Pyloric stenosis

Question 1

What is the pyloric sphincter?

Answer 1

A ring of smooth muscle that forms the canal between the stomach and the duodenum.

Question 2

What is pyloric stenosis?

Answer 2

Hypertrophy and therefore thickening of the pylorus, which prevents food travelling from the stomach to the duodenum as normal.

Question 3

What happens after feeding?

Answer 3

There’s an increasingly powerful peristalsis in the stomach as it tries to push food into the duodenum. Eventually, it becomes so powerful that it ejects the food into the oesophagus, leading to projectile vomiting.

Question 4

What are the features of pyloric stenosis?

Answer 4

• presents within the first few weeks of life
• baby is usually thin, pale and generally failing to thrive
• projectile vomiting

Question 5

What are the findings on examination?

Answer 5

Firm, round mass felt in the upper abdomen - olive shaped (caused by the hypertrophic muscle of the pylorus). Visible peristalsis as the stomach tries to push its contents past the obstruction.

Question 6

What are the investigations and findings?

Answer 6

Blood gas analysis shows hypochloric (low chloride) metabolic alkalosis due to vomiting of HCl acid from the stomach. Abdominal ultrasound visualizes the thickened pylorus.

Question 7

What is the management for pyloric stenosis?

Answer 7

Laparoscopic pyloromyotomy (Ramstedt’s operation). The incision is made in the smooth muscle of the pylorus to widen the canal, allowing food to pass from the stomach to duodenum as normal.