Pyloric stenosis is a condition that affects infants, typically between three to five weeks of age, causing severe and progressive vomiting. This condition occurs when the pylorus, the muscle between the stomach and the small intestine, thickens and obstructs food from passing through.

Though relatively rare, pyloric stenosis requires prompt medical attention to prevent complications such as dehydration and weight loss.

This blog aims to provide a comprehensive overview of pyloric stenosis, including its symptoms, diagnosis, and treatment options.

Symptoms of Pyloric Stenosis

The symptoms of pyloric stenosis usually become apparent between the third and fifth weeks of an infant’s life. Key symptoms include:

• Projectile Vomiting: This is the primary symptom of pyloric stenosis. The vomiting is forceful and can project several feet away. It typically occurs shortly after feeding and can become more frequent and severe over time.
• Persistent Hunger: Despite frequent vomiting, infants with pyloric stenosis often appear hungry and want to eat soon after vomiting.
• Weight Loss or Poor Weight Gain: Due to the inability to keep food down, affected infants may fail to gain weight or may lose weight.
• Dehydration: Symptoms of dehydration may include a decrease in wet diapers, dry mouth, crying without tears, and lethargy.
• Stomach Contractions: Visible waves of peristalsis may be seen across the infant’s abdomen, reflecting the stomach’s effort to move food past the obstruction.
• Changes in Bowel Movements: Infants with pyloric stenosis may have fewer bowel movements and may experience constipation.

Causes and Risk Factors of Pyloric Stenosis

While the exact cause of pyloric stenosis remains unclear, several factors are thought to contribute to its development:

• Pyloric stenosis is more common in infants with a family history of the condition. If a parent has had pyloric stenosis, their child is at a higher risk. The risk increases even more if a sibling has had it.
• Certain genetic mutations are associated with a higher risk of pyloric stenosis. Research is ongoing to identify specific genes involved in this condition.
• Pyloric stenosis is more common in male infants, with a male-to-female ratio of about 4:1. The reasons for this gender difference are not fully understood but may be linked to hormonal or genetic factors.
• First-born infants are more likely to develop pyloric stenosis than their younger siblings. This correlation might be due to a combination of genetic predisposition and environmental factors that affect first-born children differently.
• Infants born prematurely are at an increased risk of developing pyloric stenosis. The underdevelopment of their gastrointestinal system may contribute to the condition.
• Maternal smoking has been linked to an increased risk of pyloric stenosis. Exposure to nicotine and other harmful substances may affect the developing foetus and increase the likelihood of this condition.
• Early introduction of solid foods or changes in feeding practices have been considered potential contributing factors, although the evidence is not conclusive.

Diagnosis of Pyloric Stenosis

The diagnosis of pyloric stenosis typically involves a combination of medical history, physical examination, and diagnostic tests:

Medical History

The first step in diagnosing pyloric stenosis is a detailed review of the infant’s symptoms. Parents often report frequent and severe vomiting, which is typically projectile and happens shortly after feeding. They may also note persistent hunger, weight loss, and signs of dehydration.

The healthcare provider will ask about the infant’s feeding habits and growth patterns. Poor weight gain or weight loss despite regular feedings is a significant red flag. A family history of pyloric stenosis can increase the likelihood of the condition, so the doctor will enquire about any relatives who have had the condition.

Physical Examination

During the physical examination, the doctor will palpate the infant’s abdomen to feel an olive-shaped mass in the upper right quadrant. This mass is the hypertrophied pyloric muscle, which is a classic sign of pyloric stenosis.

The doctor may observe visible waves of peristalsis moving from left to right across the infant’s abdomen after feeding, indicating the stomach’s efforts to push food past the obstructed pylorus.

Ultrasound

An abdominal ultrasound is the most commonly used and effective diagnostic tool for pyloric stenosis. It can visualise the thickened pyloric muscle and measure its dimensions. A pyloric muscle thickness greater than 3-4 mm and a pyloric channel length greater than 15-18 mm are indicative of pyloric stenosis.

Barium Swallow

In some cases, if the ultrasound results are inconclusive, a barium swallow test may be performed. The infant drinks a barium solution, and X-rays are taken to observe the passage of the liquid through the digestive tract. A “string sign,” where the barium flows through a narrow pyloric canal, can confirm the diagnosis.

Blood Tests

Blood tests are performed to assess the infant’s electrolyte levels and hydration status. Frequent vomiting can lead to dehydration and electrolyte imbalances, such as low potassium and chloride levels and elevated bicarbonate levels. These findings help in planning the necessary preoperative management.

Upper Gastrointestinal (GI) Series

Occasionally, an upper GI series may be used to evaluate the stomach and intestines. The infant ingests a contrast material, and a series of X-rays are taken to visualise the upper digestive tract. This test can help identify the narrowed pyloric canal and other possible abnormalities.

Treatment Options for Pyloric Stenosis

Pyloric stenosis is a condition that necessitates prompt medical intervention to prevent complications and ensure the health of the affected infant. The primary treatment for pyloric stenosis is surgical, but preoperative management to stabilise the infant is also important.

Let’s look at this in more detail:

1. Preoperative Management

Before surgery, the infant’s condition needs to be stabilised to address dehydration and electrolyte imbalances caused by persistent vomiting. This involves:

• Intravenous (IV) Fluids: To rehydrate the infant and correct electrolyte imbalances, IV fluids are administered. The fluids typically include a balanced solution containing electrolytes such as sodium, potassium, and chloride. The goal is to restore normal hydration and electrolyte levels before surgery.
• Electrolyte Correction: Blood tests are conducted to determine the specific electrolyte imbalances. Based on the results, appropriate electrolyte solutions are provided to correct these imbalances. This step is essential to reduce the risk of complications during and after surgery.
• Monitoring and Assessment: Continuous monitoring of the infant’s vital signs, hydration status, and electrolyte levels is necessary to ensure stability before proceeding with surgery.

2. Surgical Treatment

The definitive treatment for pyloric stenosis is a surgical procedure called pyloromyotomy. There are two main surgical approaches:

3. Postoperative Care

After the surgical procedure, the infant requires careful monitoring and supportive care to ensure a smooth recovery.

Immediately after the surgery, the infant is closely monitored in the recovery room for any immediate postoperative complications such as bleeding, infection, or anaesthesia-related issues.

Feeding usually resumes a few hours after surgery, starting with small amounts of clear liquids (such as an electrolyte solution) to ensure that the infant can tolerate fluids without vomiting. Gradually, the feedings are increased in volume and transitioned to breast milk or formula. The process typically spans 24 to 48 hours, intending to return to normal feeding patterns.

Pain relief is provided using medications such as acetaminophen. It’s important to manage pain effectively to keep the infant comfortable and facilitate recovery.

Monitoring for Complications: During the post-operative time, the healthcare team monitors the infant closely for potential complications such as:

• Signs of infection at the incision site include redness, swelling, warmth, or discharge. Any signs of infection need to be promptly addressed with appropriate antibiotics.
• Although rare, any signs of internal or external bleeding need to be evaluated and managed immediately.
• While some mild vomiting may occur as the digestive system adjusts, persistent or severe vomiting should be reported to the healthcare provider.

Parents are provided with instructions on how to care for the incision site, recognise signs of complications, and gradually reintroduce regular feeding. They are also informed about follow-up appointments to monitor the infant’s recovery and growth.

Preventive Measures and Parental Guidance

While there are no definitive preventive measures for pyloric stenosis, early recognition of symptoms and prompt medical attention are pivotal. Parents should be aware of the signs of pyloric stenosis and seek medical advice if their infant exhibits persistent vomiting, poor weight gain, or other related symptoms.

Parents play a vital role in supporting their infant’s recovery after pyloromyotomy. Key steps include:

• Follow Medical Advice: Adhere to the paediatrician’s recommendations for feeding and care after surgery.
• Monitor for Complications: Watch for signs of infection, such as redness, swelling, or discharge at the incision site, and report any concerns to the healthcare provider.
• Gradual Feeding: Start with small, frequent feedings of clear liquids, gradually progressing to regular feeding as advised by the healthcare provider.
• Provide Comfort: Offer comfort and reassurance to the infant, who may be fussy or uncomfortable during the recovery period.
• Attend Follow-Up Appointments: Regular follow-up visits with the paediatrician are essential to monitor the infant’s recovery and ensure proper growth and development.

Sources:

• https://www.mayoclinic.org/diseases-conditions/pyloric-stenosis/symptoms-causes
• https://my.clevelandclinic.org/health/diseases/pyloric-stenosis-hps
• https://www.chop.edu/conditions-diseases/pyloric-stenosis
• https://www.hopkinsmedicine.org/health/conditions-and-diseases/pyloric-stenosis
• https://www.webmd.com/parenting/baby/pyloric-stenosis
• https://www.medicalnewstoday.com/articles/pyloric-stenosis#emergency-help
• https://www.healthline.com/health/pyloric-stenosis#treatment
• https://www.cincinnatichildrens.org/health/p/pyloric-stenosis