A 4-month-old boy is brought to the office due to occasional episodes of vomiting and irritability over several weeks. The vomitus occasionally resembles formula but is often green. The patient is irritable both before and after vomiting, typically refuses to feed, and often cannot be consoled. His mother has tried various formulas, without success, to improve the symptoms. The patient was born at 39 weeks gestation via cesarean delivery. An omphalocele diagnosed during the prenatal period was surgically repaired at birth without complications. Vital signs are normal. The neck is supple, and the anterior fontanelle is flat. The abdomen is soft, nontender, and nondistended. Bowel sounds are normal. Rectal examination shows normal, brown stool that is negative for fecal occult blood. Which of the following is the most likely cause of this patient's current symptoms?

Question

A 4-month-old boy is brought to the office due to occasional episodes of vomiting and irritability over several weeks.  The vomitus occasionally resembles formula but is often green.  The patient is irritable both before and after vomiting, typically refuses to feed, and often cannot be consoled.  His mother has tried various formulas, without success, to improve the symptoms.  The patient was born at 39 weeks gestation via cesarean delivery.  An omphalocele diagnosed during the prenatal period was surgically repaired at birth without complications.  Vital signs are normal.  The neck is supple, and the anterior fontanelle is flat.  The abdomen is soft, nontender, and nondistended.  Bowel sounds are normal.  Rectal examination shows normal, brown stool that is negative for fecal occult blood.  Which of the following is the most likely cause of this patient's current symptoms?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d619_baeb_bc81_f3941ce30d2b_MD0003_00 This patient has bilious emesis, a symptom highly worrisome for intestinal obstruction (eg, intussusception, malrotation). His history of omphalocele, or failed reduction of physiologic bowel herniation in utero, makes intestinal malrotation the most likely cause. This abnormality in fetal gut rotation is usually present to some degree in patients with omphalocele because these two embryologic events occur at a similar gestational age, but malrotation may not be identified until the patient is symptomatic. Malrotation is also associated with other congenital anomalies, such as diaphragmatic hernia and heterotaxy syndrome. omphalocele Malrotation may remain asymptomatic or cause acute or chronic symptoms. Symptomatic malrotation occurs with the following: Midgut volvulus (ie, intestinal torsion), a life-threatening complication, usually presents in neonates with acute bilious emesis and abdominal distension. However, intermittent volvulus, which is likely the diagnosis in this patient, can cause chronic symptoms of episodic, often bilious, vomiting and abdominal pain, which may manifest as irritability and inconsolability in infants. Duodenal obstruction is caused by Ladd bands, fibrous, peritoneal tissues that cross the duodenum and attach the cecum to the abdominal wall. Complete duodenal obstruction typically presents acutely in newborns, whereas partial obstruction can present later with chronic vomiting (bilious or nonbilious), feeding refusal, and failure to thrive. A high degree of clinical suspicion is required because examination between episodes may be unremarkable. Diagnosis is confirmed using upper gastrointestinal series, and treatment is surgical (Ladd procedure) to divide the peritoneal bands and reposition the bowel. (Choice A) Food protein-induced enterocolitis syndrome is a non-IgE-mediated food allergy that typically presents in infancy with nonbilious, rather than bilious, emesis after ingestion of a trigger food (eg, cow's milk). (Choice B) Gluten-sensitive enteropathy (celiac disease), a rare diagnosis in infants, can cause episodic gastrointestinal symptoms (eg, abdominal pain, diarrhea) after gluten ingestion. Vomiting can occur but would be nonbilious. Moreover, formula does not contain gluten. (Choice C) Pyloric stenosis classically presents at age 3-5 weeks with nonbilious projectile vomiting after every feeding attempt. This patient's age and intermittent bilious emesis make this diagnosis unlikely. (Choice D) An immature lower esophageal sphincter is responsible for gastroesophageal reflux (ie, spit-up) commonly seen in infants. However, spit-up resembles formula (or breastmilk) and is never bilious. Educational objective: Intestinal malrotation is a common cause of bilious emesis in infants, particularly those with other associated congenital anomalies (eg, omphalocele). Chronic, episodic symptoms can occur with intermittent volvulus. References: Intestinal rotational abnormalities and midgut volvulus. (http://www.ncbi.nlm.nih.gov/pubmed/27894424) Intestinal malrotation in infants with omphalocele: a systematic review and meta-analysis. (http://www.ncbi.nlm.nih.gov/pubmed/30309732)

A 4-Month-Old Boy Is Brought to the Office Due to Occasional