Overview
Definition:
Pyloric stenosis is a condition in infants characterized by the thickening of the pyloric sphincter muscle, leading to obstruction of gastric emptying
Open pyloromyotomy is the surgical procedure to relieve this obstruction.
Epidemiology:
It is one of the most common surgical emergencies in infancy, typically presenting between 3 to 12 weeks of age
Incidence is estimated at 2-5 per 1000 live births, with a male predominance (4:1 to 5:1)
First-born males are at higher risk
There is a familial predisposition.
Clinical Significance:
Untreated pyloric stenosis leads to severe dehydration, electrolyte imbalances, malnutrition, and can be life-threatening
Prompt diagnosis and surgical intervention are crucial for a favorable outcome and preventing long-term complications.
Clinical Presentation
Symptoms:
Non-bilious projectile vomiting, typically starting after the first week of life
Emesis is forceful and can project food several feet
Gradual weight loss or failure to gain weight
Persistent hunger despite vomiting
Dehydration signs: decreased urine output, dry mucous membranes, sunken fontanelle.
Signs:
A palpable, firm, olive-shaped mass in the upper abdomen, usually to the right of the midline
Visible gastric peristaltic waves progressing from left to right across the abdomen
Signs of dehydration, including lethargy and decreased skin turgor.
Diagnostic Criteria:
Diagnosis is primarily clinical, confirmed by imaging
Classic presentation of projectile non-bilious vomiting in an infant with a palpable pyloric mass is highly suggestive.
Diagnostic Approach
History Taking:
Detailed history of vomiting: onset, frequency, volume, character (bilious vs
non-bilious), projectile nature
Feeding history and weight gain pattern
Urine output and stool frequency
Family history of pyloric stenosis.
Physical Examination:
Careful palpation of the abdomen for a pyloric mass (gastric olive)
Observation for gastric peristalsis
Assessment of hydration status: fontanelle, mucous membranes, skin turgor, capillary refill
Vital signs monitoring.
Investigations:
Abdominal ultrasound is the imaging modality of choice: measures pyloric muscle thickness (>3 mm) and channel length (>15 mm), and demonstrates delayed gastric emptying
Upper GI series (barium swallow) can show a "string sign" or "shoulder sign" but is less preferred due to radiation and potential aspiration risk
Electrolyte and blood gas analysis to assess for dehydration and metabolic alkalosis (hypochloremic, hypokalemic metabolic alkalosis is common).
Differential Diagnosis:
Gastroesophageal reflux (GERD), milk allergy, overfeeding, intestinal obstruction (e.g., malrotation with volvulus), infectious gastroenteritis, neurological causes of vomiting.
Management
Initial Management:
Fluid resuscitation and correction of electrolyte imbalances are paramount before surgery
Intravenous fluids (e.g., normal saline with potassium supplementation) are administered
Nasogastric tube may be inserted for gastric decompression if vomiting is severe.
Medical Management:
Medical management is generally not indicated for established pyloric stenosis
surgery is the definitive treatment
However, correction of dehydration and metabolic derangements is essential prior to surgery.
Surgical Management:
The standard treatment is a Ramstedt pyloromyotomy, an open surgical procedure
Indications include confirmed diagnosis of pyloric stenosis with significant symptoms and signs of dehydration
The technique involves incising the thickened pyloric muscle longitudinally, splitting it down to the mucosa without entering the lumen
Historically, open surgery is performed via a circumumbilical or right upper quadrant incision.
Supportive Care:
Postoperative care involves monitoring vital signs, pain control, and gradual reintroduction of oral feeds
Intravenous fluids are continued until adequate oral intake is established
Early feeding can usually commence within 4-6 hours postoperatively
Close monitoring for signs of complications like wound infection, bleeding, or persistent vomiting.
Complications
Early Complications:
Bleeding from the incision or within the abdominal cavity
Wound infection
Incomplete pyloromyotomy leading to persistent vomiting
Perforation of the gastric mucosa during the procedure
Injury to adjacent organs (e.g., pancreas).
Late Complications:
Gastric outlet obstruction due to stricture or adhesions (rare)
Chronic abdominal pain
Increased risk of peptic ulcer disease in adulthood (debated).
Prevention Strategies:
Meticulous surgical technique to avoid mucosal injury
Proper wound care
Aggressive fluid and electrolyte management pre- and post-operatively
Early identification and management of any signs of complications.
Prognosis
Factors Affecting Prognosis:
The overall prognosis for pyloric stenosis after pyloromyotomy is excellent
Factors influencing recovery include the severity of preoperative dehydration and malnutrition, presence of any intraoperative complications, and speed of return of bowel function.
Outcomes:
Most infants return to their birth weight and achieve normal feeding patterns within a few weeks
Long-term outcomes are generally very good with minimal residual issues
Recurrence of stenosis is extremely rare.
Follow Up:
Routine follow-up is usually not required unless there are specific concerns or complications
Parents should be advised on signs of feeding intolerance or post-operative complications
Gradual increase in oral feeds is guided by the infant's tolerance.
Key Points
Exam Focus:
Classic presentation: projectile non-bilious vomiting in a male infant, 3-12 weeks old
Palpable "olive" and visible peristalsis
Ultrasound findings: thickened pylorus
Ramstedt pyloromyotomy is the definitive treatment
Hypochloremic metabolic alkalosis.
Clinical Pearls:
Always palpate for the pyloric mass carefully in infants with unexplained vomiting
Differentiate from GERD by the projectile nature and presence of weight loss
The procedure is a simple myotomy, not a resection.
Common Mistakes:
Delaying diagnosis due to misattribution to simple reflux or overfeeding
Inadequate correction of dehydration and electrolyte imbalance preoperatively
Inadvertent mucosal perforation during pyloromyotomy.