Pyloric stenosis

What is pyloric stenosis?

Pyloric stenosis is a blockage of the opening from the stomach to the small intestine. Pyloric stenosis is also called hypertrophic pyloric stenosis. The pylorus is a muscle around this opening. Normally, this muscle keeps food in the stomach when it tightens and lets food out of the stomach when it relaxes. But when the muscle below the stomach is thick and tight, like in pyloric stenosis, it cannot relax properly to allow breast milk or formula through. This means the breast milk or formula you feed your baby cannot pass easily from the stomach to the intestine, which makes your baby vomit (throw up).

Pyloric stenosis

Signs and symptoms of pyloric stenosis

The symptoms of pyloric stenosis usually appear between two and six weeks of life but may occur later. The condition is rare in babies older than three months.

Symptoms may include:

• persistent projectile vomiting within 30 minutes after feeding
• constant hunger (initially), especially after vomiting
• sleepiness
• smaller and fewer bowel movements
• weight loss
• dehydration, indicated by lack of tears, reduced wet diapers, dry mouth/lips, etc.

If you feel that your baby is dehydrated or has these symptoms, see a health-care provider right away.

Causes of pyloric stenosis

The cause of pyloric stenosis is not clearly understood and is likely multifactorial – considering environmental exposures, maternal history and other factors. In some babies, there is a family history of pyloric stenosis, suggesting that genes also play a role.

is pyloric stenosis diagnosed?

An abdominal ultrasound will be done to confirm the diagnosis of pyloric stenosis before your child is taken to the operating room. The ultrasound will measure the pyloric muscle thickness and length.

A health history, physical assessment and blood work may be completed when your infant arrives at the hospital to rule out other causes of dehydration and assess for dehydration.

What your child's health-care provider can do

Your baby's health-care provider will listen to your story and will examine your baby. If they suspect pyloric stenosis, they will order blood tests and an ultrasound. An ultrasound is the most common method of diagnosing pyloric stenosis.

Many babies with pyloric stenosis may be dehydrated and may have electrolyte imbalances in their blood due to vomiting. They will need intravenous (IV) fluids and will require their electrolytes to be corrected before surgery can be performed. They may have a tube inserted through their nose to their stomach to help empty the contents of the stomach. During this time, your child will not be allowed to eat.

Your child will remain hydrated with the IV fluids that they are receiving and blood work may be repeated to ensure their electrolytes are within acceptable ranges prior to proceeding with surgery. If your baby has pyloric stenosis, they will need a surgery called a pyloromyotomy. During a pyloromyotomy, the surgeon will cut the tight muscle between the stomach and the small intestine. This loosens the muscle so the stomach can empty. Food will then be able to pass easily into the small intestine.

For more information, please see the article: "Pyloromyotomy: Surgery for pyloric stenosis".

Follow-up care for pyloric stenosis

In most cases, your child will not need long-term follow-up. You should schedule a visit with your child’s primary care provider within one week of discharge from hospital.

When to get medical assistance

See your baby's health-care provider right away or visit the nearest Emergency Department if:

• your are concerned that your baby is dehydrated
• your baby has constant projectile vomiting
• your baby is losing weight
• your baby is not peeing as much as usual or has no tears when crying
• your baby seems very tired or drowsy