Pyloric stenosis: Difference between revisions

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==Background==
==Background==
* More common in males (5:1) & firstborn children (30%)
[[File:Gray1046.png |thumb|Outline of stomach, showing its anatomical landmarks, including the pylorus.]]
* Symptoms usually begin between 3-6 weeks of age, rarely after 12 weeks  
*More common in males (5:1) & firstborn children (30%)
*Prematurity and macrolide use are also thought to be risk factors
*Most common surgical cause of vomiting in infants
*The main diagnostic criterion is a measurement of more than 3 mm in thickness of the muscular layer on ultrasound.<ref>Dias, S et al Insights Imaging. 2012 Jun; 3(3): 247–250.</ref>
*Abnormal elongation of the canal is characterised as greater than 17 mm in length .<ref>Teele RL, Smith EH. Ultrasound in the diagnosis of idiopathic hypertrophic pyloric stenosis. N Engl J Med. 1977 May 19. 296(20):1149-50.</ref><ref>Sargent SK, Foote SL, Mooney DP, Shorter NA. The posterior approach to pyloric sonography. Pediatr Radiol. 2000 Apr. 30(4):256-7</ref>
 
==Clinical Features==
*Symptoms usually begin between 3-6 weeks of age, rarely after 12 weeks
*[[Nausea and vomiting (peds)|Vomiting]], immediately postprandial, nonbilious, often projectile, but desires to feed ("hungry vomiter")
*Palpable mass in in RUQ to epigastric region after vomiting, occasionally may see reverse peristaltic fluid wave across abdomen
*If untreated, will see signs of [[dehydration (peds)|dehydration]], weight loss, [[lethargy]], [[pediatric shock|shock]]


==Diagnosis==
# Immediate post-prandial, non-bilious, often projectile vomiting, but desires to feed ("hungry vomiter")
# Palpable mass in in RUQ to epigastric region, occassionally may see peristaltic waves
# Labs might show a low K, Low Cl, & hypo-Cl alkolosis
# Imaging
## Abdominal xray: May show large stomach bubble
## U/S: ~ 95% Sn/Sp
==Differential Diagnosis==
==Differential Diagnosis==
#Adrenal crisis
{{Pediatric abdominal pain DDX}}
#hyperkalemic acidosis
#hypokalemic alkalosis


==Treatment==
==Evaluation==
# IVF
[[File:Pyloric-stenosisLocal.jpg|thumb|Pyloric stenosis as seen on ultrasound in a 6 week old.]]
## Normal electrolytes and no e/o dehydration
[[File:PS longitudinal Subramaniam.gif|thumbnail|Longitudinal view of thickened and elongated pylorus muscle<ref>http://www.thepocusatlas.com/pediatrics/</ref>]]
### 5% dextrose w/ 0.25% NaCl and 2 meq KCl per 100 mL
*Labs may show [[hypokalemia]] and hypochloremic [[metabolic alkalosis]]
## Moderate or severe dehydration
 
### Higher NaCl concentrations (0.5% to normal saline) and higher rates of administration (1.5 to 2 times maintenance)
===Imaging===
# NGT
''Primary test of choice''
# Surgery
*[[ultrasound: abdomen|Ultrasound]]: thickened (>3 mm) and elongated (>17 mm) pylorus ~ 95% Sn/Sp<ref>Rohrschneider WK, Mittnacht H, Darge K, Tröger J. Pyloric muscle in asymptomatic infants: sonographic evaluation and discrimination from idiopathic hypertrophic pyloric stenosis. Pediatr Radiol. 1998 Jun;28(6):429-34.</ref>
## Can be delayed 24-36 hr to rehydrate infant
 
''Other tests that may show findings''
*[[Abdominal x-ray]]: may show large stomach bubble with absence of air in small bowel or colon
**Characteristic caterpillar sign (gastric contractions against hypertrophied pylorus)
*Upper GI: string sign (narrowed pyloric lumen), double track sign (duplicated mucosa), beak sign (abnormality of pyloric opening)
 
==Management==
*[[IVF]]
**Normal electrolytes and no evidence of dehydration
***5% dextrose with 0.25% NaCl and 2 meq KCl per 100 mL
**Moderate or severe dehydration
***Higher NaCl concentrations (0.5% to normal saline) and higher rates of administration (1.5 to 2 times maintenance)
**Ensure correction of bicarbonate level, as it may be a hypoventilation risk
*[[Nasogastric tube]]
*Surgery
**Can be delayed 24-36 hr to rehydrate infant and correct electrolytes


===Precautions===
===Precautions===
* Ensure that kidneys are functional prior to giving potassium  
*Ensure that kidneys are functional prior to giving [[potassium]]
* Do not give LR
*Do not give lactated ringers
* May lead to worsening alkalosis --> apnea in infants
**May lead to worsening alkalosis > apnea in infants
 
==Disposition==
*Admission


==Source==
==See Also==
UpToDate
*[[Abdominal Pain (Peds)]]


[[Category:Peds]]
==References==
<references/>
[[Category:Pediatrics]]
[[Category:GI]]
[[Category:GI]]
[[Category:Surgery]]

Latest revision as of 20:07, 17 March 2022

Background

Outline of stomach, showing its anatomical landmarks, including the pylorus.
  • More common in males (5:1) & firstborn children (30%)
  • Prematurity and macrolide use are also thought to be risk factors
  • Most common surgical cause of vomiting in infants
  • The main diagnostic criterion is a measurement of more than 3 mm in thickness of the muscular layer on ultrasound.[1]
  • Abnormal elongation of the canal is characterised as greater than 17 mm in length .[2][3]

Clinical Features

  • Symptoms usually begin between 3-6 weeks of age, rarely after 12 weeks
  • Vomiting, immediately postprandial, nonbilious, often projectile, but desires to feed ("hungry vomiter")
  • Palpable mass in in RUQ to epigastric region after vomiting, occasionally may see reverse peristaltic fluid wave across abdomen
  • If untreated, will see signs of dehydration, weight loss, lethargy, shock

Differential Diagnosis

Pediatric Abdominal Pain

0–3 Months Old

3 mo–3 y old

3 y old–adolescence

Evaluation

Pyloric stenosis as seen on ultrasound in a 6 week old.
Longitudinal view of thickened and elongated pylorus muscle[4]

Imaging

Primary test of choice

  • Ultrasound: thickened (>3 mm) and elongated (>17 mm) pylorus ~ 95% Sn/Sp[5]

Other tests that may show findings

  • Abdominal x-ray: may show large stomach bubble with absence of air in small bowel or colon
    • Characteristic caterpillar sign (gastric contractions against hypertrophied pylorus)
  • Upper GI: string sign (narrowed pyloric lumen), double track sign (duplicated mucosa), beak sign (abnormality of pyloric opening)

Management

  • IVF
    • Normal electrolytes and no evidence of dehydration
      • 5% dextrose with 0.25% NaCl and 2 meq KCl per 100 mL
    • Moderate or severe dehydration
      • Higher NaCl concentrations (0.5% to normal saline) and higher rates of administration (1.5 to 2 times maintenance)
    • Ensure correction of bicarbonate level, as it may be a hypoventilation risk
  • Nasogastric tube
  • Surgery
    • Can be delayed 24-36 hr to rehydrate infant and correct electrolytes

Precautions

  • Ensure that kidneys are functional prior to giving potassium
  • Do not give lactated ringers
    • May lead to worsening alkalosis > apnea in infants

Disposition

  • Admission

See Also

References

  1. Dias, S et al Insights Imaging. 2012 Jun; 3(3): 247–250.
  2. Teele RL, Smith EH. Ultrasound in the diagnosis of idiopathic hypertrophic pyloric stenosis. N Engl J Med. 1977 May 19. 296(20):1149-50.
  3. Sargent SK, Foote SL, Mooney DP, Shorter NA. The posterior approach to pyloric sonography. Pediatr Radiol. 2000 Apr. 30(4):256-7
  4. http://www.thepocusatlas.com/pediatrics/
  5. Rohrschneider WK, Mittnacht H, Darge K, Tröger J. Pyloric muscle in asymptomatic infants: sonographic evaluation and discrimination from idiopathic hypertrophic pyloric stenosis. Pediatr Radiol. 1998 Jun;28(6):429-34.