Meckel's diverticulum.

(M3.PD.16.67) A 2-year-old is brought to the emergency department by his mother for intermittent abdominal pain. She states the pain seems to be relieved by flexing his knees to his chest. The mother states that she noticed this morning that he passed stool mixed with blood and mucus. On exam, you note abdominal tenderness. An abdominal ultrasound is performed, and the results are shown in Figure A. What is the most common underlying cause of this patient's condition?

(M2.PD.15.35) A 14-month-old boy has iron-deficiency anemia refractory to iron therapy. His stool is repeatedly positive for occult blood. The parents bring the child to the emergency room after they notice some blood in his stool. Which of the following is the diagnostic gold standard for this patient's most likely condition?

(M1.GI.14.70) A 1-year-old previously healthy baby boy presents to the emergency department with 3 hours of intermittent abdominal pain, vomiting, and one episode of dark red stools. On exam, his abdomen is tender to palpation, and there are decreased bowel sounds. A CT scan reveals air fluid levels and a cystic mass in the ileum. Gross specimen histology reveals gastric tissue. What is the cause of this patient's problems?

(M1.GI.14.64) A concerned father brings his 2 year-old son to the clinic for evaluation. In the past 24 hours, the child has had multiple episodes of painless bloody stools. On physical examination, the child's vital signs are within normal limits. There is mild generalized discomfort on palpation of the abdomen but no rebound or guarding. A technetium-99m (99mTc) pertechnetate scan indicates increased activity in two locations within the abdomen. Cells originating in which organ account for the increased radionucleotide activity?

(M1.GI.13.33) An 8-month-old boy is brought to the emergency room by his mother who notes that the child has not been passing stool regularly. Palpation and radiographic imaging of the umbilical region reveal the presence of fecal material in an abnormal out-pocketing of bowel. Which of the following is a common complication seen in this condition?

(M1.GI.12.2) A 2-year-old male is brought to his pediatrician by his mother because of abdominal pain and blood in the stool. Scintigraphy reveals uptake in the right lower quadrant of the abdomen. Persistence of which of the following structures is the most likely cause of this patient's symptoms?