Peds GI Flashcards
Pyloric Stenosis
general
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
pyloric stenosis
RF
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
pyloric stenosis
Sx
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)
pyloric stenosis
Signs
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
pyloric stenosis
pyloric stenosis
patho
pyloric stenosis
labs
Laboratory studies
Hypochloremicmetabolic alkalosis
Hypokalemia
Dehydration leads to retention of sodium and elimination of potassium
Elevated bloodureanitrogen(BUN) and creatinine withsevere dehydration
pyloric stenosis
Imaging
US criteria
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
Target signordonut sign:classic cross-sectional appearance of thepylorusin the shape of a target or donut
pyloric stenosis
pyloric stenosis
Preoperative care
Fluid replacement + decompression
Correct electrolyte abnormalities
Restoration of acid-base balance
pyloric stenosis
Surgery and post op
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
Hirschsprung Disease
general
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”
Hirschsprung Disease (HD)
patho
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)
Total colonic aganglionosis including a short segment of the terminal ileum
HD
Triad
Classic triad of symptoms:
Delayed passage ofmeconium
> 48 hours in a term infant
Abdominal distension
Bilious vomiting
HD
Clin Man
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)
HD
Later presentations
Less severe functional obstruction (ultrashort-segment HD - < 4 cm from theinternal anal sphincter)
Symptoms and signs:
Chronic refractoryconstipation
Abdominal distension
Failure to thrive
HD
Dx from Hx
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)
HD
Dx testing
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)
HD
Tx
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
HD
Meckel’s Diverticulum
general
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
Meckels Diverticulum
Etiology
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)
Meckels diverticulum
Clin Man
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
Meckels diverticulum
Meckel’s scan:
Nuclear medicine scan utilizing radioactively labeled technetium that binds togastric mucosa
First-line test for hemodynamically stable patients and if suspicion is high
ts for GI bleeding
for stable pts
Arteriography:
Invasive test used when bleeding is brisk enough to necessitate blood transfusion
An anomalous branch of thesuperior mesenteric artery feeding the Meckel’sdiverticulum can be identified
Meckels divertulum
Computed tomography (CT)angiography:
More sensitive than arteriography for less-brisk hemorrhage
meckels diverticulum
Tests for SBO and diverticulitis
CT scan of the abdomen and pelvis:
Will identifySBO, inflammatory changes,perforation
Diagnostic laparoscopy:
Performed if imaging studies are equivocal (difficult to distinguish an inflamed diverticulum fromappendicitis on imaging)
Can be therapeutic as well as diagnostic
Meckels diverticulum
Asymptomatic
Tx
Asymptomatic
AMeckel’sdiverticulum incidentally found on imaging:no treatment necessary
AMeckel’sdiverticulum found during surgery(for another condition):
Resection recommended:
- All children
- Healthy, adults (< 50 years of age) with a Meckel’sdiverticulum > 2 cm long or palpable abnormalities/fibrous bands are noted
- Adults >50 years of age or withcomorbidities and a palpable abnormality
No resection recommended: if patient is >50 years of age and there is no palpable abnormality
Meckels diverticulum
Symptomatic
Tx
Supportive:
Intravenous hydration andresuscitation
Blood transfusion if necessary (for GI bleeding)
Bowel rest, nasogastric decompression (forSBO)
Intravenous antibiotics (for Meckel’sdiverticulitis)
Surgery(definitive treatment):
Emergent if signs ofsepsis,peritonitis,perforation
Resection of a Meckel’sdiverticulum
Segmentalsmall bowelresection (including a Meckel’sdiverticulum):
To include ulcerated bleeding mucosa
If the adjacentsmall bowel is severely inflamed/ischemic
Intussusception
general
Condition in which part of the intestine (intussusceptum) telescopes into another part (intussuscipiens) of the intestine leading to obstruction; if untreated → progress tobowel ischemia
Ileocecal/ileocolic
Most common, accounts for 85%–90% of cases
Epidemiology:
Most common cause ofbowel obstructionin the 6–36-month age group
60% of cases within 1st year of life
Most prevalent around viral season (viral gastroenteritis)
intussusception
Etiology
Idiopathic(~80% of cases) with no identifiable lead point:
Most common in children
Rare in adults
Infection (causes Peyer’spatchenlargement):
Upper respiratory tract infection (30%) - adenovirus
Bacterialenteritis
Recentrotavirusimmunization or infection
Underlying pathology:
Meckel’sdiverticulum
Most common
Inversion of the outpouching of the GI tissue
Henoch-Schönlein purpura(causes thickening of the intestinal mucosa)
Lymphoma
Intestinal polyps or tumors
intussusception
Peyer’s patches
“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)
Intussusception is consideredidiopathicif it does not involve a lead point
Lead point:
A lesion that gets trapped duringperistalsis and drags a segment of intestines into a distal part of the intestine
Tumor/polyp
Meckel’sdiverticulum
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
Transmuralnecrosisandperforationmay occur with prolonged ischemia
intussusception
Clinical Presentation – Infants/Toddlers
Triad
Sudden onset, cramping, severe intermittentabdominal 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)
intussusception
Classic triad
Classic triad(only present in 15% of cases):
- Intermittent abdominal pain
- Sausage-shapedmassin the RUQ
- Currant-jelly stool:
Blood mixed with mucus
Suggests mucosalnecrosisand sloughing
Latepresentation
intussusception
pediatric PE findings
Physical exam:
General appearance:
Pallor
Inconsolable crying
Lethargy
Palpation:
Sausage-shapedmassin the RUQ
Dance’s sign: scaphoid (empty) RLQ
May or may not have focal abdominal tenderness
Guarding, rebound → usually late signs associated withbowel ischemia
Auscultation: high-pitched bowel sounds (indicative of obstruction)
intussusception- Peds
Imaging:
Abdominal ultrasound:
Best initial test
Target sign:the invaginated portion of the bowel appears as aringon 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
intussusception- peds
Contrast or pneumatic enema:
Confirmatory
Therapeutic as well as diagnosticfor ileocecal intussusception
Performed using ultrasound orfluoroscopy
Procedure:
Air/contrast is injected into the intestines to create pressure, which ejects the trapped part of the bowel out of the distal bowel
intussusception
Tx
Initial management:
NPO
Nasogastric decompression
Fluidresuscitation
Nonsurgical reduction:
1st-line therapy for:
Ileocecal intussusception
Stable patientswithout peritonitis/evidence ofperforation/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)
intussusception
Surgical management:
Indications:
Unstable patient, peritonitis; evidence of perforation/ischemia
Completely unsuccessful reduction attempt with enema
A persistent filling defect after reduction, suggesting a tumor
For asmall bowel-to-small bowel intussusception
intussusception
Surgical options
Hutchinson maneuver:
Manual reduction of the intussusception
If there is no lead point identified, only manual reduction is needed
Concomitantappendectomyis sometimes performed
Can be performed open or laparoscopically
Bowel resection:
Forbowel perforation, nonviable bowel, or lead point identified
intussusception
Clinical Presentation – Older Children/Adults
intussusception- adult
PE findings
Physical exam:
Abdominal distention
Focal or diffuse tenderness
Peritonitisis a late presentation = ischemia/perforation
intussusception - adult
imaging
Imaging:
AbdominalX-ray:
Nonspecific
Can show obstructive pattern:
Dilatedsmall bowelloops
Pneumoperitoneum if perforation occurred
Abdominal CT scan:
Smallbowel obstruction:
Dilatedsmall bowelloops
Collapsed distalsmall bowelandcolon
Bowel wall thickening
Target sign
intussusception- adult
Tx
Asymptomatic intussusception without obstruction:
Usually an incidental finding on CT scan
Will resolve spontaneously and does not require an intervention
Intussusception associated withbowel obstruction:
Associated with pathologic lead point (> 90% of cases)
Can involvesmall bowelorcolon
Requires surgery
General approach is the same as for anybowel obstruction
