Pyloric stenosis

Overview

Pyloric stenosis (pie-LOHR-ik stuh-NOH-sis) is a narrowing of the opening between the stomach and the small intestine. This uncommon condition in infants can trap food in the stomach.

Typically, a ring-shaped muscular valve closes to hold food in the stomach or opens to allow food to pass into the small intestine. With pyloric stenosis, the muscle tissue is enlarged. The opening becomes very narrow, and little to no food passes into the intestine.

Pyloric stenosis usually leads to forceful vomiting, dehydration, poor nutrition and weight loss. Babies with pyloric stenosis may seem to be hungry all the time.

Pyloric stenosis is treated with surgery.

The passage between the stomach and small intestine is called the pylorus. The valve that controls the opening may be called the pyloric muscle, pyloric sphincter or pyloric valve.

The enlargement of the pyloric muscle is called hypertrophy. Pyloric stenosis also is called hypertrophic pyloric stenosis.

Symptoms

Symptoms of pyloric stenosis usually appear within 3 to 6 weeks after birth. Pyloric stenosis is rare in babies older than 3 months.

Symptoms include:

• Vomiting after feeding. The baby may vomit forcefully, ejecting breast milk or formula up to several feet away. This is known as projectile vomiting. Vomiting usually happens right after feeding. Vomiting might be mild at first and worsen over time.
• Constant hunger. Babies who have pyloric stenosis often want to eat soon after vomiting.
• Stomach contractions. Wavelike ripples across your baby's belly may be visible after feeding but before vomiting. This is a sign of the stomach muscles trying to move food out of the stomach.
• Dehydration. A baby may show signs of low body fluids, also called dehydration. These signs may include few wet diapers, lack of energy, dry mouth and lips, and crying without tears.
• Changes in stool. Since pyloric stenosis prevents food from reaching the intestines, babies with this condition might be constipated.
• Weight loss. The lack of nutrition can cause a baby not to gain weight or to lose weight.

When to see a doctor

Other conditions have symptoms like pyloric stenosis. It's important to get a prompt and accurate diagnosis. See your baby's doctor if your baby:

• Projectile vomits after feeding.
• Is hungry again immediately after vomiting.
• Seems less active or unusually irritable.
• Has few wet or soiled diapers.
• Isn't gaining weight or is losing weight.

Causes

The causes of pyloric stenosis are unknown, but genes and environmental factors might play a role. Pyloric stenosis usually isn't present at birth but develops afterward.

Risk factors

Pylorid stenosis is not a common condition. It is more likely in babies who:

• Are boys.
• Are first-born children.
• Were born prematurely.
• Have a family history of pyloric stenosis.
• Were born to a cigarette smoker.
• Were exposed to certain antibiotics late in the pregnancy or after birth.
• Are bottle-fed.

Complications

Pyloric stenosis can lead to:

• Failure to grow and develop. The lack of nutrition causes poor growth, weight gain and development.
• Dehydration. Frequent vomiting can cause low fluid levels, called dehydration. This condition also may result in an imbalance in minerals called electrolytes. These minerals help regulate important functions throughout the body.
• Jaundice. Rarely, a substance secreted by the liver, called bilirubin, can build up. This may cause a yellowing of the skin and or the whites of the eyes. This condition is called jaundice.