Pyloric stenosis is a condition characterized by the narrowing of the pylorus, the opening between the stomach and the small intestine. While commonly associated with infants, pyloric stenosis can also occur in adults, though it is rare. In adults, it is also known as adult idiopathic hypertrophic pyloric stenosis (AIHPS). This condition can significantly impact the quality of life if left untreated.
Understanding Pyloric Stenosis
In pyloric stenosis, the pylorus muscle thickens, leading to a narrowing of the pyloric canal and obstructing the passage of food from the stomach to the small intestine. Unlike infantile pyloric stenosis, which typically develops within the first few weeks of life, adult pyloric stenosis can occur at any age and may have various underlying causes. Adult hypertrophic pyloric stenosis (AHPS) is a rare disease and presents as pyloric obstruction.
Symptoms of Pyloric Stenosis in Adults
The symptoms of pyloric stenosis in adults can differ from those observed in infants. Adults with this condition may experience:
- Persistent nausea and vomiting, especially after meals
- Abdominal pain or discomfort in the upper abdomen
- Early satiety (feeling full quickly when eating)
- Unintentional weight loss
- Bloating and abdominal distension
- Dehydration due to frequent vomiting
- Fatigue and weakness
These symptoms can develop gradually over time, making the condition challenging to diagnose in its early stages. The most common symptoms of AIHPS are postprandial nausea, vomiting, early satiety, and epigastric pain.
Causes and Risk Factors
The exact etiology of AIHPS is unclear, with both genetic and environmental factors involved. The causes of pyloric stenosis are unknown, but genes and environmental factors might play a role. Several factors may contribute to its development:
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Primary Causes
In some cases, pyloric stenosis in adults may be idiopathic, meaning it occurs without a known cause. This form is often referred to as primary adult hypertrophic pyloric stenosis.
Secondary Causes
Secondary pyloric stenosis can result from various underlying conditions or factors, including:
- Peptic ulcer disease
- Chronic inflammation of the stomach lining (gastritis)
- Scarring from previous surgeries
- Tumors or polyps in the pyloric region
- Crohn's disease affecting the stomach or duodenum
- Vagal nerve dysfunction
The majority of researchers believe it to be the persistence of the mild juvenile form of HPS, which is further strengthened by the fact that both infantile and adult IHPS have similar histological and anatomical changes. Some researchers postulate edema, spasm, or inflammation triggers pyloric occlusion in a predisposed individual. Other possible etiologies include protracted pylorospasm, vagal hyperactivity, and changes in Auerbach’s plexus.
Hypertrophic Pyloric Stenosis (HPS) has been classified in various ways by multiple authors. The most universally accepted classifications are by Danikas et al. and Zarineh et al. Danikas et al. divided HPS into three types: Type 1, which is infantile HPS diagnosed at a late stage; Type 2, which is the most common type, and which occurs during adult life and is likely secondary to underlying GI pathologies, such as peptic ulcer disease, malignancy, and certain inflammatory diseases; and Type 3, which is idiopathic HPS of adult onset. Zarineh et al. divided HPS into primary, which has no underlying cause and under which AIHPS would be classified, and secondary, caused by an underlying disorder like the excessive healing of gastric or duodenal ulcers, malignancy, GISTs, postoperative intraabdominal adhesions, bezoars, and increased vagal activity causing pylorus hypertrophy.
Diagnosis of Pyloric Stenosis in Adults
Diagnosing pyloric stenosis in adults typically involves a combination of clinical evaluation, imaging studies, and sometimes endoscopic procedures. Diagnosing AIHPS is based on a high index of clinical suspicion and suggestive radiological and endoscopic signs with the definitive diagnosis being made by the pathologist. The diagnostic process may include:
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- Physical examination and medical history review
- Upper gastrointestinal series (barium swallow)
- Abdominal ultrasound
- CT scan or MRI of the abdomen
- Upper endoscopy to visualize the pylorus directly
- Gastric emptying studies to assess stomach function
The sign can also be elicited by manual pressure on the stomach. Abdominal CT scan shows nonspecific distal gastric wall thickening in some cases. However, it is mainly used to rule out secondary causes of HPS including malignancy. Endoscopy usually shows a unique ‘Cervix sign,’ which is a fixed, markedly narrowed pylorus with a smooth border, and which persists after anticholinergic therapy. It can be differentiated from pylorospasm when pressure is applied through the endoscope. Pathology shows grossly elongated and thickened pylorus.
These diagnostic tools help healthcare providers confirm the presence of pyloric stenosis and rule out other potential causes of similar symptoms.
Treatment Options for Adult Pyloric Stenosis
The treatment approach for pyloric stenosis in adults depends on the severity of the condition and its underlying cause. Multiple treatments have been proposed for AIHPS, including endoscopic dilation, pyloromyotomy with or without pyloroplasty, gastrectomy with a Billroth 1 gastroduodenostomy. Laparoscopic pyloroplasty is a less invasive option. Currently, there is no evidence of one surgical technique being superior to another. Options may include:
Conservative Management
For mild cases, dietary modifications and medications to manage symptoms may be recommended. This can include:
- Eating smaller, more frequent meals
- Avoiding high-fat and high-fiber foods
- Using prokinetic medications to improve stomach emptying
- Treating underlying conditions like peptic ulcers or gastritis
Endoscopic Procedures
In some cases, endoscopic balloon dilation of the pylorus may be performed to widen the narrowed passage. Endoscopic dilation has a high rate of recurrence and provides only temporary relief of symptoms. It is an option in high-risk surgical patients. Burbridge used an AXIOS stent (Boston Scientific, Marlborough, MA), a novel, endoscopic, fully covered, metal-apposition stent, to take an aggressive approach to dilating the patient's pylorus. Duke is one of few centers using the stent for this off-label use. Because use of the AXIOS stent for this off-label purpose is relatively novel, Burbridge notes that long-term outcomes following its removal are not well known.
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Surgical Intervention
For severe or refractory cases, surgical treatment may be necessary. The most common surgical approach is pyloroplasty, which involves widening the pyloric opening. In some instances, a partial gastrectomy (removal of part of the stomach) may be required.
Long-Term Outlook and Potential Complications
With proper treatment, many adults with pyloric stenosis can experience significant symptom relief and improved quality of life. However, untreated or poorly managed pyloric stenosis can lead to complications such as:
- Chronic malnutrition and weight loss
- Electrolyte imbalances due to persistent vomiting
- Dehydration
- Gastroesophageal reflux disease (GERD)
- In severe cases, gastric perforation or obstruction
Regular follow-up with a healthcare provider is essential to monitor the condition and adjust treatment as needed.
Adult Hypertrophic Pyloric Stenosis (AHPS) with Double Pylorus Formation
Adult hypertrophic pyloric stenosis (AHPS) is a rare disease and presents in adult life as pyloric obstruction. It is a benign disease resulting from hypertrophy of the circular fibers of the pyloric canal. Double pylorus is also a rare condition due to a gastroduodenal fistula connecting from the gastric antrum to the duodenum. A 42‐year‐old woman without a history of vomiting in infancy presented with postprandial abdominal distension and repeated vomiting. Abdominal computed tomography showed gastric dilatation and wall thickening of the distal stomach. Endoscopy and contrast gastrography revealed gastric outlet obstruction due to stenosis and an ulcer in the antral and pyloric region. Endoscopic ultrasonography revealed circumferential thickening of the muscularis propria layer of the pylorus. Her symptoms improved with treatment consisting of drainage, fasting, and a proton pump inhibitor. Two weeks after onset, follow‐up endoscopy revealed a healing ulcer and double channel pylorus. Based on her clinical course and findings of clinical images, she was diagnosed with gastric outlet obstruction due to AHPS that was improved by double channel pylorus formation.
The clinical and imaging findings suggested that the double pylorus formed in the following manner. When retrospectively reviewed the endoscopic images from the EGD examination that the patient had undergone 1 year prior to the current admission, antral narrowing was observed. She may have had asymptomatic AHPS at that time. When the patient came to the emergency room, endoscopy and contrast gastrography revealed gastric outlet obstruction due to stenosis and a deep ulcer in the stenotic antrum. During the hospital admission, the deep ulcer made a fistula with the duodenum that would eventually become a double pylorus.
AHPS can be classified into the following three types. The first type is the late stage of infantile hypertrophic pyloric stenosis (HPS). The second type is HPS commencing in adult life but secondary to other diseases such as hiatal hernia, duodenal ulcer, gastric ulcer, tumors, or inflammatory diseases. Endoscopic ultrasonography is helpful in diagnosing AHPS. In our case, the pyloric canal was elongated and narrow due to the stenotic antral and pyloric region, and the thickness of the distal gastric wall was increased on CT. EUS revealed circumferential thickening of the pyloric muscle with a maximum thickness of more than 10 mm.
Patients with AHPS who have persistent symptoms usually undergo surgical treatment such as partial gastrectomy, gastroenterostomy, pyloromyotomy, or pyloroplasty. In our case, a gastric ulcer may have been present in the prepyloric region for a short while before the onset of gastric obstruction, because the narrowed antrum that had been observed by endoscopy 1 year previously suggested that the patient had been suffering from asymptomatic AHPS at that time. During the present hospitalization, after gastric ulcer treatment, the pylorus was found to have double channels that connected to the duodenal bulb and the descending duodenum, respectively. The endoscopic examination that had been performed at the onset of gastric outlet obstruction revealed a deep ulcer in the stenotic antrum, and the ulcer might have penetrated through the antral wall and formed a fistula with the descending duodenal.
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