Which condition should an infant who has a meconium ileus be monitored for?
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Meconium ileus is a type of neonatal intestinal obstruction that occurs when abnormally thick meconium impacts in the ileum causing blockage of intestinal flow. Most infants with meconium ileus have cystic fibrosis, a congenital condition characterized by abnormally thick intestinal secretions and pancreatic insufficiency. The pathogenesis of meconium ileus is due to hyperviscous mucus secreted by abnormal intestinal glands, abnormal concentrating processes in the proximal small intestine, and pancreatic enzyme insufficiency. The clinical presentation of meconium ileus is that of abdominal distention, bilious vomiting, and failure to pass meconium. Cases of meconium ileus are usually evaluated with plain abdominal radiograph and contrast enema. Numerous air-filled loops of bowel on the supine view with characteristic absence of air-fluid levels are commonly seen on the radiograph, but the presence of calcification suggests intestinal perforation. Contrast enema examination is useful in cases with microcolon. Uncomplicated meconium ileus obstruction can be relieved by giving one or more dilute diatrizoate sodium enema (with Nacetylcysteine added) under fluoroscopy. Surgery is indicated when there is progressive distention or signs of clinical deterioration despite multiple enemas, as well as in complicated cases like meconium peritonitis, ileal atresia or stenosis, ileal perforation, and volvulus with or without pseudocyst formation. Show
The first bowel movement that a newborn with cystic fibrosis passes is called meconium ileus. It is normally very thick and sticky and usually passes in the first 12-24 hours after birth.1,2 Meconium ileus and cystic fibrosisThe meconium in newborns with cystic fibrosis (CF) is thicker and stickier than usual and this may block a part of the small intestine called the ileum. Thus, meconium ileus is a bowel obstruction in newborns. It is estimated that 80 to 90% of infants with meconium ileus have cystic fibrosis.1,2 In its 2017 Annual Data Report, the Cystic Fibrosis Foundation reports that meconium ileus is the first symptom that points to CF in 13.1% of babies eventually found to have CF. Of those, 13.8% of those babies had a severe enough blockage that it caused bowel perforation.3 How is it diagnosed?Babies with meconium ileus may not pass the first stool for several days, vomit, and have a swollen belly. In some cases, a prenatal ultrasound may reveal that the baby’s intestines are blocked. After birth, if meconium ileus is suspected, the child’s doctor will order an X-ray of the abdomen. X-rays may show a blockage, larger than normal small intestines, and smaller than usual colon because nothing is passing through. What is the treatment for meconium ileus?If meconium ileus is suspected, doctors will prescribe an enema that contains medicines to help break up the meconium. During this period, the baby will be fed and given the medicine through an intravenous line (IV). A small nasogastric tube (NG) will be placed in the infant’s nose to help remove excess air and fluid in the stomach.1 If the X-ray reveals a perforation or twisted intestines, or if the enema doesn’t work, immediate surgery is needed. This surgery is called a bowel resection. Surgery for meconium ileusOnly 13.8% of babies with meconium ileus need surgery for bowel obstruction or perforation.3 In bowel resection surgery, a piece of the small intestine is brought out to the surface of the skin to create an ileostomy. This is temporary. The bowel is reconnected later. Infants that have this surgery are cared for afterward in the Newborn Intensive Care Unit (NICU) until they are ready to go home.1 Uncomplicated meconium ileus typically presents immediately at birth with the recognition of abdominal distention, a unique feature of inspissated meconium filling and obstructing the distal small bowel. This problem may first have been heralded by an in utero genetic diagnosis of CF and an ultrasound suggestive of intestinal obstruction with echogenic bowel. In addition to the distention, intestinal obstruction is heralded by bilious vomiting and failure to stool. In contrast, complicated meconium ileus will present either in utero or postnatally with evidence of bowel obstruction complicated by evidence of previous intestinal perforation and/or necrosis: Crescents or speckles of intra-abdominal calcification may be present, or on clinical assessment there may be evidence of peritonitis including an erythematous or edematous abdominal wall and/or demonstrable abdominal tenderness.38 View chapterPurchase book Read full chapter URL: https://www.sciencedirect.com/science/article/pii/B9780323072557000830 Paediatric Abdominal ImagingAndreas Adam CBE, MB, BS(Hons), PhD, PhD (hon caus), DSc (hon caus), FRCP, FRCR, FRCS, FFRRCSI(Hon), FRANZCR(Hon), FACR(Hon), FMedSci, in Grainger & Allison's Diagnostic Radiology, 2021 Functional Immaturity of the Colon and Meconium Plug SyndromeImmature left colon (syn. small left colon) and meconium plug syndrome are relatively common causes of neonatal bowel obstruction. There is overlap in both the clinical features and radiology of the two conditions, and the terms are often used interchangeably in the literature. The former refers to a transient functional obstruction of the colon, which occurs as a result of immaturity of the myenteric plexus. It is common in the infants of diabetic mothers and in those whose mothers have a history of substance abuse. Meconium plug syndrome is a temporary colonic obstruction caused by pellets of meconium. It is associated with both cystic fibrosis (CF) and Hirschsprung disease, both of which should be excluded if a diagnosis of meconium plug syndrome is made. Premature infants and infants of mothers who received magnesium sulphate therapy have an increased incidence of meconium plug syndrome, though the latter is disputed in the literature. In both conditions, the affected infants present with symptoms and signs of bowel obstruction. There is delayed passage of meconium. The plain radiograph shows distension of both small and large bowel loops to the level of the inspissated meconium plugs. In small left colon syndrome, the contrast enema typically shows a microcolon distal to the splenic flexure, at which point there is an abrupt transition to a mildly dilated proximal colon (Fig. 71.13). The main differential diagnosis is long-segment Hirschsprung disease, and biopsy may be required if symptoms do not improve. In meconium plug syndrome, the lodged meconium plugs are the cause of the obstruction, but the findings are essentially the same. The plugs lodge in the region of the splenic flexure, proximal to which there is colonic dilatation. Unlike small left colon syndrome, a microcolon is unusual. The (water-soluble) contrast enema is also therapeutic and once the meconium plugs are passed per rectum, the infant mechanical obstruction recovers. View chapter on ClinicalKey Meconium IleusIn Diagnostic Imaging: Pediatrics (Third Edition), 2017 DIAGNOSTIC CHECKLISTConsider• Causes of distal obstruction & microcolon •Diluted hyperosmolar WSCE for simple MI therapy Enema rarely curative in complicated MI (requires surgery) AP radiograph in a full-term newborn with failure to pass meconium (& whose parents are CF gene carriers) shows a distal bowel obstruction without soft tissue mass effect or signs of meconium peritonitis. With this history, MI is the primary diagnostic consideration. Supine WSCE in the same patient shows a microcolon & reflux of contrast into meconium-filled TI, most consistent with meconium ileus. Contrast did not reach dilated bowel.A 2nd supine WSCE was performed in the same patient. There is now reflux of the high osmolality 1:1 diluted Gastroview (950 mOsm) into multiple dilated bowel loops proximal to the obstructing meconium .AP abdominal radiograph in the same patient 1 day after the 2nd enema shows much less dilation of the bowel proximal to the previously obstructed TI. There is mild residual contrast in the persistently small, unused colon. This is considered a successful treatment enema for MI. Newborn AP radiograph shows calcification in the right upper quadrant (RUQ) (suggestive of meconium peritonitis) plus dilated bowel loops of a distal bowel obstruction. Both parents were CF gene carriers. US shows a round fluid collection in the RUQ with punctate echogenic foci in the wall, likely corresponding to the calcification seen on the radiograph. There is also a small amount of ascites. The WSCE (not shown) confirmed a microcolon with impacted TI pellets, giving a diagnosis of complicated MI.Anteroposterior radiograph in a 2-day-old patient shows distended loops of bowel with mottled density overlying many of the loops, probably meconium & not pneumatosis. Decubitus view showed no free air or fluid levels. WSCE in the same patient shows a microcolon. The terminal ileum is filled with meconium pellets, like “pearls on a string” AP radiograph in a neonate shows no free air or air-fluid levels but does show dilated loops of bowel, suggestive of distal bowel obstruction. No Ca²⁺ to suggest perforation are seen. WSCE in a prone patient shows a microcolon WSCE in the same patient on the following day shows a persistent dilated loop of contrast-filled bowel with new extravasation of contrast into the peritoneal cavity Anteroposterior radiograph in a 2-day-old neonate shows a relatively gasless abdomen with round, rim calcification indicative of a pseudocyst formation, typically due to an in utero perforation. Transverse US with extended view feature in the same patient shows a thick-walled, meconium-filled pseudocyst consistent with meconium peritonitis, similar to the radiograph.Transverse US in the same patient shows thick, echogenic bowel , a nonspecific finding that is frequently seen in patients with complicated meconium ileus.Anteroposterior radiograph in a full-term neonate who failed to pass meconium shows multiple dilated bowel loops consistent with distal bowel obstruction. No free air or calcification are noted. WSCE in the same patient shows a tiny microcolon with multiple obstructing meconium pellets in the terminal ileum , findings pathognomonic for meconium ileus.Intraoperative photograph shows the manual removal of inspissated meconium through an enterotomy in this patient with MI who had serial WSCEs that were unsuccessful. WSCE shows a tiny microcolon with reflux of contrast into a meconium-filled TI, most consistent with MI. Treatment followed with 1/2 strength Gastrografin.WSCE in a neonate shows contrast proximal to TI meconium. Later images showed decompression of the obstruction & passage of meconium consistent with successful noninvasive therapy. View chapterPurchase book Read full chapter URL: https://www.sciencedirect.com/science/article/pii/B978032344306750133X Pediatric SurgeryCourtney M. Townsend JR., MD, in Sabiston Textbook of Surgery, 2022 Meconium IleusMeconium ileus is a unique form of neonatal obstruction that occurs in infants with CF, an autosomal recessive disorder resulting from a mutation in the CF transmembrane regulator gene(CFTR). It is estimated that 3.3% of the white population in the United States are asymptomatic carriers of the mutatedCFTRgene. The abnormal chloride transport in patients with CF results in tenacious viscous secretions with a protein concentration of almost 80% to 90%. It affects a wide variety of organs, including the intestine, pancreas, lungs, salivary glands, reproductive organs, and biliary tract. Meconium ileus in the newborn represents the earliest clinical manifestation of CF, affecting approximately 10% to 15% of patients with this inherited disease. The incidence of CF ranges from 1 in 1000 to 2000 live births. Infants present with three cardinal signs in the first 24 to 48 hours of life: (1) generalized abdominal distention; (2) bilious emesis; and (3) failure to pass meconium. Maternal polyhydramnios occurs in approximately 20% of cases. In simple meconium ileus, the terminal ileum is dilated and filled with thick, tarlike, inspissated meconium. Smaller pellets of meconium are found in the more distal ileum, leading into a relatively small colon. In patients with simple meconium ileus, important plain abdominal radiographic findings include dilated and gas-filled loops of small bowel, absence of air-fluid levels, and a mass of meconium in the right side of the abdomen mixed with gas to give a ground-glass or soap bubble appearance. Abdominal radiographs show dilated bowel loops with relatively absent air-fluid levels because of thick, viscous meconium. A contrast enema using the water-soluble ionic solution gastrografin can both be diagnostic, demonstrating a small, narrow-caliber colon and inspissated meconium pellets in the terminal ileum, as well as therapeutic, as it aids in the evacuation of meconium by pulling water into the colon. It is imperative for an infant to be well hydrated and monitored closely. It is successful in relieving the obstruction in up to 75% of cases, with a bowel perforation rate of less than 3%. The pilocarpine iontophoresis sweat test revealing a chloride concentration of more than 60 mEq/L is the most definitive method to confirm the diagnosis of CF. A more immediate test is detection of the mutatedCFTR gene. Operative management ofsimple meconium ileus is required when the obstruction is persistent despite contrast enema, along with 5 mL of 10%N-acetylcysteine (Mucomyst) solution administered every 6 hours through a nasogastric tube. Historically, the dilated terminal ileum was resected and various types of stomas were created, allowing intestinal decompression and recovery. However, enterotomy, irrigation with warmed saline solution or 4%N-acetylcysteine, and simple evacuation of the luminal meconium without a stoma has also been advocated.N-acetylcysteine serves to break the disulfide bonds in the meconium to facilitate separation from the bowel mucosa. The meconium is manipulated into the distal colon or removed through the enterotomy. After the obstruction is relieved, the enterotomy is closed in standard fashion. If meconium evacuation is incomplete, a T-tube may be left in place in the ileum to facilitate continued postoperative irrigation. What disease is meconium ileus associated with?Meconium ileus is a bowel obstruction that occurs when the meconium in your child's intestine is even thicker and stickier than normal meconium, creating a blockage in a part of the small intestine called the ileum. Most infants with meconium ileus have a disease called cystic fibrosis.
Which of the following assessment findings in the neonate may indicate a meconium ileus?Babies with meconium ileus may have these symptoms: No passing of the first stool (meconium) Green vomit (also called bilious because it contains bile, a liquid made in the liver to help digest fats) Swollen belly (abdomen), maybe soon after birth.
Why is meconium ileus diagnostic for cystic fibrosis?Meconium ileus is frequently an early sign of cystic fibrosis. Cystic fibrosis is a genetic condition that causes your child's intestinal secretions to be abnormally thick and sticky. These secretions stick to the lining of your child's intestine, causing obstructions.
Which of the following conditions can cause failure to pass meconium?Other Causes of Failure to Pass Meconium
Neonatal medical conditions that can be associated with a failure to pass meconium include hypothyroidism, hypercalcemia, hypokalemia, sepsis and congestive heart failure.
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