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Pyloric Stenosis in Infants

Narrowing of the outlet of the stomach in infancy, causing severe vomiting

  • Symptoms usually develop 3–8 weeks after birth
  • Five times more common in boys
  • Sometimes runs in families
  • Lifestyle is not a significant factor

In pyloric stenosis, the ring of muscle that forms the outlet from the stomach to the duodenum (the first part of the small intestine) becomes thickened and narrowed due to excess growth of the muscle tissue. As a result, only a small amount of milk can pass into the duodenum, and the remainder builds up in the stomach until the baby vomits. The condition is five times more common in boys. The cause of pyloric stenosis is unknown, but it may run in families.

What are the symptoms?

The symptoms of pyloric stenosis develop gradually, usually between 3 and 8 weeks after birth, and may include:

  • Persistent vomiting, which is sometimes projectile (ejected forcefully).

  • Immediate hunger after vomiting.

  • Infrequent bowel movements.

If vomiting is persistent or projectile, consult your doctor immediately.

What might be done?

The doctor will examine your baby’s abdomen, usually during a feed, to feel for a swelling around the stomach outlet. If pyloric stenosis is suspected, your child will probably be admitted to hospital because affected babies frequently become dehydrated and may need to be given intravenous fluids. To confirm the diagnosis, ultrasound scanning and/or specialized X-rays (see Contrast X-rays) of the abdomen may be carried out. The treatment for pyloric stenosis is a minor operation to widen the stomach outlet. Feeds can then be increased gradually until the baby’s intake is normal. After surgery, babies usually make a full recovery, and the condition does not recur.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

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