A hiatal hernia occurs when the upper part of the stomach pushes up into the chest cavity through a small opening in the diaphragm, the muscular sheet separating the abdomen and chest. This displacement can lead to various digestive and respiratory issues, though many individuals experience no symptoms. Understanding the role of a common chest X-ray (CXR) in identifying this condition is important, as it is a frequent initial test.
Understanding the Hiatal Hernia
A hiatal hernia is an anatomical issue involving the diaphragm, the muscle responsible for breathing. The esophagus normally passes from the chest into the abdomen through a small opening in the diaphragm called the hiatus before connecting to the stomach. A hernia forms when this hiatus widens, allowing a portion of the stomach to move upward into the chest.
The condition is categorized into two main types based on how the stomach protrudes. The most common (90% to 95% of cases) is the sliding hiatal hernia, where the junction between the esophagus and stomach slides up into the chest. The less common, and potentially more serious, is the paraesophageal hernia, where the stomach’s upper section moves up next to the esophagus while the junction remains in place.
The development of a hiatal hernia is linked to factors that increase persistent pressure on the surrounding muscles. These factors include aging, which weakens muscle tone, and chronic conditions like severe coughing or straining during bowel movements. Obesity and pregnancy also contribute to increased pressure within the abdomen, which can lead to hernia formation.
Chest X-Ray Visibility and Limitations
A chest X-ray (CXR) is a standard initial screening tool, but it is generally not the reliable method for definitively diagnosing a hiatal hernia, especially smaller ones. The CXR captures images based on differences in density (bone, air, and fluid), making soft tissue visualization challenging. A small, sliding hiatal hernia often goes unnoticed because its contours are difficult to distinguish from the surrounding heart and mediastinal structures.
A hiatal hernia can sometimes be an incidental finding on a routine chest X-ray performed for other reasons. When visible, it typically appears as a rounded, soft-tissue mass located behind the heart in the retrocardiac space. The presence of an air-fluid level or a gas bubble in this area is a more specific sign, indicating that a portion of the air-filled stomach has moved into the chest.
Visibility is influenced by the hernia’s size and type. Very large paraesophageal hernias, where a substantial part of the stomach resides in the chest, are more likely to be seen as a prominent retrocardiac mass. Smaller hernias, particularly the common sliding type, may only be visible intermittently or may be completely missed because they can reduce (slide back down) depending on the patient’s position during the X-ray. A normal chest X-ray cannot reliably exclude the presence of a hiatal hernia.
Definitive Diagnostic Imaging and Procedures
Due to the limitations of a standard chest X-ray, clinicians rely on specialized imaging and procedural tests for a definitive diagnosis. The most appropriate initial imaging study is often the barium swallow, also known as an esophagram or upper gastrointestinal series. During this dynamic test, the patient swallows a contrast liquid containing barium, which coats the lining of the esophagus and stomach, making them clearly visible on X-ray.
The barium swallow is highly effective because it allows doctors to observe the hernia’s size, exact location, and type (sliding or paraesophageal). It is also the best tool for visualizing the gastroesophageal junction relative to the diaphragm and for detecting functional issues, such as the backflow of stomach contents. This test provides structural and functional information for guiding treatment decisions.
Another diagnostic procedure is an upper gastrointestinal endoscopy (EGD). This involves inserting a thin, flexible tube with a camera down the throat to directly visualize the esophagus, stomach, and the beginning of the small intestine. While endoscopy can detect a hiatal hernia, its primary value lies in assessing for complications, such as inflammation, erosions, or ulcers caused by chronic acid reflux. Computed tomography (CT) scans are generally not used for routine diagnosis but are reserved for complex cases, such as surgical planning or when complications like a twisted stomach are suspected.
When Symptoms Indicate a Need for Testing
Many people with a hiatal hernia never experience symptoms, and the condition is often discovered incidentally. When symptoms do occur, they are typically related to the reflux of stomach acid and contents into the esophagus. The most common complaint is frequent heartburn, a burning sensation in the chest, which is a hallmark of gastroesophageal reflux disease (GERD).
Other common indications include regurgitation of food or sour liquid into the mouth and difficulty or pain when swallowing. Individuals may also experience chest discomfort intense enough to mimic a heart issue, persistent belching, or a feeling of being full soon after starting a meal. These symptoms occur because the displaced stomach portion interferes with the normal function of the lower esophageal sphincter.
If these symptoms are persistent, severe, or do not improve with over-the-counter medications and lifestyle changes, a medical consultation is warranted. Seeking professional evaluation is important if you experience alarming signs, such as unexplained weight loss, frequent vomiting, or passing black stool, which can indicate internal bleeding. A doctor can then determine the appropriate course of action, often beginning with a focused history and physical exam before recommending definitive tests like the barium swallow or endoscopy.