A hiatal hernia occurs when a portion of the stomach pushes upward through the diaphragm, the large dome-shaped muscle that separates the chest cavity from the abdomen. This structural defect allows the upper part of the stomach to enter the chest cavity through the esophageal hiatus. This article explores how the computed tomography (CT) scan fits into the diagnostic process for identifying and managing a hiatal hernia.
Anatomy of a Hiatal Hernia
The diaphragm is a sheet of muscle that plays a central role in breathing and acts as a physical barrier between the chest and abdominal organs. A natural opening in this muscle, the hiatus, normally accommodates the esophagus as it passes down to connect with the stomach. A hiatal hernia develops when the stomach or other abdominal contents migrate through this hiatus and into the chest.
The most common form is the sliding hiatal hernia (Type I), accounting for up to 95% of cases. In this type, the junction between the esophagus and the stomach slides up and down into the chest cavity. This movement often contributes to symptoms of gastroesophageal reflux disease (GERD) because the natural anti-reflux barrier is compromised.
The less common type is the paraesophageal hernia, which includes Types II, III, and IV. With a true paraesophageal hernia (Type II), the gastroesophageal junction remains below the diaphragm, but a part of the stomach bulges up alongside the esophagus. These hernias are more serious because they carry a higher risk of complications, such as the stomach becoming twisted or having its blood supply cut off.
CT Scan Capability and Limitations
A computed tomography (CT) scan is a highly effective tool that can visualize the presence of a hiatal hernia, particularly the larger varieties. The cross-sectional images provide excellent anatomical detail of the abdomen and chest. This capability often leads to the detection of a hiatal hernia as an incidental finding when a patient undergoes a scan for an unrelated health concern.
For larger hernias, the CT scan clearly shows the stomach or other abdominal organs protruding above the diaphragm and into the chest cavity. It is especially useful for confirming the presence and size of a paraesophageal hernia, which is a key step in surgical planning. Radiologists look for specific markers, such as the “collar sign,” which shows the point where the herniated organ is constricted at the level of the diaphragm.
The primary strength of the CT scan is its ability to identify serious complications that require immediate attention. If a hernia is causing obstruction or strangulation, the CT scan can reveal signs of compromised blood flow, such as a lack of contrast enhancement in the stomach wall. In these emergency scenarios, the CT scan is a rapid and definitive method for guiding urgent surgical intervention.
However, the CT scan is not typically the first-line diagnostic test when a hiatal hernia is specifically suspected. It can sometimes miss smaller, intermittent sliding hernias because it provides a static image of the organs at a single point in time. Functional studies, which capture movement, are often better at illustrating the subtle motion characteristic of a sliding hernia.
Standard Diagnostic Procedures
When a hiatal hernia is suspected due to symptoms like chronic heartburn or regurgitation, doctors typically rely on specialized tests that provide both structural and functional information. The preferred initial examination is the Barium Swallow, also known as an upper GI series or esophagram. This procedure involves the patient drinking a liquid containing barium, which coats the lining of the digestive tract.
As the patient swallows, a sequence of X-ray images is taken, allowing doctors to watch the movement of the esophagus and stomach in real-time. The Barium Swallow is superior for assessing the size of the hernia and observing the axial movement of the gastroesophageal junction, which is crucial for distinguishing between sliding and paraesophageal types.
Another widely used procedure is an Endoscopy, or Esophagogastroduodenoscopy (EGD), where a flexible tube with a camera is passed down the throat. While the endoscope can confirm the presence of a hiatal hernia, its main function is to assess the damage caused by chronic acid reflux. The endoscopy looks for signs of inflammation in the esophagus, known as esophagitis, or more serious conditions like Barrett’s esophagus. These procedures are often favored over the CT scan because they provide functional details and mucosal evaluation that static imaging cannot.
Managing a Confirmed Diagnosis
Once a hiatal hernia is confirmed, management strategies depend largely on the presence and severity of symptoms. For the majority of patients with small, asymptomatic sliding hernias, treatment focuses on conservative lifestyle modifications. These changes include dietary adjustments, such as avoiding acidic or fatty foods that trigger reflux, and not lying down immediately after eating.
Medical management is often the first step for symptomatic patients experiencing acid reflux. Medications known as proton pump inhibitors (PPIs) are commonly prescribed to reduce the amount of acid produced by the stomach, alleviating heartburn and allowing the esophageal lining to heal. H2-receptor blockers are another class of medication that can reduce acid production.
Surgical intervention is considered when symptoms are severe, complications arise, or medical management fails. For paraesophageal hernias, surgery is often recommended to prevent the risk of incarceration or strangulation, which can be life-threatening. The procedure typically involves pulling the stomach back into the abdomen, closing the widened hiatus, and often an anti-reflux procedure, such as a fundoplication, to strengthen the lower esophageal sphincter.