Final answer:
The symptoms are suggestive of intussusception, where part of the intestine telescopes into another section. Diagnosis is typically through abdominal ultrasound, and the next step would be to perform this imaging to confirm the diagnosis and check for complications.
Step-by-step explanation:
The patient's presentation of sudden severe abdominal pain and currant jelly stools is suggestive of intussusception, particularly in pediatric cases. Intussusception is a condition where a part of the intestine folds into the section next to it, leading to bowel obstruction and compromised blood supply.
The diagnosis of intussusception often includes a physical examination, ultrasound, and sometimes an air or barium enema, which can serve both as a diagnostic and therapeutic measure. Considering the urgency due to the severity of symptoms, obtaining an abdominal ultrasound is typically the next step to confirm the diagnosis and to assess for any complications such as bowel necrosis.