> - bilious [[Vomiting]] is a surgical emergency > - dilated loops on XR = bowel loops diameter > vertebral body diameter # small bowel atresia - intestinal atresia is the most common cause of neonatal intestinal obstruction - ==duodenal atresia== classically has a **double bubble** appearance on X-ray - ~1/3 of cases are associated with Down syndrome - vomiting begins within a day or two of birth (the higher the atresia, the earlier the vomiting), and infants fail to pass meconium - **bilious vomiting** is most common in jejunoileal obstruction, but can occur in duodental atresia as lesions are often distal to the ampulla of vater. - in jejunal atresia the x ray generally has a few dilated loops, whereas i ileal atresia there are usualy multiple dilated loops and prominent abdominal distension double bubble due to dilation of stomach and proximal duodenum: ![[DF0BD96F-F648-41C4-93ED-CFA270854BF2.jpeg]] # malrotation and midgut volvulus see [[Volvulus]] - in classical malrotation the midgut fails to complete its normal rotational development such that the duodenogejunal flexure lies to the right of the midline, the caecum is free-floating, and the small bowel mesentery is attached to a narrow pedicle. - this predisposes the midgut to **volvulus** around the superior mesenteric vessels - most cases (~75%) present in the neonatal period with sudden onset of pain, irritability, and **bilious vomiting**. - as strangulation ensues, there is progressive abdo distension, rectal bleeding, and hypovolaemic shock - early dx and surgery are essential to preserve gut viability - get ==upper GI contrast study== # meconium ileus - an obstruction of the small bowel, usually distal ileum, caused by highly viscoid meconium - most cases are due to [[Cystic Fibrosis]] ; btwen 10-15% of infants with CF present this way - distension early in neonatal period, progressive **bile-stained** vomiting and failure ot pass meconium, though small pale rectal plugs may be passed - fluid levels are uncommon on XR bc viscoid meconium,wich may give intenstine a bubbly appearance - intraperitoneal calcifications are *indicative of foetal perforation* - surgery is required for complicated meconium ileus, but uncomplicated cases *may be managed with an isotonic contrast enema* # Hirschsprung disease - caused by failed migration of colonic ganglion cells, leading to tonic intestinal contraction and functional obstruciton - most cases involve the rectosgmoid colon, but aganglionosis of the entire colon (and rarely, the small bowel) can occur - males > females - presents with delayed apssage of meconium, reluctance to feed, abdo distension, and vomiting which may be *bilious* - contrast enema may show transition zone - diagnosis confirmed by ==rectal biopsy== - *initial management:* rectal lavage w/ warmed 0.9% saline, which also helps to distinguis hirschsprung disease from meconium plug obstruciton, in which a plae plug is passed - infants w/ marked distension, explosive diarrhoea, or fever require close monitoring for ==hirschsprung enterocolitis, a potentially fatal complication== - tx with broad-spectrum abx and repeated rectal lavage # hypertrophic pyloric stenosis see [[pyloric stenosis]] - acquired obstruction of the gastric outlet due to progressive thickening and elongation of the circular muscle of the pylorus - RF: - male > F - white - formula fed - maternal smoking - FMx - infants develop ==non-bilious vomiting== after feeds, typically from age 2-6 weeks, which becomes progressively more frequent and forceful leading to dehydration and weight loss - appear hungry after emesis - classically ==hypochloraemic, [[hypokalemia|hypo-k]], and [[Blood gas#Metabolic alkalosis]]==, which is thought to be present in only half of cases. - high PPV if pH > 7.45, Cl < 98, and BE > 3 - ==dx with ultrasound== - pyloromyotomy delayed until correction of alkalosis (HCO3 <30) to reduce risk of postoperative aponea