Ella, a 9-month-old female, is brought to the emergency room by her parents due to episodes of crying and pulling her legs up to her chest that have been occurring every 15–20 minutes over the past day. During these episodes, Ella appears pale and irritable. The parents report that she has had non-bilious vomiting initially, but it became green and bilious as the day progressed. On examination, Ella appears lethargic between crying episodes, her abdomen is distended, and a palpable “sausage-shaped mass” is noted in the right upper quadrant. Ultrasound confirmed the diagnosis which revealed a characteristic ‘target lesion’ and the patient is successfully treated with pneumatic enema. Which of the following is the hallmark symptom of this disease in children?

Liam, an 8-month-old male infant, is brought to the emergency room by his parents due to intermittent episodes of crying and drawing his legs to his chest over the past 24 hours. The episodes last for about 10 minutes, during which Liam appears extremely uncomfortable, followed by periods of lethargy. The parents report one instance of bloody, mucus-filled stool described as “currant jelly.” On examination, Liam has a distended abdomen and a palpable “sausage-shaped mass” in the right upper quadrant. An ultrasound reveals a “donut sign” in the ileocecal region. What is the most common location for this disorder in children?

Mark, a 3-day-old male neonate, is brought to the hospital by his parents due to concerns that he has not passed meconium since birth. They report that his abdomen has become progressively distended, and he has vomited green, bilious material twice in the last 24 hours. He was born full-term via vaginal delivery with no complications, and his Apgar scores were normal. He has been feeding poorly since birth and appears increasingly irritable. Medical and Family History: No significant medical history in the family.No known genetic conditions, but the parents are first-time caregivers with no history of similar neonatal presentations in their family. Physical Examination: Vitals: Temperature: 98.6°F, HR: 130 bpm, RR: 50 breaths/min, BP: 70/40 mmHg. General Appearance: Irritable neonate with poor feeding and abdominal distension. Abdomen: Markedly distended with visible bowel loops. Tympanic to percussion, with tenderness on palpation.No organomegaly. Rectal Examination: Tight anal sphincter with explosive release of stool and gas upon withdrawal of the finger Diagnostic Workup: 1.Abdominal X-ray: Dilated bowel loops with an abrupt transition zone in the distal sigmoid colon. 2.Contrast Enema: Transition zone between the dilated proximal bowel and the narrowed distal bowel. 3.Rectal biopsy: Absence of ganglion cells in the submucosal and myenteric plexuses. Hypertrophied nerve fibers confirmed on histopathology. Which of the following is a life-threatening complication of this disease?

Mark, a 3-day-old male neonate, is brought to the hospital by his parents because he has not passed meconium since birth. They report progressively worsening abdominal distension and two episodes of green, bilious vomiting in the past 24 hours. Mark was born full-term via vaginal delivery with no complications and normal Apgar scores. He has been feeding poorly and appears increasingly irritable. Medical and Family History: No significant medical or family history of similar conditions. Physical Examination: Vitals: Temperature: 98.6°F, HR: 130 bpm, RR: 50 breaths/min, BP: 70/40 mmHg. General Appearance: Irritable neonate with poor feeding and abdominal distension. Abdomen: Markedly distended with visible bowel loops, tympanic to percussion, and tenderness on palpation. No organomegaly. Rectal Examination: Tight anal sphincter with explosive release of stool and gas upon finger withdrawal. You suspect congenital aganglionic megacolon (Hirschsprung disease) in this patient. Which of the following is the definitive diagnostic test for Hirschsprung disease?

Mark, a 3-day-old male neonate, is brought to the hospital by his parents due to concerns that he has not passed meconium since birth. His abdomen has become progressively distended, and he has experienced two episodes of green, bilious vomiting in the last 24 hours. He was born full-term via vaginal delivery with normal Apgar scores. He has been feeding poorly and appears increasingly irritable. Medical and Family History: No significant medical history or genetic conditions. Parents are first-time caregivers with no family history of similar neonatal presentations. Physical Examination: Vitals: Temperature: 98.6°F, HR: 130 bpm, RR: 50 breaths/min, BP: 70/40 mmHg. General Appearance: Irritable neonate with poor feeding and abdominal distension. Abdomen: Markedly distended with visible bowel loops, tympanic to percussion, tenderness on palpation, and no organomegaly. Rectal Examination: Tight anal sphincter with explosive release of stool and gas upon withdrawal of the finger. Diagnostic Findings: Biopsy: Absence of ganglion cells in the submucosal and myenteric plexuses, with hypertrophied nerve fibers confirmed on histopathology. Question: What is the most common site of involvement in this disorder?

A 42-year-old male presents to the clinic with a two-month history of intermittent burning epigastric pain localized to the upper abdomen. The pain occurs 3 to 4 hours after eating, frequently wakes him up at night, and is temporarily relieved by eating or taking over-the-counter antacids. He denies significant weight loss, fever, or changes in bowel habits but reports occasional bloating and nausea. His history is significant for frequent NSAID use for chronic knee pain and smoking about 10 cigarettes per day. On physical examination, the patient has mild epigastric tenderness without guarding or rebound tenderness. Vital signs are normal, and there is no evidence of melena or occult blood. What is the most common location for this type of ulcer?