A 7-month-old boy is brought to the emergency department due to persistent bilious vomiting for the past 6 hours. The infant has had no fever, diarrhea, or recent illness. His last bowel movement was 24 hours ago. The patient has no chronic medical conditions and has had no surgeries. Temperature is 37 C (98.6 F), blood pressure is 70/50 mm Hg, pulse is 180/min, and respirations are 65/min. Cardiac examination demonstrates normal heart sounds with no rubs or murmurs. The lungs are clear to auscultation bilaterally. The child moans on soft palpation of the abdomen, which is distended and hypertympanic. Bowel sounds are absent on auscultation. Which of the following is the most likely cause of this patient's symptoms?

Question

A 7-month-old boy is brought to the emergency department due to persistent bilious vomiting for the past 6 hours.  The infant has had no fever, diarrhea, or recent illness.  His last bowel movement was 24 hours ago.  The patient has no chronic medical conditions and has had no surgeries.  Temperature is 37 C (98.6 F), blood pressure is 70/50 mm Hg, pulse is 180/min, and respirations are 65/min.  Cardiac examination demonstrates normal heart sounds with no rubs or murmurs.  The lungs are clear to auscultation bilaterally.  The child moans on soft palpation of the abdomen, which is distended and hypertympanic.  Bowel sounds are absent on auscultation.  Which of the following is the most likely cause of this patient's symptoms?

Quizplus · Accepted Answer

11ec25c8_d5e6_c3bb_bc81_1164485752ff_MD0003_00 This patient's presentation is concerning for intestinal malrotation with midgut volvulus, a potentially life-threatening condition that should be suspected in any infant with bilious emesis. Patients with malrotation are predisposed to midgut volvulus because arrest of normal gut rotation during fetal development results in a narrow mesenteric base of the intestine. This allows the small bowel to twist freely around the superior mesenteric artery. malrotation Malrotation with midgut volvulus is most common in the first year of life (particularly the first month) but can occur at any age. Presentation in infants is typically acute and includes signs of small bowel obstruction, such as bilious emesis, absent bowel sounds, and abdominal distension and tenderness. Hypovolemic and/or septic shock can also occur, which is likely in this patient with hemodynamic instability (eg, tachycardia, hypotension). In contrast to the acute findings usually seen in infants, older children and adults often have chronic symptoms of periodic vomiting and abdominal pain due to intermittent volvulus. Regardless of patient age, volvulus is a surgical emergency. Without treatment (ie, laparotomy to untwist the volvulus), patients are at risk for bowel necrosis, perforation, and death. (Choice A) The typical presentation of acute appendicitis is acute abdominal pain along with fever and nonbilious vomiting in a school-aged child or adolescent. This patient's age, the presence of bilious emesis, and the lack of fever make appendicitis less likely. (Choice C) Necrotizing enterocolitis is characterized by intestinal wall inflammation and necrosis due to invasion of gas-producing bacteria. Symptoms include feeding intolerance, bilious emesis, and abdominal distension, but necrotizing enterocolitis occurs primarily in premature infants in the first few weeks of life. (Choice D) Pyloric stenosis typically presents at age 3-5 weeks with projectile, nonbilious vomiting after feeding. A palpable abdominal mass may also be present on examination. This patient's age and the presence of bilious emesis make pyloric stenosis unlikely. (Choice E) Viral gastroenteritis is a common cause of vomiting and abdominal pain in children; however, emesis is typically nonbilious, and findings such as fever and diarrhea would be expected. In addition, bowel sounds are usually hyperactive, not absent. Educational objective: Small bowel obstruction due to intestinal malrotation with midgut volvulus is a life-threatening surgical emergency. It should be suspected in any infant with acute abdominal distension, bilious emesis, and hemodynamic instability. Complications include bowel necrosis and perforation. References: Intestinal rotation abnormalities and midgut volvulus. (http://www.ncbi.nlm.nih.gov/pubmed/27894424)

A 7-Month-Old Boy Is Brought to the Emergency Department Due