Pyloric Stenosis | |
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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 onset | 2 to 12 weeks old [1] |
Causes | Unknown [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] |
Treatment | Surgery [1] |
Prognosis | Excellent [1] |
Frequency | 1.5 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]
The cause of pyloric stenosis is unclear. [2] Risk factors in babies include birth by cesarean section, preterm birth, bottle feeding, and being firstborn. [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 in both the short term and 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 surgical management first carried out in 1912 by Conrad Ramstedt. [1] [2] Before surgical treatment, most babies with pyloric stenosis died. [1]
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.
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 ]
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 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 ]
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 ]
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 ]
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]
The stomach is a muscular, hollow organ in the upper 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 the cephalic phase in which the sight and smell of food and the act of chewing are stimuli. In the stomach a chemical breakdown of food takes place by means of secreted digestive enzymes and gastric acid.
Gastric dilatation volvulus (GDV), also known as gastric dilation, twisted stomach, or gastric torsion, is a medical condition that affects dogs and rarely cats and guinea pigs, in which the stomach becomes overstretched and rotated by excessive gas content. The condition also involves compression of the diaphragm and caudal vena cavae. The word bloat is often used as a general term to mean gas distension without stomach torsion, or to refer to GDV.
The pylorus 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".
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.
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, where 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.
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.
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.
A vagotomy is a surgical procedure that involves removing part of the vagus nerve. It is performed in the abdomen.
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, such as peptic ulcer disease affecting the area around the pylorus, and malignant causes, such as gastric cancer.
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.
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.
Vomiting is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose.
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.
Biliary reflux, also called bile reflux, duodenogastroesophageal reflux (DGER) or duodenogastric reflux, is a condition that occurs when bile and/or other contents like bicarbonate and pancreatic enzymes flow upward (refluxes) from the duodenum into the stomach and esophagus.
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.
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.
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.
Stomach reduction surgery, also known as bariatric surgery, is a medical procedure aimed at facilitating weight loss by reducing the size of the stomach, thereby limiting food intake and promoting satiety with smaller portions. It is frequently used for cases where traditional weight loss approaches, consisting of diet and physical activity, have proven insufficient, or when obesity already significantly affects well-being and general health.