Review Question - QID 216506

An 11-year-old boy presents with abdominal pain and nausea for the past week. His parents state that their son has been complaining of gradually worsening pain, prompting them to bring him in today. The patient typically has a healthy appetite and mostly prefers to eat packaged snacks. He also drinks milk daily. Today, the patient complained of severe pain in the periumbilical region. He has not had any fevers or diarrhea. His temperature is 98.7°F (37.1°C), blood pressure is 122/82 mmHg, pulse is 83/min, respirations are 15/min, and oxygen saturation is 99% on room air. Physical exam reveals discomfort to palpation over the periumbilical region. A radiograph of the abdomen is performed as seen in Figure A. Which of the following is the most appropriate next step in management?