A previously healthy 12-month-old boy is brought to the emergency department by his parents because of a 1-day history of intermittent abdominal pain, loss of appetite, and vomiting. His parents say that he seems disoriented. He appears pale and ill. His temperature is 36.8°C (98.2°F), pulse is 128/min, respirations are 36/min, and blood pressure is 84/62 mm Hg. Abdominal examination shows mild distention; increased, high-pitched bowel sounds are heard. A mass is palpated in the left upper quadrant. Test of the stool for occult blood is positive. An x-ray of the abdomen is shown. Which of the following is the most likely underlying cause of this patient's current symptoms? A) Fecalith B) Foreign body obstruction C) Functional ileus D) Malrotation of the midgut E) Telescoping of the bowel

A previously healthy 12-month-old boy is brought to the emergency department by his parents because of a 1-day history of intermittent abdominal pain, loss of appetite, and vomiting. His parents say that he seems disoriented. He appears pale and ill. His temperature is 36.8°C (98.2°F), pulse is 128/min, respirations are 36/min, and blood pressure is 84/62 mm Hg. Abdominal examination shows mild distention; increased, high-pitched bowel sounds are heard. A mass is palpated in the left upper quadrant. Test of the stool for occult blood is positive. An x-ray of the abdomen is shown. Which of the following is the most likely underlying cause of this patient's current symptoms? A) Fecalith B) Foreign body obstruction C) Functional ileus D) Malrotation of the midgut E) Telescoping of the bowel