Intestinal atresia

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Intestinal Atresia

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2. Questions 1. incidence of intestinal atresia in down 2. Paradoxical aciduria in pyloric stenosis 3. VACTERAL 4. omphalocele and related 5. what age duodenal atresia be treated 6. incidence of intestinal [email protected] 3. Intestinal obstruction occurs in 1/1,500 live birthsTwo types Simple -Simple obstruction is associated with thefailure of progression of abnormal flow of luminalcontents. Strangulating-Strangulating obstruction isassociated with impaired blood flow to the intestinein addition to obstruction of the flow of luminalcontents. it can lead to bowel infarction [email protected] 4. Pathophysiology Accumulation of ingested food, gas, and intestinalsecretions proximal to the point of obstruction,leading to distention of the bowel. As the bowel dilates, intestinal absorption decreasesand secretion of fluid and electrolytes increases. i.e.isotonic intravascular depletion usually associatedwith hypokalemia. Gut proximal to the obstruction initially demonstratesan increase in contractile activity, which is followedby a marked decrease with hypoactive [email protected] 5. The combination of fluid accumulation (distention)and hypomotility is associated with nausea andvomiting. Blood flow to the obstructed bowel decreases as thebowel dilates. Blood flow is shifted away from the mucosa, withloss of mucosal integrity. Bacteria proliferate in the stagnant bowel, with apredominance of coliforms and anaerobes. Bacterial translocation across the bowel wall,potentially resulting in endotoxemia, bacteremia, [email protected] 6. Congenital obstructive lesions ofthe intestines Intrinsic atresia, stenosis, meconium ileus, aganglionic megacolon. extrinsic malrotation, constricting bands, intra-abdominal hernias, [email protected] 7. Atresia - complete obstruction of the bowellumen stenosis - partial block of luminal contents Intestinal atresia is common in the duodenum,jejunum, and ileum and rare in the colon. Intestinal atresia accounts for 33% of all casesof neonatal intestinal obstruction affects males and females with equal frequency. Intestinal atresia impairs the development of themyenteric plexus below the level of atresia,[email protected] 8. Clinical presentation Depends on cause, level of obstruction, and time between the obstructing event and the [email protected] 9. High intestinal obstruction Polyhydramnios accompanies high intestinalobstruction. Aspiration of 1520 mL or more of gastric fluid,especially if it is bile stained, is suggestive of ahigh intestinal obstruction Meconium stools can be passed initially if theobstruction is in the upper part of the smallintestine or if the obstruction developed late inintrauterine [email protected] 10. The classic symptoms of obstruction include nauseaand vomiting, abdominal distention, and obstipation. Obstruction high in the intestinal tract involving theduodenum or proximal jejunum results in large-volume, frequent, bilious emesis. Pain is intermittent and is usually relieved byvomiting. The pain is localized to the epigastrium orperiumbilical area, and there is little abdominaldistention. hypochloremic metabolic [email protected] 11. Distal small bowel obstruction moderate or marked abdominal distention withemesis that is progressively feculent. Pain is usually diffuse over the entire [email protected] 12. Incomplete obstructions as with intestinal stenosis, constricting bands, duplications incomplete volvulus), signs may appear shortly after birth or may bedelayed an indeterminate [email protected] 13. Investigations ABG - Hypochloremic metabolic alkalosis TLC - Marked leukocytosis with or withoutthrombocytopenia Stool Routine - Hematochezia in a patient withobstruction suggests bowel infarction. Serum amylase and lipase - determinationsshould be performed to rule out [email protected] 14. Bowel obstruction is usually suggested on thebasis of history (including prenatalultrasonography) and physical examination Imaging is used to confirm the diagnosis andlocalize the area of obstruction. Plain supine and erect or decubitus radiographsare the initial [email protected] 15. X- ray abdomen upright or cross-table lateral position distention of the bowel is noted above theobstruction and a series of fluid levels withsuperimposed gas in the distended loops Pneumoperitoneum if there is a perforation with free air in thesubphrenic regions or over the liver in the left lateraldecubitus [email protected] 16. X- ray abdomen Calcification within the peritoneal cavity indicates meconium peritonitis. meconium ileus characteristic ground-glass appearance in the rightlower quadrant with trapped bubbles of air withinthe obstructing meconium may be seen in patientswith meconium [email protected] 17. X- ray abdomen Air is usually demonstrable radiographically in thestomach of a normal infant immediately afterbirth; within 1 hr, air may reach the proximal portion ofthe small intestine and segments of the colon; air may become visible in the distal parts of thecolon as early as the 3rd hr or as late as 18 [email protected] 18. Ultrasonography Ultrasonography identifying pyloric stenosis, malrotation, and volvulus or intussusception CT scan sensitive and specific for diagnosing small bowelobstruction, especially in children >2 [email protected] 19. Water-soluble contrast enemas are useful indiagnosing malrotation, meconium ileus, meconiumplug, and intussusception. In meconium ileus, meconium plug, andintussusception, the enema may be diagnostic andrelieve the obstruction. Oral or nasogastric contrast medium is used toidentify obstructing lesions in the proximal bowel(atresia, volvulus, malrotation). Water-soluble agents are used if perforation [email protected] 20. MANAGEMENT Initial treatment fluid resuscitation and stabilizing the patient. Nasogastric decompression usually provides relief of pain and vomiting broad-spectrum antibiotics are usually started in ill-appearing neonates withbowel obstruction and those with suspectedstrangulating [email protected] 21. Surgery Patients with strangulation must have immediatesurgical relief before the bowel infarcts, resulting ingangren and intestinal perforation. Nonoperative conservative management limited to children with suspected adhesions orinflammatory strictures that may resolve withnasogastric decompression or anti-inflammatorymedications. If clinical signs of improvement are not evident within1224 hr, then operative intervention is [email protected] 22. Duodenal atresia Due to failure to recanalize the lumen after thesolid phase of intestinal development in the 4thand 5th wk of gestation. The incidence of duodenal atresia is 1/10,000births Accounts for 2540% of all intestinal atresias. Half the patients are born prematurely. Down syndrome occurs in 2030% of patientswith duodenal atresia. Other congenital anomalies that are associatedwith duodenal atresia include malrotation (20%),esophageal atresia (1020%), congenital heartdisease (1015%), and anorectal and renalanomalies (5%)[email protected] 23. Types intact membrane obstructing the lumen, a short fibrous cord connecting two blind duodenalpouches, or a gap between the nonconnecting ends of theduodenum. An unusual cause of obstruction is a windsock web,which is a distensible flap of tissue associated withanomalies of the biliary tract. membranous form of atresia is most common, withobstruction occurring distal to the ampulla of Vater inthe majority of patients. Duodenal obstruction can also be a result of anextrinsic compression such as an annular pancreasor from Ladd bands in patients with [email protected] 24. CLINICAL MANIFESTATIONS The hallmark is bilious vomiting without abdominaldistention, which is usually noted on the 1st day oflife. Peristaltic waves may be visualized early in thedisease process. A history of polyhydramnios is present in half thepregnancies and is caused by a failure of absorptionof amniotic fluid in the distal intestine. Jaundice is present in one third of the [email protected] 25. The diagnosis is suggested by the presence of adouble-bubble sign on plain abdominalradiographs. The appearance is caused by a distended and gas-filled stomach and proximal duodenum. Contrast studies may occasionally be needed toexclude malrotation and volvulus because intestinalinfarction may occur within 612 hr if the volvulus isnot relieved. Prenatal diagnosis of duodenal atresia is readilymade by fetal [email protected] 26. TREATMENT Initial - Nasogastric or Orogastric decompressionand intravenous fluid replacement. Echocardiogram and radiology of the chest andspine should be performed to evaluate forassociated anomalies. Definitive correction of the atresia is usuallypostponed to evaluate and treat these life-threatening [email protected] 27. Surgery duodenoduodenostomy. The dilated proximal bowel can be tapered in anattempt to improve peristalsis. A gastrostomy tube can be placed to drain thestomach and protect the airway. Intravenous nutritional support or a transanastomoticjejunal tube is needed until infants start to [email protected] 28. If obstruction is due to Ladd bands with malrotation,an operation is necessary without delay. After division of the abnormal peritoneal folds orbands, the entire large intestine is placed within theleft side of the abdomen, after 1st removing theappendix, with the small bowel on the rightthe fetalposition of nonrotation. Appendectomy is performed to avoid latermisdiagnosis of [email protected] 29. Malrotation can also coexist with an intrinsicduodenal obstruction, such as a membrane orstenosis;passing a balloon-tipped catheter into thejejunum below the site of obstruction, inflating theballoon, and slowly withdrawing the catheter mayidentify this. Annular pancreas is best treated byduodenoduodenostomy without dividing thepancreas, leaving as short a defunctioned loop aspossible. Duodenal diaphragmatic obstruction is managedby [email protected] 30. Jejunal and Ileal Atresia andObstruction Jejunoileal atresia have been attributed tointrauterine vascular accidents leading to ischemicnecrosis of the sterile bowel and resorption of theaffected segments. Polyhydramnios occurs in 25% of affected patients Monozygotic twins are at higher risk Premature birth occurs in 30% of infants. Atresia has also been associated with lowbirthweight, multiple births, and maternal cocaineuse and cigarette [email protected] 31. Type I accounts for 20% of the atresias and is anintraluminal diaphragm that obstructs the lumenwhile continuity is maintained between the proximaland distal bowel Type II a small-diameter solid cord connects the proximaland distal bowel, accounting for about 35% [email protected] 32. Type III is divided into two subtypes. Type IIIa accounts for 35% of all atresias both ends of the bowel end in blind loops accompaniedby a small mesenteric defect. Type IIIb extensive mesenteric defect loss of the normal blood supply to the distal bowel. The distal ileum coils around the ileocolic artery, fromwhich it derives its entire blood supply, producing anapple-peel appearance. This anomaly is associatedwith prematurity, an unusually short distal ileum, andsignificant foreshortening of the [email protected] 33. Type IV multiple segments of bowel atresia accounts for 5% of all bowel [email protected] 34. Meconium ileus Approximately 10% of infants with cystic fibrosis developmeconium ileus; 8090% of infants presenting with meconium ileus havecystic fibrosis. simple meconium ileus the last 2030 cm of ileum is collapsed and filled with pelletsof pale-colored stool, above which a dilated loop of varyinglength appears obstructed by meconium of the consistencyof thick syrup or glue. complicated meconium ileus Accompained by Volvulus, atresia, or perforation of thebowel Perforation in utero produces meconium peritonitis.Intraperitoneal meconium can cause dense adhesions,leading postnatally to adhesive intestinal obstruction, [email protected] 35. CLINICAL MANIFESTATION Most symptomatic in the 1st day of life withabdominal distention and bile-stained emesis orgastric aspirate. 60 to 75% of the infants fail to pass meconium. Jaundice has been found in 2030% of the patients. Plain radiographs demonstrate many air-fluid levelsor peritoneal calcification associated with meconiumperitonitis. Contrast studies of the upper and lower bowel candelineate the level of obstruction and differentiateatresia from meconium ileus, meconium plug, andHirschsprung [email protected] 36. In meconium ileus- typical hazy or ground-glass appearance in the rightlower quadrant. Small bubbles of gas trapped inmeconium are dispersed within this area. Because of their viscid contents, moderately dilatedloops of bowel do not have the air-fluid levels usuallyseen radiographically on the erect projection. If there is meconium peritonitis, patchy calcificationmay be noted, usually in the flanks. Pneumoperitoneum - as free air between the liverand the diaphragm on an upright radiograph of theabdomen; if there is a large amount of free air, theentire abdomen may look like a football fromdistention with air; the ligamentum teres issometimes clearly visible in the [email protected] 37. TREATMENT Initial -fluid and electrolyte balance Prophylactic antibiotics Ileal or jejunal atresia resection of the dilated proximal portion of thebowel followed by end-to-end anastomosis. In uncomplicated meconium ileus, Gastrografin enemas will diagnose the obstructionand wash out the inspissated material. Gastrografinis hypertonic and care must be taken to avoiddehydration, shock, and bowel perforation, mayhave to be repeated after 812 [email protected] 38. 50% of patients with simple meconium ileus do notadequately respond to water-soluble enemas andneed laparotomy. Operative management is indicated when theobstruction cannot be relieved by repeated attemptsat nonoperative management and for infants withcomplicated meconium ileus. In simple meconium ileus, the plug can be relievedby manipulation or direct enteral irrigation with N-acetylcysteine following an enterotomy. In complicated cases, bowel resection, peritoneallavage, abdominal drainage, and stoma formationmay be necessary. Total parenteral nutrition will be [email protected] 39. [email protected]