While you were anticipating your new baby, you probably mentally
prepared yourself for the messier aspects of child rearing: poopy
diapers, food stains, and of course, spit up. But what's normal
and what's not when it comes to spitting up or vomiting in
What Is Pyloric Stenosis?
, a condition that affects the
during infancy, isn't normal - it can cause your baby to vomit
forcefully and often and may cause other problems such as
dehydration and salt and fluid imbalances. Keep reading to
understand why getting immediate treatment for pyloric stenosis is
Pyloric stenosis is a narrowing of the pylorus, the lower part
of the stomach through which food and other stomach contents pass
to enter the small intestine. When an infant has pyloric stenosis,
the muscles in the pylorus have become enlarged to the point where
food is prevented from emptying out of the stomach.
infantile hypertrophic pyloric stenosis
gastric outlet obstruction
, pyloric stenosis is fairly common - it affects about three out of
1,000 babies in the United States. Pyloric stenosis is about four
times more likely to occur in firstborn male infants. It has also
been shown to run in families - if a parent had pyloric stenosis,
then an infant has up to a 20% risk of developing the condition.
Pyloric stenosis occurs more commonly in Caucasian infants than in
babies of other ethnic backgrounds, and affected infants are more
likely to have blood type B or O.
Most infants who develop pyloric stenosis are usually between 2
weeks and 2 months of age - symptoms usually appear during or after
the third week of life. It is one of the more common causes of
intestinal obstruction during infancy that requires surgery.
What Causes Pyloric Stenosis?
It is believed that babies who develop the condition are not
born with pyloric stenosis, but that the progressive thickening of
the pylorus occurs after birth. An affected infant begins showing
symptoms when the pylorus is so thickened that the stomach can no
longer empty properly.
It is not known exactly what causes the thickening of the
muscles of the pylorus - it may be a combination of several
factors. Some researchers believe that maternal hormones could be a
contributing cause. Others believe that the thickening of the
muscle is the stomach's response to some type of allergic
reaction in the body.
Some scientists believe that babies with pyloric stenosis lack
receptors in the pyloric muscle that detect nitric oxide, a
chemical in the body that tells the pylorus muscle to relax. As a
result, the muscle is in a state of contraction almost continually,
which causes it to become larger and thicker over time. It may take
some time for this thickening to occur, which is why pyloric
stenosis usually appears in babies a few weeks after birth.
Signs and Symptoms
Symptoms of pyloric stenosis generally begin around 3 weeks of
age. They include:
- The first symptom of pyloric stenosis is usually
. At first it may seem that the baby is simply spitting up
frequently, but then it tends to progress to
, in which the breast milk or formula is ejected forcefully from
the mouth, in an arc, sometimes over a distance of several feet.
Projectile vomiting usually takes place soon after the end of a
feeding, although in some cases it may be delayed for hours.
Rarely, the vomit may contain blood.
In some cases, the vomited milk may smell curdled because it has
mixed with stomach acid. The vomit will not contain bile, a
greenish fluid from the liver that mixes with digested food after
it leaves the stomach.
Despite vomiting, a baby with pyloric stenosis is usually hungry
again soon after vomiting and will want to eat. The symptoms of
pyloric stenosis can be deceptive because even though a baby may
seem uncomfortable, he may not appear to be in great pain or at
first look very ill.
Changes in stools
- Babies with pyloric stenosis usually have fewer, smaller stools
because little or no food is reaching the intestines.
Constipation or stools that have mucus in them may also be
Failure to gain weight and lethargy
- Most babies with pyloric stenosis will fail to gain weight or
will lose weight. As the condition worsens, they are at risk for
developing fluid and salt abnormalities and becoming dehydrated.
infants are lethargic and less active than usual, and they will
develop a sunken "soft spot" on their heads, sunken
eyes, and a doughy, softened, or wrinkled appearance of the skin
on the belly and upper parts of the arms and legs. Because urine
output is decreased, it may be more than 4 to 6 hours between wet
After feeds, increased stomach contractions may make noticeable
waves of peristalsis
, which move from left to right over the infant's belly as
the stomach tries to empty itself against the thickened
It's important to talk to your child's doctor if your
baby experiences any of these symptoms.
Other conditions can have similar symptoms as pyloric stenosis.
gastroesophageal reflux disease
(GERD) usually begins before 8 weeks of age, with excess spitting
up, or reflux - which may resemble vomiting - taking place after
feedings. However, most infants with GERD do not experience
projectile vomiting, and although they may have poor weight gain,
they tend to have normal stools.
In infants, symptoms of
- inflammation in the digestive tract that can be caused by viral
or bacterial infection - may also somewhat resemble pyloric
stenosis. Vomiting and dehydration are seen with both conditions;
however, infants with gastroenteritis usually also have diarrhea
with loose, watery, or sometimes bloody stools. Diarrhea usually
isn't seen with pyloric stenosis.
Diagnosis and Treatment
Your child's doctor will ask detailed questions about the
baby's feeding and vomiting patterns, including the appearance
of the vomit. The most important part of diagnosing pyloric
stenosis is a reliable and consistent history and description of
The baby will be fully examined, and any weight loss or failure
to maintain growth since birth will be noted. During the exam, the
doctor will attempt to feel if there is a pyloric mass - a firm,
movable lump that feels like an olive and is sometimes detected in
the belly of an infant with pyloric stenosis. If the doctor feels
this mass, it's a strong indication that the baby has pyloric
stenosis; the baby will be referred to a pediatric surgeon and
hospitalized for further treatment.
If the baby's feeding history and physical examination
suggest pyloric stenosis but no "olive" is felt, then an
ultrasound of the baby's abdomen will usually be performed. The
enlarged, thickened pylorus can be seen on ultrasound images.
Sometimes instead of an ultrasound, a barium swallow is
performed. The baby swallows a small amount of a chalky liquid
(barium), and then special X-rays are taken to view the pyloric
region of the stomach to see if there is any narrowing or
Infants suspected of having pyloric stenosis usually undergo
blood tests because the continuous vomiting of stomach acid, as
well as the resulting dehydration from fluid losses, can cause salt
) imbalances in the blood that need to be corrected.
When an infant is diagnosed with pyloric stenosis, either
through physical examination, ultrasound, or barium swallow, the
baby will be admitted to the hospital and prepared for surgery. Any
dehydration or electrolyte problems in the blood will be corrected
with intravenous (IV) fluids, usually within 24 hours.
A surgical procedure called
which involves cutting through the thickened muscles of the
pylorus, is performed to relieve the obstruction from pyloric
stenosis. The pylorus is examined through a very small incision,
and the muscles that are overgrown and thickened are spread.
Nothing is cut out - the stitches are under the skin and there are
no stitches or clips to remove.
After surgery, most babies are able to return to normal feedings
fairly quickly. The baby starts feeding again 3 to 4 hours after
the surgery, and the baby can return to breast-feeding or the
formula that he was on prior to the surgery. Because of swelling at
the surgery site, the baby may still vomit small amounts for a day
or so after surgery. As long as there are no complications, most
babies who have undergone pyloromyotomy can return to a normal
feeding schedule and be sent home within 48 hours of the
If you are
, you may be concerned about being able to continue feeding while
your baby is hospitalized. The hospital should be able to provide
you with a breast pump and assist you in its use so that you can
continue to express milk until your baby can once again feed
After a successful pyloromyotomy, your infant will not need to
follow any special feeding schedules. Your child's doctor will
probably want to examine your child at a follow-up appointment to
make sure the surgical site is healing properly and that your
infant is feeding well and maintaining or gaining weight.
Pyloric stenosis should not recur after a complete
pyloromyotomy. If your baby continues to display symptoms weeks
after the surgery, it may suggest another medical problem, such as
inflammation of the stomach (gastritis) or GERD - or it could
indicate that the initial pyloromyotomy was incomplete.
When to Call Your Child's Doctor
Pyloric stenosis is a medical emergency that requires immediate
treatment. Call your child's doctor if your baby has any of the
- persistent or projectile vomiting after feeding
- poor weight gain or weight loss
- decreased activity or lethargy
- few or no stools over a period of 1 or 2 days
- signs of dehydration such as decreased urination (more than 4
to 6 hours between wet diapers); wrinkly or doughy appearance of
the skin on the arms, legs, or belly; sunken "soft
spot" on the head; sunken eyes; or jaundice (yellowing of
Steven Dowshen, MD
Date reviewed: November 2007
Originally reviewed by:
Aviva Katz, MD
Note: All information is for educational purposes only. For specific medical advice,
diagnoses, and treatment, consult your doctor.
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