Pyloric Stenosis: A Must-Know Topic for all Aspirants

Introduction

If you're preparing for the AIIMS PG entrance or any medical competitive exam, pyloric stenosis is a high-yield topic you can’t afford to skip. It’s one of the most common causes of non-bilious projectile vomiting in infants—and a favorite of examiners!

In this blog post, we’ll break down everything you need to know about pyloric stenosis in an easy, concept-based format that sticks, while keeping it SEO-rich for medical readers like you.


What is Pyloric Stenosis?

Pyloric stenosis (also called infantile hypertrophic pyloric stenosis) is a congenital condition where the pyloric muscle (the muscle between the stomach and duodenum) becomes abnormally thickened, leading to gastric outlet obstruction.

🧠 Exam Tip: It usually presents between 2 to 6 weeks of age, more commonly in first-born male infants.


Why Does It Happen?

The exact cause of pyloric stenosis is not fully understood, but here are some contributing factors:

  • Genetic predisposition

  • Macrolide antibiotic exposure (e.g., erythromycin)

  • Male sex predominance (4:1 male to female ratio)


Key Clinical Features (Easy Mnemonics & Points)

🔑 Remember the “3 Ps” of pyloric stenosis:

  • Projectile vomiting (non-bilious)

  • Palpable olive mass in the epigastric region

  • Peristaltic waves visible after feeding

👶 Classic Scenario: A 4-week-old baby, vomiting forcefully after feeds, still hungry after vomiting, and losing weight.


Diagnosis: How is it Confirmed?

1. Clinical Examination

  • Olive-shaped mass in the right upper abdomen

  • Visible gastric peristalsis (left to right)

2. Investigations

  • Ultrasound is the gold standard:

    • Pyloric muscle thickness > 3 mm

    • Pyloric channel length > 15–18 mm

  • Lab findings (due to vomiting):

    • Hypochloremic, hypokalemic metabolic alkalosis

🎯 Exam Focus: Remember the "metabolic alkalosis" with paradoxical aciduria due to volume depletion.


Management of Pyloric Stenosis

Step 1: Stabilization

Correct dehydration and electrolyte imbalances before surgery.

  • IV fluids: Normal saline + potassium

  • Monitor electrolytes and urine output

Step 2: Surgery

Ramstedt’s Pyloromyotomy – A longitudinal incision through the hypertrophied muscle to relieve obstruction.

🩺 Prognosis is excellent after surgery, with most infants recovering completely.


Differential Diagnosis (Don’t Confuse in Exams!)

  • Gastroesophageal reflux

  • Intestinal atresia (bilious vomiting)

  • Malrotation with volvulus (urgent!)

🔍 Key point: Pyloric stenosis = non-bilious vomiting
Malrotation = bilious vomiting


Radiological Clues (Image-Based Questions)

  • Ultrasound – elongation & thickening of pyloric muscle

  • Barium study (if USG unavailable):

    • “String sign” or “Double tract sign”

    • “Shoulder sign” – bulging pylorus

📸 These signs are popular in AIIMS/INI-CET image-based MCQs!


Your’s Role in Pyloric Stenosis

  • Monitor for dehydration signs (sunken fontanelle, dry mucosa)

  • Ensure NPO (nil per os) status pre-surgery

  • Maintain IV fluid and electrolyte balance

  • Post-op care: monitor for vomiting, pain, and wound infection


Key Facts to Revise Before Exam

FeaturePyloric Stenosis
Age of Onset2–8 weeks
VomitingProjectile, non-bilious
MassOlive-like, epigastric
Electrolyte DisturbanceHypokalemic, hypochloremic alkalosis
TreatmentRamstedt's pyloromyotomy
ImagingUSG: muscle >3 mm, length >15 mm
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Dev chaudhary
Dev chaudhary I'm Dev and I am 27 year old.I provide you amazing articles related to health & medical education on the Medicaldudes.com

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