II. Epidemiology

  1. Ages 4-12 weeks old (mean 3 weeks)

III. Pathophysiology

  1. Hypertrophy of pylorus of Stomach causing a gastric outlet obstruction

IV. Risk factors

  1. Bottle Feeding
  2. Family History of Pyloric Stenosis (especially northern european)
  3. Male gender (4 times more common than in girls)

V. Symptoms: Vomiting

  1. Non-Bilious Vomiting
  2. Starts intermittently
  3. Progressively increases in frequency and severity
  4. Projectile Vomiting in up to 70% of cases

VI. Signs

  1. Typically, otherwise well appearing infant with benign Abdomen
  2. Palpable swelling ("olive") present in >60% of cases in past when delayed presentation was common
    1. In 2016 olive is rare due to early presentations
    2. Inferior to xiphoid process and inferior or deep to left liver edge

VII. Labs

  1. Basic metabolic panel
    1. Hypochloremic hypokalemic Metabolic Alkalosis
      1. Rarely seen due to early presentations in U.S.

VIII. Imaging: Ultrasound

  1. Technique
    1. Linear probe in subxiphoid location, horizontal probe
    2. Look for gastric rugae, smooth outer serosal surface, slightly thicker wall
    3. Trace the outer surface of the Stomach down to the pylorus and duodenum
      1. Duodenal wall is much thinner than pylorus
  2. Diagnosis
    1. Thickened and elongated pylorus
      1. Pylorus wall thickness >3 mm
      2. Pylorus length >15 mm (variable)
    2. No relaxation
    3. No fluid passage within channel
      1. May see very minimal flow (string sign)

IX. Complications

  1. Pediatric Dehydration
  2. Hypochloremic hypokalemic Metabolic Alkalosis
    1. Rarely seen due to early presentations in U.S.

X. Management

  1. Correct fluid and electrolyte abnormalities
  2. Surgery (pyloromyotomy)

XI. Resources

  1. Pyloric Stenosis Ultrasound
    1. https://vimeo.com/156797541

XII. References

  1. Bukata (2013) Pediatric Emergencies, EM Bootcamp, CEME
  2. Nazer (2013) Pediatric Hypertrophic Pyloric Stenosis, EMedicine
    1. http://emedicine.medscape.com/article/929829-overview#showall

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Ontology: Pyloric Stenosis (C0034194)

Definition (NCI) Narrowing of the pyloric lumen caused either by hypertrophy of the surrounding muscles or tissue scarring due to a chronic peptic ulcer.
Definition (MSH) Narrowing of the pyloric canal with varied etiology. A common form is due to muscle hypertrophy (PYLORIC STENOSIS, HYPERTROPHIC) seen in infants.
Concepts Finding (T033)
MSH D011707
ICD10 K31.1
SnomedCT 367403001
English Pyloric Stenosis, PYLORIC STENOSIS, pyloric stenosis (diagnosis), pyloric stenosis, Pyloric Stenosis [Disease/Finding], gastric outflow obstruction, pyloric stenoses, pyloric stenosi, gastric outlet obstruction, pyloric obstruction, Gastric Outlet Obstruction, Pylorus--Stenosis, Pyloric stenosis, PS - Pyloric stenosis, Pyloric stenosis (disorder), pylorus; stenosis, pylorus; stricture, stenosis; pylorus, stricture; pylorus, Stenosis, Pyloric, Pyloric stenosis NOS, Stenosis pyloric
Portuguese ESTENOSE PILORICA, Estenose pilórica, Estenose pilórica NE, Estenose Pilórica
Spanish ESTENOSIS PILORICA, Estenosis pilórica, Estenosis pilórica NEOM, estenosis pilórica (trastorno), estenosis pilórica, Estenosis Pilórica
German PYLORUSSTENOSE, Pylorusstenose NNB, Pylorusstenose
Dutch pylorusstenose, stenose pylorus, pylorusstenose NAO, pylorus; stenose, pylorus; strictuur, stenose; pylorus, strictuur; pylorus, Pylorusstenose, Stenose, pylorus-
Italian Stenosi del piloro, Stenosi del piloro NAS, Stenosi pilorica
French Sténose du pylore SAI, STENOSE DU PYLORE, Sténose pylorique, Sténose du pylore
Japanese 幽門狭窄NOS, ユウモンキョウサクNOS, ユウモンキョウサク, 幽門狭窄, 幽門狭窄症
Swedish Pylorusförträngning
Czech pylorus - stenóza, Pylorostenóza, Pylorostenóza NOS
Finnish Mahanportin ahtauma
Russian PILOROSTENOZ, ПИЛОРОСТЕНОЗ
Polish Zwężenie odźwiernika
Hungarian Pylorus stenosis k.m.n., Stenosis pylorikus, Pylorus stenosis
Norwegian Pylorusstenose, Magemunnsforsnevring