Pyloric Stenosis — NCLEX Cheat Sheet
Projectile vomit, olive massAlso known as: projectile vomiting baby · stomach outlet blockage · hypertrophic pyloric stenosis
Use this quick-reference guide to spot, treat, and prevent Pyloric Stenosis on the NCLEX. Keep it handy during review and on exam day!
🩺📒 The 1-minute cheat sheet
⚠️ Causes
- Pyloric muscle hypertrophy
- Firstborn males, 2–8 wks old
🩺 Signs
- Projectile NON-bilious vomiting
- Olive-shaped RUQ mass
- Hungry after vomiting, FTT
🧪 Labs
- Metabolic ALKALOSIS, ↓ K+, ↓ Cl-
- Dehydration from vomiting
✅ Do
- Correct fluids/lytes pre-op
- Pyloromyotomy = definitive fix
📚 Pyloric Stenosis — full study notes
The cheat sheet above is your quick recall card. These notes go deeper — what it is, what to do first, what must be reported, and what to teach.
Key points
Understand these first- The hallmark is forceful, projectile vomiting of nonbilious (no bile) stomach contents shortly after feeding.
- The infant remains hungry and eager to feed again right after vomiting.
- A firm, movable, olive-shaped mass may be palpated in the right upper quadrant.
- Visible peristaltic waves may move left to right across the upper abdomen after feeding.
- Loss of stomach acid through vomiting causes hypochloremic, hypokalemic metabolic alkalosis.
- Progressive dehydration, weight loss or failure to gain, and decreased urine output develop.
Nursing priorities
What to do, in order- Keep the infant NPO and provide IV fluids to correct dehydration and electrolyte imbalances before surgery.
- Correct fluid, chloride, and potassium imbalances and monitor electrolytes; surgery is delayed until the infant is stable.
- Monitor strict intake and output, daily weights, and vital signs.
- Prepare the family for pyloromyotomy (surgical correction), which is the definitive treatment.
- Postoperatively, begin small frequent feeds as ordered, position upright after feeds, and minimize handling.
Red flags — report now
Escalate immediately- Bile-stained (green) vomit suggests a different, lower obstruction and must be reported immediately.
- Severe dehydration signs (sunken fontanelle, no wet diapers, lethargy) require prompt fluid resuscitation.
- Uncorrected electrolyte imbalance and alkalosis must be addressed before any surgery proceeds.
- Persistent vomiting after pyloromyotomy beyond the expected period should be reported.
Labs & values
Numbers to know- Chloride: normal 98-106 mEq/L, decreased (hypochloremia)
- Potassium: normal 3.5-5.0 mEq/L, decreased (hypokalemia)
- pH: normal 7.35-7.45, elevated (metabolic alkalosis)
- Sodium: normal 135-145 mEq/L
Patient teaching
What patients must know- After surgery, feed small frequent amounts as directed and burp the infant frequently.
- Hold the infant upright during and after feeds and avoid excessive handling to reduce vomiting.
- Some vomiting may continue for a day or two after surgery, but report persistent or projectile vomiting.
- Watch for and report fewer wet diapers, dry mouth, or unusual sleepiness as signs of dehydration.
❓ Pyloric Stenosis: NCLEX FAQs
What are the priority nursing interventions for Pyloric Stenosis?
Keep the infant NPO and provide IV fluids to correct dehydration and electrolyte imbalances before surgery. Correct fluid, chloride, and potassium imbalances and monitor electrolytes; surgery is delayed until the infant is stable. Monitor strict intake and output, daily weights, and vital signs. Prepare the family for pyloromyotomy (surgical correction), which is the definitive treatment.
What are the warning signs of Pyloric Stenosis a nurse must report?
Bile-stained (green) vomit suggests a different, lower obstruction and must be reported immediately. Severe dehydration signs (sunken fontanelle, no wet diapers, lethargy) require prompt fluid resuscitation. Uncorrected electrolyte imbalance and alkalosis must be addressed before any surgery proceeds. Persistent vomiting after pyloromyotomy beyond the expected period should be reported.
What do I need to know about Pyloric Stenosis for the NCLEX?
The hallmark is forceful, projectile vomiting of nonbilious (no bile) stomach contents shortly after feeding. The infant remains hungry and eager to feed again right after vomiting. A firm, movable, olive-shaped mass may be palpated in the right upper quadrant. Visible peristaltic waves may move left to right across the upper abdomen after feeding.
What patient teaching is important for Pyloric Stenosis?
After surgery, feed small frequent amounts as directed and burp the infant frequently. Hold the infant upright during and after feeds and avoid excessive handling to reduce vomiting. Some vomiting may continue for a day or two after surgery, but report persistent or projectile vomiting. Watch for and report fewer wet diapers, dry mouth, or unusual sleepiness as signs of dehydration.
Quick Tip
The hallmark is forceful, projectile vomiting of nonbilious (no bile) stomach contents shortly after feeding.
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