Pyloric stenosis

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Pyloric stenosis
Other namesPylorostenosis, infantile hypertrophic pyloric stenosis
Gray1046.svg
Outline of stomach, showing its anatomical landmarks, including the pylorus.
Specialty General surgery
Symptoms Projectile vomiting after feeding [1]
Complications Dehydration, electrolyte problems [1]
Usual onset2 to 12 weeks old [1]
CausesUnknown [2]
Risk factors Cesarean section, preterm birth, bottle feeding, first born [3]
Diagnostic method physical examination, [1] ultrasound [4]
Differential diagnosis Gastroesophageal reflux, [1] intussusception [5]
TreatmentSurgery [1]
Prognosis Excellent [1]
Frequency1.5 per 1,000 babies [1]

Pyloric stenosis is a narrowing of the opening from the stomach to the first part of the small intestine (the pylorus). [1] Symptoms include projectile vomiting without the presence of bile. [1] This most often occurs after the baby is fed. [1] The typical age that symptoms become obvious is two to twelve weeks old. [1]

Contents

The cause of pyloric stenosis is unclear. [2] Risk factors in babies include birth by cesarean section, preterm birth, bottle feeding, and being first born. [3] The diagnosis may be made by feeling an olive-shaped mass in the baby's abdomen. [1] This is often confirmed with ultrasound. [4]

Treatment initially begins by correcting dehydration and electrolyte problems. [1] This is then typically followed by surgery, although some treat the condition without surgery by using atropine. [1] Results are generally good both in the short term and in the long term. [1]

About one to two per 1,000 babies are affected, and males are affected about four times more often than females. [1] The condition is very rare in adults. [6] The first description of pyloric stenosis was in 1888 with surgery management first carried out in 1912 by Conrad Ramstedt. [1] [2] Before surgical treatment most babies died. [1]

Signs and symptoms

Babies with this condition usually present any time in the first weeks to 6 months of life with progressively worsening vomiting. It is more likely to affect the first-born with males more commonly than females at a ratio of 4 to 1. [7] The vomiting is often described as non-bile stained ("non bilious") and "projectile vomiting", because it is more forceful than the usual spitting up (gastroesophageal reflux) seen at this age. Some infants present with poor feeding and weight loss but others demonstrate normal weight gain. Dehydration may occur which causes a baby to cry without having tears and to produce less wet or dirty diapers due to not urinating for hours or for a few days. Symptoms usually begin between 3 and 12 weeks of age. Findings include epigastric fullness with visible peristalsis in the upper abdomen from the infant's left to right. [8] Constant hunger, belching, and colic are other possible signs that the baby is unable to eat properly.

Cause

Rarely, infantile pyloric stenosis can occur as an autosomal dominant condition. [9] It is uncertain whether it is a congenital anatomic narrowing or a functional hypertrophy of the pyloric sphincter muscle.[ citation needed ]

Pathophysiology

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. While the exact cause of the hypertrophy remains unknown, one study suggested that neonatal hyperacidity may be involved in the pathogenesis. [10] This physiological explanation for the development of clinical pyloric stenosis at around 4 weeks and its spontaneous long term cure without surgery if treated conservatively, has recently been further reviewed. [11]

Persistent vomiting results in loss of stomach acid (hydrochloric acid). The vomited material does not contain bile because the pyloric obstruction prevents entry of duodenal contents (containing bile) into the stomach. The chloride loss results in a low blood chloride level which impairs the kidney's ability to excrete bicarbonate. This is the factor that prevents correction of the alkalosis leading to metabolic alkalosis. [12]

A secondary hyperaldosteronism develops due to the decreased blood volume. The high aldosterone levels causes the kidneys to avidly retain Na+ (to correct the intravascular volume depletion), and excrete increased amounts of K+ into the urine (resulting in a low blood level of potassium).[ citation needed ]The body's compensatory response to the metabolic alkalosis is hypoventilation resulting in an elevated arterial pCO2.

Diagnosis

Pyloric stenosis as seen on ultrasound in a 6-week-old Pyloric-stenosisLocal.jpg
Pyloric stenosis as seen on ultrasound in a 6-week-old

Diagnosis is via a careful history and physical examination, often supplemented by radiographic imaging studies. Pyloric stenosis should be suspected in any infant with severe vomiting. On physical 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', [14] and is sometimes evident after the infant is given formula to drink. Rarely, there are peristaltic waves that may be felt or seen (video on NEJM) due to the stomach trying to force its contents past the narrowed pyloric outlet.[ citation needed ]

Most cases of pyloric stenosis are diagnosed/confirmed with ultrasound, if available, showing the thickened pylorus and non-passage of gastric contents into the proximal duodenum. Muscle wall thickness 3 millimeters (mm) or greater and pyloric channel length of 15 mm or greater are considered abnormal in infants younger than 30 days. Gastric contents should not be seen passing through the pylorus because if it does, pyloric stenosis should be excluded and other differential diagnoses such as pylorospasm should be considered. The positions of superior mesenteric artery and superior mesenteric vein should be noted because altered positions of these two vessels would be suggestive of intestinal malrotation instead of pyloric stenosis. [7]

Although the baby is exposed to radiation, an upper GI series (X-rays taken after the baby drinks a special contrast agent) can be diagnostic by showing the pylorus with elongated, narrow lumen and a dent in the duodenal bulb. [7] This phenomenon caused "string sign" or the "railroad track/double track sign" on X-rays after contrast is given. Plain x-rays of the abdomen sometimes shows a dilated stomach. [15]

Although upper gastrointestinal endoscopy would demonstrate pyloric obstruction, physicians would find it difficult to differentiate accurately between hypertrophic pyloric stenosis and pylorospasm.[ citation needed ]

Blood tests will reveal low blood levels of potassium and chloride in association with an increased blood pH and high blood bicarbonate level due to loss of stomach acid (which contains hydrochloric acid) from persistent vomiting. [16] [17] There will be exchange of extracellular potassium with intracellular hydrogen ions in an attempt to correct the pH imbalance. These findings can be seen with severe vomiting from any cause.[ citation needed ]

Treatment

Vertical pyloromyotomy scar (large) 30 hrs post-op in a one-month-old baby Pyloromyotomie.jpg
Vertical pyloromyotomy scar (large) 30 hrs post-op in a one-month-old baby
Horizontal pyloromyotomy scar 10 days post-op in a one-month-old baby PyloricStenosisHorizontal.jpg
Horizontal pyloromyotomy scar 10 days post-op in a one-month-old baby
Horizontal pyloromyotomy scar 35 years post-op in a three-month-old baby Pylorusstenose.jpg
Horizontal pyloromyotomy scar 35 years post-op in a three-month-old baby

Infantile pyloric stenosis is typically managed with surgery; [18] very few cases are mild enough to be treated medically.

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 the abnormally high blood pH seen in combination with low chloride levels with IV fluids. This can usually be accomplished in about 24–48 hours.[ citation needed ]

Intravenous and oral atropine may be used to treat pyloric stenosis. It has a success rate of 85–89% compared to nearly 100% for pyloromyotomy, however it requires prolonged hospitalization, skilled nursing and careful follow up during treatment. [19] It might be an alternative to surgery in children who have contraindications for anesthesia or surgery, or in children whose parents do not want surgery.[ citation needed ]

Surgery

The definitive treatment of pyloric stenosis is with surgical pyloromyotomy known as Ramstedt's procedure (dividing the muscle of the pylorus to open up the gastric outlet). This surgery can be done through a single incision (usually 3–4 cm long) or laparoscopically (through several tiny incisions), depending on the surgeon's experience and preference. [20]

Today, the laparoscopic technique has largely supplanted the traditional open repairs which involved either a tiny circular incision around the navel or the Ramstedt procedure. Compared to the older open techniques, the complication rate is equivalent, except for a markedly lower risk of wound infection. [21] This is now considered the standard of care at the majority of children's hospitals across the US, although some surgeons still perform the open technique. Following repair, the small 3mm incisions are hard to see.

The vertical incision, pictured and listed above, is no longer usually required, though many incisions have been horizontal in the past years. Once the stomach can empty into the duodenum, feeding can begin again. Some vomiting may be expected during the first days after surgery as the gastrointestinal tract settles. Rarely, the myotomy procedure performed is incomplete and projectile vomiting continues, requiring repeat surgery. Pyloric stenosis generally has no long term side-effects or impact on the child's future.[ citation needed ]

Epidemiology

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. [22] It is commonly associated with people of Scandinavian ancestry, and has multifactorial inheritance patterns. [9] Pyloric stenosis is more common in Caucasians than Hispanics, Blacks, or Asians. The incidence is 2.4 per 1000 live births in Caucasians, 1.8 in Hispanics, 0.7 in Blacks, and 0.6 in Asians. It is also less common amongst children of mixed race parents. [23] Caucasian male babies with blood type B or O are more likely than other types to be affected. [22]

Infants exposed to erythromycin are at increased risk for developing hypertrophic pyloric stenosis, especially when the drug is taken around two weeks of life [24] and possibly in late pregnancy and through breastmilk in the first two weeks of life. [25]

Related Research Articles

<span class="mw-page-title-main">Stomach</span> Digestive organ

The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach is involved in the gastric phase of digestion, following chewing. It performs a chemical breakdown by means of enzymes and hydrochloric acid.

<span class="mw-page-title-main">Duodenum</span> First section of the small intestine

The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In mammals it may be the principal site for iron absorption. The duodenum precedes the jejunum and ileum and is the shortest part of the small intestine.

<span class="mw-page-title-main">Pylorus</span> Part of the stomach that connects to the duodenum

The pylorus, or pyloric part, connects the stomach to the duodenum. The pylorus is considered as having two parts, the pyloric antrum and the pyloric canal. The pyloric canal ends as the pyloric orifice, which marks the junction between the stomach and the duodenum. The orifice is surrounded by a sphincter, a band of muscle, called the pyloric sphincter. The word pylorus comes from Greek πυλωρός, via Latin. The word pylorus in Greek means "gatekeeper", related to "gate" and is thus linguistically related to the word "pylon".

<span class="mw-page-title-main">Nissen fundoplication</span> Surgical procedure to treat gastric reflux and hiatal hernia

A Nissen fundoplication, or laparoscopic Nissen fundoplication when performed via laparoscopic surgery, is a surgical procedure to treat gastroesophageal reflux disease (GERD) and hiatal hernia. In GERD, it is usually performed when medical therapy has failed; but, with a Type II (paraesophageal) hiatus hernia, it is the first-line procedure. The Nissen fundoplication is total (360°), but partial fundoplications known as Thal, Belsey, Dor, Lind, and Toupet fundoplications are alternative procedures with somewhat different indications and outcomes.

<span class="mw-page-title-main">Gastric bypass surgery</span> Type of bariatric surgery

Gastric bypass surgery refers to a technique in which the stomach is divided into a small upper pouch and a much larger lower "remnant" pouch and then the small intestine is rearranged to connect to both. Surgeons have developed several different ways to reconnect the intestine, thus leading to several different gastric bypass procedures (GBP). Any GBP leads to a marked reduction in the functional volume of the stomach, accompanied by an altered physiological and physical response to food.

<span class="mw-page-title-main">Gastrectomy</span> Surgical removal of the stomach

A gastrectomy is a partial or total surgical removal of the stomach.

<span class="mw-page-title-main">Pancreaticoduodenectomy</span> Major surgical procedure involving the pancreas, duodenum, and other organs

A pancreaticoduodenectomy, also known as a Whipple procedure, is a major surgical operation most often performed to remove cancerous tumours from the head of the pancreas. It is also used for the treatment of pancreatic or duodenal trauma, or chronic pancreatitis. Due to the shared blood supply of organs in the proximal gastrointestinal system, surgical removal of the head of the pancreas also necessitates removal of the duodenum, proximal jejunum, gallbladder, and, occasionally, part of the stomach.

<span class="mw-page-title-main">Duodenal cancer</span> Medical condition

Duodenal cancer is a cancer in the first section of the small intestine known as the duodenum. Cancer of the duodenum is relatively rare compared to stomach cancer and colorectal cancer. Its histology is usually adenocarcinoma.

<span class="mw-page-title-main">Sleeve gastrectomy</span> Surgical weight-loss procedure involving reduction of stomach size

Sleeve gastrectomy or vertical sleeve gastrectomy, is a surgical weight-loss procedure, typically performed laparoscopically, in which approximately 75 - 85% of the stomach is removed, along the greater curvature, which leaves a cylindrical, or "sleeve"-shaped stomach the size of a banana. Weight loss is affected not only through the reduction of the organ's size, but by the removal of the portion of it that produces ghrelin, the hormone that stimulates appetite. Patients can lose 50-70 percent of excess weight over the course of the two years that follow the surgery. The procedure is irreversible, though in some uncommon cases, patients can regain the lost weight, via resumption of poor dietary habits, or dilation of the stomach over time, which can require gastric sleeve revision surgery to either repair the sleeve or convert it to another type of weight loss method that may produce better results, such as a gastric bypass or duodenal switch.

<span class="mw-page-title-main">Vagotomy</span> Surgical procedure

A vagotomy is a surgical procedure that involves removing part of the vagus nerve. It is performed in the abdomen.

<span class="mw-page-title-main">Gastric outlet obstruction</span> Medical condition

Gastric outlet obstruction (GOO) is a medical condition where there is an obstruction at the level of the pylorus, which is the outlet of the stomach. Individuals with gastric outlet obstruction will often have recurrent vomiting of food that has accumulated in the stomach, but which cannot pass into the small intestine due to the obstruction. The stomach often dilates to accommodate food intake and secretions. Causes of gastric outlet obstruction include both benign causes, as well as malignant causes, such as gastric cancer.

<span class="mw-page-title-main">Angular incisure</span>

The angular incisure is a small notch on the stomach. It is located on the lesser curvature of the stomach near the pyloric end. Its location varies depending on how distended the stomach is.

<span class="mw-page-title-main">Right gastric vein</span>

The right gastric vein drains blood from the lesser curvature of the stomach into the hepatic portal vein. It is part of the portal circulation.

<span class="mw-page-title-main">Vomiting</span> Involuntary, forceful expulsion of stomach contents, typically via the mouth

Vomiting is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose.

<span class="mw-page-title-main">Duodenal atresia</span> Medical condition

Duodenal atresia is the congenital absence or complete closure of a portion of the lumen of the duodenum. It causes increased levels of amniotic fluid during pregnancy (polyhydramnios) and intestinal obstruction in newborn babies. Newborns present with bilious or non-bilous vomiting within the first 24 to 48 hours after birth, typically after their first oral feeding. Radiography shows a distended stomach and distended duodenum, which are separated by the pyloric valve, a finding described as the double-bubble sign.

Pyloromyotomy is a surgical procedure in which a portion of the muscle fibers of the pyloric muscle are cut. This is typically done in cases where the contents from the stomach are inappropriately stopped by the pyloric muscle, causing the stomach contents to build up in the stomach and unable to be appropriately digested. The procedure is typically performed in cases of "hypertrophic pyloric stenosis" in young children. In most cases, the procedure can be performed with either an open approach or a laparoscopic approach and the patients typically have good outcomes with minimal complications.

Wilhelm Conrad Ramstedt was a German surgeon remembered for describing Ramstedt's operation.

<span class="mw-page-title-main">Pyloroplasty</span>

Pyloroplasty is a surgery performed to widen the opening at the lower part of the stomach, also known as the pylorus. When the pylorus thickens, it becomes difficult for food to pass through. The surgery is performed to widen the band of muscle known as the pyloric sphincter, a ring of smooth, muscular fibers that surrounds the pylorus and helps to regulate digestion and prevent reflux. The widening of the pyloric sphincter enables the contents of the stomach to pass into the first part of the small intestine known as the duodenum.

Stomach Intestinal Pylorus-Sparing (SIPS) surgery is a type of weight-loss surgery. It was developed in 2013 by two U.S. surgeons, Daniel Cottam from Utah and Mitchell S. Roslin from New York.

<span class="mw-page-title-main">Antrectomy</span> Type of gastric resection surgery

Antrectomy, also called distal gastrectomy, is a type of gastric resection surgery that involves the removal of the stomach antrum to treat gastric diseases causing the damage, bleeding, or blockage of the stomach. This is performed using either the Billroth I (BI) or Billroth II (BII) reconstruction method. Quite often, antrectomy is used alongside vagotomy to maximise its safety and effectiveness. Modern antrectomies typically have a high success rate and low mortality rate, but the exact numbers depend on the specific conditions being treated.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Ranells JD, Carver JD, Kirby RS (2011). "Infantile hypertrophic pyloric stenosis: epidemiology, genetics, and clinical update". Advances in Pediatrics. 58 (1): 195–206. doi:10.1016/j.yapd.2011.03.005. PMID   21736982.
  2. 1 2 3 Georgoula C, Gardiner M (August 2012). "Pyloric stenosis a 100 years after Ramstedt". Archives of Disease in Childhood. 97 (8): 741–5. doi:10.1136/archdischild-2011-301526. PMID   22685043. S2CID   2780184.
  3. 1 2 Zhu J, Zhu T, Lin Z, Qu Y, Mu D (September 2017). "Perinatal risk factors for infantile hypertrophic pyloric stenosis: A meta-analysis". Journal of Pediatric Surgery. 52 (9): 1389–1397. doi: 10.1016/j.jpedsurg.2017.02.017 . PMID   28318599.
  4. 1 2 Pandya S, Heiss K (June 2012). "Pyloric stenosis in pediatric surgery: an evidence-based review". The Surgical Clinics of North America. 92 (3): 527–39, vii–viii. doi:10.1016/j.suc.2012.03.006. PMID   22595707.
  5. ↑ Marsicovetere P, Ivatury SJ, White B, Holubar SD (February 2017). "Intestinal Intussusception: Etiology, Diagnosis, and Treatment". Clinics in Colon and Rectal Surgery. 30 (1): 30–39. doi:10.1055/s-0036-1593429. PMC   5179276 . PMID   28144210.
  6. ↑ Hellan M, Lee T, Lerner T (February 2006). "Diagnosis and therapy of primary hypertrophic pyloric stenosis in adults: case report and review of literature". Journal of Gastrointestinal Surgery. 10 (2): 265–9. doi:10.1016/j.gassur.2005.06.003. PMID   16455460. S2CID   25249604.
  7. 1 2 3 Naffaa L, Barakat A, Baassiri A, Atweh LA (July 2019). "Imaging Acute Non-Traumatic Abdominal Pathologies in Pediatric Patients: A Pictorial Review". Journal of Radiology Case Reports. 13 (7): 29–43. doi:10.3941/jrcr.v13i7.3443. PMC   6738493 . PMID   31558965.
  8. ↑ "Pyloric stenosis: Symptoms". MayoClinic.com. 2010-08-21. Archived from the original on 2012-02-25. Retrieved 2012-02-21.
  9. 1 2 Fried K, Aviv S, Nisenbaum C (November 1981). "Probable autosomal dominant infantile pyloric stenosis in a large kindred". Clinical Genetics. 20 (5): 328–30. doi:10.1111/j.1399-0004.1981.tb01043.x. PMID   7333028. S2CID   40464656.
  10. ↑ Rogers, Ian; Vanderbom, Frederick (2014-02-26). The Consequence and Cause of Pyloric Stenosis of Infancy. More Books Lembert Academic Publishers. ISBN   978-3-659-52125-6.
  11. ↑ Rogers IM (December 2014). "Pyloric stenosis of infancy and primary hyperacidity--the missing link". Acta Paediatrica. 103 (12): e558-60. doi:10.1111/apa.12795. PMID   25178682. S2CID   38564423.
  12. ↑ Kerry Brandis, Acid-Base Physiology Archived 2005-12-10 at the Wayback Machine . Retrieved December 31, 2006.
  13. ↑ Dawes, Laughlin. "Pyloric stenosis | Radiology Case | Radiopaedia.org". radiopaedia.org. Archived from the original on 20 April 2017. Retrieved 20 April 2017.
  14. ↑ Shaoul R, Enav B, Steiner Z, Mogilner J, Jaffe M (March 2004). "Clinical presentation of pyloric stenosis: the change is in our hands" (PDF). The Israel Medical Association Journal. 6 (3): 134–7. PMID   15055266.
  15. ↑ Riggs, Webster; Long, Larry (May 1971). "The Value of the Plain Film Roentgenogram in Pyloric Stenosis". American Journal of Roentgenology. 112 (1): 77–82. doi:10.2214/ajr.112.1.77. ISSN   0361-803X. PMID   5582036.
  16. ↑ "Pyloric Stenosis - Clinical Practice Guidelines". The Royal Children's Hospital Melbourne. Archived from the original on 31 January 2022. Retrieved 17 March 2022.
  17. ↑ Bhatt, Binoy; Reddy, Srijaya K. "Chapter 140: Pyloric Stenosis". Access Anesthesiology. Archived from the original on 17 March 2022. Retrieved 17 March 2022.
  18. ↑ Askew N (October 2010). "An overview of infantile hypertrophic pyloric stenosis". Paediatric Nursing. 22 (8): 27–30. doi:10.7748/paed.22.8.27.s27. PMID   21066945.
  19. ↑ Aspelund G, Langer JC (February 2007). "Current management of hypertrophic pyloric stenosis". Seminars in Pediatric Surgery. 16 (1): 27–33. doi:10.1053/j.sempedsurg.2006.10.004. PMID   17210480.
  20. ↑ "Medical News:Laparoscopic Repair of Pediatric Pyloric Stenosis May Speed Recovery – in Surgery, Thoracic Surgery from". MedPage Today. 2009-01-16. Archived from the original on 2012-02-23. Retrieved 2012-02-21.
  21. ↑ Sola JE, Neville HL (August 2009). "Laparoscopic vs open pyloromyotomy: a systematic review and meta-analysis". Journal of Pediatric Surgery. 44 (8): 1631–7. doi:10.1016/j.jpedsurg.2009.04.001. PMID   19635317.
  22. 1 2 Dowshen, Steven (November 2007). "Pyloric Stenosis". The Nemours Foundation. Archived from the original on 2008-01-12. Retrieved 2007-12-30.
  23. ↑ Pediatrics, Pyloric Stenosis at eMedicine
  24. ↑ Maheshwai N (March 2007). "Are young infants treated with erythromycin at risk for developing hypertrophic pyloric stenosis?". Archives of Disease in Childhood. 92 (3): 271–3. doi:10.1136/adc.2006.110007. PMC   2083424 . PMID   17337692.
  25. ↑ Kong YL, Tey HL (June 2013). "Treatment of acne vulgaris during pregnancy and lactation". Drugs. 73 (8): 779–87. doi:10.1007/s40265-013-0060-0. PMID   23657872. S2CID   45531743.
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