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| {{Pyloric stenosis}} | | {{Pyloric stenosis}} |
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| '''For patient information click [[{{PAGENAME}} (patient information)|here]]'''} | | '''For patient information click [[{{PAGENAME}} (patient information)|here]]''' |
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| {{CMG}} | | {{CMG}} |
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| {{Editor Help}} | | {{SK}} Congenital hypertrophic pyloric stenosis; infantile hypertrophic pyloric stenosis; pyloric stenosis, congenital |
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| ==Overview== | | ==[[Pyloric stenosis overview|Overview]]== |
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| '''Pyloric stenosis''' (or '''[[infantile hypertrophic pyloric stenosis]]''') is a condition that causes severe vomiting in the first few months of life. There is narrowing ('''[[stenosis]]''') of the opening from the stomach to the intestines, due to spasm and [[hypertrophy]] of the muscle surrounding this opening (the '''[[pylorus]]'''). It is uncertain whether there is a real congenital narrowing or whether there is a functional hypertrophy of the muscle which develops in the first few weeks of life.
| | ==[[Pyloric stenosis historical perspective|Historical Perspective]]== |
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| Males are more commonly affected than females, with firstborn males affected about four times as often, and there is a [[genetic predisposition]] for the disease.<ref name="kh">{{cite web |url= http://www.kidshealth.org/parent/medical/digestive/pyloric_stenosis.html |title= Pyloric Stenosis |publisher= The Nemours Foundation |date= November 2007 |last= Dowshen |first= Steven |accessdate= 2007-12-30 }}</ref> It is commonly associated with people of Jewish ancestry.<ref>[http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=7333028&dopt=AbstractPlus Probable autosomal dominant infantile pyloric stenosis in a large kindred.] Retrieved September 14, 2007</ref> Caucasians and babies with [[blood type]] B or O are more likely to be affected.<ref name="kh"/>
| | ==[[Pyloric stenosis pathophysiology|Pathophysiology]]== |
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| Pyloric stenosis also occurs in adults where the cause is usually a narrowed pylorus due to scarring from chronic peptic ulceration. This is a completely different condition from the infantile form. | | ==[[Pyloric stenosis causes|Causes]]== |
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| ==Pathophysiology== | | ==[[Pyloric stenosis differential diagnosis|Differentiating Pyloric stenosis from other Diseases]]== |
| 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. The vomited material does not contain [[bile]] because the pyloric obstruction prevents entry of duodenal contents (containing bile) into the stomach.
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| This results in loss of gastric acid ([[hydrochloric acid]]). The [[chloride]] loss results in [[hypochloremia]] which impairs the kidney's ability to excrete bicarbonate. This is the significant factor that prevents correction of the alkalosis.<ref name="Acidbase">Kerry Brandis, [http://www.anaesthesiamcq.com/AcidBaseBook/ab7_3.php Acid-Base Physiology]. Retrieved December 31, 2006.</ref>
| | ==[[Pyloric stenosis epidemiology and demographics|Epidemiology and Demographics]]== |
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| A secondary [[hyperaldosteronism]] develops due to the [[hypovolaemia]]. The high [[aldosterone]] levels causes the kidneys to:
| | ==[[Pyloric stenosis risk factors|Risk Factors]]== |
| * avidly retain Na<sup>+</sup> (to correct the intravascular [[volume depletion]])
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| * excrete increased amounts of K<sup>+</sup> into the urine (resulting in [[hypokalaemia]]).
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| The body's compensatory response to the metabolic alkalosis is hypoventilation resulting in an elevated arterial pCO<sub>2</sub>.
| | ==[[Pyloric stenosis natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
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| ==Symptoms== | |
| Babies with this condition usually present within the first few weeks to months of life with progressively worsening [[vomiting]]. The vomiting is often described as non-bile stained and "projectile vomiting", because it is more forceful than the usual spittiness ([[gastroesophageal reflux]]) seen at this age. Some infants present with poor feeding and weight loss, but others demonstrate normal weight gain.
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| ==Diagnosis== | | ==Diagnosis== |
| | | [[Pyloric stenosis history and symptoms| History and Symptoms]] | [[Pyloric stenosis physical examination | Physical Examination]] | [[Pyloric stenosis laboratory findings|Laboratory Findings]] | [[Pyloric stenosis x ray|X Ray]] | [[Pyloric stenosis ultrasound|Ultrasound]] | [[Pyloric stenosis other imaging findings|Other Imaging Findings]] | [[Pyloric stenosis other diagnostic studies|Other Diagnostic Studies]] |
| A careful history and physical examination, often supplemented by radiographic studies are required for diagnosis. There should be suspicion for pyloric stenosis in any young infant with severe vomiting. On exam, [[palpation]] of the abdomen may reveal a mass in the [[epigastrium]]. This mass, which consists of the enlarged pylorus, is referred to as the 'olive,' and is sometimes evident after the infant is given formula to drink. It is an elusive diagnostic skill requiring much patience and experience. There are often palpable (or even visible) [[peristalsis|peristaltic]] waves due to stomach trying to force its contents past the narrowed pyloric outlet.
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| At this point, most cases of pyloric stenosis are diagnosed/confirmed with [[Medical ultrasonography|ultrasound]], if available, showing the thickened pylorus. Although somewhat less useful, an [[upper GI series]] (x-rays taken after the baby drinks a special [[contrast agent]]) can be diagnostic by showing the narrowed pyloric outlet filled with a thin stream of contrast material; a "[[string sign]]" or the "railroad track sign". For either type of study, there are specific measurement criteria used to identify the abnormal results. Plain x-rays of the abdomen are not useful, except when needed to rule out other problems.
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| Blood tests will reveal [[hypokalemia|hypokalemic]], [[hypochloremia|hypochloremic]] [[metabolic alkalosis]] due to loss of [[gastric acid]] (which contain hydrochloric acid and potassium) via persistent vomiting; these findings can be seen with severe vomiting from any cause.
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| ===Upper GI Series===
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| *The pyloric 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 '''double-track sign'''. This sign demonstrates the intervening redundant mucosa outlined as a filling defect by the contrast material.
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| *UGI is performed with the infant in the right anterior oblique position, to facilitate gastric emptying.
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| *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'''.
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| *Luminal barium may be transiently trapped between the peristaltic wave and the muscle, and this is termed the '''tit sign'''.
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| *Eventual success of gastric peristaltic activity will propel contrast material through the pyloric mucosal interstices, with the appearance as either the string sign or the double-track sign, although at times more than one layer of contrast material may be appreciated in the mucosal filling defect.
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| (Images courtesy of RadsWiki)
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| <gallery>
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| Image:Hypertrophic-pyloric-stenosis-001.jpg
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| </gallery>
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| ===Ultrasonography===
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| *USG demonstrates the thickened prepyloric antrum bridging the duodenal bulb and distended stomach.
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| *Demonstration of the pylorus is achieved by identifying the duodenal cap, distended stomach, and intervening pyloric channel.
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| *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 ('''nipple sign''') and can be seen filling the lumen on transverse sections.
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| *The length of the hypertrophied canal is variable and may range from '''as little as 14 mm to more than 20 mm'''.
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| *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'''.
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| *'''The actual numeric value is less important than the overall morphology of the canal and the real-time observations.'''
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| (Images courtesy of RadsWiki)
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| <gallery>
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| Image:Hypertrophic-pyloric-stenosis-002.jpg
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| Image:Hypertrophic-pyloric-stenosis-003.jpg
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| Image:Hypertrophic-pyloric-stenosis-004.jpg
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| </gallery>
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| ==Treatment== | | ==Treatment== |
| [[Image:Pyloromyotomie.jpg|thumb|left||Pyloromyotomy scar (rather large) 30 hrs post-op in a 1 month-old baby]] | | [[Pyloric stenosis medical therapy|Medical Therapy]] | [[Pyloric stenosis surgery|Surgery]] | [[Pyloric stenosis primary prevention|Primary Prevention]] | [[Pyloric stenosis secondary prevention|Secondary Prevention]] | [[Pyloric stenosis cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Pyloric stenosis future or investigational therapies|Future or Investigational Therapies]] |
| Infantile pyloric stenosis is typically managed with surgery.
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| It is important to understand that the danger of pyloric stenosis comes from the dehydration and electrolyte disturbance rather than the underlying problem itself. Therefore, the baby must be initially stabilized by correcting the dehydration and hypochloremic alkalosis with IV fluids. This can usually be accomplished in about 24-48 hours.
| | ==Case Studies== |
| | [[Pyloric stenosis case study one|Case#1]] |
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| Definitive treatment of pyloric stenosis is with surgical pyloromyotomy (dividing the [[muscle]] of the [[pylorus]] to open up the gastric outlet). This is a relatively straightforward surgery that can be done through a single larger incision or [[Laparoscopic surgery|laparoscopically]] (through several tiny incisions), depending on the surgeon's experience and preference.
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| Once the stomach can empty into the [[duodenum]], feeding can commence.
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| There is occasionally recurrence in the immediate post-operative period, but the condition generally has no longterm impact on the child's future.
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| ==References==
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| {{reflist}}
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| ==Additional Resources==
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| * Hulka F, Campbell TJ, Campbell JR, Harrison MW. Evolution in the recognition of infantile hypertrophic pyloric stenosis. ''Pediatrics'' 1997;'''100'''(2):E9. [http://pediatrics.aappublications.org/cgi/reprint/100/2/e9 Fulltext]. PMID 9233980.
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| * {{Chorus|00675}}
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| * [http://www.ich.ucl.ac.uk/factsheets/families/F040097/ UCL Institute of Child Health]
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| {{SIB}}
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| {{Gastroenterology}} | | {{Gastroenterology}} |
| {{Congenital malformations and deformations of digestive system}} | | {{Congenital malformations and deformations of digestive system}} |
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| [[Category:Surgery]] | | [[Category:Surgery]] |
| [[Category:Gastroenterology]] | | [[Category:Gastroenterology]] |
| | [[Category:Disease]] |
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| [[de:Pylorusstenose]] | | [[de:Pylorusstenose]] |
