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Pyloric stenosis
From WikEM
Contents
Background
- More common in males (5:1) & firstborn children (30%)
- Symptoms usually begin between 3-6 weeks of age, rarely after 12 weeks
- The main diagnostic criterion is a measurement of more than 3 mm in thickness of the muscular layer.[1]
- Abnormal elongation of the canal is characterised as greater than 17 mm in length .[2][3]
Clinical Features
- 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
Differential Diagnosis
Pediatric Abdominal Pain
0–3 Months Old
- Emergent
- Nonemergent
3 mo–3 y old
- Emergent
- Nonemergent
3 y old–adolescence
- Emergent
- Nonemergent
Evaluation
- Labs may show hypokalemia, hypochloremia metabolic alkalosis
Imaging
Any of the following signs may be seen
- Abdominal xray: may show large stomach bubble
- Upper GI: string sign (narrowed pyloric lumen), double track sign (duplicated mucosa), beak sign (abnormality of pyloric opening)
- U/S: thickened (>3 mm) and elongated (>17 mm) pylorus ~ 95% Sn/Sp[4]
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)
- Normal electrolytes and no evidence of dehydration
- NGT
- Surgery
- Can be delayed 24-36 hr to rehydrate infant and correct electrolytes
- Ensure correction of bicarbonate level, as it may be a hypoventilation risk
Precautions
- Ensure that kidneys are functional prior to giving potassium
- Do not give LR
- May lead to worsening alkalosis > apnea in infants
See Also
References
- ↑ Dias, S et al Insights Imaging. 2012 Jun; 3(3): 247–250.
- ↑ Teele RL, Smith EH. Ultrasound in the diagnosis of idiopathic hypertrophic pyloric stenosis. N Engl J Med. 1977 May 19. 296(20):1149-50.
- ↑ Sargent SK, Foote SL, Mooney DP, Shorter NA. The posterior approach to pyloric sonography. Pediatr Radiol. 2000 Apr. 30(4):256-7
- ↑ 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.
