Pyloric Stenosis

Question 1

Define pyloric stenosis

Answer 1

Hypertrophy of the pyloric sphincter muscle causing gastric outlet obstruction

Question 2

What is the aetiology of pyloric stenosis

Answer 2

Hyperacidity from antral distention with feeding and hypertrophy of the pylorus from repeated contraction
Poor pyloric muscle neuronal innervation
Lack of intestinal pacemaker cells of Cajal
Nitric oxide synthase deficiency

Question 3

What are the risk factors for pyloric stenosis

Answer 3

Male sex (4:1 ratio)
First born children
Family history, especially on the maternal side
Prematurity
Medications: macrolides e.g. erythromycin, prostaglandins
Turner’s syndrome

Question 4

What are the symptoms of pyloric stenosis

Answer 4

Presents at 2-8 weeks of age

Non-bilious vomiting: 30 mins after a feed, gradually becomes for forceful and becomes projectile
Feeds: initially normal → loss in interest
Irritability (extreme hunger)
Weight loss/not gaining weight
Decreased wet nappies
Constipation

Question 5

What are the differentials for pyloric stenosis

Answer 5

Posseting.reflux
Gastro-oesophageal reflux
Gastritis
Systemic infection
Overfeeding
UTI
Malrotation of the gut
Food allergy
Duodenal atresia

Question 6

What are the signs of pyloric stenosis on examination

Answer 6

Obs: tachycardia (dehydration)

General
Dehydration: dry mucous membranes, reduced skin turgor, depressed fontanelle, sunken eyes, prolonged CRT

Abdominal
Abdominal mass (pyloric mass), feels like an olive RUQ
Peristaltic waves (wave from left to right)

Question 7

What investigations should be done for pyloric stenosis

Answer 7

Test feed: give a milk feed to allow the infant to calm down for exam

Blood gas: hypochloraemic hypokalaemic metabolic alkalosis
U&Es: hypokalaemia, hypochloraemia, hyponatraemia
LFTs
Glucose
FBC

US abdomen: Pyloric muscle thickness >3 mm | Pyloric canal length >15 mm

Question 8

What is the management for pyloric stenosis

Answer 8

1. Admit + A-E assessment
2. Make NBM
3. IV fluid resuscitation (1.5x maintenance rate with 5% dextrose + 0.45% saline)
4. Once urine output is adequate, add potassium to fluids
5. Surgery: Ramstedt pyloromyotomy (when bicarb <28 and chloride >95)

Question 9

What are the complications of pyloromyotomy

Answer 9

Post-operative emesis
Surgical wound infection
Surgical mucosal perforation
Incomplete myotomy

Question 10

What is the prognosis for pyloric stenosis

Answer 10

Prognosis excellent
Success of the surgical treatment is near 100%
Complication rates are negligible
Morbidity and length of hospital stay following surgery are slightly increased in preterm infants
Indirect Hyperbilirubinaemia resolves with rehydration