In the context of duodenal obstruction, what is true for children over 1 week old?

In children over 1 week old, malrotation is indeed a recognized cause of duodenal obstruction. As infants grow, the risk of complications arising from embryological anomalies, such as malrotation, increases, leading to potential obstruction. Malrotation involves an abnormal positioning of the intestines, which can result in occlusion of the duodenum due to mesenteric twisting and can present acutely with vomiting or bowel obstruction.

Duodenal atresia, while a significant cause of obstruction in newborns, typically manifests in the first few days of life, making it less common in infants beyond this age. Meckel's diverticulum, which can lead to obstruction, also happens but its incidence as a sole cause of duodenal obstruction is rare in this age group. Pyloric stenosis, a common condition typically presenting with projectile vomiting in infants aged 3 to 12 weeks, does not usually lead to duodenal obstruction but rather affects the pylorus at the outlet of the stomach.

Thus, recognizing malrotation as the leading cause of duodenal obstruction in children older than one week aligns with the understanding of how these various anatomical and physiological issues impact this age group's gastrointestinal tract.