Pediatric Surgery—Pyloric Stenosis
Concept
Thickening of the muscle of the pylorus resulting in func- tional outlet obstruction. Most common surgical cause of emesis in infants. Unknown etiology.
Way Question May be Asked?
“Called to ED to evaluate a 9 week old infant with a his- tory of intermittent non-bilious emesis that is now projec- tile vomiting. What do you want to do?” May be given an infant with clear signs of dehydration and may be an older infant (up to 2 years old). Key is whether or not the vom- iting was bilious.
How to Answer?
History
FHx of pyloric stenosis
Bilious vs. non-bilious vomiting
Vomiting of undigested formula shortly after feeding Intermittent emesis progressing to projectile
Infant hungry between episodes of vomiting
Physical Exam
Sunken fontanelle Dry mucous membranes Decreased skin turgor Abdominal exam:
Thickened pylorus or “olive” in epigastrum (need infant to be quiet and stomach empty) Observation of gastric peristaltic waves
Diagnostic Tests
Full labs especially K+ (hypokalemic, hypochloremic metabolic alkalosis)
U/S
Elongated pyloric channel Thickened pyloric diameter Increased pyloric wall thickness Barium UGI
Elongated narrow pyloric channel (“string sign”) Gastric outlet obstruction
Surgical Treatment
(1) Correct electrolyte abnormalities (this is an elective surgical procedure)
(2) D51/2NS
(3) Pyloromyotomy (Ramstedt technique) general anesthesia
transverse epigastric or RUQ incision grasp pylorus between two fingers incision with scalpel into serosa/muscle
back of scalpel handle to blunt complete pyloromy- otomy
should see bulging mucosa
careful not to perforate underlying mucosa
(if perforate, close and cover with omental patch, or close myotomy and rotate pylorus 45˚ and per- form pyloromyotomy again)
(4) Can start feeding 6–12 h post-op with dilute milk and advance as tolerated
(5) Small episodes of emesis not uncommon in imme- diate post-op period, pursue with UGI for incom- plete pyloromyotomy if extends past POD#2.
Common Curveballs
Pt will have low K+ and asked how you will manage Being asked when you will start feeding the child Mucosal perforation during your pyloromyotomy, now
what?
Scenario will change and pt will have malrotation, antral web, or duodenal stenosis
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Incomplete pyloromyotomy
Asked to describe Paradoxic Aciduria
(vomiting leads to loss of fluid with high K+, H+, and Cl-concentrations. Volume deficit leads to aldos- terone mediated Na+ resorption with loss of K+
and body tries to hold onto K+ leading to excretion of H+ ions leading to paradoxic aciduria)→treat by replacing volume before administering K+!
Being asked how to calculate volume of fluid to be administered to the infant and given a weight in kg
Strikeouts
Mistaking diagnosis for one of the many etiologies for neonatal bowel obstruction
Not being able to describe how to resuscitate the pt pre- op
Describing laparoscopic pyloromyotomy
Not being able to explain the hypokalemic, hypochloremic metabolic alkalosis that typically accompanies these pts
Strikeouts 93
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