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What is pyloric stenosis? — Pyloric stenosis is a condition that causes forceful vomiting in babies. It is caused by a problem with the "pylorus," which is the opening between the stomach and the first part of the small intestine (figure 1).
Normally, food passes through the pylorus without a problem. But in pyloric stenosis, the muscle in the pylorus gets too thick and blocks the opening. Then, food can't pass from the stomach to the intestine. This causes symptoms.
Pyloric stenosis happens most often in young babies, especially in babies 3 to 6 weeks old. It rarely happens in babies older than 3 months. Doctors don't know for sure what causes pyloric stenosis, but the condition sometimes runs in families.
What are the symptoms of pyloric stenosis? — Pyloric stenosis causes vomiting, usually right after a feeding. The vomiting, called "projectile vomiting," is forceful. This type of vomiting is different from the less forceful vomiting that happens when a baby spits up. In pyloric stenosis, vomit shoots far out from the baby's mouth.
It is common for babies with pyloric stenosis to seem hungry and want to feed again after they vomit.
Should I call my baby's doctor or nurse? — Yes. If your baby has these symptoms, tell their doctor or nurse.
Is there a test for pyloric stenosis? — Yes. The doctor or nurse will ask about your baby's symptoms and do an exam. This will help the doctor or nurse decide whether your baby's vomiting is normal (spitting up) or not.
If the doctor or nurse thinks your baby could have pyloric stenosis, they will probably do an imaging test called an ultrasound. An ultrasound uses sound waves to create pictures of the inside of the body.
How is pyloric stenosis treated? — Pyloric stenosis is usually treated with surgery. During surgery, the doctor will widen the pylorus so that food can pass through it from the stomach to the intestines.