Patients suffering from IHPS presents with signs and symptoms within three to six weeks from birth. The following signs and symptoms are commonly seen among infants with IHPS:

• Projectile vomiting: Babies with IHPS will have forceful vomiting of ingested milk after 30 minutes of intake [5]. The severity of the infant’s vomiting increases with the pyloric narrowing of the lumen.
• Persistent hunger: Infants with IHPS who frequently vomit will feel hungry more often.
• Dehydration: The incessant vomiting may cause fluid and electrolyte imbalance that may lead to life-threatening dehydration.
• Constipation: Patients diagnosed with IHPS may have obvious changes with their bowel movement due to the inadequate emptying gastric contents to the lower intestinal tract.
• Weight changes: The pyloric stenosis in infant may prevent the infant from gaining weight and may also cause weight loss in advanced cases.
• Abdominal contractions: Infants suffering from IHPS will show signs of wave-like contractions in the upper abdominal area due to the stomach propulsive force that pushes the food contents through a narrowed pyloric opening.

• Weight Loss

  She was referred for abdominal pain, fever, weight loss and eosinophilia. A sonographic examination revealed a concentric pyloric stenosis, with antral palsy and ascites. [ncbi.nlm.nih.gov]

  Weight problems. Pyloric stenosis can keep a baby from gaining weight, and sometimes can cause weight loss. [mayoclinic.com]

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

  loss or poor weight gain. [rch.org.au]

  Weight changes: The pyloric stenosis in infant may prevent the infant from gaining weight and may also cause weight loss in advanced cases. [symptoma.com]

• Asymptomatic

  The pylorus of 84 asymptomatic infants was prospectively evaluated with respect to morphology (pyloric length, pyloric diameter, muscle thickness and pyloric volume) and function (gastric peristalsis and emptying, pyloric opening and the fluid passage [ncbi.nlm.nih.gov]

  Lagrasta and Franco Bagnoli, Infantile hypertrophic pyloric stenosis and asymptomatic joint hypermobility, The Journal of Pediatrics, 138, 4, (596), (2001). [dx.doi.org]

• Anemia

  Hemolytic anemia induced by dapsone transmitted through breast milk. Ann Intern Med. 1982;96(4):465–6. PubMed CrossRef Google Scholar 15. Webster GF. [doi.org]

• Vomiting

  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. [msdmanuals.com]

  Postoperative Care After surgical treatment, vomiting of the initial feeds is quite common, but vomiting of all feeds persisting beyond 5 days may be a sign that the surgical treatment was inadequate. [sages.org]

  They include: Vomiting. The first symptom is usually vomiting. [kidshealth.org]

  They include: Vomiting - The first symptom of pyloric stenosis is usually vomiting. [web.archive.org]

• Projectile Vomiting

  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. [msdmanuals.com]

  Watch for these signs and symptoms: Projectile vomiting. Pyloric stenosis often causes projectile vomiting — the forceful ejection of milk or formula up to several feet away — within 30 minutes after your baby eats. [web.archive.org]

  But these babies don't have projectile vomiting. gastroenteritis (inflammation in the digestive tract that can be caused by viral or bacterial infection) also can cause vomiting and dehydration. [kidshealth.org]

• Abdominal Pain

  She was referred for abdominal pain, fever, weight loss and eosinophilia. A sonographic examination revealed a concentric pyloric stenosis, with antral palsy and ascites. [ncbi.nlm.nih.gov]

  Abdominal pain. Wave-like motion of the abdomen shortly after feeding and just before vomiting occurs. Cleveland Clinic News & More Cleveland Clinic News & More [my.clevelandclinic.org]

  Additional symptoms of pyloric stenosis include the following: Abdominal pain Belching Constipation or diarrhea (stools may be loose, green, and contain mucus; bowel movements may stop altogether) Dehydration (loss of body fluids and electrolytes through [healthcommunities.com]

• Failure to Thrive

  Abstract We report a newborn with fetal alcohol syndrome with severe feeding intolerance and failure to thrive due to pyloric stenosis. [ncbi.nlm.nih.gov]

  Failure to thrive/weight loss may progress to increasing volume depletion. An olive-shaped mass may be palpable in the right upper abdomen. Ultrasound shows pyloric channel length >17 mm and pyloric muscle thickness >4 mm. [bestpractice.bmj.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]

  Everyone has an image of what the classic infant with Pyloric Stenosis looks like: Child has evidence of failure to thrive and appears wrinkled and dehydrated. [pedemmorsels.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]

• Abdominal Mass

  Olive-sized abdominal mass. A mass about the size of an olive may be felt in the upper abdomen. The mass should be hard, mobile, and non-tender. Pylorospasm. A spasm of the pyloric muscle may occur due to increased motility. [encyclopedia.com]

• Heart Disease

  Prostaglandin E1 (PGE1) is widely used in neonates with cyanotic congenital heart disease who depend on the patency of the ductus arteriosus for oxygenation. [ncbi.nlm.nih.gov]

  Condition Adult Congenital Heart Disease (ACHD) Learn about adult congenital heart disease treatments, symptoms & diagnosis from the experts in common heart diseases & defects at Children's Colorado. [childrenscolorado.org]

  Saha 2012 excluded infants with previous abdominal surgery, inflamed umbilicus, another surgical procedure during the same anaesthesia, diagnostic dilemma, congenital heart disease or significant comorbidities. [cochranelibrary.com]

A detailed clinical history of the infant may give away the diagnosis of IHPS. Physical examination of the abdomen will reveal a wave-like motion of the stomach area during ingestion of milk. An olive size lump will be palpable at the area of the gastric outlet reflecting the hypertrophic muscle of the disease. Blood tests are ordered to determine the presence of electrolyte imbalance and uncover early signs of dehydration. Imaging studies like abdominal ultrasound, computed tomography (CT scan), and magnetic resonance imaging (MRI) confirm the diagnosis pyloric stenosis [6].

Infantile hypertrophic pyloric stenosis should always be treated as a medical emergency in the emergency room setting. It is imperative that the acid-base balance and the electrolyte deficiency should be corrected promptly to avoid grave complications [7]. Signs of shock due to dehydration are immediately treated with an intravenous bullous of crystalloid fluids at 20 mL/Kg. Infants presenting with milder symptoms are given intravenous fluids at 1.5 to 2 times the normal maintenance rate with 5% dextrose in 0.33% or 0.25% sodium chloride admixed with 2-4 mEq of Potassium Chloride per 100 ml solution.

Urine output and acid base balance are continually monitored while in the patient is admitted in the hospital. The definitive treatment for pyloric stenosis is the surgical correction of the obstruction by pyloromyotomy. This procedure may be performed through laparoscopic surgery for shorter hospital stay and for cosmetic reasons [8]. A cohort study in the United Kingdom, demonstrated that laparoscopic pyloromyotomy shortens time until full feedings, lessens incidence of emesis, and lowers the requirement of analgesia among IHPS patients [9]. Post-operative infants are regularly monitored for the recurrence of persistent vomiting which is a sign of an inadequate pyloromyotomy procedure [10].

Patients suffering from infantile hypertrophic pyloric stenosis carry an excellent prognosis after surgical intervention. In fact, infants may be given small portion of feedings in increasing frequency a few hours post operatively. Patients subjected to laparoscopic pyloromyotomy will have faster recovery, better cosmesis, and lesser post-operative emesis compared to those exposed to the traditional surgical approach [4]. Untreated patients may develop dehydration and serious malnutrition problems in the future.

The definitive etiology of pyloric stenosis is still unknown, although studies have been focusing on the active role of genes and environment on its occurrence and prevalence. Parents with pyloric stenosis are most like to give birth to children with IHPS. Pyloric stenosis in adults and may be idiopathic or secondary to ulcers, tumors or inflammatory diseases. 

In the United States, the current incidence of infantile hypertrophic pyloric stenosis is 2 to 4 cases per 1000 live births. Mortality rate is usually very low and unexpected. Deaths usually occurs with the late diagnosis of the pyloric stenosis due to dehydration and hypovolemic shock. IHPS has predilection with the white race compared to the black, Hispanic and Asian races. They appear less common among siblings with mixed racial lineages.

Males are predisposed to IHPS more than females with 4 is to 1 ratio, with 30% of cases occurring among first born males. Pyloric stenosis begins to manifest within the first 3 weeks of life where it is usually diagnosed at that age group. 

The pathogenesis of pyloric stenosis is primarily due to the marked hypertrophy and hyperplasia or the circular and longitudinal muscle layer of the pylorus. These cellular changes leads to the lengthening of the pyloric canal and the pyloric sphincter becomes thickened. The soft tissue mucosa becomes grossly edematous and thick leading to the mechanical obstruction of the gastric outlet to the small intestine. Advanced cases of pyloric stenosis may lead to stomach dilatation due to long standing partial obstruction.

The etiology of IHPS is described to be multifactorial involving hereditary factors and extrinsic factors [1]. Other etiologic factors like infantile hypergastrinemia, exposure to macrolide antibiotics [2], abnormal myenteric plexus innervation, and neuron devoid of nitric oxide synthase. Children who bottle fed are at risk in developing IHPS during infancy [3].

IHPS is a congenital defect of the pylorus that presents within the third to sixth weeks of life; thus, no modifiable activities or lifestyle modifications can be afforded to prevent its occurrence. It genetic nature, may prompt attending pediatricians to carefully examine the abdomen and note for early signs of pyloric stenosis among siblings of parents with IHPS. There are no guidelines for the prevention of aquired pyloric stenosis.

Pyloric stenosis is an uncommon medical condition that results from the muscular thickening of the gastric pylorus. Pyloric stenosis is commonly seen among infant patients presenting with forceful vomiting, dehydration, and weight loss. Infantile pyloric stenosis is the most common cause of intestinal obstruction among infants. Pyloric stenosis rarely occurs in adults and may be caused by ulcers, tumors or inflammatory diseases.

Definition

Pyloric stenosis is a clinical condition characterized by the partial or complete obstruction of the pyloric lumen usually due to muscular hypertrophy or hyperplasia of the luminal walls.

Cause

Genetic transmission is implicated for most of the cases. Environmental factors like maternal macrolide therapy, infant bottle feeding, and infantile gastrinemia play a role. Rarely pyloric stenosis may be aquired. 

Symptoms

Infants will frequently present with post prandial projectile vomiting 30 minutes after feeding. They will appear to be hungry a few minutes after vomiting. Patients will have signs of dehydration and weight loss. A wave-like movement of the stomach will be physically observable among infants.

Diagnosis

A detailed clinical examination and history will clinch the diagnosis. Blood tests for acid-base balance and electrolytes are monitored. Imaging studies can definitively establish its diagnosis.

Treatment and follow-up

The condition is a medical emergency that will require immediate fluid resuscitation, and correction of the acid-base and electrolyte imbalance. The definitive treatment is surgical pyloromyotomy.

1. Panteli C. New insights into the pathogenesis of infantile pyloric stenosis. Pediatr Surg Int. Sep 16 2009.
2. Lund M, Pasternak B, Davidsen RB, Feenstra B, Krogh C, Diaz LJ, et al. Use of macrolides in mother and child and risk of infantile hypertrophic pyloric stenosis: nationwide cohort study. BMJ. Mar 11 2014; 348:g1908.
3. McAteer JP, Ledbetter DJ, Goldin AB. Role of bottle feeding in the etiology of hypertrophic pyloric stenosis.JAMA Pediatr. Dec 2013; 167(12):1143-9.
4. Taqi E, Boutros J, Emil S, Dube S, Puligandla P, Flageole H. Evaluation of surgical approaches to pyloromyotomy: a single-center experience. J Pediatr Surg. May 2007; 42(5):865-8.
5. Cincinnati Children's Hospital Medical Center. Evidence based clinical practice guideline for hypertrophic pyloric stenosis. Cincinnati (OH): Cincinnati Children's Hospital Medical Center; 2007 Nov 14.
6. Maheshwari P, Abograra A, Shamam O. Sonographic evaluation of gastrointestinal obstruction in infants: a pictorial essay. J Pediatr Surg. Oct 2009; 44(10):2037-42.
7. Pandya S, Heiss K. Pyloric stenosis in pediatric surgery: an evidence-based review. Surg Clin North Am. Jun 2012; 92(3):527-39, vii-viii.
8. Saha N, Saha DK, Rahman MA, Aziz MA, Islam MK. Laparoscopic versus Open Pyloromyotomy for Infantile Hypertropic Pyloric Stenosis: An Early Experience. Mymensingh Med J. Jul 2012; 21(3):430-4.
9. Aldridge RD, MacKinlay GA, Aldridge RB. Choice of incision: the experience and evolution of surgical management of infantile hypertrophic pyloric stenosis. J Laparoendosc Adv Surg Tech A. Feb 2007; 17(1):131-6.
10. Leclair MD, Plattner V, Mirallie E, Lejus C, Nguyen JM, Podevin G. Laparoscopic pyloromyotomy for hypertrophic pyloric stenosis: a prospective, randomized controlled trial. J Pediatr Surg. Apr 2007; 42(4):692-8.