Hiatal Hernia in Dogs and Cats: Radiographic Findings and Differentiation

Hiatal Hernia in Dogs and Cats: Radiographic Findings and Differentiation

A hiatal hernia occurs when part of the stomach moves through the esophageal hiatus of the diaphragm and into the thoracic cavity. In dogs and cats, hiatal hernias are uncommon and are most frequently congenital in some dog breeds, although they can also be acquired following trauma or other causes. Although it is a type of diaphragmatic hernia, it differs from traumatic diaphragmatic rupture in its location, radiographic appearance, and typical clinical presentation.

Hiatal hernia can occur in both dogs and cats. Radiographic recognition may be challenging because the hernia can be intermittent, meaning the stomach may move into the thorax during one examination and return to its normal abdominal position before another study is performed.

Understanding the expected radiographic findings can help veterinarians distinguish hiatal hernia from other thoracic, esophageal, and diaphragmatic abnormalities.

What Hiatal Hernia Looks Like on Radiographs

The radiographic appearance of a hiatal hernia depends on how much of the stomach has entered the thorax and whether the herniated portion contains gas, fluid, food, and/or soft tissue.

A common radiographic finding is a rounded soft tissue and/or gas-containing structure within the caudal thorax, immediately cranial to the cranial crus of the diaphragm.

Other findings may include:

• Cranial displacement of the gastroesophageal junction
• Gas and/or fluid within the thoracic esophagus
• Focal widening of the caudal mediastinum (particularly on the VD view)
• Abnormal positioning of the gastric cardia or fundus or craniodorsal displacement of the stomach.
• Reduced visibility of the stomach in its expected abdominal position
• Esophageal dilation

A hiatal hernia can resemble a caudal mediastinal mass, esophageal foreign body or dilation, or a focal pulmonary opacity. Orthogonal views are important for determining whether the abnormality is associated with the upper gastrointestinal tract, lungs, or diaphragm.

Because sliding hiatal hernias are dynamic and may only be present intermittently on imaging, radiographs can appear normal despite compatible clinical signs. Repeat radiographs, fluoroscopy, contrast studies, endoscopy, or advanced imaging may be considered when clinical suspicion remains high.

For a broader approach to thoracic imaging, review SignalPET’s guide to thoracic radiograph interpretation.

How Hiatal Hernia Differs From Diaphragmatic Hernia

A hiatal hernia occurs through the normal esophageal hiatus and usually involves the gastroesophageal junction or part of the stomach.

A diaphragmatic hernia caused by rupture occurs through an abnormal defect in the diaphragm. It may allow the liver, stomach, spleen, and/or intestinal tract to displace into the thoracic cavity.

Radiographic findings that support diaphragmatic rupture include:

• Partial or complete loss of the diaphragmatic outline
• One or more abdominal organs within the thorax
• Gas-filled intestinal loops in the thoracic cavity
• Displacement of the cardiac silhouette
• Compression of the lungs

With hiatal hernia, the diaphragmatic contour may remain relatively intact, and the abnormality is more likely to be centered near the esophageal hiatus in the caudal mediastinum.

Learn more in SignalPET’s article on diaphragmatic hernia in dogs and cats.

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Why the Distinction Matters

Hiatal hernia and traumatic diaphragmatic rupture differ in pathophysiology, clinical implications, diagnostic workup, prognosis, and treatment. 

Patients with hiatal hernia may present with regurgitation, vomiting, dysphagia, coughing, or recurrent aspiration pneumonia. Evaluation may focus on gastroesophageal reflux, esophagitis, esophageal function, and aspiration risk. Often managed medically initially without immediate urgency. Prognosis is generally good with appropriate medical or surgical management.

Traumatic diaphragmatic rupture is more commonly associated with respiratory distress, a history of trauma and can be life threatening. These patients may require stabilization, assessment for concurrent injuries, and surgical repair. Prognosis depends on several factors such as severity of respiratory or organ compromise, concurrent injuries or time to surgical intervention.

Accurate differentiation helps the veterinary team assess urgency, select appropriate additional diagnostics, and communicate the suspected condition clearly to the pet owner.

How AI Assists in Detecting Diaphragmatic and Hiatal Hernia

Subtle abnormalities near the diaphragm and caudal thorax can be difficult to identify because of superimposition from intrathoracic , and cranial abdominal structures or suboptimal patient positioning.

SignalPET provides an additional review layer by systematically assessing radiographs for clinically meaningful abnormalities, including diaphragmatic hernia.

AI-assisted interpretation may help draw attention to:

• An abnormal diaphragmatic contour
• Caudal thoracic gas or soft tissue opacity
• Displacement of abdominal organs
• Associated pulmonary changes

AI supports rather than replaces the veterinarian’s interpretation. This is especially important in suspected hiatal hernia because the condition may be intermittent and may require additional imaging for confirmation.

SignalPET’s Immediate Report and Complete Report provide different levels of radiographic support, from rapid AI screening to full-case interpretation that incorporates the patient’s clinical context.