Home » Diseases » In cats » Chronic Hypertrophic Pylorus Gastropathy, CHPG (Narrowing of the Gastric Outlet)

Chronic Hypertrophic Pylorus Gastropathy, CHPG (Narrowing of the Gastric Outlet) in cats

Occurrence: very rare
Location of illness: Abdomen/pelvis

Author: Dr. med. vet. Gisa Löwe | Last modified: 03.12.2025

When to visit the vet?

Non-urgent see a veterinarian within 2–3 days

If the condition worsens / symptoms persist, consult a veterinarian.

ChronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. Hypertrophic Pyloric Gastropathy (CHPG) in cats is a condition characterized by a thickening of the muscle layer in the pylorus region, the outlet of the stomach, which leads to narrowing and impairs the normal passage of food into the intestineThe intestine is the medical term for the gut, including the small intestine (intestinum tenue) and the large intestine (intestinum crassum). It plays a central role in the digestion and absorption of nutrients..

The most important facts at a glance

Chronic Hypertrophic Pyloric Gastropathy (CHPG) in cats is a condition in which the muscle layer around the pylorus, the transition from the stomach to the small intestineThe intestine is the medical term for the gut, including the small intestine (intestinum tenue) and the large intestine (intestinum crassum). It plays a central role in the digestion and absorption of nutrients., thickens and narrows, hindering food flow. This thickening can be caused by chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. inflammatory conditions or fibrous tissue changes. Factors such as genetic predispositions, chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. diseases, and certain dietary habits can increase the risk for CHPG. Symptoms include frequent Vomiting, loss of appetite, and Weight loss. DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made through clinical examinations, blood tests, and diagnostic imagingDiagnostic imaging includes medical procedures that create images of the inside of the body to diagnose, monitor, or treat diseases and injuries. Examples include X-ray, ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI). procedures such as ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. or endoscopyEndoscopy is a diagnostic procedure that uses an endoscope (a thin, flexible tube with a light source and a camera at the end) to examine and visualize the inside of the body, often for diagnostic or therapeutic purposes. to recognize the thickening of the pyloric region and take biopsies for examination.

Treatment focuses on alleviating symptoms and facilitating food passage. Dietary adjustments and medications such as proton pump inhibitors can be used. In severe cases, surgical intervention may be required. The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. depends on the severity of the condition and the treatment, with early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and treatment increasing the chances of improvement. Preventive measures such as a balanced diet and regular veterinary examinations can help reduce the risk. Current research approaches are investigating genetic predispositions, non-invasive diagnostic methods, and new treatment approaches to better understand and treat the disease.

Causes

The pylorus is the part of the stomach that forms the transition to the small intestineThe intestine is the medical term for the gut, including the small intestine (intestinum tenue) and the large intestine (intestinum crassum). It plays a central role in the digestion and absorption of nutrients.. In a healthy cat, the pylorus opens and closes to regulate food flow. In CHPG, there is a thickening of the muscle layer around the pylorus, which narrows the opening. This thickening can be inflammation-related or caused by a fibrous tissue change. The exact mechanisms leading to the thickening are not yet fully understood, but it is believed that chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. stimuli or inflammatory conditions could play a role.

Possible causes for the development of CHPG include genetic predispositions, as some cat breeds may be more susceptible to this condition. ChronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. diseases leading to recurrentRecurrent refers to a disease that repeatedly returns or worsens after a temporary remission or improvement. inflammation could also play a role as triggering factors. Additionally, certain dietary habits or food allergies may promote the development of CHPG.

Another factor could be the age of the cat. Older cats are more likely to show structural changes in the digestive tract, which could increase the risk of developing pyloric stenosisA stenosis is a narrowing or constriction of a body channel or opening that can impede the normal flow of fluids or other substances, such as blood in arteries or air in the airways.. Hormonal changes or metabolicMetabolic refers to metabolism, i.e. the entirety of chemical processes that take place in a living organism to enable life processes. Metabolic disorders can cause a variety of Diseases in Dogs and cats. diseases could also contribute to the thickening by disrupting the normal function of the gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract.

Symptoms

Very common symptoms:

Common symptoms:

Weight Loss

The symptoms of CHPG are often subtle and can easily be confused with other gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. problems. One of the most common symptoms is chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. Vomiting, which can occur either immediately after eating or several hours later. The vomitus may contain undigested food and is often accompanied by mucus.

Other symptoms include weight loss despite normal or increased appetite. This is because food is not efficiently transported from the stomach to the intestineThe intestine is the medical term for the gut, including the small intestine (intestinum tenue) and the large intestine (intestinum crassum). It plays a central role in the digestion and absorption of nutrients., resulting in reduced nutrient absorptionAbsorption refers to the uptake of substances by living cells or tissues. In the context of veterinary medicine, it often refers to the absorption of nutrients, drugs, or toxins from the digestive tract into the bloodstream.. In addition, affected cats may show signs of abdominalThe term “abdominal” refers to anything that concerns the belly or the abdomen. It is an adjectival expression used to describe the location, symptoms, or conditions that occur in the abdominal area. pain, which can be noticeable through restlessness, increased meowing, or altered behavior.

In some cases, there may also be changes in bowel movements, with cats suffering from either constipationConstipation is another word for infrequent bowel movements where the stool is hard and difficult to pass. In dogs and cats, this can be caused by diet, lack of exercise, or underlying health issues. or DiarrheaDiarrhea refers to the condition of frequent, watery bowel movements, which can be a sign of infections, digestive disorders, or other health problems.. This results from impaired digestion and absorptionAbsorption refers to the uptake of substances by living cells or tissues. In the context of veterinary medicine, it often refers to the absorption of nutrients, drugs, or toxins from the digestive tract into the bloodstream. of food in the gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract.

Diagnosis

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of CHPG in cats usually begins with a thorough clinical examination and taking a medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. to rule out other possible causes for the symptoms. Blood tests are typically performed to assess the cat’s general health status and rule out other systemic diseases.

An important diagnostic step is diagnostic imagingDiagnostic imaging includes medical procedures that create images of the inside of the body to diagnose, monitor, or treat diseases and injuries. Examples include X-ray, ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI)., particularly an abdominal ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. examination. An experienced veterinarian can detect a thickening of the pyloric region. In some cases, an X-rayX-ray is an imaging technique that uses X-rays to create images of the inside of the body. It is often used to diagnose bone fractures, lung diseases, and other conditions. examination with contrast medium may also be used to visualize the passage of food through the stomach.

An endoscopic examination can also be helpful to directly visualize the stomach lining and the pylorus. Biopsies can also be taken to perform a histopathologicalHistopathological refers to the microscopic examination of tissue samples for the diagnosis of diseases. This technique is used to identify the specific characteristics of diseases at the cellular level in dogs and cats. examination, which can provide information about the type of tissue change.

Therapy

Treatment for CHPG focuses on alleviating symptoms and facilitating the passage of food. In mild cases, dietary adjustments, such as feeding smaller, more frequent meals with easily digestible food, can be helpful. Special dietary supplements that promote digestion may also be used.

Proton pump inhibitors or H2 receptor antagonists can be used medicinally to reduce gastric acid production and protect the lining of the stomach. Motility-promoting drugs can also be used to improve gastric emptying.

In more severe cases, where there is significant anatomical narrowing, surgical intervention may be required. A commonly used procedure is pyloromyotomy or pyloroplasty, in which the narrowed muscle layer is incised or reshaped to widen the opening and facilitate the passage of food.

Prognosis and follow-up care

The prognosis for cats with CHPG depends heavily on the severity of the condition and the chosen treatment method. With early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and appropriate treatment, especially if surgical correction is performed, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. is favorable in many cases. Most cats show significant improvement in their symptoms after treatment and can lead a normal life.

For cats treated only medically, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. can be more variable, as the condition is chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. and requires a lifelong management strategy. Regular monitoring and adjustment of therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. are crucial in such cases to prevent the recurrence of symptoms.

Prevention

The preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of ChronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. Hypertrophic Pyloric Gastropathy (CHPG) in cats can be challenging, as the exact causes of this condition are not fully understood. Nevertheless, there are some measures that could reduce the risk. A balanced diet plays an essential role. It is important to offer your cat high-quality, easily digestible food that is specifically tailored to their needs. Avoid giving your cat fatty or hard-to-digest foods, as these can strain the gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract.

Regular veterinary examinations are also crucial to identify and treat health problems early. Make sure your cat maintains a healthy weight, as overweight can increase the risk of various health problems. A low-stress environment can also help promote your cat’s overall well-being, which may reduce the risk of gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. diseases.

In addition, regularly monitoring your cat’s behavior and eating habits can help you become aware of potential problems early on. If you notice changes in your cat’s appetite or behavior, do not hesitate to consult a veterinarian. Early interventions can help maintain your cat’s health in the long term.

Outlook on current research

In recent years, research into ChronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. Hypertrophic Pyloric Gastropathy (CHPG) in cats has made progress by focusing on the genetic and environmental factors that contribute to the development of this condition. Researchers are striving to identify genetic predispositions that could make certain cat breeds more susceptible to this condition. These genetic studies could lead to more targeted treatments in the future, specifically tailored to the affected breeds.

Another important area of research relates to the development of non-invasive diagnostic methods. Currently, diagnosis often requires diagnostic imagingDiagnostic imaging includes medical procedures that create images of the inside of the body to diagnose, monitor, or treat diseases and injuries. Examples include X-ray, ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI). procedures and endoscopic examinations, which can be stressful for the animal. Researchers are investigating the possibility of identifying specific biomarkers in blood or urine that could indicate CHPG early. This could enable a faster and less invasiveInvasive describes medical procedures or pathogens that enter the body or penetrate tissue. In medicine, invasive procedures can range from minimally invasive techniques to open surgery. diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients..

Additionally, the effectiveness of various medicinal treatment approaches is being researched. While surgical interventions like pyloroplasty are commonly used to correct the narrowing, there is interest in developing medications that could reduce the hypertrophyHypertrophy is the enlargement of an organ or tissue due to an increase in cell size. It can occur as a normal response to increased stress or demands, such as muscle hypertrophy from training, or be pathological, such as enlargement of the heart muscle due to high blood pressure. of the pyloric tissue. Research is investigating whether certain anti-inflammatory drugsAnti-inflammatory drugs are medications that reduce inflammation. They can be divided into nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids and are used in dogs and cats to reduce Inflammatory conditions and Pain. or hormoneHormones are chemical messengers produced by endocrine glands and released into the bloodstream to affect specific cells or organs in the body. They regulate numerous bodily functions, including growth, metabolism, and reproduction. therapies could represent an effective alternative to surgery.

Another aspect of current research is the investigation of nutritional factors that could influence CHPG. Researchers are working to develop special diets that could reduce the risk of developing or worsening the disease. These diets often focus on easily digestible ingredients and an adapted fiber composition to relieve the gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract.

Finally, researchers are striving to better understand the underlying mechanisms of tissue hypertrophyHypertrophy is the enlargement of an organ or tissue due to an increase in cell size. It can occur as a normal response to increased stress or demands, such as muscle hypertrophy from training, or be pathological, such as enlargement of the heart muscle due to high blood pressure.. By studying cell proliferation and the role of growth factors, scientists hope to develop targeted therapies that directly address abnormal tissue proliferation. This basic research is crucial for establishing long-term treatment strategies that combat not only the symptoms but also the causes of CHPG.

Frequently asked questions (FAQs)

What is ChronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. Hypertrophic Pylorus Gastropathy in Cats? CHPG is a condition in which the gastric outlet (pylorus) narrows due to a thickening of the tissue. This narrowing can impede the normal flow of food from the stomach to the intestineThe intestine is the medical term for the gut, including the small intestine (intestinum tenue) and the large intestine (intestinum crassum). It plays a central role in the digestion and absorption of nutrients., leading to a variety of digestive problems.
What symptoms occur with CHPG? The most common symptoms include vomiting, weight loss, loss of appetite, and occasionally abdominalThe term "abdominal" refers to anything that concerns the belly or the abdomen. It is an adjectival expression used to describe the location, symptoms, or conditions that occur in the abdominal area. pain. Some cats may also show signs of dehydrationDehydration occurs when the body loses more fluid than it takes in. This can lead to a number of problems, including headaches, Dizziness, and in extreme cases, renal failure or Cardiovascular collapse. or weakness as the condition progresses.
How is CHPG diagnosed? DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. usually requires a combination of diagnostic imagingDiagnostic imaging includes medical procedures that create images of the inside of the body to diagnose, monitor, or treat diseases and injuries. Examples include X-ray, ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI). procedures such as ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. or X-ray and endoscopic examinations. Sometimes blood tests are also necessary to rule out other conditions.
What treatment options are available for CHPG? Treatment can be surgical or medical. In severe cases, surgery is often recommended to correct the narrowing. In less severe cases, medications and special diets can help relieve the symptoms.
Is CHPG curable? While the symptoms can often be well controlled with treatment, CHPG is not considered completely curable. The treatment aims to improve the cat’s quality of life and avoid complications.
Which cats are most at risk of developing CHPG? Certain breeds, such as Persian cats, appear to be more susceptible to CHPG. Older cats are also at higher risk of developing this condition.
Can diet influence the development of CHPG? Yes, diet can play a role. A diet that contains easily digestible ingredients and a balanced fiber composition can help reduce the strain on the stomach and alleviate symptoms.
Are there long-term complications with untreated CHPG? Untreated CHPG can lead to serious complications such as chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. Vomiting, severe Weight loss, and dehydrationDehydration occurs when the body loses more fluid than it takes in. This can lead to a number of problems, including headaches, Dizziness, and in extreme cases, renal failure or Cardiovascular collapse.. These can significantly impair the cat’s quality of life and even become life-threatening.
How can I support my veterinarian in the treatment of CHPG? Close cooperation with your veterinarian is important. Adhere to recommended diets and medication plans, and closely observe your cat’s behavior and symptoms to provide accurate information to the veterinarian.
Are there preventive measures against CHPG? While there are no specific preventive measures, a healthy diet and regular veterinary check-ups can help reduce the risk and detect early signs of the disease.