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Overview |
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Definition |
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Pyloric stenosis is characterized by hypertrophy and hyperplasia of the
muscular layers in the pylorus. It is the most common cause of gastrointestinal
obstruction in infants and is also called infantile hypertrophic pyloric
stenosis (IHPS). It appears in approximately 2 per 1,000 live births, presenting
in the first few months of life with persistent and often projectile vomiting.
If not treated quickly, dehydration and electrolyte imbalance will ensue. The
condition was first described in detail by the Danish pediatrician Hirschsprung
in 1887. In recent years, prompt use of ultrasonography to establish a diagnosis
followed by surgical intervention has reduced the incidence of alkalosis and
resulted in a shorter clinical course. |
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Etiology |
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The proximate cause of IHPS is hypertrophy and hyperplasia of both the
circular and longitudinal muscle layers of the pylorus. The pyloric canal
lengthens and its walls thicken, leading to a narrowing of the gastric
antrum.
The etiology is unknown; however, the condition appears to be multifactorial
in origin. Investigators have hypothesized the following causes:
- Primary muscle disorder leading to postnatal hypertrophy
- Allergy-induced edema leading to narrowing of the pyloric opening and
causing hypertrophy of stomach muscles due to the work against the narrow
foramen
- Infantile hypergastrinemia, associated with prostaglandin elevation
and nitric oxide deficiency; however, this may be secondary to gastric stasis
and distention
- Abnormal muscle innervation
- Trisomy 18 has been associated with pyloric stenosis
- Maternal stress in third trimester of
pregnancy
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Risk Factors |
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- Age: Approximately 95% of cases are diagnosed in infants aged 3 to 12
weeks.
- Sex: It is 4 to 5 times more prevalent in males and more common in
firstborn males.
- Race: It is most common in Caucasians (2.4 per 1,000 live births, vs.
1.8 in Hispanics, 0.7 in African-Americans, 0.6 in Asians).
- Birth weight: Low birth weight is associated with a lower rate of
occurrence of IHPS.
- Maternal age: Older maternal age as well as higher maternal
educational level is associated with a lower incidence of IHPS.
- Oral erythromycin given to the
neonate
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Signs and Symptoms |
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- Progressive nonbilious emesis, often becoming projectile. May be
intermittent or may occur after each feeding
- Persistent hunger
- Weight loss
- Dehydration
- Lethargy
- Diminished stools
- Marasmus and protein calorie malnutrition (in severe cases)
- Jaundice (in 5% of
cases)
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Differential
Diagnosis |
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- Peptic ulcer
- Gastroenteritis
- Gastroesophageal reflux
- Pyloric atresia
- Pyloric antral web
- Pyloric diaphragm
- Poor feeding practices
- Hiatal hernia
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Diagnosis |
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Physical Examination |
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Consideration of IHPS should not be delayed due to the potential for
dangerous fluid and electrolyte imbalance. Examine for epigastric distention and
visible gastric peristaltic waves moving across the epigastrium from left to
right. Firm, nontender, mobile 2-to-3-cm mass ("olive") may be palpated deep in
the epigastrium to the right of midline; present in 60% to 80% of cases.
Palpation is best attempted after emesis when infant is
calm. |
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Laboratory Tests |
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- pH, electrolytes, BUN, creatinine: Hypochloremic, hypokalemic
alkalosis is often seen as a result of dehydration and loss of hydrochloric
acid
- Elevated conjugated bilirubin
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Imaging |
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- Ultrasonography: Method of choice due to its accuracy and noninvasive
nature. Criteria for diagnosis include pyloric muscle thickness greater than 4
mm, pyloric length greater than 14 mm, or pyloric ratio (wall thickness: pyloric
diameter) >0.27. The pyloric ratio has the advantage of being a
weight-independent indicator.
- Upper gastrointestinal imaging: Barium study indicated if sonography
is unavailable or inconclusive, or if an alternative diagnosis such as
gastroesophageal reflux is being considered. Signs include elongated pyloric
channel ("string sign") and pyloric muscle bulging into antrum ("shoulder
sign").
- X rays: indicated only to rule out presence of free
air.
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Other Diagnostic
Procedures |
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Upper GI endoscopy may be used if imaging is inconclusive or atypical
clinical features are present. |
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Treatment Options |
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Treatment Strategy |
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IHPS is a medical emergency. Immediate attention must be given to correcting
fluid loss, electrolytes, and acid-base balance. Surgery is the curative
treatment. |
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Drug Therapies |
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Some infants have responded to treatment with atropine sulfate, 0.04
mg/kg/day IV, with the dose increasing by 0.01 mg/kg/day until vomiting ceased
(1 to 8 days). Then the atropine was continued orally at twice the effective
intravenous dose for two weeks. The infants began gaining weight before
regression of pyloric thickening was established ultrasonographically.
Normalization of pyloric muscle caliber was shown by ultrasonography 4 to 12
months later. Investigators have suggested that the pyloric muscle hypertrophy
might be worsened by the spasms that occur in IHPS. |
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Surgical Procedures |
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The Ramstedt pyloromyotomy is the treatment of choice. The antropyloric mass
is split, leaving the mucosal layer intact. The procedure is performed through a
short transverse incision or laparoscopically. Newer approaches include
supra-umbilical skin-fold or umbilical incisions for better cosmetic results.
The infant should have nothing to eat or drink before surgery and for 12 to 24
hours after surgery.
Endoscopic balloon dilatation of the pylorus has provided short-term
symptomatic relief for some patients but is not curative. |
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Complementary and Alternative
Therapies |
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Periconceptional nutrition has benefits in the prevention of congenital
hypertrophic pyloric stenosis. Therefore, periconceptional counseling should
include discussion of diet and folic acid intake. |
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Nutrition |
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Nutrition, multivitamins, and folic acid play a role in reducing the
incidence of congenital defects, including congenital hypertrophic pyloric
stenosis, although the underlying biologic mechanisms of these protective
effects are still not understood (Czeizel 1995). Synthetic folic acid
(monoglutamate) is preferred over natural folate because of its rapid absorption
and stability. Food folate is fragile and easily destroyed by heat. In addition,
dietary folate consists of polyglutamates which must be converted into
monoglutamate before they can be absorbed (Hall and Solehdin 1998).
A multicenter study in the greater metropolitan areas of Boston,
Philadelphia, and Toronto from 1993 to 1996 evaluated the benefit of
periconceptional multivitamin use. Infants with and without birth defects and
aborted fetuses with birth defects were divided into eight case groups
representing common congenital anomalies. Mothers of infants six months old or
less were interviewed about vitamin use. Controls were 521 infants without birth
defects and 442 infants with defects other than those being investigated. Data
assessment revealed that periconceptional multivitamin supplementation may
extend benefits beyond protection against neural tube defects and may reduce the
incidence of other congenital anomalies, including congenital hypertrophic
pyloric stenosis. However, other than folic acid, it was not clear which
nutrient or nutrient combinations might affect non-neural tube defects (Werler
et al. 1999).
A review of recent studies finds confirmation of these results and concludes
that periconceptional daily folic acid supplementation plays a key role in
reducing the incidence of neural tube defects and other congenital anomalies,
including congenital hypertrophic pyloric stenosis. A dose of 0.4 mg folic acid
per day should be supplemented in the periconceptional period to reduce the
morbidity and mortality due to these birth defects. High risk mothers, mothers
with a child previously affected by neural tube defects, mothers with diabetes
mellitus, and women on anti-epileptic medications and other folate antagonists
are advised to take 4 to 5 mg periconceptional folic acid daily. Because 50% of
pregnancies are not planned, women of childbearing age, especially women
considering pregnancy, should be advised of the need for periconceptional folic
acid supplementation (Hall and Solehdin 1998).
While unproven, re-establishing normal bowel flora following antibiotic
treatment and eliminating allergenic foods from the diets of the infant and
breast-feeding mother may alleviate gastric irritability and inflammation.
Common allergenic foods include dairy products, peanuts, soy, eggs, fish, and
wheat, among others (Marks and Marks 1993). The breast-feeding mother should
consider avoiding other foods such as caffeine, spicy foods, beans, and
Brassica vegetables (e.g., broccoli), which can stimulate colic or
general gastric upset in the neonate. Formula-fed infants may benefit from a
change to a soy preparation or an easily digested hydrosylate formula. Normal
bowel flora may be re-established by supplementing with lactobacilli such as
L. acidophilus and especially Bifidus spp. The breast-feeding
mother can take one capsule with meals; alternatively, one capsule per day in
three divided doses may be administered to the newborn (using the powder inside
an opened capsule) (Vaughan and Mollet 1999). |
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Herbs |
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Traditional colic formulas may be beneficial in easing gastrointestinal spasm
and preventing hypertrophy/hyperplasia of the pylorus. Formulas typically
include dill (Anethum graveolens) and/or chamomile (Matricaria
recutita), given to the infant by drops or to the breast-feeding mother.
(These herbs have traditionally been used for treatment of dyspepsia (Blumenthal
et al. 1998)). Catnip (Nepeta cateria) may also be
included. |
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Homeopathy |
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While homeopathic remedies for prevention or treatment of pyloric stenosis
have not been investigated in scientific studies, the following remedies are
used clinically by homeopathic doctors for this condition:
- Antimonium crudum for vomiting of curdled milk after
breast-feeding; the baby for whom this remedy is appropriate may be irritable
and refuse to nurse.
- Phosphoros indicated for violent vomiting as soon as feeding is
completed. The infant for whom this treatment is appropriate tends to be mild
mannered and generally with a good appetite despite the symptoms
described.
- Silica for vomiting in breast-fed infants who have a delicate
constitution and slow development.
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Acupuncture |
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Acupuncture may well play a role in alleviating causative factors that would
otherwise lead to pyloric stenosis and/or helping in recovery from surgery.
These mechanisms have not yet been explored in scientific
research. |
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Massage |
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Touch is an important part of infant well being. While it is plausible that
massage relieves gastrointestinal spasm and reduces stress, this application in
the treatment of pyloric stenosis has not been investigated in scientific
studies. |
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Other
Considerations |
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Prevention |
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- Caution should be exercised in prescribing oral erythromycin to
neonates (see section entitled Risk Factors).
- Stress reduction during pregnancy, particularly the third trimester
(see section entitled Etiology).
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Complications/Sequelae |
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- Emesis persisting after surgery suggests incomplete pyloromyotomy,
gastritis, hiatal hernia, or another cause for obstruction.
- Postoperative complications include duodenal perforation or small
bowel obstruction secondary to
adhesions.
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Prognosis |
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Fast diagnosis and treatment are necessary to avoid life-threatening fluid
and electrolyte imbalance. If IHPS is detected quickly, the prognosis for
recovery and catch-up growth is very good. Surgery is curative and mortality is
very low (less than 0.5%). |
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References |
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Ballard RB, Rozycki GS, Knudson MM, Pennington SD. The surgeon's use of
ultrasound in the acute setting. Surg Clin North Am.
1998;78(2):337-364.
Beers MH, Berkow R, eds. The Merck Manual of Diagnosis and Therapy.
Whitehouse Station, NJ: Merck & Co.; 1999:2213.
Blumenthal M, Busse WR, Goldberg A, et al., eds. The Complete German
Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston,
Mass: Integrative Medicine Communications; 1998:107, 121.
Czeizel AE. Nutritional supplementation and prevention of congenital
abnormalities. Curr Opin Obstet Gynecol. 1995;7(2):88-94.
Hall J, Solehdin F. Folic acid for the prevention of congenital anomalies.
Eur J Pediatr. 1998;157(6):445-450.
Honein MA, Paulozzi LJ, Himelright IM, et al. Infantile hypertrophic pyloric
stenosis after pertussis prophylaxis with erythromycin: a case review and cohort
study. Lancet. 1999;354(9196):2101-2105.
Hulka F, Campbell TJ, Campbell JR, Harrison MW. Evolution in the recognition
of infantile hypertrophic pyloric stenosis. Pediatrics.
1997;100(2):E9.
Lowe LH, Banks WJ, Shyr Y. Pyloric ratio: efficacy in the diagnosis of
hypertrophic pyloric stenosis. J Ultrasound Med. 1999;18(11):773-777.
Marks DR, Marks LM. Food allergy. Manifestations, evaluation, and management.
Postgrad Med. 1993;93(2):191-196, 201.
Nagita A, Yamaguchi J, Amemoto K, Yoden A, Yamazaki T, Mino M.
Management and ultrasonographic appearance of infantile hypertrophic pyloric
stenosis with intravenous atropine sulfate. J Pediatr Gastroenterol Nutr.
1996;23(2):172-177.
Singh J. Pediatrics, Pyloric Stenosis. In: Adler J, Brenner B, Dronen S, et
al., eds. Emergency Medicine: An On-line Medical Reference. Accessed at
www.emedicine.com/cgi-bin/foxweb.exe/showsection@d:/em/ga?book=emerg&sct=PEDIATRIC
on August 18, 2000.
Vaughan EE, Mollet B. Probiotics in the new millennium. Nahrung.
1999;43(3):148-153.
Werler MM, Hayes C, Louik C, Shapiro S, Mitchell AA. Am J Epidemiol.
1999;150(7):675-682. |
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Copyright © 2000 Integrative Medicine
Communications This publication contains
information relating to general principles
of medical care that should not in any event be construed as specific
instructions for individual patients. The publisher does not accept any
responsibility for the accuracy of the information or the consequences arising
from the application, use, or misuse of any of the information contained herein,
including any injury and/or damage to any person or property as a matter of
product liability, negligence, or otherwise. No warranty, expressed or implied,
is made in regard to the contents of this material. No claims or endorsements
are made for any drugs or compounds currently marketed or in investigative use.
The reader is advised to check product information (including package inserts)
for changes and new information regarding dosage, precautions, warnings,
interactions, and contraindications before administering any drug, herb, or
supplement discussed herein. | |