PEDS GI Pt. 1

What type of obstruction causes non‑bilious vomiting?

Obstruction above the duodenum, such as near the ampulla of Vater.

What should be ordered when a newborn has limb abnormalities and an imperforate anus?

Echocardiogram, renal ultrasound, and X‑ray, because these defects commonly occur together in VACTERL.

When does duodenal atresia typically manifest?

Around 24–36 hours of life.

Why do newborns stay in the hospital for a couple of days after birth?

To monitor for conditions like duodenal atresia that present after the first day of life.

What is the classic physical exam finding in pyloric stenosis?

A nontender, firm, mobile “olive‑like” mass in the abdomen.

Why is vomiting non‑bilious in pyloric stenosis?

Because the obstruction is above the ampulla of Vater.

What are common demographic features of pyloric stenosis?

Heavy male predominance, often firstborn, sometimes with family history.

Why might parents report constipation in pyloric stenosis?

Because the baby is not receiving or passing adequate amounts of milk due to vomiting.

Why is meconium passage not delayed in pyloric stenosis?

Because the GI tract is anatomically intact

Around what structure does the midgut rotate during development?

The superior mesenteric artery.

What is a key anatomic clue for malrotation?

All bowel structures lie to the right of the midline.

Why is midgut volvulus an emergency?

Because twisting can obstruct the superior mesenteric artery and cause bowel necrosis.

Where does an omphalocele occur?

Through the umbilical cord, centrally located.

What covers the bowel in an omphalocele?

A peritoneal sac.

What is the embryologic origin of the omphalocele sac?

A different mesenteric duct structure.

Is omphalocele midline?

Yes — it is centrally located.

Where is gastroschisis typically located?

Right of center, in the right peri‑umbilical area.

Is gastroschisis covered by a sac?

No — the bowel is exposed.

Why do infants with congenital diaphragmatic hernia develop respiratory failure at birth?

Abdominal organs occupy the chest, preventing lung expansion during the first breath.

What physical exam findings suggest congenital diaphragmatic hernia?

Bowel sounds in the chest, respiratory distress, and heart sounds shifted to the right.

What must be done when a newborn fails to pass meconium?

Obtain an abdominal X‑ray.

What is the classic X‑ray finding in meconium ileus?

Soap‑bubble appearance from thick mucus trapping gas and meconium.

What diagnostic test can also be therapeutic in meconium ileus?

Contrast enema.

What cells are missing in Hirschsprung disease?

Ganglion cells of the colon.

What exam is used to evaluate for Hirschsprung disease?

Digital rectal exam to check for explosive release of stool or retained meconium.

Why does bilious vomiting indicate obstruction below the ampulla of Vater?

Because bile enters the GI tract at the ampulla, so obstruction below it allows bile to mix with gastric contents.

Why do limb abnormalities plus an imperforate anus trigger cardiac and renal imaging?

Because VACTERL defects cluster, so finding one increases suspicion for others.

Why does duodenal atresia present after 24 hours instead of immediately at birth?

Because symptoms begin once feeding starts and gastric contents accumulate.

Why does pyloric stenosis cause metabolic alkalosis?

Because persistent vomiting leads to loss of stomach acid.

Why is pyloric stenosis non‑bilious but duodenal atresia is bilious?

Pyloric stenosis is above the ampulla of Vater, while duodenal atresia is below it.

Why does malrotation predispose to volvulus?

Because abnormal rotation leaves the mesentery narrow, making twisting easier.

Why is infection risk higher in gastroschisis than omphalocele?

Because gastroschisis lacks a protective sac.

Why is omphalocele associated with other congenital anomalies?

Because it results from a developmental defect in midline closure.

Why does congenital diaphragmatic hernia shift heart sounds to the right?

Because abdominal organs push the mediastinum away from the herniated side.

Why does congenital diaphragmatic hernia cause immediate respiratory distress?

Because the lungs cannot expand due to bowel occupying the thoracic cavity.

Why does meconium ileus produce a soap‑bubble appearance?

Because thick mucus traps gas bubbles within meconium.

Why does Hirschsprung disease cause failure to pass meconium?

Because the aganglionic segment cannot relax, causing functional obstruction.

What are the upper obstruction GI disorders in pediatrics?

Esophageal atresia/TEF, Duodenal atresia, Intestinal atresia, Hypertrophic pyloric stenosis, Malrotation and volvulus

What are the lower obstruction GI disorders in pediatrics?

Omphalocele, Gastroschisis, Congenital diaphragmatic hernia, Meconium ileus, Meconium plug syndrome

What are the acquired GI disorders in pediatrics?

Hirschsprung’s disease, Necrotizing enterocolitis, Imperforate anus

What are the hallmarks of failure to pass meconium?

Failure to pass meconium in 24 hours, Abdominal distention, Reluctance to feed, Bilious vomiting

What does bilious vomiting indicate in failure to pass meconium?

The obstruction was somewhere below the duodenum

What is the differential for failure to pass meconium?

Duodenal atresia, Intestinal atresia, Malrotation and volvulus, Hirschsprung, Meconium ileus, Meconium Plug, Imperforate anus

What is the first step in the workup for failure to pass meconium?

Rule out imperforate anus or any other anal abnormality

What x‑ray finding suggests duodenal atresia or malrotation?

Double bubble

What x‑ray finding suggests lower intestinal obstruction?

Multiple dilated loops of bowel

What upper GI finding suggests malrotation?

Duodenal c‑loop does not cross midline

What upper GI finding suggests malrotation with volvulus?

Bird’s beak sign

What upper GI finding suggests jejunal/ileal atresia?

Transition zone in small bowel

What contrast enema finding suggests meconium ileus?

Total microcolon

What contrast enema finding suggests meconium plug syndrome?

Filling defects in the large bowel

What contrast enema finding suggests Hirschsprung’s disease?

Transition zone

What should be strongly considered in the workup of failure to pass meconium?

rectal manometry

What condition is suspected when there's a double bubble finding on XRAY?

down syndrome.

What other condition, besides malrotation with volvulus, would bird's beak be seen in?

achlasia.

What is atresia?

closed or absent of a natural passage of the body

What is stenosis?

narrowed

What is volvulus?

an obstruction caused by twisting of the stomach or intestine

What does VACTERL stand for?

Vertebral anomalies, Anus (imperforate), Cardiac defects, Trachea, Esophagus, Renal, Limbs

What vertebral anomaly is associated with VACTERL?

Spina bifida

What cardiac defects are associated with VACTERL?

VSD, ASD

What is VACTERL?

Group of growth abnormalities that occur during fetal growth development. Need 3 (some sources say 2)

What is the embryologic cause of esophageal atresia/TEF?

An interruption in the separation of the foregut into the trachea and esophagus during the fourth week of gestation

What do all types of esophageal atresia/TEF involve?

incomplete formation of the esophagus

How often is esophageal atresia associated with TEF?

90% of the time

How often is EA associated with VACTERL?

10%

Why is polyhydramnios seen in EA/TEF?

because the baby can’t swallow anything, so that fluid isn’t regulated

What are the types of EA/TEF?

EA with distal TEF (87%), Isolated EA (8%), Isolated TEF (4%), EA with proximal TEF (1%), EA with double TEF (1%)

What are symptoms of esophageal atresia/TEF?

Respiratory distress shortly after birth, worsening with feeding

What is a prenatal sign of esophageal atresia/TEF?

polyhydramnios.

What is the best initial test for esophageal atresia/TEF?

plain film (cxr/axr) which will show a blind upper pouch in about 92% of cases.

What additional test should be ordered in EA/TEF?

Echocardiogram

How many EA/TEF patients have congenital heart disease?

30–50%

What is the management of esophageal atresia/TEF?

Surgical Peds Consult, NG Decompression, IV fluids, IV nutrition or gastrostomy, IV ABX.

What is the definitive treatment for EA/TEF?

surgical repair.

What is duodenal atresia?

Congenital absence or complete closure of part of the duodenal lumen. Defect occurs in early embryonic stages.

What conditions are associated with duodenal atresia?

trisomy’s, cardiac lesion, and VACTERL

What prenatal finding suggests duodenal atresia?

polyhydramnios

Why does polyhydramnios occur in duodenal atresia?

The baby can take in fluid but only up until the duodenum, so then it becomes overflow incontinence and goes back up through the mouth, remaining with mom in the sac.

What are symptoms of duodenal atresia?

bilious vomiting within hours after birth, failure to pass meconium, failure to thrive, scaphoid abdomen with epigastric distension

What is the best initial diagnostic step for duodenal atresia?

abdominal xray → “double bubble sign”

What is the management of duodenal atresia?

Peds surg consult, IV fluids and nutrition, May defer surgery, but if so get a contrast enema to r/o malrotation.

What is the corrective surgery done for duodenal atresia?

duodenoduodenostomy.

What post-op management is done for duodenal atresia?

obs, continue parental nutrition until stool passes, prophylactic IV abx.

What is the best initial diagnostic step for duodenal atresia, and what sign is seen?

abdominal xray which shows double bubble sign.

What are operative findings in duodenal atresia?

annular pancreas

What is an annular pancreas?

Rare congenital condition where a ring of pancreatic tissue surrounds the second part of the duodenum causing obstruction of the duodenum.

What must NEVER be done in annular pancreas?

NEVER DIVIDE the pancreas

What causes intestinal atresia (in contrast to duodenal atresia)?

atresia elsewhere in the GI tract are typically caused by vascular accidents in utero.

How often is intestinal atresia associated with cystic fibrosis?

10% will have cystic fibrosis.

What are symptoms of intestinal atresia?

Similar to duodenal atresia

What determines the severity of abdominal distension in intestinal atresia?

The severity of distension is proportional to how far the obstruction is down the GI tract.

What is the best initial diagnostic test for intestinal atresia?

abdominal X-ray

What radiographic signs are associated with intestinal atresia?

Triple bubble or apple peel

What does triple bubble indicate?

Triple bubble in cases after the duodenum

Where are the three bubbles in triple bubble found?

The bubbles are below the duodenum, the duodenum itself, and the stomach.

What is apple peel associated with?

superior mesenteric artery disruption

What additional diagnostic test can aid in intestinal atresia workup?

contrast enema

What is Type I intestinal atresia?

short area of stenosis or a membranous web occluding the lumen

What is type 1 atresia similar to?

Almost like ischemia, one part of the segment doesn’t enlarge like the other end of the intestine.