Pediatric or congenital GI diseases Flashcards
What is the most common presentation of tracheoesophageal fistula? (STEP)
• manifests most commonly as a connection of distal esophagus and trachea
• occurs in the setting of esophageal atresia
• The result is that the proximal esophagus ends in a blind pouch and the distal esophagus is open into the trachea.
*patients present with vomiting, polyhydramnios, abdominal distension and aspiration
If you see tracheoesophageal fistula, you are worried about what other constellation of congenital abnormalities? (STEP)
The majority of these infants have other congenital abnormalities including:
- cardiac defects (e.g. ventricular septal defect),
- genitourinary anomalies (e.g. renal agenesis),
- gastrointestinal malformations (e.g. imperforate anus),
- or musculoskeletal abnormalities (e.g. polydactyly).
What intrauterine signs of tracheoesophageal fistula are to be expected?
During intrauterine life:
- polyhydramnios is very common and
- lack of stomach gas on prenatal ultrasound is an indication of this abnormality.
After birth, what symptoms suggest tracheoesophageal fistula? (STEP)
The clinical presentation is typically soon after birth.
- Infants have episodes of coughing and choking with symptoms worsening at feeding.
- Feeding may lead to aspiration and infection (pneumonia).
- aspiration pneumonia may result in pulmonary edema
- Surgical correction is usually required during the first days of life although some patients with very small fistulae may occasionally present later in childhood or even as adults.
Projectile vomiting at 3 weeks of age might suggest what congenital abnormality?
- Infantile hypertrophic pyloric stenosis (IHPS)
- This lesion is more common in male than female infants and can occur in up to 1 in 200 live male births.
- Structurally, there is hypertrophy and hyperplasia of the smooth muscle in the gastric wall at the level of the pylorus that leads to narrowing of the antrum that can cause near complete obstruction.
- The proximal stomach is typically secondarily dilated.
- The typical clinical presentation is with projectile vomiting that generally occurs at approximately 3 weeks of age.
What’s up with Meckel’s diverticulum?
- This is the most common congenital malformation of the small intestine
- Structurally, it arises due to partial persistence of the vitelline (omphalomesenteric) duct or yolk stalk.
- A small blind pouch forms that protrudes from the terminal ileum and typically measures 2 to 3 cm in length and width.
- Sometimes persistence of the duct occurs with a thin sinus tract or fibrous band extending to the umbilicus that may cause small bowel obstruction.
- The wall of a Meckel Diverticulum often contains gastric mucosa which may undergo such typical gastric diseases as peptic ulceration.
Omphalocele and Gastroschisis look very similar but occur by different mechanisms. What are these mechanisms?
- Omphalocele
- This rare malformation is caused by a failure of the intestines to return from the extraembryonic celom to the abdominal cavity at 10 weeks of gestation.
- An omphalocele consists of a defect in the abdominal wall at the attachment site of the umbilical cord.
- A large sac composed of amnionic membranes is filled with loops of bowel.
- Gastroschisis
- superficially similar (bowel protruding from the abdomen), but occurs by a different mechanism.
- In gastroschisis, the cause of the bowel protrusion is a paraumbilical defect in the abdominal wall. (more like an intrauterine hernia)
A 22 year old patient is complaining of symptoms that point to volvulus. What congenital abnormality might predispose them to this event?
Malrotation
- This important anomaly of the large intestine occurs during development when the intestines are prevented from assuming their normal position inside the abdomen.
- This usually occurs as the intestines are returning to the abdominal cavity just after 10 weeks gestation.
- Most patients are asymptomatic, but the typical presentation is with volvulus of the large bowel.
What’s up with Intestinal stenosis/atresia?
Stenosis refers to congenital narrowing of the bowel whereas atresia refers to complete failure of development causing a blind ending.
- These lesions are uncommon and generally occur along with other malformations as part of a malformation syndrome or in the setting of cystic fibrosis.
- Usually, only a segment of bowel is involved and vascular insufficiency during development is a likely cause.
What congenital disorders concerning the rectum and anus are worrysome?
- Imperforate anus/Rectal agenesis
- This malformation occurs with a spectrum of severity ranging from a thin membrane of tissue covering the anus to the worst disease which is complete agenesis of the rectum.
- More severe forms are often associated with other cloacal or urogenital abnormalities. (look for constellations of malformations)
What are the main issues with Hirschprung Disease
- AKA = congenital megacolon due to the massive dilatation of the intestinal lumen which is the most prominent clinical feature.
- Usually children are detected by a failure to pass meconium soon after birth.
- When only short segments of bowel are involved, presentation may be delayed until later in life occasionally due to perforation of a distended megacolon.
- The disease occurs more commonly in male infants with a sex ratio of M:F=4:1.
- The disease is caused by a number of mutations most of which are in RET receptor or ligand genes that control development of the nervous plexi of the colon.
- Endothelin 3 and endothelin receptor genes are also important regions of mutation.
- These mutations lead to failure of the bowel nerve plexi (both Auerbach and Meissner) to form in a segment of the bowel wall with a resulting absence of ganglion cells.
- Usually, there is a constricted segment of bowel lacking ganglion cells that begins in the rectum and extends a variable distance proximally. The normally innervated bowel upstream of the aganglionic segment is typically dilated.
- Treatment is by surgical resection of the abnormal segment of bowel.
What are the presenting manifestations of hirschprung disease?
- AKA = congenital megacolon due to the massive dilatation of the intestinal lumen which is the most prominent clinical feature.
- Usually children are detected by a failure to pass meconium soon after birth.
- (REASON FOR NON NEONATE PRESENTATION) When only short segments of bowel are involved, presentation may be delayed until later in life occasionally due to perforation of a distended megacolon.
- Usually, there is a constricted segment of bowel lacking ganglion cells that begins in the rectum and extends a variable distance proximally. The normally innervated bowel upstream of the aganglionic segment is typically dilated.
- Treatment is by surgical resection of the abnormal segment of bowel.
Mutations in the RET or endothelin genes can do what?
causes of hirschprung disease (congenital megacolon)
- These mutations lead to failure of the bowel nerve plexi (both Auerbach and Meissner) to form in a segment of the bowel wall with a resulting absence of ganglion cells.
- Usually, there is a constricted segment of bowel lacking ganglion cells that begins in the rectum and extends a variable distance proximally. The normally innervated bowel upstream of the aganglionic segment is typically dilated.
what causes Neonatal necrotizing enterocolitis (NEC)?
- NEC mainly occurs as a complication of prematurity that develops in the first week to 10 days of life and is manifested by abdominal distension and bloody stools.
- Generally occurrence is associated with hypoxemia (such as in RDS) where blood is shunted away from the intestine to provide scarce oxygen resources to more important organs.
- Ishcemic damage to the bowel wall leads to invasion of organisms, formation of gas gangrene within the bowel wall (pneumatosis intestinalis) with subsequent perforation and peritonitis.
- Any part of the bowel may be affected although the most commonly involved areas are the terminal ileum, cecum, and right colon. Medical therapy includes bowel rest and antibiotics; if this fails, surgical resection of the involved bowel is performed.
What are the clinical manifestations of NEC?
NEC = Neonatal necrotizing enterocolitis
- NEC mainly occurs as a complication of prematurity that develops in the first week to 10 days of life and is manifested by abdominal distension and bloody stools (RDS is another association, ischemia)
- Ishcemic damage to the bowel wall leads to invasion of organisms, formation of gas gangrene within the bowel wall (pneumatosis intestinalis) with subsequent perforation and peritonitis.
