NEONATAL ABDOMINAL EMERGENCIES LOW OBSTRUCTION HIGH OBSTRUCTION
INTESTINAL OBSTRUCTION High obstruction - proximal to mid-ileumileum Few dilated, air filled bowel loops Complete obstruction diagnosed by KUB Partial obstruction diagnosed by UGI Low obstruction - distal ileum & colon Many dilated air-filled bowel loops Contrast enema study of choice LOW INTESTINAL OBSTRUCTION
LOW OBSTRUCTION Typically present with failure to pass meconium or constipation 90% of normal neonates pass meconium in 1 st 24 hours; 99% in 1 st 48 hours LOW OBSTRUCTION Hirschprung s disease Functional immaturity Meconium plug, small left colon Meconium ileus Ileal atresia Colonic atresia
CONTRAST ENEMA Water soluble contrast Dilute gastrograffin (4:1) Patient immobilization Octagon board Foley catheter Do not inflate balloon Initial imaging in lateral projection HIRSCHPRUNG S DISEASE Arrest in migration of ganglion cells Extends proximally from anus Without skip areas Rare form is total colonic aganglionosis Transition zone most specific finding Rectosigmoid 75% Descending colon 15%
Rectosigmoid Index Normal rectum wider than sigmoid Opposite noted in Hirschprung s s R/S > 1.0 normal R S R Meconium plug R/S >1 S Hirschprung s R/S <1 HIRSCHPRUNG S DISEASE Enema has poor diagnostic accuracy False negative: 20-25% 25% Should not be relied for diagnosis If diagnosis suspected should undergo rectal biopsy O Donovan. AJR 1996;167:520 Smith. Pediatr Surg Int 1991;6:318 Taxman. Am J Dis Child 1986;140:881
Enterocolitis Major cause of morbidity & mortality Incidence increases with delayed diagnosis Diarrhea, fever, abdominal distension, abdominal pain & hematochezia Fecal stasis & bowel dilatation with secondary infection MECONIUM PLUG SYNDROME Failure to pass meconium in 1st 24 hrs Characterized by multiple meconium plugs Usually improves following enema Clatworthy. Surgery 1956;39:131-41
SMALL LEFT COLON SYNDROME Caliber change near splenic flexure Associated w/ maternal diabetes Ddx - Hirschprung s disease Davis. AJR 1974;1974;120:322-9 Pitfall Hirschprung s transition zone can be at splenic flexure Biopsy if symptoms persist
MECONIUM ILEUS Inspissated meconium in distal ileum Almost always associated w/ CF Presenting feature in 5-10% w/ CF Complications include volvulus, perforation, peritonitis iti & microcolon MECONIUM ILEUS Bubbly appearance in rlq Paucity of air fluid levels Reflux into nondilated distal ileum Dilated small bowel
MECONIUM PERITONITIS Results from intrauterine perforation Primarily from meconium ileus Calcification of peritoneal meconium Site of perforation usually not found ILEAL ATRESIA Secondary to vascular insult Atresias may be multiple +/- Microcolon
COLONIC ATRESIA Secondary to vascular insult Type I Complete obstruction by diaphragm Type II Obstruction by atretic cord Type III Complete separation of proximal & distal colon CONTRAST ENEMA DDX Microcolon Meconium ileus Ileal atresia Total colonic aganglionosis Colonic atresia
CONTRAST ENEMA DDX Transition zone Hirschprung s Small left colon syndrome CONTRAST ENEMA DDX Normal Hirschprung s Ileal atresia
HIGH INTESTINAL OBSTRUCTION HIGH OBSTRUCTION Midgut malrotation ti Duodenal atresia/stenosis/web Jejunal atresia/stenosis
MIDGUT MALROTATION Most important UGI obstruction in newborn Arrest in normal rotation of midgut Results in abnormal mesenteric fixation Obstruction 2 o twisting around SMA (volvulus) or abnl peritoneal attachments (Ladds bands) ASSOCIATED CONDITIONS Always present Omphalocele Gastroschisis Congenital diaphragmatic hernia Increased incidence Duodenal/jejunal atresia/stenosis Hirschprung disease Heterotaxy syndrome
MIDGUT MALROTATION RADIOGRAPHIC FINDINGS Normal Partial / complete obstruction Proximal / mid small bowel
UGI Patient immobilization Octagon board Do not overdistend stomach Observe initial passage of barium through duodenum directly with fluoroscopy Image in frontal & lateral projections MIDGUT MALROTATION UGI FINDINGS Abnormal duodenal-jejunal junction Normal = left of left vertebral pedicle at level of duodenal bulb Duodenal obstruction Corkscrew appearance of small bowel
Midgut volvulus Spiraling of bowel around SMA Beaked deformity of bowel Closed loop obstruction Ladd s bands Condensations of mesentery Cross & compress duodenum Simple obstruction
Pitfalls False positive diagnosis Low DJJ due to bowel dilatation Low DJJ due to splenomegaly Low DJJ due to renal agenesis Duodenal redundancy False negative diagnosis Abnormal DJJ rarely to left of spine and at level of bulb MIDGUT MALROTATION If UGI findings equivocal identify position of cecum 80% of children with malrotation have abnormal cecal position
MIDGUT MALROTATION US/CT FINDINGS Reversal of mesenteric vessels SMV to left of SMA Whirlpool appearance of vessels Not accurate enough for 1 o dx Whirlpool appearance of midgut volvulus
DUODENAL OBSTRUCTION Most common cause of high obstruction Atresia > stenosis > web 3/4 distal to papilla & associated with bilious vomiting 1/3 associated w/ Down s syndrome May be part of VACTERL association JEJUNAL ATRESIA Due to vascular insult Atresia > Stenosis Atresias may be multiple Normal caliber colon
NEONATAL ABDOMINAL EMERGENCIES