Pyloric stenosis overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Mohamadmostafa Jahansouz M.D.[2]
Overview
Infantile 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 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.
Historical Perspective
In 1717, Dr.patrick Blair reported autopsy findings of pyloric stenosis for first time and in 1912 Conrad Ramstedt observed an uneventful recovery in a patient followinf pyloroplasty that remains standard procedure for pyloric stenosis today.
Classification
There is no established system for the classification of pyloric stenosis but it may be classified as infantile pyloric stenosis and adult-onset hypertrophic pyloric stenosis (HPS).
Pathophysiology
The pathogenesis of infantile hypertrophic pyloric stenosis is not fully understood but it may be due abnormal innervation of the pyloric smooth muscle.
Causes
Common causes of adult-onset hypertrophic pyloric stenosis (HPS) include persisting duodenal hyperacidity, inheritance of a parietal cell mass (PCM) at the upper end of the normal range which causes persisting duodenal hyperacidity.
Differentiating Pyloric stenosis overview from Other Diseases
Diseases like gastroentritis ,urinary tract infections ,pyelonephritis ,adrenal insufficiency ,acute renal failure and inborn errors of metabolism are the most common causes of infantile pyloric stenosis.
Epidemiology and Demographics
Pyloric stenosis occurs in 1 of every 200-300 live births and it is four times more common in males.it is rare in Asians, and it is 2 to 3 times more common in Caucasian compared to African American babies.In one study the prevalence of congenital hypertrophic pyloric stenosis in Donetsk region in the course of 11 years (1989-1999) was 0.73:1000 or 1:1370 newborn infants annual with range of 0.54 to 1.01:1000.[1]Studies show the mortality rate of pyloric stenosis is very low and usually results from delays in diagnosis that causes sever dehydration and shock.
Risk Factors
The most potent risk factors in the development of infantile pyloric stenosis are bottle-feed infant, cesarean section delivery, first-born infant, preterm birth and exposure to macrolides, nitrofurantoin, penicillins and trimethoprim-sulphamethoxazole during pregnancy.
Screening
Screening for pyloric stenosis is not recommended.
Natural History, Complications, and Prognosis
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.
Vomiting after surgery is the most common complication of infantile hypertrophic pyloric stenosis. Failure to gain weight in the newborn ,Bleeding and Infection after surgery are the other complications of infantile pyloric stenosis.
Diagnosis
Diagnostic Criteria
History and Symptoms
Babies with this condition usually present within the first few weeks to months of life with progressively worsening non-bile stained and projectile vomiting.
Physical Examination
Patients with infantile pyloric stenosis usually appear ill and toxic. physical examination of patients with infantile pyloric stenosis is usually remarkable for palpation of an abdominal mass in epigastrium.This mass, which consists of the enlarged pylorus, is referred to as the 'olive,'.
Laboratory Findings
Most common laboratory findings consistent with the diagnosis of infantile pyloric stenosis and adult type pyloric stenosis include hypokalemia , hypochloremia, and metabolic alkalosis.