GI - Pyloric Stenosis

Question 1

What is Pyloric Stenosis?

Answer 1

Hypertrophy and consequent narrowing of the Pylorus, to prevent food travelling from the stomach to the duodenum.

Question 2

What is the Pyloric Sphincter?

Answer 2

Ring of smooth circular muscle that forms the canal between the stomach and the duodenum.

Question 3

Aetiology of Projectile Vomiting (2).

Answer 3

1. After feeding, increasingly powerful peristalsis in the stomach as it tries to push food down into the duodenum.
2. Eventually so powerful that it ejects food into oesophagus, out of mouth and across room.

Question 4

Epidemiology of Pyloric Stenosis (4).

Answer 4

1. Typical Presentation in Weeks 2-4 of Life (rarely, up to 4 months).
2. 4x commoner in males.
3. 10-15% have positive family history.
4. Commoner in 1st borns.

Question 5

Stereotypical Patient in Pyloric Stenosis (3).

Answer 5

1. Hungry Baby.
2. Presenting in first few weeks of life.
3. Thin, Pale and generally Failing to Thrive.

Question 6

Clinical Features of Pyloric Stenosis (5).

Answer 6

1. Projectile Vomiting (typically 30 minutes after a feed).
2. Observable Peristalsis in Abdomen (after feeding).
3. Firm Round Mass in Upper Abdomen (Hypertrophy of Pyloric Muscle - feels like a ‘large olive’).
4. Hypochloraemic Hypokalaemic Alkalosis.
5. Constipation and Dehydration.

Question 7

Why is there Hypochloraemic Hypokalaemic Alkalosis? (3).

Answer 7

1. Severe vomiting leads to loss of Chloride (loss of HCl).
2. Loss of protons causes alkalosis.
3. Loss of protons causes increased renal resorption of protons in exchange for Potassium ions.

Question 8

Diagnosis of Pyloric Stenosis.

Answer 8

Abdominal Ultrasound : Visualise thickened pylorus.

Question 9

Management of Pyloric Stenosis.

Answer 9

Pyloromyotomy (Ramstedt’s Operation) : Incision into smooth muscle of Pylorus to widen canal.

Question 10

Prognosis of Pyloric Stenosis.

Answer 10

Excellent following Ramstedt’s Operation.