Pyloric stenosis is a narrowing of the opening from the stomach to the small intestine caused by thickening of the pyloric muscle. It typically affects infants younger than 6 months old, and boys are more commonly affected than girls. The main symptoms are projectile vomiting shortly after feeding due to impaired emptying of food from the stomach. Treatment involves surgically cutting the thickened pyloric muscle to widen the opening.

2.  Pyloric stenosis is a narrowing of the pylorus, the
opening from the stomach into the small intestine.

3.  Pyloric stenosis or pylorostenosis is narrowing
(stenosis) of the opening from the stomach to the first
part of the small intestine known as the duodenum,
due to enlargement (hypertrophy) of the muscle
surrounding this opening (the pylorus, meaning
"gate"), which spasms when the stomach empties

4.  Pyloric stenosis occurs most often in infants younger
than 6 months. It is more common in boys than in
girls.

5.  The cause of the thickening is unknown.
 Genes may play a role, since children of parents who
had pyloric stenosis are more likely to have this
condition.

6.  Genes may play a role, since children of parents who
had pyloric stenosis are more likely to have this
condition

7.  Normally, food passes easily from the stomach into
the first part of the small intestine through a valve
called the pylorus. With pyloric stenosis, the muscles
of the pylorus are thickened. This prevents the
stomach from emptying into the small intestine.

8.  The gastric outlet obstruction due to the hypertrophic
pylorus impairs emptying of gastric contents into
the duodenum. As a consequence, all ingested food
and gastric secretions can only exit via vomiting,
which can be of a projectile nature.

9. Vomiting is the first symptom in most children:
 Vomiting may occur after every feeding or only after
some feedings
 Vomiting usually starts around 3 weeks of age, but
may start any time between 1 week and 5 months of
age
 Vomiting is forceful (projectile vomiting)
 The infant is hungry after vomiting and wants to feed
again

10.  Other symptoms appear several weeks after birth and
may include:
 Abdominal pain
 Burping
 Constant hunger
 Dehydration
 Failure to gain weight or weight loss
 Wave-like motion of the abdomen shortly after
feeding and just before vomiting occurs

11. The condition is usually diagnosed before the baby is 6
months old.
 A physical exam may reveal:
 Signs of dehydration, such as dry skin and mouth, less
tearing when crying, and dry diapers
 Swollen belly
 Olive-shaped mass when feeling the upper belly, which is
the abnormal pylorus
 Ultrasound of the abdomen may be the first imaging
test. Other tests that may be done include:
 Barium x-ray -- reveals a swollen stomach and narrowed
pylorus
 Blood tests -- often reveals an electrolyte imbalance

12.  Treatment for pyloric stenosis involves surgery to
widen the pylorus. The surgery is called
pyloromyotomy.
 If putting the infant to sleep for surgery is not safe, a
device called an endoscope with a tiny balloon at the
end is used. The balloon is inflated to widen the
pylorus.
 In infants who cannot have surgery, tube feeding or
medicine to relax the pylorus is tried.

13.  The definitive treatment of pyloric stenosis is with
surgical pyloromyotomy known as Ramstedt's
procedure (dividing the muscle of the pylorus to open
up the gastric outlet). This is a relatively
straightforward surgery that can possibly be done
through a single incision (usually 3–4 cm long) or
laparoscopically (through several tiny incisions),
depending on the surgeon's experience and
preference.