Cats and dogs can develop several different types of hernias. Most pet owners have heard of umbilical or inguinal hernias. However, this article focuses on a less familiar condition called a hiatal hernia.
Hiatal hernias can affect a pet’s comfort, nutrition, and respiratory health. Therefore, understanding how they develop, how veterinarians diagnose them, and when treatment is necessary can help pet owners make informed decisions. I hope you find this information helpful and consider sharing it with other pet lovers.
What Is a Hiatal Hernia?
To understand a hiatal hernia, it helps to review the anatomy of the diaphragm. The diaphragm is a large muscle that separates the chest cavity from the abdominal cavity and plays a critical role in breathing.
There are three normal openings in the diaphragm:
- The aortic hiatus
- The caval foramen
- The esophageal hiatus
The esophagus, small blood vessels, and the vagus nerve normally pass through the esophageal hiatus.
A hiatal hernia occurs when abdominal organs move abnormally through the esophageal hiatus and into the caudal mediastinum, which is the space within the chest just in front of the spine.
Types of Hiatal Hernias
Veterinarians recognize four types of hiatal hernias in cats and dogs:
Type I: Sliding Hiatal Hernia
This is the most common type. The abdominal portion of the esophagus and part of the stomach slide intermittently through the esophageal hiatus into the chest.
Type II: Paraesophageal Hiatal Hernia
In this form, the esophagus remains in its normal position. However, a portion of the stomach herniates alongside it through a defect in the phrenoesophageal membrane.
Type III: Mixed Hiatal Hernia
This rare form combines features of Type I and Type II hernias. It occurs infrequently in dogs.
Type IV: Complex Hiatal Hernia
This type resembles a Type III hernia but also involves herniation of additional abdominal organs such as the liver or small intestine.
Congenital vs Acquired Hiatal Hernias
Hiatal hernias may be congenital or acquired later in life. Congenital cases are more common, especially in young dogs.
Potential causes of acquired hiatal hernias include:
- Trauma
- Brachycephalic airway syndrome
- Chronic vomiting
- Upper airway obstruction
- Persistently increased negative intrathoracic pressure
What Does a Hiatal Hernia Look Like Clinically?
Certain dog breeds are over-represented, particularly brachycephalic breeds such as English Bulldogs, French Bulldogs, Chow Chows, and Chinese Shar-Peis. Most affected dogs are less than one year of age.
Clinical signs vary widely. In fact, some dogs show no outward signs at all. When clinical signs occur, they often relate to reflux, esophageal irritation, or aspiration.
Common signs include:
- Regurgitation
- Vomiting, with or without blood
- Coughing
- Increased respiratory rate
- Difficulty swallowing
- Excessive drooling
- Poor body condition
- Weight loss
Because signs can be subtle or intermittent, diagnosis often requires targeted imaging.
How Is a Hiatal Hernia Diagnosed?
Veterinarians cannot diagnose a hiatal hernia based on clinical signs alone. Instead, imaging studies are required to confirm the diagnosis and correlate findings with clinical symptoms.
Recommended diagnostic tests may include:
- Thoracic radiographs
- Positive contrast esophagram
- Abdominal and thoracic ultrasonography
- Fluoroscopy to assess swallowing and esophageal motion
- Computed tomography
- Esophagoscopy to evaluate esophagitis, strictures, or reflux injury
How Is Hiatal Hernia Treated?
Not all pets with hiatal hernias require treatment. Animals without clinical signs often do well without intervention.
However, surgery is recommended for pets with significant or persistent clinical signs, especially those with regurgitation, aspiration pneumonia, or failure to thrive.
Surgical correction typically includes three procedures performed together:
- Esophagopexy to secure the esophagus
- Hiatal plication to reduce the size of the esophageal hiatus
- Gastropexy to anchor the stomach in a normal position
Before surgery, veterinarians must address complications such as esophagitis, gastroesophageal reflux, or aspiration pneumonia to minimize anesthetic risk.
Prognosis After Surgery
Published veterinary studies report a good long-term outcome, with approximately 80% of patients experiencing significant improvement or resolution of clinical signs after surgery.
Some pets continue to have gastroesophageal reflux and require ongoing medical management. Even so, most animals experience a meaningful improvement in quality of life.
Key Takeaways About Hiatal Hernia in Cats and Dogs
Hiatal hernia is uncommon but clinically important in cats and dogs. Some pets show no symptoms and require no treatment. Others develop signs that significantly impact comfort and health.
With appropriate diagnosis and treatment, including surgery when indicated, most affected pets enjoy an excellent prognosis and improved quality of life.
