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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 two available rotavirus vaccines, compare their dosage and availability, compare their safety and efficacy with the previously available vaccine, and explain their potential impact on rotavirus-induced diarrhea.

  • Recommend appropriate oral rehydration therapy (ORT) products and treatment regimens for varying degrees of dehydration severity.

  • Properly assess the effectiveness of ORT using both clinical and laboratory parameters.

  • Be able to educate 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 female who presented to the ED with a 3-day history of fever, vomiting, and diarrhea.


The child was in her baseline state of health, having just been seen by her pediatrician for her 9-month well-child check earlier in the week. Three days before presentation, she was noted to have a tactile fever, confirmed at 100.4°F (38.0°C) axillary, as well as diminished energy. Two days before presentation, she awoke from sleep, experiencing nonbilious, nonbloody emesis. Throughout that day, she had five similar episodes of vomiting, typically after attempts at oral intake. She continued to have low-grade fevers.

One day before presentation to the ED, she had only two episodes of emesis, but she developed diarrhea. The stools, totaling five that day, were initially described as slightly formed. As the day progressed, the stools became watery, voluminous, and contained small specks of blood. The patient’s appetite continued to be poor, with very limited solid intake. On the pediatrician’s recommendation, the family offered the patient liquids including formula, water, and Pedialyte, but she refused, preferring cola and diluted apple juice.

On the morning of presentation to the ED, the patient had another large, watery stool and was unusually fussy. Her diaper was dry, with no urine output the night prior. The family could not accurately assess the number of wet diapers she had in the last 24 hours, given the difficulty distinguishing watery stool from urine. They also noted that her lips appeared dry and she had diminished tears.


Lydia was born at 38 weeks via spontaneous vaginal delivery without complications. She required 1 day of phototherapy for hyperbilirubinemia. She was discharged from the nursery within 3 days of birth. She has experienced approximately six upper respiratory tract infections and two episodes of otitis ...

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