• Dehydration is the primary cause of morbidity and mortality; thus, treatment goals include prevention of dehydration, treatment of dehydration when present, and reduction of the severity and duration of symptoms
• Oral rehydration therapy (ORT) encompasses 2 phases of treatment:
  • Rehydration phase: Electrolytes and water are administered as oral rehydration solution (ORS) to replenish fluid losses
    • Should be performed rapidly within 3-4 hours
  • Maintenance phase: Restoration of ongoing fluid and electrolyte losses, and adequate dietary intake
    • Continued until resolution of symptoms
• Age-appropriate diet (including solids) for rapid realimentation is recommended once adequate degree of hydration is attained
• Breastfeeding should be continued especially for breastfed patients
• Changes in formula milk or avoidance of milk-based products is not necessary

Oral Rehydration Solutions (ORS)

• The formula recommended by the World Health Organization (WHO)
  • Concentration of 75 mEq/L sodium, 75 mmol/L glucose with total osmolarity of 245 mOsm/L, or ½ teaspoon of salt and 6 teaspoons of sugar in 1 L of water 
  • Lower osmolarity that is proportionally reduced sodium and glucose concentrations
  • The formulation has been shown to reduce vomiting and the need for IV fluids
• The WHO-recommended amount to be given based on weight and age are as follows:

• 1st-line treatment for patients with acute diarrhea accompanied by mild-moderate dehydration
• May also be considered in mild-moderately dehydrated patients with vomiting or severe diarrhea
• Severe vomiting, abdominal ileus, altered mental status, gastrointestinal disease with absorption concerns, and in state of hemodynamic shock are contraindications to oral rehydration solutions

Intravenous (IV) Fluids or Nasogastric (NG) Oral Rehydration Solutions (ORS)

• Given for 4-6 hours or until adequate hydration is achieved
• IV fluids are recommended in the following patients:
  • Severely dehydrated
  • In whom oral hydration has failed due to severe vomiting or excessive stool output
  • Patients in shock or altered mental status
  • Patients with intestinal ileus or intestinal obstruction
• Nasogastric ORS may be given to moderately dehydrated patients who cannot tolerate oral administration of ORS and to children who are too weak and refuse to drink that may cause insufficient hydration if only by oral intake 
• Nasogastric feeding allows continuous oral rehydration solutions administration at a slow and steady amount
• Rehydrated state should be maintained by continuous replacement of losses

Mild Dehydration

• Administer 50-100 mL of ORS to children <2 years old, 100-200 mL to children 2-10 years old, or unlimited amounts for children >10 years old, after each loose stool, or 20 mL/kg body weight/hour to replace estimated fluid deficit
• Several trials support the use of nasogastric oral rehydration solutions feeding even in patients with continuous vomiting or with presence of oral ulcers
• Continue breastfeeding or resume age-appropriate feeding
• Rapid IV hydration may also be administered

Moderate to Severe Dehydration

• Start patient on rapid IV rehydration
• Administer 20 mL/kg body weight of IV lactated Ringer’s solution or normal saline solution (0.9% NaCl) until pulse, perfusion and mental status return to normal, followed by 100 mL/kg body weight of oral rehydration solution for 4 hours or 5% dextrose ½ normal saline IV at 2x maintenance fluid rates
  • Alternatively, give 100 mL/kg body weight. Then, for infants <1 year give 30 mL/kg/body weight within the 1st hour, followed by 70 mL/kg/body weight within 5 hours. For children >1 year, 30 mL/kg/body weight IV fluid may be given within the 1st 30 minutes, followed by 70 mL/kg/body weight within 2.5 hours
  • Administration of oral rehydration solutions may encourage early resumption of feeding
  • Study shows that giving of oral rehydration solutions may lead to rapid resolution of acidosis compared to IV fluid