Understanding Pyloric Stenosis: Diagnosis and Management

This episode explores pyloric stenosis, a common cause of gastric outlet obstruction in infants. Learn about its causes, clinical presentation, diagnostic methods, and the medical and surgical treatments to manage this condition effectively. Transcript PODCAST INTRO: Hello and welcome back to “Surgery 101”, the podcast about all things surgical brought to you with the help of the Department of Surgery at the University of Alberta. We’re available at the iTunes Music Store at surgery101.org and also at MedEd Portal. We’ve been publishing podcasts for a couple of years now and I’m delighted to bring you our 20th episode. Today we’ll be hearing from pediatric surgeon Dr. Bryan Dicken about the condition of pyloric stenosis. He’ll be telling us why you might want to know about this condition, what the cause is, how children present with this condition, and what to look for on physical examination and biochemistry. He’ll also be discussing how to make the diagnosis and reviewing medical and surgical treatment of the condition. So let’s talk about projectile vomiting here on “Surgery 101”. [00:08:06] Dr. Bryan Dicken: So to begin with, “Pyloric Stenosis”, this is an important entity to consider as it is a very common cause of gastric outlet obstruction. It occurs in anywhere between 1 in 300 and 1 in 500 live births. It has a propensity to involve males in about a 4 to 5 to 1 ratio over females and classically occurs in the firstborn male. There are some pitfalls in the diagnosis of pyloric stenosis. Most importantly is the risk of profound dehydration. Failure to thrive and even death has been reported in this entity. The particular relevance to the family physician is that there is frequently a misdiagnosis which leads to multiple formula changes which are attributed to milk intolerance or allergies. Typically, however, the pyloric stenotic child presents as a well-baby who has been feeding well up to approximately two weeks of age and then develops a sudden intolerance to feeding which is inappropriately labeled as milk intolerance or milk allergy. They typically present with vomiting and lethargy. The pathophysiology of pyloric stenosis is vague and in fact to date there is no definitive cause identified. However, there have been some putative factors such as seasonal variation, erythromycin exposure, prenatally prematurity and even transpyloric feeding tubes have been suggested as etiologies. The mechanism, however, results in hypertrophy and hyperplasia of the primary circular muscle of the pylorics and the underlying mucosa and the resultant is a partial or complete pyloric obstruction. The clinical presentation of pyloric stenosis, as mentioned, is typically a well-child that presents with non-bilious vomiting between about two and eight weeks of life. It peaks between three and five weeks of life. Having said that, there are reports of newborns as early as one day of life that have presented with pyloric stenosis. Classically it is a progressive “wet burps” which then progresses through every feed and eventually becomes classically projectile. They may have tinges of blood or coffee ground emesis associated with esophagitis or gastritis, but the child otherwise appears normal and they feed voraciously despite their vomiting. They may have diarrhea which has been referred to as starvation stools and of course this is frequently mistaken for gastroenteritis or even feeding intolerance. About 2 to 5% may present with jaundice secondary to immaturity of the Glucuronyl transferase activity as well as the dehydration associated with this condition. On physical examination there may be signs of marked dehydration such as a sunken fontanelle, dry mucous membranes and more importantly, poor urine output, as evident by a decrease in the number of daily wet diapers. In addition, the child may be found to be quite lethargic, jaundiced and a very light sign would be a decrease in skin turgor. They may have visible peristaltic waves in the upper abdomen, which is particularly marked with decompressing the stomach with an NG tube and then allowing the child a small volume of dextrose in water, which perpetuates the peristaltic waves across the upper abdomen. And more importantly, is the finding of a small palpable olive or tumor, which is classically felt at the level of the umbilicus and to the right with firm pressure downward against the spine, that the palpable pylori can be easily palpated. 80% of children will have this finding clinically. The most important finding, however, is the presence of laboratory abnormalities, which includes a hypokalemic hypochloramic metabolic alkalosis. The absence of alkalosis should make one very suspicious that it is not a pyloric stenosis. Some important differential diagnoses to include, however, would be gastroesophageal reflux disease, gastroenteritis, increased intracranial pressure from any cause, metabolic disorders, congenital causes such as Webb’s stenosis or duplications, food allergies and finally congenital adrenal syndrome. The “Treatment of Pyloric Stenosis” it is important to note that this is not a surgical emergency, but it is a potential medical emergency. It needs appropriate resuscitation prior to any consideration of the operating theater. This typically involves a fluid bolus of either normal saline or Ringer’s lactate between 20 and 40 milliliters per kilogram or until an appropriate urine output is achieved. An appropriate urine output in this particular instance would be that of 1ml per kg per hour. An NG should be placed only if there’s marked emesis, as it may perpetuate the electrolyte losses by decompressing the gastric juices. The patient should be made NPO upon suspicion of a pyloric stenosis and kept NPO until postoperatively. Labs should be measured at presentation and then at approximately 12 hour intervals until they are corrected. A corrected electrolyte profile would include a bicarbonate which is less than or equal to 25 and a potassium which is within the normal range. It is incredibly important to avoid all narcotics when treating pyloric stenosis as this tends to suppress the respiratory drive and can result in death of the infant. Rarely should patients get potassium boluses. They can be simply added to the IV solutions