV fluids for mild-to-moderate dehydration—ORS is equally effective and avoids IV complications 2
• Do not withhold ORS in favor of immediate IV access unless severe dehydration criteria are met 1, 2
• Do not use sports drinks or juice for rehydration—incorrect osmolarity worsens electrolyte imbalances 2
• Do not prescribe antibiotics empirically for simple watery diarrhea—this increases resistance and may worsen STEC infections 2, 5

Discharge Criteria

Patients can be discharged when: 2

• Dehydration is successfully corrected with ORS
• Patient tolerates oral intake
• Reliable follow-up is available