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Gastric Outlet Obstruction

Updated : September 22, 2023





Background

Gastric outlet obstruction is characterized by a blockage or narrowing at the point where the stomach empties its contents into the small intestine. This obstruction can occur for various reasons, leading to various symptoms and complications. Gastric outlet obstruction can also result from either a benign or malignant mechanical blockage or a motility disorder that disrupts the normal gastric emptying process.

From an anatomical perspective, these mechanical obstructions can occur at various locations within the digestive tract, including the distal stomach, pyloric channel, or duodenum. Furthermore, these obstructions may be intrinsic, originating within the stomach or duodenum itself, or extrinsic, stemming from external factors that put pressure on the stomach.

Epidemiology

The exact prevalence of gastric outlet obstruction (GOO) remains uncertain. In the era prior to the widespread use of proton pump inhibitors, the primary contributor to GOO was peptic ulcer disease. However, with improved management of H. pylori infections and the adoption of PPI, the incidence of GOO due to PUD has dwindled to approximately 5%. In recent times, a significant majority, ranging from 50% to 80% of GOO cases are associated with underlying malignancies.

Specifically, peripancreatic malignancies are responsible for GOO in approximately 15% to 20% of cases. In terms of gender distribution, males are more frequently affected than females, with a ratio of approximately 3 to 4 males for every female for both malignant and benign causes of GOO. In neonates, hypertrophic pyloric stenosis (HPS) is a prevalent etiology of GOO.

It occurs at a rate of 1.5 to 3 cases per 1000 live births and is notably more common in males, with a ratio of 1 in 150 for males compared to 1 in 750 for females. However, HPS is a rare occurrence in older children and adolescents. This condition arises from widespread hypertrophy and hyperplasia of the pyloric smooth muscles, causing narrowing of the antrum and subsequently leading to GOO.

Anatomy

Pathophysiology

The pathophysiology of Gastric Outlet Obstruction (GOO) involves the disruption of normal gastric emptying due to various factors, leading to a range of clinical symptoms and complications. GOO can result from either benign or malignant causes. The obstruction can occur at different anatomical locations, including the distal stomach, pyloric channel, or duodenum.

These obstructions may be intrinsic, originating within the stomach or duodenum itself, or extrinsic, caused by factors external to the stomach. The accumulation of undigested food or other materials in the stomach can form bezoars, which obstruct the passage of food from the stomach to the small intestine. The majority of malignant GOO cases are related to underlying cancers.

These can include gastric cancer, pancreatic cancer, or other tumors that compress or invade the stomach or duodenum. Tumors may physically block the passage of food, and the growth of the tumor can contribute to the obstruction. Approximately 15% to 20% of GOO cases are attributed to malignancies in the peripancreatic region. These tumors can exert pressure on the stomach or duodenum, leading to obstruction.

Etiology

Benign Cause

  • Anastomotic strictures
  • Annular pancreas
  • Crohn disease
  • Eosinophilic gastroenteritis
  • Gastric volvulus
  • Gastric tuberculosis
  • Gastric bezoars
  • Peptic Ulcer Disease

Malignant Cause

  • Distal Gastric Cancer
  • Gastric Carcinoid
  • Gastric Lymphoma
  • Gallbladder Carcinoma
  • Pancreatic Adenocarcinoma

Motility Disorder

  • Gastroparesis
  • Diabetes Mellitus

Genetics

Prognostic Factors

When benign causes of gastric outlet obstruction are diagnosed and treated promptly, the prognosis is generally good. Surgical or medical interventions can often provide relief, and patients can resume normal digestive function. If caused due to malignant causes typically carries a poor prognosis. This is because cancer-related obstructions are often advanced by the time they are diagnosed.

Clinical History

The presentation and range of symptoms in gastric outlet obstruction are closely tied to the root cause of the obstruction. Nausea and vomiting frequently stand out as the primary symptoms among affected patients. In cases marked by the sudden onset of symptoms, healthcare providers may consider several potential underlying issues, including peptic ulcer disease, gallstones, pancreatitis, volvulus, or specific instances of percutaneous endoscopic gastrostomy tube migration.

When benign factors are at play in GOO cases, early satiety (reported in 53% of cases) and bloating (occurring in 50% of cases) are the more prevalent symptoms. In contrast, malignant causes tend to manifest with a broader array of symptoms, including pain, weight loss, vomiting, and malnutrition. This disparity underscores the importance of considering the full clinical picture and the specific symptomatology when evaluating and diagnosing patients with GOO.

Physical Examination

During a physical examination, healthcare providers may observe signs indicating hypovolemia and weight loss in patients with gastric outlet obstruction. Abdominal distension, accompanied by a phenomenon known as a “succussion splash,” is apparent in approximately 25% of cases and is indicative of retained gastric contents. Notably, if a succussion splash is detected more than four hours following a meal, it raises suspicion of GOO with a sensitivity of about 50%.

Gathering a comprehensive drug history is crucial to uncover any usage of non-steroidal anti-inflammatory drugs (NSAIDs), aspirin, opioids, or anticholinergic medications, as these substances can contribute to or exacerbate GOO. Additionally, it is imperative to provide education and guidance to patients who smoke, strongly advising against the continuation of this habit due to its potential impact on the condition.

Age group

Associated comorbidity

Associated activity

Acuity of presentation

Differential Diagnoses

Brunner Gland Adenoma

Congenital Duodenal Webs

Chronic Granulomatous Disease

Gallstone Obstruction

Hiatal Hernia

Pancreatic Pseudocysts

Strongyloides Hyperinfection

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

The treatment for gastric outlet obstruction can vary depending on its underlying cause and characteristics. In cases of benign GOO, initial management typically involves conservative measures, such as acid suppression, NSAID avoidance, and treatment for H. pylori infection. If these conservative approaches fail, endoscopic dilation or surgery may be considered.

For malignant GOO, treatment options include resection (if curative), decompressive gastrostomy, bypass surgery, endoscopic stenting, and endoscopic ultrasound-guided gastroenterostomy. Surgery may also be an option for benign GOO if the obstruction cannot be safely dilated or persists despite other treatments.

Additionally, GOO caused by extrinsic compression, like chronic pancreatitis, may warrant early consideration for surgery due to limited responsiveness to less invasive interventions. Ultimately, the choice of treatment for GOO depends on the specific diagnosis, severity of obstruction, and individual patient factors, with a range of options available to alleviate symptoms and improve overall well-being.

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Surgical intervention is a viable consideration in the treatment of benign gastric outlet obstruction under certain circumstances. It becomes a suitable option when the pylorus, the muscular valve controlling the passage from the stomach to the small intestine, cannot be safely dilated due to an obstructive blockage.

Furthermore, surgery may be warranted if the obstruction persists despite diligent attempts at resolution through endoscopic and medical management. In cases where the obstruction arises from extrinsic factors, such as chronic pancreatitis or other external compressive forces, the response to endoscopic balloon dilation tends to be less favorable.

Therefore, it is prudent to consider surgical intervention early in the management of GOO caused by such extrinsic compression. This proactive approach acknowledges that these types of obstructions may not readily respond to less invasive measures and highlights the importance of timely surgical assessment and intervention.

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

For Benign Obstruction

For the management of benign gastric outlet obstruction (GOO) resulting from peptic ulcer disease, it is advisable to initiate a conservative approach as the initial course of action.

This conservative strategy entails several essential steps, such as implementing acid suppression therapies, promoting the avoidance of NSAIDs, and conducting assessments to identify and subsequently treat Helicobacter pylori infection. Commencing with acid suppression forms a pivotal component of this conservative management approach.

The aim is to reduce gastric acid production, thereby alleviating the irritation and inflammation that can contribute to the obstruction. This can be achieved through the use of proton pump inhibitors (PPIs) or H2-receptor antagonists, which effectively decrease acid secretion and create a more favorable environment for healing. 

Another crucial facet of this approach is the avoidance of NSAIDs, as they can exacerbate peptic ulcer disease and potentially worsen the obstruction. Educating patients on the risks associated with NSAID use and encouraging alternative pain management options is essential to prevent further complications. 

Simultaneously, it is imperative to investigate and address the presence of H. pylori infection. This bacterium is a known contributor to peptic ulcers and can perpetuate the cycle of ulceration and obstruction.

Conducting tests to confirm H. pylori presence and subsequently providing appropriate antibiotic therapy is pivotal in resolving this aspect of the condition. Should these conservative measures prove ineffective in alleviating the gastric outlet obstruction, more invasive interventions may be warranted.

These interventions can encompass endoscopic procedures, such as dilation, which involves the widening of the narrowed passage within the stomach. Alternatively, surgical interventions may be considered as a last resort to physically correct the obstruction and facilitate proper gastric emptying. 

For Malignant Obstruction 

In cases of malignant gastric outlet obstruction, a range of therapeutic options can be considered to alleviate the obstruction and improve the patient’s quality of life. These options encompass resection, decompressive gastrostomy, bypass surgery, endoscopic stenting, and endoscopic ultrasound-guided gastroenterostomy, among others. 

Medication

 

simethicone 

40-125 mg orally 4 times each day as required post-meals at bedtime
Administer a single dose in a range of 160-500 mg post-meals at bedtime
Do not exceed the maximum dose of more than 500 mg each day



 
 

Media Gallary

References

Gastric Outlet Obstruction

Updated : September 22, 2023




Gastric outlet obstruction is characterized by a blockage or narrowing at the point where the stomach empties its contents into the small intestine. This obstruction can occur for various reasons, leading to various symptoms and complications. Gastric outlet obstruction can also result from either a benign or malignant mechanical blockage or a motility disorder that disrupts the normal gastric emptying process.

From an anatomical perspective, these mechanical obstructions can occur at various locations within the digestive tract, including the distal stomach, pyloric channel, or duodenum. Furthermore, these obstructions may be intrinsic, originating within the stomach or duodenum itself, or extrinsic, stemming from external factors that put pressure on the stomach.

The exact prevalence of gastric outlet obstruction (GOO) remains uncertain. In the era prior to the widespread use of proton pump inhibitors, the primary contributor to GOO was peptic ulcer disease. However, with improved management of H. pylori infections and the adoption of PPI, the incidence of GOO due to PUD has dwindled to approximately 5%. In recent times, a significant majority, ranging from 50% to 80% of GOO cases are associated with underlying malignancies.

Specifically, peripancreatic malignancies are responsible for GOO in approximately 15% to 20% of cases. In terms of gender distribution, males are more frequently affected than females, with a ratio of approximately 3 to 4 males for every female for both malignant and benign causes of GOO. In neonates, hypertrophic pyloric stenosis (HPS) is a prevalent etiology of GOO.

It occurs at a rate of 1.5 to 3 cases per 1000 live births and is notably more common in males, with a ratio of 1 in 150 for males compared to 1 in 750 for females. However, HPS is a rare occurrence in older children and adolescents. This condition arises from widespread hypertrophy and hyperplasia of the pyloric smooth muscles, causing narrowing of the antrum and subsequently leading to GOO.

The pathophysiology of Gastric Outlet Obstruction (GOO) involves the disruption of normal gastric emptying due to various factors, leading to a range of clinical symptoms and complications. GOO can result from either benign or malignant causes. The obstruction can occur at different anatomical locations, including the distal stomach, pyloric channel, or duodenum.

These obstructions may be intrinsic, originating within the stomach or duodenum itself, or extrinsic, caused by factors external to the stomach. The accumulation of undigested food or other materials in the stomach can form bezoars, which obstruct the passage of food from the stomach to the small intestine. The majority of malignant GOO cases are related to underlying cancers.

These can include gastric cancer, pancreatic cancer, or other tumors that compress or invade the stomach or duodenum. Tumors may physically block the passage of food, and the growth of the tumor can contribute to the obstruction. Approximately 15% to 20% of GOO cases are attributed to malignancies in the peripancreatic region. These tumors can exert pressure on the stomach or duodenum, leading to obstruction.

Benign Cause

  • Anastomotic strictures
  • Annular pancreas
  • Crohn disease
  • Eosinophilic gastroenteritis
  • Gastric volvulus
  • Gastric tuberculosis
  • Gastric bezoars
  • Peptic Ulcer Disease

Malignant Cause

  • Distal Gastric Cancer
  • Gastric Carcinoid
  • Gastric Lymphoma
  • Gallbladder Carcinoma
  • Pancreatic Adenocarcinoma

Motility Disorder

  • Gastroparesis
  • Diabetes Mellitus

When benign causes of gastric outlet obstruction are diagnosed and treated promptly, the prognosis is generally good. Surgical or medical interventions can often provide relief, and patients can resume normal digestive function. If caused due to malignant causes typically carries a poor prognosis. This is because cancer-related obstructions are often advanced by the time they are diagnosed.

The presentation and range of symptoms in gastric outlet obstruction are closely tied to the root cause of the obstruction. Nausea and vomiting frequently stand out as the primary symptoms among affected patients. In cases marked by the sudden onset of symptoms, healthcare providers may consider several potential underlying issues, including peptic ulcer disease, gallstones, pancreatitis, volvulus, or specific instances of percutaneous endoscopic gastrostomy tube migration.

When benign factors are at play in GOO cases, early satiety (reported in 53% of cases) and bloating (occurring in 50% of cases) are the more prevalent symptoms. In contrast, malignant causes tend to manifest with a broader array of symptoms, including pain, weight loss, vomiting, and malnutrition. This disparity underscores the importance of considering the full clinical picture and the specific symptomatology when evaluating and diagnosing patients with GOO.

During a physical examination, healthcare providers may observe signs indicating hypovolemia and weight loss in patients with gastric outlet obstruction. Abdominal distension, accompanied by a phenomenon known as a “succussion splash,” is apparent in approximately 25% of cases and is indicative of retained gastric contents. Notably, if a succussion splash is detected more than four hours following a meal, it raises suspicion of GOO with a sensitivity of about 50%.

Gathering a comprehensive drug history is crucial to uncover any usage of non-steroidal anti-inflammatory drugs (NSAIDs), aspirin, opioids, or anticholinergic medications, as these substances can contribute to or exacerbate GOO. Additionally, it is imperative to provide education and guidance to patients who smoke, strongly advising against the continuation of this habit due to its potential impact on the condition.

Brunner Gland Adenoma

Congenital Duodenal Webs

Chronic Granulomatous Disease

Gallstone Obstruction

Hiatal Hernia

Pancreatic Pseudocysts

Strongyloides Hyperinfection

The treatment for gastric outlet obstruction can vary depending on its underlying cause and characteristics. In cases of benign GOO, initial management typically involves conservative measures, such as acid suppression, NSAID avoidance, and treatment for H. pylori infection. If these conservative approaches fail, endoscopic dilation or surgery may be considered.

For malignant GOO, treatment options include resection (if curative), decompressive gastrostomy, bypass surgery, endoscopic stenting, and endoscopic ultrasound-guided gastroenterostomy. Surgery may also be an option for benign GOO if the obstruction cannot be safely dilated or persists despite other treatments.

Additionally, GOO caused by extrinsic compression, like chronic pancreatitis, may warrant early consideration for surgery due to limited responsiveness to less invasive interventions. Ultimately, the choice of treatment for GOO depends on the specific diagnosis, severity of obstruction, and individual patient factors, with a range of options available to alleviate symptoms and improve overall well-being.

Surgical intervention is a viable consideration in the treatment of benign gastric outlet obstruction under certain circumstances. It becomes a suitable option when the pylorus, the muscular valve controlling the passage from the stomach to the small intestine, cannot be safely dilated due to an obstructive blockage.

Furthermore, surgery may be warranted if the obstruction persists despite diligent attempts at resolution through endoscopic and medical management. In cases where the obstruction arises from extrinsic factors, such as chronic pancreatitis or other external compressive forces, the response to endoscopic balloon dilation tends to be less favorable.

Therefore, it is prudent to consider surgical intervention early in the management of GOO caused by such extrinsic compression. This proactive approach acknowledges that these types of obstructions may not readily respond to less invasive measures and highlights the importance of timely surgical assessment and intervention.

For the management of benign gastric outlet obstruction (GOO) resulting from peptic ulcer disease, it is advisable to initiate a conservative approach as the initial course of action.

This conservative strategy entails several essential steps, such as implementing acid suppression therapies, promoting the avoidance of NSAIDs, and conducting assessments to identify and subsequently treat Helicobacter pylori infection. Commencing with acid suppression forms a pivotal component of this conservative management approach.

The aim is to reduce gastric acid production, thereby alleviating the irritation and inflammation that can contribute to the obstruction. This can be achieved through the use of proton pump inhibitors (PPIs) or H2-receptor antagonists, which effectively decrease acid secretion and create a more favorable environment for healing. 

Another crucial facet of this approach is the avoidance of NSAIDs, as they can exacerbate peptic ulcer disease and potentially worsen the obstruction. Educating patients on the risks associated with NSAID use and encouraging alternative pain management options is essential to prevent further complications. 

Simultaneously, it is imperative to investigate and address the presence of H. pylori infection. This bacterium is a known contributor to peptic ulcers and can perpetuate the cycle of ulceration and obstruction.

Conducting tests to confirm H. pylori presence and subsequently providing appropriate antibiotic therapy is pivotal in resolving this aspect of the condition. Should these conservative measures prove ineffective in alleviating the gastric outlet obstruction, more invasive interventions may be warranted.

These interventions can encompass endoscopic procedures, such as dilation, which involves the widening of the narrowed passage within the stomach. Alternatively, surgical interventions may be considered as a last resort to physically correct the obstruction and facilitate proper gastric emptying. 

For Malignant Obstruction 

In cases of malignant gastric outlet obstruction, a range of therapeutic options can be considered to alleviate the obstruction and improve the patient’s quality of life. These options encompass resection, decompressive gastrostomy, bypass surgery, endoscopic stenting, and endoscopic ultrasound-guided gastroenterostomy, among others. 

simethicone 

40-125 mg orally 4 times each day as required post-meals at bedtime
Administer a single dose in a range of 160-500 mg post-meals at bedtime
Do not exceed the maximum dose of more than 500 mg each day



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