A 4-year-old girl presents with 24 hours of nausea, vomiting, and diarrhea. She is interactive, with a mild fever and no abdominal tenderness. What is the most appropriate next step in management?

• A. Administer ondansetron and perform a PO challenge test
• B. Start IV rehydration with observation
• C. Administer promethazine and proceed with a PO challenge test
• D. Observe and discharge with no treatment

Answer: (A)

When a child with gastroenteritis is vomiting but remains interactive and not severely dehydrated, the best first step is to enable oral rehydration by reducing vomiting with an antiemetic and then test whether they can tolerate oral fluids. Ondansetron is effective in children with vomiting from gastroenteritis and helps them keep down oral rehydration solutions, which is safer and often sufficient for mild dehydration. After giving an antiemetic, a oral challenge test—offering small sips of an oral rehydration solution and observing tolerance—allows you to determine if she can maintain hydration without IV fluids. If she can keep fluids down, continue oral rehydration and monitoring.

Starting IV fluids isn’t indicated here because there aren’t signs of significant dehydration or poor perfusion, and the child is already interactive. Promethazine is not preferred due to potential sedation and other adverse effects in children. Simply observing and discharging without treatment risks ongoing dehydration and vomiting without addressing her symptoms.