Gastroenterology Flashcards
Intussusception
A condition in which a portion of the bowel invaginates or telescopes into an adjacent segment, usually proximal to the ileocecal valve
Most common cause of bowel obstruction in first 2 years of life (males more than females). Usually seen between 3mo and 3y of age.
Cause is often unknown
Risk factors include conditions with potential lead points like Meckel’s, intestinal lymphoma (older than 6years), Henoch-Shonlein purpura, parasites, polyps, adenovirus or rotavirus, celiac disease, and CF
Intussusception history and exam
1) Presents with abrupt-onset, colicky abdominal pain in apparently healthy children, often accompanied by flexed knees and vomiting. Child may appear well in between episodes if intussusception is released
2) Class triad is abdominal pain, vomit and bloody mucis in stool* (curant jelly stool). This stool finding is late and hemoccult positive
3) On exam, look for abdominal tenderness, a positive stool guaiac, a palpable sausage-shaped RUQ abdominal mass, and absence of bowel in RLQ (“empty” on palpation)
Dx and Tx for intussusception
1) Abdominal plain films are often normal early in the disease, but later they may show SBO, perf, or soft tissue mass. US is test of choice and may show target sign.
2) Correct any volume or lyte issues. Check CBC for leukocytosis and consider NGT for decompression
3) in setting of high clinical suspicion, an air-contrast barium enema should be done ASAP as it is diagnostic in over 95% of cases and curative in more than 80%. If kid is unstable or has peritoneal signs or if enema reduction is unsuccessful, perform surgical reduction and resection of gangrenous bowel
Pyloric stenosis
Hypertrophy of pyloric sphincter, leading to gastric outlet obstruction. More common in firstborn males. Associated with TEFs, a maternal history of pyloric stenosis, and erythromycin ingestion
History and exam of pyloric stenosis
1) Nonbilious emesis typically begins around 3w of age and progresses to projectile emesis after most or all feedings
2) Babies initially feed well but eventually suffer from malnutrition and dehydration
3) Exam may reveal palpable olive-shaped, mobile, nontender epigastric mass and visible gastric peristaltic waves
Dx of pyloric stenosis
1) Abdominal US is the imaging modality of choice and reveals a hypertrophic pylorus
2) Barium studies show a narrow pyloric channel (string sign) or a pyloric beak.
Classic metabolic issue is hypochloremic, hypokalemic metabolic alkalosis (persistent emesis of HCl)
Tx of pyloric stenosis
1) Correct existing dehydration and acid-base/lyte issues.
2) Surgical correction with pyloromyotomy
Meckel’s
Caused by failure of the omphalomesenteric (or vitelline) duct to obliterate. Resulting heterotopic gastric tissue causes ulcers and bleeding.
Most common congenital abnormality of the small intestine, affecting up to 2% of children (more in males). Most frequently occurs in kids less than 2years old.
History and exam for Meckel’s
1) Typically ASx, and often discovered incidentally
2) Classically presents with sudden, intermittent, painless rectal bleeding
3) May result in complications such as intestinal obstruction, diverticulitis (which may mimic acute appendicitis), volvulus, and intussusception
Dx of Meckel’s
1) A meckel scintigraphy (Tc99m pertechnetate; detects ectopic gastric tissue) is diagnostic
2) Plain films have limited value but can be useful in diagnosing obstruction or perforation
Tx of Meckel’s
In presence of active bleeding, treatment is surgical excision of the diverticulum together with the adjacent ileal segment (ulcers frequently develop in adjacent ileum)
Rule of 2s
Refers to Meckel’s
1) Most common in children under 2
2) 2x more in males
3) 2 types of tissue (pancreatic and gastric)
4) 2 inches long
5) Found within 2 feet of ileocecal valve
6) 2% of population
Hirschsprung’s Disease
Congenital lack of ganglion cells in distal colon, leading to uncoordinated peristalsis reduced motility. Associated with male gender, Down Syndrome, Waardenburg’s, and MEN2
History and exam of Hirschsprung
1) Neonates present with failure to mass meconium within 48h after birth, accompanied by bilious vomiting and FTT. Children with less severe lesions may present later in life with chronic constipation
2) Physical exam may show abdominal distension and explosive discharge of stool following rectal exam. Lack of stool in rectum or abnormal sphincter tone.
dx of Hirschsprung
1) Barium enema is the imaging study of choice and reveals a narrowed distal colon with proximal dilation. Plain films reveal distended bowel loops with a paucity of air in rectum
2) Anorectal manometry detects failure of the internal sphincter to relax after distention of the rectal lumen. It is typically used in atypical presentations or older kids
3) Rectal biopsy confirms dx and reveals absence of the myenteric (Auerbach’s) plexus and submucosal (Meissner’s) plexus along with hypertrophied nerve trunks enhanced with acetylcholinesterase stain
Tx of Hirschsprung
Traditionally a 2 stage surgical repair used involving creation of a diverting colostomy at time of dx followed several weeks later by a definitive “pull through” procedure connecting remaining colon to rectum
Malrotation with volvulus
Congenital malrotation of midgut results in abnormal positioning of the small intestine (cecum in the right hypochondrium) and formation of fibrous bands (Ladd’s bands). Bands predispose to obstruction and constriction of blood flow
History and exam for malrotation with volvulus
1) Often presents in the first month of life with bilious emesis, crampy abdominal pain, distention, and passage of blood or mucus in the stool
2) Post-surgical adhesions can lead to obstruction and volvulus at any point in life
Dx of malrotation with volvulus
1) AXR may reveal the characteristic bird beak appearance and air-fluid levels but may also appear normal
2) If patient is table, an upper GI is study of choice and shows an abnormal location of the ligament of Treitz. US may be used, but its sensitivity is contingent on experience of user
tx of malrotation with volvulus
1) NG tube insertion to decompress intestine. IVFs
2) Emergent surgical repair when volvulus is gastric; surgery or endoscopy when it is intestinal
Necrotizing enterocolitis
Condition in which portion of bowel undergoes necrosis. Most common GI emergency in neonates. Most frequently seen in premature infants, but can occur in full termers too
History and exam for necrotizing enterocolitis
1) Symptoms usually present within the first few days or weeks of life and are nonspecific, including feeding intolerance, delayed gastric emptying, abdominal distention, and bloody stools
2) Symptoms may rapidly progress to intestinal perf, peritonitis, abdominal erythema, and shock. Maintain high index of suspicion.
Dx of necrotizing enterocolitis
1) Lab findings are nonspecific and may show hyponatremia, metabolic acidosis, leukopenia, or leukocytosis with L shift, thrombocytopenia, and coagulopathy (DIC with prolonged PT/aPTT and positive D-Dimer)
2) Plain abdominal radiographs may show dilated bowel loops, pneumatosis intestinalis (intramural air bubbles representing gas produced by bacteria within bowel wall), portal venous gas or abdominal free air. Serial abdominal plain films should be taken every 6h
3) US may also be helpful in discerning free air, areas of loculation or walled-off abscesses and bowel necrosis
Tx of necrotizing enterocolitis
1) Initiate supportive measures including NPO, an orogastric tube for gastric decompression, correction of dehydration and lyte issues, TPN, IV ABx
2) Indications for surgery are perf (free air under diaphragm) or worsening radiographic signs on serial abdominal plain films. An ileostomy with mucuous fistula is typically performed with a reanastomosis later
3) Complications include formation of intestinal strictures and short bowel syndrome
