The mother of a 2-year-old boy calls the office for guidance regarding his recent illness. He has passed 4-6 stools daily over the last 2 days. The feces are liquid and contain no blood or mucus. His highest temperature reading at home was 37.8 C (100 F). He is eating, drinking, and being playful as usual. The patient has no prior medical problems and is up to date with vaccinations. He recently began going to day care. The mother is advised to bring the patient to the office for further evaluation. While awaiting medical evaluation, which of the following oral fluids is most effective to prevent dehydration in this patient?
Humans consume approximately 2 L of fluid each day and secrete an additional 7 L of fluid from upper digestive organs (eg, salivary glands, stomach, pancreas, gallbladder). Nearly all of this fluid is reabsorbed from the gastrointestinal lumen by the small intestine epithelium. The osmotic gradient for water reabsorption is largely established by the active cotransport of sodium into the apical end of enterocytes coupled with chloride, glucose, or amino acids. Sodium is then transported out of the basolateral end of the enterocyte (sodium/potassium ATPase), which pulls water down its osmotic gradient from the gastrointestinal lumen through the tight junctions between enterocytes and into the lamina propria (and ultimately the bloodstream).
This young patient who recently began going to day care likely has acute infectious diarrhea of a viral etiology (eg, rotavirus, norovirus). Infections that target the small intestine cause watery diarrhea by blocking the active transport of sodium chloride into the enterocyte or by increasing chloride excretion into the gastrointestinal lumen (mediated by elevated intracellular cyclic AMP, cyclic GMP, or calcium). In this setting, oral rehydration with a hypotonic, equimolar sodium-glucose solution maximizes water and sodium reabsorption by the remaining functional enterocytes, and is the most effective oral therapy for maintaining volume and electrolyte status in children with acute infectious diarrhea.
(Choice A) Chicken broth with added salt is a hyperosmolar solution that can cause hypernatremia and is, therefore, not recommended.
(Choice B) Diluted or undiluted cow's milk is not an effective rehydration solution during acute diarrhea due to impaired digestion of milk components, which can promote osmotic diarrhea.
(Choice C) Filtered water alone is not usually sufficient to prevent dehydration in patients with acute infectious diarrhea due to the increased solute load in the gastrointestinal lumen, which causes most of the free water to be retained in the intestine and excreted in the feces.
(Choices D and F) Although sports drinks and sugary fruit juices contain glucose, they often have significantly lower sodium concentrations and high osmolality. This ultimately reduces water reabsorption and may promote osmotic diarrhea.
Educational objective:
Children with watery diarrhea should be treated with oral rehydration solutions containing hypotonic, equimolar concentrations of sodium and glucose to help prevent dehydration and electrolyte abnormalities.