Strategies for Diagnosing and Treating Dehydration in Children

From Medscape Medical News CME
Laurie Barclay , Désirée Lie,

10/16/2009

Clinical Context

Fluid and electrolyte disturbances form diarrhea and vomiting result in 1.5 million patient visits yearly in the US and 300 deaths. Several methods are available to assess hydration and the need for rehydration and hospital admission in children.

This is a review of the clinical assessment of dehydration in children with diarrhea and vomiting and recommended strategies for rehydration at home, in the office, and in the hospital.


Study Highlights

Parental report of vomiting, diarrhea, and reduced oral intake is sensitive but not specific for identifying dehydration in children.
If tear production is normal, then the chance of dehydration is low.
The most useful individual physical signs are prolonged capillary filing time, abnormal skin turgor, and abnormal respiratory pattern.
The use of scales based on combinations of physical examination findings is better than individual clinical signs.
4 factors predict dehydration: capillary refill time of more than 2 seconds, absence of tears, dry mucous membranes, and ill appearance.
The presence of 2 or more of these suggests dehydration of at least 5%. General appearance, degree of sunken eyes, dry mucous membranes, and reduced tear production are associated with length of hospital stay and the need for intravenous fluids in children.

Capillary refill time is performed at ambient room temperature on the sternum of infants and a finger or arm at the level of the heart in older children.
Skin turgor is performed by pinching the skin on the lateral abdominal wall at the umbilical level.
The ratio of serum urea nitrogen to creatinine, serum urea nitrogen alone, and urine specific gravity have poor sensitivity and specificity in children.
Serum bicarbonate levels less than 17 mEq/L may improve sensitivity of identifying hypovolemia, but levels less than 13 mEq/L are associated with poorer hydration and recovery with rehydration.

The American Academy of Pediatrics recommends ORT as the preferred treatment of fluid and electrolyte losses in children with mild to moderate dehydration with similar success as intravenous fluid replacement.
The same ORT can be used for replacement, maintenance, and rehydration.
ORT is contraindicated in abdominal ileus, altered mental status, or intestinal malabsorption.

Nasogastric rehydration with ORT is an alternative to intravenous rehydration.
As soon as rehydration is completed, children can return to an age-appropriate diet.
World Health Organization ORT contains 90 mEq/L of sodium vs 50 mEq for commercial ORT preparations, which also contain 25 g/L of dextrose and 30 mEq/L of bicarbonate, and they are recommended vs homemade solutions to reduce preparation errors.
For mild dehydration, 50 mL/kg of ORT solution should be administered with a spoon, syringe, or medicine cup by giving 1 mL/kg to the child every 5 minutes.
The Holliday-Segar method involves a rule of 1 oz per hour for infants, 2 oz per hour for toddlers, and 3 oz per hour for older children.
To replace ongoing losses, 10 mL/kg for every loose stool and 2 mL/kg for every emetic episode should be given.

For moderate dehydration, 100 mL/kg of ORT should be given for 4 hours in the office or emergency department; if treatment is successful, the child can be sent home for maintenance therapy by caregivers.
Severe dehydration should be managed with intravenous fluids until stabilization.
Treatment includes 20 mL/kg of lactated Ringer's solution for 10 to 15 minutes (repeated as needed), and up to 60 mL/kg may be needed within 1 hour.
Electrolyte measurements are important in severe and moderate dehydration.
Children with fever may require extra 1 mL/kg per degree centigrade every hour in addition to maintenance therapy.
Postoperatively and in those with infection or injury, 20% to 50% less fluid and fluid with higher sodium content may be needed.
Pharmacologic treatment is not indicated in diarrhea because of concerns of toxicity, and Lactobacillus has not been demonstrated to be useful.
A single dose of ondansetron can facilitate ORT by reducing vomiting and the need for intravenous treatment.

Clinical Implications

Physical signs predictive of dehydration include capillary refill time of more than 2 seconds, absence of tears, dry mucous membranes, and ill appearance.
ORT or nasogastric rehydration with ORT fluid is recommended for mild to moderate dehydration and intravenous rehydration for severe dehydration.