Peds GI

Question 1

Pyloric Stenosis

general

Answer 1

Functional obstruction of the gastric outlet caused by hypertrophy and hyperplasia of the pyloric sphincter muscle

Epidemiology:
Most common cause ofintestinal obstructionin infants
Occurs in 1–3 of every 1,000 infants in the United States

Etiology:
Unknown
Genetic and environmental factors might play a role
Usually not present at birth

Question 2

pyloric stenosis

RF

Answer 2

Sex
More common in boys — especially firstborn children — than in girls

Race
More common in whites of northern European ancestry

Premature birth (before 37 weeks)
More common in babies born prematurely than in full-term babies

Family history
History of pyloric stenosis in mother or father

Smoking during pregnancy
Nearly double the risk of pyloric stenosis

Exposure to macrolide antibiotics
Example: erythromycin to treat whooping cough
Mothers who took certain antibiotics in late pregnancy

Question 3

pyloric stenosis

Sx

Answer 3

Symptoms
Initially,regurgitationafter feeding
Later, non-bilious, projectile vomiting immediately after feeding
Usually starts after 2-4 weeks of age
Poor weight gain
Infant shows signs of hunger (irritability, increasedsucking reflex)

Question 4

pyloric stenosis

Signs

Answer 4

Signs
Firm, mobile, olive-shaped, 2-cmmass above and to the right of the umbilicus inepigastrium
Gastric peristaltic wave across the abdomen after feeding
Signs ofdehydration:
Sunkenfontanelles, delayed capillary refill, dry mucous membranes, and/or decreasedurineoutput may be present

NON bilious vomit

Vomiting might be mild at first and gradually become more severe as the pylorus opening narrows

Question 5

pyloric stenosis

Question 6

pyloric stenosis

patho

Answer 6

Question 7

pyloric stenosis

labs

Answer 7

Laboratory studies
Hypochloremicmetabolic alkalosis
Hypokalemia
Dehydration leads to retention of sodium and elimination of potassium
Elevated bloodureanitrogen(BUN) and creatinine withsevere dehydration

Question 8

pyloric stenosis

Imaging
US criteria

Answer 8

Ultrasound
Pyloric muscle thickness: > 4mm(the most discriminating and accurate criterion)
Pyloric muscle length: > 15mm
Pyloric diameter: > 15mm

Contrast studies
If diagnosis not confirmed by ultrasound, but still suspected

Question 9

Answer 9

Target signordonut sign:classic cross-sectional appearance of thepylorusin the shape of a target or donut

pyloric stenosis

Question 10

pyloric stenosis

Preoperative care

Answer 10

Fluid replacement + decompression
Correct electrolyte abnormalities
Restoration of acid-base balance

Question 11

pyloric stenosis

Surgery and post op

Answer 11

Surgery
Ramstedt pyloromyotomy:
Short transverseskinincision plus longitudinal incision of pyloric muscle up to submucosa

Postoperative care
Oral feeding can be initiated within 12–24 hours
Persistent vomiting suggests incomplete pyloromyotomy or an alternative diagnosis

Question 12

Hirschsprung Disease

general

Answer 12

Congenital anomaly of thecolon that is caused by the absence of ganglion cells at the Meissner’s plexus (submucosa) and Auerbach’s plexus (muscularis) of the terminal rectum that extends proximally
Associated with mutations in multiplegenes that are important for the growth and differentiation ofneural crest cells, most commonly in theRETgene
~1 in 5,000 live births in the US

Classification:
Sporadic:
Most common (70%)
Familial forms
As part of a genetic syndrome:
Down syndrome (DS)/trisomy 21: ~10% of individuals withHD have DS

“achalasia of the colon”

Question 13

Hirschsprung Disease (HD)

patho

Answer 13

Caused by the failure of neural crest-derivedganglion cells to migrate into the distal colon → functional obstruction due to the arrest ofperistalsis

Aganglionic segment also have abnormal alterations in the expression ofreceptors,channels, cytoskeletalproteins, and neurotrophic factors

Auerbach’s plexus – causes smooth muscle relaxation
Meissner’s plexus – controls flow, epithelial cell absorption, and secretion

The rectum is always involved
Rectosigmoidcolon is most common (“short-segment disease”): 80%
Extension proximal to thesigmoid colon(“long-segment disease”): 15%–20%
Total colonic: 5% of cases

Muscularhypertrophy and dilatation of bowel proximal to obstruction, with possible progression tomegacolon and rupture (usually in thececum)

Question 14

Answer 14

Total colonic aganglionosis including a short segment of the terminal ileum

Question 15

HD

Triad

Answer 15

Classic triad of symptoms:
Delayed passage ofmeconium
> 48 hours in a term infant
Abdominal distension
Bilious vomiting

Question 16

HD

Clin Man

Answer 16

Triad

Additional signs and symptoms in the neonatal period:
Explosive expulsion of gas and stool afterdigital rectal examination (temporary relief of obstruction)
Enterocolitis (more common if the diagnosis is delayed):
Sepsis withfever
Vomiting,diarrhea, and abdominal distension → toxic megacolon
Bowel perforation (cecal/appendiceal)

Question 17

HD

Later presentations

Answer 17

Less severe functional obstruction (ultrashort-segment HD - < 4 cm from theinternal anal sphincter)

Symptoms and signs:
Chronic refractoryconstipation
Abdominal distension
Failure to thrive

Question 18

HD

Dx from Hx

Answer 18

Suspected based on the clinical presentations in the neonatal or postnatal periods…No meconium in 24 hours start to worry about HD!

Most individualsare diagnosed in the 1st month of life

Less severe disease may not present with symptoms until 3 years of age (10% of cases)

Question 19

HD

Dx testing

Answer 19

Contrast enema:
Pathognomonic sign of the “transition zone” (funnel-shaped segment between the aganglionicrectum and the proximal dilatedcolon)

Anorectal manometry:
Helpful inscreening individuals with ultrashort-segmentHD

Rectalbiopsy: necessary for confirmation of the diagnosis (absence ofganglion cells)

Question 20

HD

Tx

Answer 20

Surgical resectionof the aganglionic segment of the bowel is the only definitive treatment

Ultrashort-segmentHD(aganglionosis < 4 cm from theinternal anal sphincter):
Medical management with diet, stool softeners,laxatives
Surgical management may be needed

Question 21

HD

Question 22

Meckel’s Diverticulum

general

Answer 22

Persistent remnant of an embryonic structure known as the omphalomesenteric (vitelline) duct
A true diverticulum (contains all layers of the bowel wall)
Located in the middle to distalileum

Epidemiology
the most common congenital gastrointestinal (GI) tract anomaly

Most commonly presents with symptoms at 2–4 years of age

Increasedincidencein children with major malformations involving the:
Umbilicus
GI tract
Nervous system
Heart

Question 23

Meckels Diverticulum

Etiology

Answer 23

Omphalomesenteric duct:
Connects themidgutto theyolk sacin utero
Normally involutes between the 5th and 6th weeks of gestation

Omphalomesenteric duct that does not fully involute can give rise to:
AMeckel’s diverticulum(most common persistent remnant)
Omphalomesentericcysts
Omphalomesentericfistula(drain through umbilicus)
Fibrousbands (can causebowel obstruction)

Question 24

Meckels diverticulum

Clin Man

Answer 24

Frequently asymptomatic
Painless lowerGI bleeding(most common):
Acute (massive hematochezia)
Chronic/slow (melena; currant jelly or maroon stools in children)

SBO:
Nausea/vomiting
Crampingabdominal pain
Abdominal distention
In children: most commonly in the form of recurrent intussusception

Meckel’sdiverticulitis:
Symptoms similar to acuteappendicitis
Signs of peritoneal irritation if perforated
Abdominal tenderness is usually more midline

Question 25

# Meckels diverticulum Meckel’s scan:

Answer 25

Nuclear medicine scan utilizing radioactively labeled technetium that binds to gastric mucosa **First-line** test for hemodynamically stable patients and if suspicion is high ts for GI bleeding | for stable pts

Question 26

Arteriography:

Answer 26

Invasive test used when bleeding is brisk enough to necessitate blood transfusion An anomalous branch of the superior mesenteric artery feeding the Meckel’s diverticulum can be identified

Question 27

# Meckels divertulum Computed tomography (CT) angiography:

Answer 27

More sensitive than arteriography for less-brisk hemorrhage

Question 28

# meckels diverticulum Tests for SBO and diverticulitis

Answer 28

CT scan of the abdomen and pelvis: Will identify SBO, inflammatory changes, perforation Diagnostic laparoscopy: Performed if imaging studies are equivocal (difficult to distinguish an inflamed diverticulum from appendicitis on imaging) Can be therapeutic as well as diagnostic

Question 29

# Meckels diverticulum Asymptomatic Tx

Answer 29

Asymptomatic A Meckel’s diverticulum incidentally found on imaging: no treatment necessary A Meckel’s diverticulum found during surgery (for another condition): Resection recommended: * All children  * Healthy, adults (< 50 years of age) with a Meckel’s diverticulum > 2 cm long or palpable abnormalities/fibrous bands are noted * Adults >50 years of age or with comorbidities and a palpable abnormality No resection recommended: if patient is >50 years of age and there is no palpable abnormality

Question 30

# Meckels diverticulum Symptomatic Tx

Answer 30

**Supportive**: Intravenous hydration and resuscitation Blood transfusion if necessary (for GI bleeding) Bowel rest, nasogastric decompression (for SBO) Intravenous antibiotics (for Meckel’s diverticulitis) **Surgery** (definitive treatment): Emergent if signs of sepsis, peritonitis, perforation Resection of a Meckel’s diverticulum Segmental small bowel resection (including a Meckel’s diverticulum): To include ulcerated bleeding mucosa If the adjacent small bowel is severely inflamed/ischemic

Question 31

Question 32

Answer 32

Question 33

# Intussusception general

Answer 33

Condition in which part of the intestine (intussusceptum) telescopes into another part (intussuscipiens) of the intestine leading to obstruction; if untreated → progress to bowel ischemia Ileocecal/ileocolic Most common, accounts for 85%–90% of cases Epidemiology: Most common cause of bowel obstruction in the 6–36-month age group 60% of cases within 1st year of life Most prevalent around viral season (viral gastroenteritis)

Question 34

# intussusception Etiology

Answer 34

Idiopathic (~80% of cases) with no identifiable lead point: Most common in children Rare in adults Infection (causes Peyer’s patch enlargement): Upper respiratory tract infection (30%) - adenovirus Bacterial enteritis Recent rotavirus immunization or infection Underlying pathology: Meckel’s diverticulum  Most common Inversion of the outpouching of the GI tissue Henoch-Schönlein purpura (causes thickening of the intestinal mucosa) Lymphoma Intestinal polyps or tumors

Question 35

# intussusception Peyer’s patches

Answer 35

“Tonsils of the intestines” Collection of lymphoid follicles in the mucus membrane that lines the small intestine Produce **immunoglobulin A** Limits the epithelial adherence and penetration of bacteria (confines the bacteria to the mucosal surfaces)

Question 36

Answer 36

Intussusception is considered idiopathic if it does not involve a lead point Lead point: A lesion that gets trapped during peristalsis and drags a segment of intestines into a distal part of the intestine Tumor/polyp Meckel’s diverticulum Duplication cyst Vascular malformation Hematoma Telescoping of bowel into itself → obstruction and impaired lymphatic drainage Increasing pressure in intussusceptum bowel wall → impairment of venous and lymphatic drainage → vascular compromise Ischemia of intussusceptum mucosa → bowel mucosa infarcts and sloughs off → **bloody stools** **Transmural necrosis** and perforation may occur with prolonged ischemia

Question 37

# intussusception Clinical Presentation – Infants/Toddlers

Answer 37

Triad Sudden onset, cramping, severe **intermittent abdominal pain** Drawing up legs toward abdomen **Inconsolable crying** Episodes occur every 15–20 minutes and become more frequent over time Vomiting: Non-bilious to bilious as obstruction worsens Occurs after a pain episode Grossly bloody stool (50% of cases)

Question 38

# intussusception Classic triad

Answer 38

Classic triad (only present in 15% of cases): * Intermittent abdominal pain * Sausage-shaped mass in the RUQ * Currant-jelly stool: Blood mixed with mucus Suggests mucosal necrosis and sloughing Late presentation

Question 39

# intussusception pediatric PE findings

Answer 39

Physical exam: General appearance: Pallor **Inconsolable crying Lethargy** Palpation: Sausage-shaped mass in the RUQ Dance’s sign: scaphoid (empty) RLQ May or may not have focal abdominal tenderness Guarding, rebound → usually late signs associated with bowel ischemia Auscultation: high-pitched bowel sounds (indicative of obstruction)

Question 40

# intussusception- Peds Imaging:

Answer 40

**Abdominal ultrasound:** **Best initial test** **Target sign**: the invaginated portion of the bowel appears as a ring on a target (outer bowel wall) **Pseudokidney sign**: the appearance of the intussuscepted segment of bowel, which mimics a kidney **Abdominal CT:** Performed only if other modalities yield unclear diagnosis Usually identifies an underlying pathology (lead point) if present

Question 41

# intussusception- peds Contrast or pneumatic enema:

Answer 41

**Confirmatory** Therapeutic as well as diagnostic for ileocecal intussusception Performed using ultrasound or fluoroscopy Procedure: Air/contrast is injected into the intestines to create pressure, which ejects the trapped part of the bowel out of the distal bowel

Question 42

# intussusception Tx

Answer 42

Initial management:  NPO Nasogastric decompression Fluid resuscitation **Nonsurgical reduction**: **1st-line therapy for**: Ileocecal intussusception Stable patients without peritonitis/evidence of perforation/ischemia Accomplished with contrast or pneumatic enema → ~90% success rate If reduction is partial, a repeat reduction can be attempted for a stable patient Recurrence rate is 10%–20% (half occurring within first 72 hours)

Question 43

# intussusception Surgical management: Indications:

Answer 43

Unstable patient, peritonitis; evidence of perforation/ischemia Completely unsuccessful reduction attempt with enema A persistent filling defect after reduction, suggesting a tumor For a small bowel-to-small bowel intussusception

Question 44

# intussusception Surgical options

Answer 44

Hutchinson maneuver:  Manual reduction of the intussusception If there is no lead point identified, only manual reduction is needed Concomitant appendectomy is sometimes performed Can be performed open or laparoscopically Bowel resection: For bowel perforation, nonviable bowel, or lead point identified

Question 45

# intussusception Clinical Presentation – Older Children/Adults

Answer 45

Question 46

# intussusception- adult PE findings

Answer 46

Physical exam: Abdominal distention Focal or diffuse tenderness Peritonitis is a late presentation = ischemia/perforation

Question 47

# intussusception - adult imaging

Answer 47

Imaging: Abdominal X-ray: Nonspecific Can show **obstructive pattern**: Dilated small bowel loops Pneumoperitoneum  if  perforation occurred Abdominal CT scan: **Small bowel obstruction**: Dilated small bowel loops Collapsed distal small bowel and colon Bowel wall thickening **Target sign**

Question 48

# intussusception- adult Tx

Answer 48

Asymptomatic intussusception without obstruction: Usually an incidental finding on CT scan Will resolve spontaneously and does not require an intervention Intussusception associated with bowel obstruction: **Associated with pathologic lead point (> 90% of cases)** Can involve small bowel or colon Requires surgery General approach is the same as for any bowel obstruction