What is the best way to treat dehydration?

Treatment of Dehydration

Oral rehydration solution (ORS) containing 50-90 mEq/L of sodium is the first-line treatment for mild to moderate dehydration, while severe dehydration (≥10% fluid deficit) requires immediate intravenous rehydration with isotonic fluids such as Ringer's lactate or normal saline. 1

Assessment of Dehydration Severity

Before initiating treatment, determine the degree of dehydration through physical examination:

• Mild dehydration (3-5% fluid deficit): Increased thirst and slightly dry mucous membranes 1
• Moderate dehydration (6-9% fluid deficit): Loss of skin turgor, dry mucous membranes, and decreased urine output 2
• Severe dehydration (≥10% fluid deficit): Severe lethargy or altered consciousness, prolonged skin tenting, and signs of shock 1

The most reliable clinical indicators are rapid deep breathing, prolonged skin retraction time, decreased perfusion, and capillary refill time (though fever, ambient temperature, and age can affect this measurement). 1

Treatment Based on Severity

Mild Dehydration (3-5% fluid deficit)

Administer ORS containing 50-90 mEq/L of sodium at 50 mL/kg over 2-4 hours. 1 Start with small volumes using a teaspoon, syringe, or medicine dropper, then gradually increase as tolerated. 2

Age-specific ongoing replacement for stool losses:

• Children <2 years: 50-100 mL of ORS after each stool 3, 2
• Older children: 100-200 mL after each stool 3, 2
• Adults: As much as they want, though those failing to respond promptly should be reassessed to exclude cholera 3, 2

Moderate Dehydration (6-9% fluid deficit)

Administer ORS containing 50-90 mEq/L of sodium at 100 mL/kg over 2-4 hours. 2 This is the same solution as mild dehydration but with increased volume. 1

Replace ongoing losses: Give 10 mL/kg of ORS for each diarrheal stool and 2 mL/kg for each episode of emesis. 2 For infants <10 kg, provide 60-120 mL ORS for each diarrheal stool or vomiting episode, up to approximately 500 mL/day. 2

Reassess hydration status after 2-4 hours: If still dehydrated, reestimate the fluid deficit and restart rehydration therapy. 2 Continue monitoring until corrected, then periodically alongside excellent support for drinking. 3

For infants unable to drink but not in shock: Use a nasogastric tube to administer ORS at 15 mL/kg body weight/hour. 3, 2

Severe Dehydration (≥10% fluid deficit)

This constitutes a medical emergency requiring immediate IV rehydration with boluses of Ringer's lactate solution or normal saline at 60-100 mL/kg in the first 2-4 hours to restore circulation. 1, 4 Once circulation is restored, transition to ORS given in small quantities to replace losses over 6-8 hours. 4

For oliguric patients with severe acidosis: Administer a physiological dose of bicarbonate to correct blood pH to 7.25. 4

Commercial ORS Products in the United States

The most widely used solutions are Pedialyte (45 mEq/L sodium) and Ricelyte (50 mEq/L sodium), which are intended for maintenance and prevention of dehydration. 3 While solutions with 75-90 mEq/L sodium are preferable for rehydration, Pedialyte and Ricelyte can be used when the alternative is physiologically inappropriate liquids or IV fluids. 3

When purging rate is very high (>10 mL/kg/hour): Solutions with 75-90 mEq/L sodium are recommended for rehydration. 3

When using fluids with >60 mEq/L sodium for maintenance: Also administer other low-sodium fluids such as breast milk, diluted or undiluted infant formula, or water to prevent sodium overload. 3

Nutritional Management During Rehydration

Breast-fed infants should continue nursing on demand throughout the illness. 1, 2 Bottle-fed infants should receive full-strength, lactose-free, or lactose-reduced formulas immediately upon rehydration. 1, 2

For children >4-6 months and adults: Begin feeding as soon as appetite returns with energy-rich, easily digestible foods. 3, 2 Offer food every 3-4 hours or more often for very young children. 3 There is no justification for "resting the bowel" through fasting. 3, 1

Give freshly prepared foods including mixes of cereal and beans or cereal and meat, with a few drops of vegetable oil added. 3

Special Considerations for Older Adults

For older adults with measured serum osmolality >300 mOsm/kg who appear well: Encourage increased fluid intake in the form of drinks preferred by the older adult, such as hot or iced tea, coffee, fruit juice, sparkling water, carbonated beverages, lager, or water. 3 Oral rehydration therapy (designed for diarrhea/vomiting) and sports drinks are NOT indicated for low-intake dehydration. 3

For older adults with osmolality >300 mOsm/kg who appear unwell: Offer subcutaneous or intravenous fluids in parallel with encouraging oral intake. 3 Appropriate volumes of subcutaneous dextrose infusions (half-normal saline-glucose 5%, 40 g/L dextrose and 30 mmol/L NaCl, or 5% dextrose solution and 4 g/L NaCl) can be used effectively with similar rates of adverse effects to intravenous infusion. 3

For older adults unable to drink: Intravenous fluids should be considered, particularly when severe dehydration exists or greater fluid volumes are needed. 3

Critical Pitfalls to Avoid

Do not use soft drinks for rehydration due to their high osmolality. 3, 1

Anti-diarrheal agents are contraindicated for the treatment of diarrheal disease. 3, 1 Loperamide should not be used when dehydration is present, as fluid and electrolyte depletion often occur in patients with diarrhea, and the use of loperamide does not preclude the need for appropriate fluid and electrolyte therapy. 5

Antimicrobial drugs are contraindicated for routine treatment of uncomplicated watery diarrhea, with specific indications limited to cholera, Shigella dysentery, amoebic dysentery, and acute giardiasis. 3

Monitor closely for failure of oral therapy: Switch to intravenous fluids if there is progression to severe dehydration, shock, altered mental status, or failure of ORS therapy. 2