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Diagnosis and treatment of pyloric stenosis

What is pyloric stenosis?

Pyloric stenosis is a condition where the opening from the stomach to the small bowel (intestines) called the pylorus becomes narrower (stenosis). It narrows due to the pylorus muscle thickening which obstructs the flow of the milk from the stomach. It is not known why this happens. Pyloric stenosis is a common condition (about 1 in 300 babies) and affects babies usually between the ages of 3 to 6 weeks occurring more frequently in boys than girls and can run in families.

What are the symptoms?

The baby vomits milk. This becomes progressively worse and more frequent until it occurs after every feed. The vomit may come with such a force that the milk is projected across the room. This is called projectile vomiting. If the condition is not treated the baby can become dehydrated and lose weight.

How is it diagnosed?

The enlarged pyloric muscle can usually be felt as a small lump in the baby’s tummy. The lump is especially evident during feeding. The doctor may do a test feed on your baby so they can feel the lump and witness the vomiting. An ultrasound scan may be performed to confirm or diagnose pyloric stenosis if a lump cannot be felt.

How is it pyloric stenosis treated?

An operation is required to split the thickened pyloric muscle. This is called a ‘pylormyotomy’. The surgeons will explain the operation to you and you will need to give consent. You will also be seen by an anaesthetist because your baby will need a general anaesthetic for the operation.

What happens before the operation?

Your baby will not be able to have any milk feeds.

The nurses will pass a tube called a gastric tube (NG tube), in through your baby’s nose in to their stomach. This is to drain the contents of the stomach to keep your baby comfortable and to stop them being sick.

Your baby will be continuously monitored to check their heart rate, breathing rate and oxygen level. A plastic tube, often called a ‘drip’ (intravenous cannula) will be inserted in to your baby’s vein to give intravenous fluids to rehydrate and keep your baby hydrated. We will do blood tests on your baby to check their balance of salts and minerals.

When your baby is rehydrated and their blood tests are within normal limits your baby can have the operation to correct their pyloric stenosis. Shortly before the operation we will give your baby some water by bottle or through their NGT to help wash their stomach out.

What does the operation involve?

The operation is usually carried out ‘laprascopically’. This means using instruments through tiny holes above and in the tummy button (laparoscopic surgery). Sometimes the operation is carried out through a small cut above the tummy button.

The operation involves cutting (splitting) the thickened muscle to widen the opening which allows the stomach contents to pass freely into the intestines.

What are the risks of the operation?

The operation is usually straightforward.

In 3 to 5 out of 100 operations the muscle split is too deep and a hole is made in the lining of the stomach. This may delay your baby’s stay in hospital.

In 1 to 2 babies out of a 100 the muscle split is insufficient the baby will continue to vomit, requiring a further operation to complete the split.

The wound can become infected, bleed and there is a small risk of damaging the stomach or intestines during the operation.

What happens after the operation?

When your baby has fully woken after the operation they can commence feeding if they want to. This is usually around 6 hours after the operation. The volume of milk your baby can have will be gradually increased. It is normal for some babies to continue to vomit for a while after the operation and in for these babies the feeds are introduced more slowly.

Your baby will continue with intravenous fluids until they are tolerating full feeds. They will be continued to be monitored and given pain relief if needed.

Your baby will be discharged when tolerating their milk (usually 24 to 48 hours after the operation).

There may be dressing on the wound, instructions about what to do with this will be given by your doctor or nurse. You should keep the area dry for 48 hours after the operation.

If stitches are used they dissolve and do not need to come out. There is often redness around the tummy button in the first few days, which usually settles. If the redness does not fade after a few days or the wound starts to swell or leak, or if your baby is in pain or has a temperature contact your GP or the hospital in case there is infection of the wound.

Are there any long term effects of pyloric stenosis?

Pyloric stenosis does not return if the operation has been successful.

Further resources

Please read our resource for more information about risks of anaesthetics.

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Please note: this is a generic information sheet relating to care at Sheffield Children’s NHS FT. These details may not reflect treatment at other hospitals. This information is not intended as a substitute for professional medical care. Always follow your healthcare professionals’ instructions. If this resource relates to medicines, please read it alongside the medicine manufacturer’s patient information leaflet. If this information has been translated into another language from English, efforts have been made to maintain accuracy, but there may still be some translation errors. If you are unsure about any of the guidance in this resource or have specific questions about how it relates to your child, always ask your healthcare professional for further advice.

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