Hypertrophic pyloric stenosis (HPS) is typically a disease seen in infants with a reported incidence of 0.1 to 0.8% but it has also been reported in about 300 adults [1] [2] [3] [4]. HPS in infants has higher incidence amongst first-born males and is encountered more frequently in Caucasian babies [5]. Maternal history of HPS is a reported risk factor [6]. Infantile HPS can be associated with syndromes like Turner's, tracheoesophageal fistula, esophageal atresia, trisomy 18 [6].

HPS is classified as primary and secondary.

Primary HPS is also called idiopathic HPS (IHPS) and is seen in infants, while it is rare in adults probably because they are asymptomatic and remain undiagnosed. The exact etiology of IHPS is unknown. It is characterized by pyloric muscle hypertrophy and hyperplasia. IHPS in infants typically develops in the first to the third month after birth with symptoms of non-bilious projectile vomiting immediately following feeds. As the disorder progresses, the infant does not gain weight and develops dehydration. There is visible gastric peristalsis. An olive-shaped mass, due to the hypertrophied pylorus, can be palpated in the epigastrium or right upper abdominal quadrant. Features of associated syndromes like Turner's may also be present. Adult onset IHPS presents in middle-aged men with epigastric pain, early satiety, nausea, and vomiting following meals [7] [8]. Unlike infants, an upper abdominal mass is rarely palpable in adult IHPS.

Secondary HPS occurs secondarily with the healing of duodenal or gastric ulcers, hypertrophic gastritis, malignant tumors, gastrointestinal stromal tumors, bezoars, vagal hyperactivity, and postoperative extrinsic adhesions [4] [9] [10]. It is associated with replacement of the pyloric muscle fibers by fibrous tissue and there is minimal or no hypertrophy of the pyloric muscle.

• Weight Loss

  Depending on the duration of symptoms, patients may suffer significant weight loss, even falling below birth weight. [mdedge.com]

  Patients present with projectile vomiting, weight loss and dehydration. Five susceptibility loci have been identified through genome-wide linkage analysis and candidate gene approaches. [ncbi.nlm.nih.gov]

  The diagnosis of IHPS can be suspected in an infant presenting with typical manifestations of non-bilious projectile vomiting after feeds and weight loss but they are not often seen in the initial course of the disease. [symptoma.com]

• Weight Gain

  A 34-day-old girl was admitted with chief complaints of projectile vomiting and poor weight gain. HPS was diagnosed on the basis of the clinical course and results of imaging studies. [ncbi.nlm.nih.gov]

  There may be a history of failure to thrive or poor weight gain. Infants often present with “projectile” vomiting. [cdemcurriculum.com]

• Multiple Congenital Anomalies

  Although AIS is usually reported as a monogenic disease resulting from androgen receptor (AR) mutations, on rare occasions it has been observed as part of a multiple congenital anomaly syndrome. [ncbi.nlm.nih.gov]

  Feeding of the baby with multiple congenital anomalies detected on physical examination was already challenging. Beginning from the 30th postnatal day, her gastric residuals increased and diagnosed as feeding intolerance. [omicsonline.org]

• Pathologist

  Differentiation of primary from secondary pyloric stenosis is frequently a task of the pathologist rather than the surgeon. The main therapy is surgical, although endoscopic dilatation has been tried. [ncbi.nlm.nih.gov]

• Cough

  Seven-week-old 32-week premature triplets were hospitalized because of rhinorrhea, cough with color change and posttussive emesis. [ncbi.nlm.nih.gov]

• Vomiting

  The vomiting was described as projectile, post-prandial, non-bilous and of large volume. The frequency of vomiting was 4 to 5 times daily. [panafrican-med-journal.com]

  Infants often present with “projectile” vomiting. They may initially only vomit after some feeds, but vomiting progressively worsens over a period of days, until the infant begins to vomit after every feed. [cdemcurriculum.com]

  A 34-day-old girl was admitted with chief complaints of projectile vomiting and poor weight gain. HPS was diagnosed on the basis of the clinical course and results of imaging studies. [ncbi.nlm.nih.gov]

• Projectile Vomiting

  A 34-day-old girl was admitted with chief complaints of projectile vomiting and poor weight gain. HPS was diagnosed on the basis of the clinical course and results of imaging studies. [ncbi.nlm.nih.gov]

  Projectile vomiting (without bile) occurs shortly after eating. Until dehydration sets in, children feed avidly and otherwise appear well, unlike many of those with vomiting caused by systemic illness. [merckmanuals.com]

• Delayed Gastric Emptying

  gastric emptying of fluid into duodenum Complications Hypochloremic metabolic alkalosis DDx Infantile pylorospasm Muscle thickness between 1.5 and 3 mm Variable caliber of antral narrowing Antral peristalsis Delayed gastric emptying Elongation of pylorus [learningradiology.com]

  Work-up revealed circumferential pyloric thickening, delayed gastric emptying, and a stenotic, elongated pyloric channel. Biopsies showed benign gastropathy, negative for Helicobacter pylori, without eosinophilic infiltrates. [ncbi.nlm.nih.gov]

  In adult HPS, UGI series findings include delayed gastric emptying due to pyloric stenosis, a narrow, elongated pyloric canal, and a mushroom sign. [symptoma.com]

  If the diagnosis remains uncertain, ultrasonography can be repeated serially or an upper gastrointestinal series can be done, which typically shows delayed gastric emptying and a string sign or railroad track sign of a markedly narrowed, elongated pyloric [merckmanuals.com]

• Failure to Thrive

  There may be a history of failure to thrive or poor weight gain. Infants often present with “projectile” vomiting. [cdemcurriculum.com]

  Presentation A 25 days old male infant presented with complaints of non-bilious vomiting and failure to thrive. The baby was normal at birth with no other obvious abnormality. [sonoworld.com]

  […] to thrive References: [1] [4] Diagnostics Initial imaging : Abdominal ultrasound → shows an elongated and thickened pylorus Elongated pylorus (normal: 15–17 mm ) Thickened pylorus muscle (normal: < 3 mm ) Pylorus transverse diameter (normal: < 13 mm [amboss.com]

  The classical presentation of IHPS includes persistent copious non-bilous vomiting (which may become projectile), visible intestinal peristalsis, palpable epigastric tumour, constipation, failure to thrive despite sucking hungrily, dehydration and electrolytes [panafrican-med-journal.com]

  Severe or neglected cases can result in significant weight loss and failure to thrive. [ipeg.org]

• Nausea

  In this case report, we describe a 14-year-old boy who presented with nausea, intermittent vomiting, and abdominal pain. He underwent upper gastrointestinal series, which demonstrated persistent narrowing of the pylorus. [ncbi.nlm.nih.gov]

  Adult onset IHPS presents in middle-aged men with epigastric pain, early satiety, nausea, and vomiting following meals. Unlike infants, an upper abdominal mass is rarely palpable in adult IHPS. [symptoma.com]

• Hunger

  The infant is irritable and demonstrates a strong rooting and sucking reflex because of hunger. Constant vomiting leads to hypokalemic and hypochloremic metabolic alkalosis. [amboss.com]

  A child with pyloric stenosis may have: Vomiting, often forceful (projectile vomiting) Hunger right after vomiting Loss of weight or poor growth despite good appetite Signs of dehydration such as less urine, very dark urine, dry mouth, and no tears when [saintlukeshealthsystem.org]

  Persistent hunger, weight loss, dehydration, lethargy, and infrequent or absent bowel movements may be seen. Stomach wall peristalsis may be visible. [patient.info]

  Findings include epigastric fullness with visible peristalsis in the upper abdomen from the person's left to right. [7] Constant hunger, belching, and colic are other possible signs that the baby is unable to eat properly. [en.wikipedia.org]

• Confusion

  Therefore, the sonographic findings should not be confused with pyloric wall thickening to avoid a false diagnosis and unnecessary surgery. The symptoms diminish with cessation of the prostaglandin therapy after a corrective cardiac operation. [ncbi.nlm.nih.gov]

  It may be agitated agitated drowsy, confused pulse oximetry tracheal tubes of various sizes, especially 7 and 8 to 13 days. B. Bilateral nasal fracture. [miketnelson.com]

• Perseveration

  Pearls and Pitfalls Establishing a Diagnosis Perseverance is the key in finding the “olive” (this may take 20 min). The infant should be quiet and relaxed (having the child nipple some water or Pedialyte ® may help). [link.springer.com]

The diagnosis of IHPS can be suspected in an infant presenting with typical manifestations of non-bilious projectile vomiting after feeds and weight loss but they are not often seen in the initial course of the disease. A careful history of onset and progression of the manifestations is essential before proceeding with the physical examination which may reveal visible peristalsis, and a palpable olive-shaped enlarged pyloric mass [11] [12]. Hypochloremic, hypokalemic metabolic alkalosis is the classical result on serum biochemistry testing. Ultrasonography is the preferred method of confirming the diagnosis in infants with endoscopy being reserved for infants with atypical clinical presentation.

Clinical diagnosis of adult HPS is difficult and upper gastrointestinal (UGI) endoscopy is necessary to exclude gastric outlet obstruction. A fixed, severely narrowed pylorus with a smooth border described as "cervix sign" is typically seen on endoscopy [13]. Video capsule endoscopy is a newer modality which has been used to detect adult HPS and differentiate it from idiopathic gastroparesis [14].

A plain X-ray of the abdomen is not helpful and may only show a distended stomach with mildly distended intestines in HPS. Fluoroscopic UGI series with barium (barium meal) will demonstrate delay in gastric emptying, peristaltic waves (caterpillar sign), an elongated pylorus with a thin lumen (string sign) which appears duplicated due to puckering of the mucosa (double-track sign), indentation of the antrum by the pylorus (shoulder sign) or base of the duodenal bulb (mushroom sign) and beak shaped pyloric entrance (beak sign). In adult HPS, UGI series findings include delayed gastric emptying due to pyloric stenosis, a narrow, elongated pyloric canal, and a mushroom sign.

Ultrasound is preferred to the UGI series in infants as it avoids radiation and can visualize the pyloric muscle. Various sonographic signs have been described such as the antral nipple sign, cervix sign, and target sign. However, sonography is not useful in adult IHPS, although some do advocate it [13]. Computed tomographic (CT) scans help to exclude secondary causes of HPS.

• Hypochloremia

  The proportion of IHPS cases with hyponatremia, hypokalemia, and hypochloremia was 18.4%, 12.5%, and 53.9%. A negative correlation was found between duration of disease and serum electrolytes. [ncbi.nlm.nih.gov]

  Althogh a few infants showed hypochloremia and metabolic alkalosis, many had normal values in serum electrolytes and blood gas analysis. [ci.nii.ac.jp]

  The cardinal findings in pyloric stenosis are dehydration, metabolic alkalosis, hypochloremia, and hypokalaemia. Loss of gastric fluid leads to volume depletion and loss of sodium, chloride, acid (H+) and potassium. [openanesthesia.org]

  Evaluation Electrolytes metabolic alkalosis hypokalemia/hypochloremia secondary to recurrent emesis Barium studies may show narrow pyloric channel "string sign" or "pyloric beak" Ultrasound hypertrophic pylorus may be observed Differential Hiatal hernia [medbullets.com]

  Breaux CW Jr, Hood JS, Georgeson KE (1989) The significance of alkalosis and hypochloremia in hypertrophic pyloric stenosis. J Pediatr Surg 24: 1250–1252. View Article Google Scholar 30. [journals.plos.org]

Distal gastrectomy with gastroduodenostomy is the treatment of choice. [ncbi.nlm.nih.gov]

Significant medical advances have improved its diagnosis, treatment and prognosis, and there is now almost a 100 per cent success rate ( Panteli 2009 ). [journals.rcni.com]

More attention should be paid to early discovery and diagnosis, which will help to improve the curative effect and prognosis of IHPS. [ncbi.nlm.nih.gov]

[…] gastric emptying of fluid into duodenum Complications Hypochloremic metabolic alkalosis DDx Infantile pylorospasm Muscle thickness between 1.5 and 3 mm Variable caliber of antral narrowing Antral peristalsis Delayed gastric emptying Elongation of pylorus Prognosis [learningradiology.com]

Treatment Conservative measures : before surgery Treatment of choice : Ramstedt pyloromyotomy (definitive management once the patient is rehydrated and electrolyte disturbances have been corrected) References: [1] [4] Prognosis [amboss.com]

Prognosis Prognosis is excellent unless diagnosis is delayed and prolonged severe dehydration occurs. Mortality is rare after pyloromyotomy. Peters B, Oomen MW, Bakx R, et al ; Advances in infantile hypertrophic pyloric stenosis. [patient.info]

Furthermore, it attempts to demonstrate that newer research regarding an NOS1 genetic etiology does not exclude, but rather can be consistent with, an infectious etiology. [ncbi.nlm.nih.gov]

In this review, the latest advances in IHPS regarding epidemiology, etiology, diagnostics and treatment will be discussed. [ncbi.nlm.nih.gov]

References: [1] [2] Epidemiological data refers to the US, unless otherwise specified. [amboss.com]

The NHI database provides an opportunity to conduct a population-based epidemiological study of IHPS. [journals.plos.org]

We believe these three conditions are due to an underlying pathophysiologic mechanism. [ncbi.nlm.nih.gov]

Newborn Surgery, Third Edition provides a comprehensive compendium of the pathophysiology, investigation and management of neonatal disorders. [books.google.com]

Nathan Askew Practice educator and ward manager, Great Ormond Street Hospital, London Nathan Askew outlines the pathophysiology, diagnosis, treatment and prognosis of this highly treatable disease process In paediatric general surgery hypertrophic pyloric [journals.rcni.com]

CONCLUSION: The newly designed Pyloric Spreader offers a new ergonomically designed instrument with a flat tip for easy placement in the pyloric muscle slit, broad instrument surface to avoid circular muscle tears, rounded tip edges to prevent mucosal [ncbi.nlm.nih.gov]

The accurate diagnosis delays with elimination of severe alkalosis and electrolyte disorder and prevention of malnutrition with administered parenteral nutrition. [omicsonline.org]

Nothing can be done to prevent HPS from occurring. What Are the Symptoms of HPS? Symptoms begin as mild vomiting that gradually worsens. With time, the emesis becomes more frequent and forceful (often described as "projectile"). [luriechildrens.org]

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