Pyloric Stenosis: Symptoms, Types, Causes and Treatment

Pyloric stenosis is a condition that narrows the opening between the stomach and the small intestine, known as the pylorus, hindering the normal passage of stomach contents. Most commonly seen in infants, but also possible in adults, this disorder leads to a variety of symptoms and requires timely medical attention. In this comprehensive article, we will explore the symptoms, types, causes, and treatment options for pyloric stenosis—offering clarity for those seeking to understand this condition.

Symptoms of Pyloric Stenosis

Pyloric stenosis can present with a spectrum of symptoms, with some variation depending on the age of the patient. Early recognition is crucial, especially in infants, to prevent complications from dehydration and nutritional deficiency.

Symptom	Age Group	Description	Source(s)
Projectile Vomiting	Infants	Forceful, non-bilious vomiting, often after feeding	1 7 10
Palpable "Olive"	Infants	Firm, movable mass in upper abdomen	1 7 10
Visible Peristalsis	Infants	Waves visible across the belly after feeding	1 4
Metabolic Alkalosis	Infants	Electrolyte imbalance, often with dehydration	1 7
Poor Weight Gain	Infants	Failure to thrive, weight loss	1 7 8
Nausea/Vomiting	Adults	Persistent, especially after meals	2 6
Early Satiety	Adults	Feeling full quickly	2 6
Epigastric Pain	Adults	Discomfort or pain in the upper abdomen	2 6

Table 1: Key Symptoms

Infant Symptoms: Classical and Evolving Patterns

In infants, hypertrophic pyloric stenosis typically manifests between the third and fourth weeks of life. The most striking symptom is projectile, non-bilious vomiting that becomes progressively worse. Despite vomiting, babies often appear hungry and eager to feed again. A distinctive "olive-shaped" mass—a thickened pylorus—may be palpable in the upper abdomen, though this finding is becoming less common due to earlier diagnosis aided by imaging 1 7 10.

Other signs include visible peristaltic waves moving from left to right across the abdomen after feeding, reflecting the stomach's effort to push food through the narrowed pylorus 4. As vomiting persists, infants can develop dehydration, poor weight gain, and a specific metabolic imbalance known as hypochloremic, hypokalemic metabolic alkalosis 1 7.

Adult Symptoms: Subtle but Serious

Though rare, pyloric stenosis can occur in adults. Unlike infants, adults usually experience nausea, vomiting (which may be less forceful), early fullness after eating, and upper abdominal pain. Over time, chronic obstruction can lead to weight loss and malnutrition 2 6. The symptom pattern in adults often overlaps with other gastrointestinal disorders, making diagnosis more challenging.

Types of Pyloric Stenosis

Pyloric stenosis is not a one-size-fits-all condition. It can arise in different forms and at various stages of life, each with distinct characteristics and underlying mechanisms.

Type	Patient Group	Defining Feature	Source(s)
Congenital (Infantile/Hypertrophic)	Infants	Thickened pyloric muscle	1 7 8 10
Adult Idiopathic	Adults	Muscle hypertrophy without clear cause	2
Acquired (Secondary)	All ages	Due to scarring, inflammation, or injury	5 6 9
Functional/Spastic	All ages	Transient muscular spasm, not structural	4

Table 2: Types of Pyloric Stenosis

Congenital Hypertrophic Pyloric Stenosis

This is the classic and most common type, affecting infants. The pyloric muscle becomes abnormally thickened, causing a mechanical blockage. It usually emerges within the first few weeks of life and is more frequent in males and firstborn children 1 7 8 10.

Adult Idiopathic Hypertrophic Pyloric Stenosis

Rare but recognized, this type occurs in adults without a clear underlying cause. It presents with gradual onset of obstruction symptoms and may be mistaken for other gastrointestinal conditions. Endoscopy may reveal the "cervix sign"—a narrowed, smooth pylorus 2.

Acquired (Secondary) Pyloric Stenosis

In both children and adults, pyloric stenosis can result from external factors. Common causes include:

• Scarring from peptic ulcers
• Inflammation or chronic gastritis
• Caustic (corrosive) ingestion leading to chemical burns and subsequent scarring 5 6 9

These cases often require different management strategies.

Functional or Spastic Pyloric Stenosis

Some cases may be due to transient or persistent spasm of the pyloric muscle, without significant structural thickening. This can lead to intermittent symptoms and may resolve spontaneously or with medical therapy 4.

Causes of Pyloric Stenosis

Understanding the causes of pyloric stenosis helps in both prevention (where possible) and targeting treatment. While the exact origins remain elusive for some types, several contributing factors have been identified.

Cause	Mechanism/Description	Group Affected	Source(s)
Genetic/Unknown	Inherited predisposition, unclear mechanism	Infants	3 7 10
Hyperacidity Theory	Excess stomach acid promotes muscle thickening	Infants	3
Peptic Ulcers	Chronic ulcer causes scarring and narrowing	Adults	6
Corrosive Ingestion	Chemical burns lead to pyloric scarring	Children/Adults	5
Ectopic Ampulla	Abnormal bile drainage causes inflammation	Adults	6
Tumors/Neoplasia	Growths block the pylorus	Adults	6
Idiopathic	No identifiable cause	Adults	2

Table 3: Causes of Pyloric Stenosis

Infantile (Congenital) Pyloric Stenosis: Genetics and Theories

The cause of infantile hypertrophic pyloric stenosis is not fully understood. Evidence suggests a genetic predisposition, as it is more common in males, firstborns, and those with a family history 1 7 10. One proposed theory is that infants may inherit a larger number of gastric parietal cells, leading to increased stomach acid production. This "hyperacidity" could stimulate the pyloric muscle to thicken abnormally 3.

Acquired Causes in Children and Adults

• Peptic Ulcers: Recurrent or chronic stomach ulcers near the pylorus can cause scarring and narrowing, resulting in obstruction 6.
• Corrosive (Caustic) Ingestion: Accidental or intentional swallowing of caustic substances can burn and scar the gastric outlet, particularly in young children 5.
• Ectopic Ampulla of Vater: Rarely, an abnormally placed bile duct opening leads to chronic irritation and inflammation, causing pyloric stenosis 6.
• Tumors: Benign or malignant growths in the region of the pylorus can physically block the passage 6.

Idiopathic Adult Pyloric Stenosis

In adults, hypertrophic pyloric stenosis can occur without any clear cause or predisposing event. This idiopathic form remains a diagnosis of exclusion after other causes have been ruled out 2.

Treatment of Pyloric Stenosis

Timely and effective treatment of pyloric stenosis is essential to ensure recovery and prevent complications. The specific approach depends on the underlying cause, patient age, and severity.

Treatment	Description	Patient Group	Source(s)
Pyloromyotomy	Surgical splitting of pyloric muscle	Infants	7 8 10 11
Laparoscopic Surgery	Minimally invasive pyloromyotomy	Infants	11
Endoscopic Dilation	Balloon widening of narrowed pylorus	Adults/Benign	2 6 9
Stent Placement	Temporary stent to keep pylorus open	Adults/Benign	9
Gastrectomy	Surgical removal of part of stomach	Severe/Adults	2 6
Medical Management	Fluid/electrolyte correction, acid suppression	All	7 8 10

Table 4: Treatment Options

Infantile Pyloric Stenosis: Pyloromyotomy

The gold standard for treating infantile hypertrophic pyloric stenosis is surgical—specifically, a pyloromyotomy. This procedure involves splitting the thickened pyloric muscle to relieve the obstruction while preserving the inner lining of the stomach 7 8 10.

Open vs. Laparoscopic Pyloromyotomy

Both open and minimally invasive (laparoscopic) techniques are effective and safe. Laparoscopic pyloromyotomy is increasingly popular due to:

• Faster recovery and shorter hospital stays
• Less postoperative vomiting
• Lower risk of wound infection
• Comparable complication rates to open surgery 11

Adult and Acquired Pyloric Stenosis: Tailored Approaches

Treatment in adults and for acquired cases is more variable. Options include:

• Endoscopic Balloon Dilation: Temporarily relieves obstruction but may require repeated sessions as strictures can recur 2 6 9.
• Self-Expandable Metallic Stents: Used as a temporary solution in some benign cases, but risk of stent migration limits their use 9.
• Surgical Intervention: For refractory cases, partial gastrectomy or bypass surgery (e.g., Billroth I gastroduodenostomy or gastrojejunostomy) may be necessary 2 6.
• Treatment of Underlying Cause: For cases due to peptic ulcers or caustic injury, additional management of the primary problem is essential 5 6.

Medical and Supportive Care

In all cases, initial management includes correcting dehydration and electrolyte imbalances, particularly in infants. Acid suppression may be used in specific cases, but is not curative for true hypertrophic pyloric stenosis 7 8 10.

Conclusion

Pyloric stenosis is a clinically significant condition characterized by narrowing at the stomach's outlet, leading to distinctive symptoms and requiring prompt intervention. Understanding its varied presentations, underlying causes, and treatment options is essential for optimal care.

Key points:

• Symptoms differ by age: projectile vomiting and palpable mass in infants; nausea, vomiting, and fullness in adults.
• Types include congenital (infantile), adult idiopathic, acquired (secondary), and functional/spastic forms.
• Causes range from genetics and hyperacidity in infants to ulcers, caustic injury, and tumors in adults.
• Treatment is most often surgical, with pyloromyotomy as first-line in infants and tailored approaches—including endoscopic and surgical options—in adults and acquired cases.

By recognizing the early signs and understanding the available management strategies, outcomes for patients with pyloric stenosis can be excellent.