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After completing this case study, the reader should be able to:

  • Recognize the signs and symptoms of diarrhea with dehydration and be able to assess the severity of the problem.

  • Describe the available rotavirus vaccines in the United States, contrast their dosage and product availability, compare their safety and efficacy with the previously available RotaShield® vaccine, and explain their worldwide impact on rotavirus-induced diarrhea.

  • Recommend appropriate oral rehydration therapy (ORT) products and treatment regimens for varying degrees of dehydration severity and assess the effectiveness of ORT using clinical parameters.

  • Outline education for parents about the limited usefulness of all antidiarrheal products and the role of ondansetron and probiotics in the treatment of acute diarrhea in children.

  • Identify the signs and symptoms of severe dehydration that require referral to an ED for immediate IV volume replacement.


Chief Complaint

Lydia Mason is a 9-month-old girl who presents to the ED with a three day history of fever, vomiting, and diarrhea. Her mother states, “I am worried that Lydia may be dehydrated.”


Lydia is an otherwise healthy child, last evaluated by her primary care provider at a scheduled well-child checkup 2 weeks ago, with no concerns identified during the appointment. Three days before presentation, she developed a tactile fever, confirmed at 100.4°F (38.0°C) rectally, and seemed more tired than usual. Two days before presentation, she awoke from sleep due to an episode of nonbloody, nonbilious emesis. Throughout that day, she had five more episodes of vomiting after attempts at oral intake. She continued to have fatigue and low-grade fevers.

One day before presentation to the ED, she had only two episodes of emesis but developed diarrhea. The stools were initially described as slightly formed, but as the day progressed, the stools became watery and voluminous. Her mother estimates that Lydia had five to eight episodes of diarrhea. Lydia’s appetite continued to be poor, with refusal of solid foods. On her primary care provider’s recommendation, Lydia’s parents offered her liquids including formula and Pedialyte, but she refused these, preferring to drink small amounts of water and dilute apple juice.

On the morning of presentation to the ED, the patient had another large, watery stool and was more fussy than usual. Her diaper was dry, with no urine output since the night prior to presentation. The family could not accurately assess the number of wet diapers she had in the last 24 hours due to her stooling frequency and consistency. They also noted this morning that her lips appeared dry and she was not producing tears when crying.

On further history, no sick contacts were noted ...

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