PYLORIC STENOSIS
Supervised By:
Professor Doctor Ali Sultan
Professor of Pediatric surgery
Prepared By:
Aser Gomaa
158
Usama Farid
156 (Presentation & Examination)
Osama Abo-Reda 157
(Definition & Theories)
(Differential diagnosis)
Osama Hamed
155
(Investigation)
Areej Youssry
152
(Treatment)
Definition:
Is a developmental narrowing of the pylorus, due to
hypertrophy of the muscle surrounding the pylorus.
Normally, food passes easily from the stomach into the
duodenum through the pylorus. In pyloric stenosis, the
muscles of the pylorus are thickened.
This prevents the stomach from emptying into the small
intestine.
Synonyms:
Hypertrophic pyloric stenosis, Gastric outlet obstruction
Incidence:
*2-4:1000 Live birth
*The disease is more common in male infants
*Male : female = 4:1
*The disease runs in families
*Most commonly if first baby
*If the parent had it there is a strong possibility that his
son will have it
*It is more common in the first 4-6 weeks
*It rarely presents beyond 6 month
Pathologically:
1.Marked hypertrophy of circular muscles.
2.The mucosa is compressed and folded.
3.Narrow lumen.
4.Stomach muscles hypertrophy
5.Rugae hypertrophy with gastritis and ulcers
Aetiology:
The exact cause of hypertrophic pyloric is still unkown.
Many theories has been postulated:
1.Defenitive genetic factors,plays a very important role
as it runs in families.
Common variants near MBNL1 and NKX2-5 are
associated with infantile hypertrophic pyloric stenosis.
2.Ganglion cell,ganglion cells in the region of the pyloric
canal are responsible for relaxation,there is immaturity
of these cells that leads to failure in relaxation.
3.Nitric oxide synthetase deficiency, Nitric oxide (NO),
produced by the neural nitric oxide synthase enzyme
(nNOS) is a transmitter of inhibitory neurons supplying
the muscle of the gastrointestinal tract. Transmission
from these neurons is necessary for sphincter relaxation
that allows the passage of gut contents, and also for
relaxation of muscle during gastric contraction. There are
deficiencies of transmission from NOS neurons in pylorus
4.Hyperacidity
5.Gastrin and other gastrointestinal hormones
6.H.Pylori association.
The most widely accepted so far is the Ganglion cell
theory.
History:
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Typical presentation of an infant with hypertrophic
pyloric stenosis (HPS) is onset of initially nonbloody,
always nonbilious vomiting at 4-8 weeks. Although
vomiting may initially be infrequent, over several days it
becomes more predictable, occurring at nearly every
feeding. Vomiting intensity also increases until
pathognomonic projectile vomiting ensues. Slight
hematemesis of either bright red flecks or a coffeeground appearance is sometimes observed.
Patients are usually not ill-looking or febrile. The baby in
the early stage of the disease remains hungry and sucks
vigorously after episodes of vomiting.
Prolonged delay in diagnosis can lead to dehydration,
poor weight gain, malnutrition, metabolic alterations,
and lethargy.
Parents often report trying several different baby
formulas because they (or their physicians) assume
vomiting is due to intolerance.
Physical examination:
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Careful physical examination provides a definitive
diagnosis for most infants with hypertrophic pyloric
stenosis. However, some of the classic signs that would
lead to diagnosis may be absent due, in part, to the early
diagnosis of hypertrophic pyloric stenosis.
An enlarged pylorus, classically described as an "olive,"
can be palpated in the right upper quadrant or
epigastrium of the abdomen in 60-80% of infants. In
order to assess the pylorus, the patient must be calm and
cooperative. A pacifier or small amount of dextrose
water may help. If the stomach is distended, aspiration
using a nasogastric tube is necessary. With the infant
supine and the examiner on the child's left side, gently
palpate the liver edge near the xiphoid process. Then
displace the liver superiorly; downward palpation should
reveal the pyloric olive just on or to the right of the
midline. To be assured of the diagnosis, the physician
should be able to roll the pylorus beneath the examining
finger. The tumor (mass) is best felt after vomiting or
during, or at the end of, feeding. The diagnosis is easily
made if the presenting clinical features are typical, with
projectile vomiting, visible peristalsis, and a palpable
pyloric tumor.
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When diagnosis is delayed, the infant may develop
severe constipation associated with signs of dehydration,
malnutrition, lethargy, and shock.
Differential diagnosis of congenital hypertrophic pyloric
stenosis:
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Adrenal Insufficiency
Bowel Obstruction in the Newborn
Duodenal Atresia
Failure to Thrive
Gastroenteritis
Pyloric membrane or pyloric duplication
Gastroesophageal Reflux
Intestinal Malrotation
Inborn errors of metabolism
* Gastric waves are occasionally visible in small,
emaciated infants who do not have pyloric stenosis.
Infrequently, gastroesophageal reflux, with or without a
hiatal hernia, may be confused with pyloric stenosis.
Gastroesophageal reflux disease can be differentiated
from pyloric stenosis by radiographic studies. Adrenal
insufficiency from the adrenogenital syndrome can
simulate pyloric stenosis, but the absence of a metabolic
alkalosis and elevated serum potassium and urinary
sodium concentrations of adrenal insufficiency aid in
differentiation. Inborn errors of metabolism can produce
recurrent emesis with alkalosis (urea cycle) or acidosis
(organic acidemia) and lethargy, coma, or seizures.
Vomiting with diarrhea suggests gastroenteritis, but
patients with pyloric stenosis occasionally have diarrhea.
Rarely, a pyloric membrane or pyloric duplication results
in projectile vomiting, visible peristalsis, and, in the case
of a duplication, a palpable mass. Duodenal stenosis
proximal to the ampulla of Vater results in the clinical
features of pyloric stenosis but can be differentiated by
the presence of a pyloric mass on physical examination
or ultrasonography.
Investigations for Infantile Hypertrophic Pyloric
Stenosis:
It is clear that for a diagnostic study to become the
imaging modality of choice, it must be demonstrated to
be, above all, accurate; further, the procedure should be
noninvasive and should be able to be performed quickly
so that results will be available immediately, without
delay in diagnosis. The examination must allow
unequivocal differentiation between normal and
abnormal conditions. At present, there are two valid and
successful methods for the imaging diagnosis of IHPS, the
UGI and sonography.
UGI Studies
Abnormal study.—In patients with IHPS, there is failure
of relaxation of the prepyloric antrum, typically described
as “elongation” of the pyloric canal. The canal is outlined
by a string of contrast material coursing through the
mucosal interstices, termed the string sign; or by several
linear tracts of contrast material separated by the
intervening mucosa. The latter is termed the doubletrack sign.
This sign demonstrates the intervening redundant
mucosa outlined as a filling defect by the contrast
material; it was reported as specific for IHPS by Haran et
al in 1966 and, therefore, may aid in differentiation from
pylorospasm. Interestingly, the fact that the redundant
mucosa in the canal is responsible for the filling defect
between the channels of contrast material was not
recognized by the authors in the illustration included in
the original article.
UGI is performed with the infant in the right anterior
oblique position, to facilitate gastric emptying. The
examination can be successfully accomplished with the
child drinking from a bottle; these infants are usually very
hungry and will drink with little effort. Insertion of a
nasogastric tube is not necessary; however, emptying of
an overdistended stomach may help to prevent vomiting,
if needed.
Fluoroscopic observations include vigorous active
peristalsis resembling a caterpillar and coming to an
abrupt stop at the pyloric antrum, outlining the external
thickened muscle as an extrinsic impression, termed the
shoulder sign. Luminal barium may be transiently
trapped between the peristaltic wave and the muscle,
and this is termed the tit sign
Sonography
Equipment.—The examination should be performed with
high-frequency transducers. We use a linear transducer
operating between 6 and 10 MHz, adjusted to the size of
the infant and the depth of the pylorus. Because the
pylorus rises anteriorly with positioning of the patient,
the transducer frequency may be adjusted for greater
detail while achieving adequate penetration to the
pyloric channel. A sector transducer may be helpful in
certain cases.
Abnormal
study.—Sonographic
examination
demonstrates the thickened prepyloric antrum bridging
the duodenal bulb and distended stomach. In infants
with IHPS, the stomach is distended to a variable degree.
This gastric distention in a vomiting infant is the first sign
available to the examiner that there is a gastric outlet
obstruction. Positioning of the patient by using gravity
allows the examination to proceed, with the focus on
identifying the duodenal cap and its connection to the
stomach. Because the variable gastric distension is likely
to displace the gastroduodenal junction, the search for
the pylorus may prove difficult.
It is, therefore, best to begin at a specific site of constant
location. We begin by placing the transducer transversely
below the xiphoid process, identifying the esophagus as
it enters the abdomen anterior to the aorta at the
diaphragmatic crus. Caudal movement of the transducer
allows identification of the gastric fundus, and continued
caudal motion subsequently allows definition of the
gastric body, antrum, and duodenal cap, regardless of
displacement or position and whether or not IHPS is
present.
In patients with IHPS, the muscle is hypertrophied to a
variable degree, and the intervening mucosa is crowded,
thickened to a variable degree, and protrudes into the
distended portion of the antrum (the nipple sign) and can
be seen filling the lumen on transverse sections .The
length of the hypertrophied canal is variable and may
range from as little as 14 mm to more than 20 mm. The
numeric value for the lower limit of muscle thickness has
varied in reports in the literature, ranging between 3.0
and 4.5 mm. In our experience and in that of others . the
actual numeric value is less important than the overall
morphology of the canal and the real-time observations.
The antropyloric canal, as part of the stomach, is a
dynamic structure, and it is seen undergoing changes in
both length and width during many examinations . The
intervening mucosa can often be observed sliding within
the canal, usually as a wave of gastric peristalsis washes
over the hypertrophied channel.
Ressucitation and Preoperative evaluation:
Vomiting of gastric contents leads to depletion of
sodium,potassium, and hydrochloric acid, which results
in hypokalemic, hypochloremic metabolic alkalosis.
The kidneys conserve sodium at the expense of
hydrogen ions,leading to paradoxical aciduria. In more
severe dehydration,renal potassium losses are also
accelerated owing to an attempt to retain fluid and
sodium.
The degree of dehydration can be estimated by clinical
examination, urine output, and serum chloride and
bicarbonate levels. Resuscitation state is determined by
serum electrolytes, skin turgor, moist mucous
membranes, and urine output. Serum bicarbonate less
than 28 mEq/dL and serum chloride over 100 mEq/dLare
generally required for safe anesthesia.
TREATMENT
Pre-operative Workup and Preparation:
-Correction of electrolyte imbalance – infants with
pyloric stenosis and vomiting typically have
derangements of serum electolytes such as low
potassium and magnesium.
-Correction of fluid balance –.Infants with electrolyte
abnormalities or dehydration require correction of both.
Due to the severity of the dehydration, these infants are
typically resuscitated with twice the maintenance volume
of normal saline solution until they void.
Then, potassium is added to the intravenous fluids, which
are changed to half-normal saline at 1.5 times
maintenance. It may take 48 hours or longer to fully
resuscitate an infant and prepare them for surgery.
Lactated Ringers Solution is not to be used as an initial
resuscitation fluid. Nasogastric tubes should be avoided
as they further deplete electrolytes.
- -Placement of nasogastric tube – after the diagnosis the
infant oral feeds for the infant are suspended. Although
prolonged placement of a nasogastric tube is to be
avoided as they further deplete electrolytes , sometimes
6-12 hours is needed to prevent further vomiting.
-Infants with less than 5% dehydration and no electrolyte
imbalance are candidates for surgery without delay
-Once an infant is resuscitated, the pyloric stenosis is
treated surgically.
Operation: Ramstedt Pyloromyotomy
Types of surgery
Two methods of surgery are used to correct pyloric
stenosis—open surgery and laparoscopic surgery.
Pyloromyotomy may be performed either as an open
procedure, via a right-upper-quadrant horizontal incision
or an umbilical incision . Operation is done under general
anesthesia.The ring of muscle (pyloric sphincter) is then
cut to widen the channel between the stomach and the
intestine.
During laparoscopic surgery, The laparoscope provides
access to the pyloric muscle so the muscle can be
cut(seromyotomy), the laparoscopic pyloromyotomy is
performed using a peri-umbilical telescope and two stab
wounds, one for a grasper and the other for the
retractable blade and the pyloric spreader. The surgeon
has the choice os whether to grasp the duodenum and
incise from duodenum toward the stomach, or to grasp
the stomach and incise from the stomach toward the
duodenum. Either way, the pyloric muscle is spread and
the adequacy of the operation verified Several other
small incisions are usually needed.Compared to the open
techniques, Recovery from the laparoscopic procedure is
quicker than is recovery from a traditional open surgery,
and the procedure leaves a smaller scar.
-Technique of Balloon dilation does not work as well as
surgery, but may be considered for infants when the risk
of general anesthesia is high
Surgical Details of the open surgery Procedure:
1. A small 3 cm incision is made in the skin with a No. 15
blade just below the right costal margin (the right rib
cage) on the anterior abdominal wall, but above the
inferior edge of the liver.
2. Care must be taken to place the incision so that it
extends laterally from the outer edge of the rectus
muscle.
3. Dissection is done through the subcutaneous tissues
with Bovie cautery.
4. The muscle layer is carefully divided using Bovie
cautery ,with the omentum or transverse colon
presenting into the wound.
5. Using very gentle traction on the omentum, the
transverse colon if not already visualized through the
wound can be presented up into the wound.
6. Gentle traction on the transverse colon will then
deliver the greater curvature of the stomach up into the
wound.
7. The anterior wall of the stomach is grasped with a
moist sponge and gentle traction on the stomach antrum
is applied – this will deliver the pylorus into the wound.
8. The avascular (without blood supply) portion of the
anterior wall of the pylorus is identified.
9. The pylorus is held between the surgeons thumb and
forefinger and a 1-2 cm longitudinal incision (along the
plane of the pylorus) is made
10. The incision is taken down through the serosal and
muscle layers until the mucosa is exposed
11. Great care must be taken not to incise the mucosa.
Extra attention must be given to the duodenal end of the
incision as the muscle layer ends abruptly.
- In the event of a duodenal perforation,or if mucosa
incised .the perforation may be closed primarily or
Pylorus sphincter closed and a new pyloromyotomy
performed .
12. The incised (cut) muscle is gently spread apart with a
hemostat until the mucosa “bulges up” to the level of the
cut serosa.
13. The peritoneum and fascia of the transversalis muscle
is closed with a running absorbable suture
14. The remaining fascial layers are closed with either
running or interrupted slowly absorbable sutures
15. The skin is closed with a subcuticular absorbable
suture such as Monocryl and adhesive Steri-strips are
placed on the wound.
-Possible surgical complications of Pyloromyotomy
may include:
 Perforation of the duodenum
 Persistent
vomiting
due
to
persistent
gastritis,inadequate operation.
 Incisional hernia
 Adverse reaction to anesthesia dt uncorrected
electrolyte imbalance.
 Bleeding
 Infection,Scarring
-Although pyloromyotomy is safe and curative and
performed virtually without operative mortality (< 0.5%)
and morbidity (< 10%), it is not without potential
complications.
Potential
intraoperative
and
postoperative
complications include bleeding, perforation, and wound
infection. Duodenal or gastric perforation, the most
serious complication, rarely occurs; however, if it goes
unrecognized before wound closure, devastating or
lethal consequences are possible.
The infant with an enteric leak develops pain, distention,
fever, and peritonitis. Ongoing fluid requirements,
generalized sepsis, vascular collapse, and death follow if
the enteric leak is not recognized and treated. Suspected
perforation
postoperatively
requires
immediate
reexploration. Recognition of this complication at the
time of surgery is important.
Mucosal perforation most commonly results from
extending the myotomy beyond the pyloric-duodenal
junction. If perforation occurs, the mucosal defect should
be repaired and the myotomy completed.
An omental patch may be sutured to the perforation
site, and a paraduodenal drain may be considered..
Bleeding is a rare complication of pyloromyotomy. Other
complications that are more common but less serious
include superficial wound infections and postoperative
vomiting. Patients with wound erythema, drainage, or
both undergo wound opening and debridement and
antibiotic therapy.
Incomplete myotomy results in ongoing gastric outlet
obstruction and requires reoperation. Patients with
prolonged preoperative obstruction develop gastric
distention and dysmotility, which may cause
postoperative emesis for up to 1 week after an adequate
pyloromyotomy.
-Postoperative :
-Crystalloid resuscitation is continued postoperatively
until the patient returns to full feeding. Recent data
suggest that infants with pyloric stenosis have an
increased incidence of postoperative apnea and
bradycardia.
These infants should be placed on an apnea and cardiac
monitor for 24 hours following the operation.
-Pain: Intraoperative, infant will receive a pain
medication that is injected into the incision.. If necessary,
acetaminophen may also be given to help ease
discomfort.
Slow feeding and gentle burping help prevent wet burps
postoperatively, infant can tolerate normal feedings
usually one to two days after surgery.Intermittent
vomiting persisting through the first postoperative week
is sometimes observed in patients with a protracted
course of emesis and severe dehydration preoperatively.
Although infant often vomits for 24 to 48 hours after
surgery, this usually disappears without any further
treatment. Occasionally, however, vomiting may persist
for 4 to 5 days. Vomiting lasting longer than 7 days
postoperatively should alert the physician to the
possibility of an incomplete pyloromyotomy.
-Incision : incision should be kept clean and dry, and no
tub baths should be given for one week after surgery.
Steri-strips (bandage-like tape) that are placed over the
incision should be left in place and then removed. They
are generally left in place for 7 to 10 days.
References:
1. Elinoff JM, Liu D, Guandalini S, Waggoner DJ. Familial
pyloric stenosis associated with developmental delays. J
Pediatr Gastroenterol Nutr. Jul 2005;41(1):129-32.
2. Chung E. Infantile hypertrophic pyloric stenosis: genes and
environment. Arch Dis Child. Dec 2008;93(12):1003-4.
3. Kawahara H, Takama Y, Yoshida H, et al. Medical
treatment of infantile hypertrophic pyloric stenosis: should
we always slice the "olive"?. J Pediatr Surg. Dec
2005;40(12):1848-51.
4. Panteli C. New insights into the pathogenesis of infantile
pyloric stenosis. Pediatr Surg Int. Dec 2009;25(12):104352.
5. Alain JL, Grousseau D, Terrier G. Extramucosal
pyloromyotomy by laparoscopy. Surg Endosc.
1991;5(4):174-5.
6. Siddiqui S, Heidel RE, Angel CA, Kennedy AP Jr.
Pyloromyotomy: randomized control trial of laparoscopic
vs open technique. J Pediatr Surg. Jan 2012;47(1):93-8.