In a sliding hernia, the muscular collar around the esophageal and diaphragmatic junction loosens, permitting the lower portion of the esophagus and the upper portion of the stomach to rise into the chest due to increased intra–abdominal pressure. This muscle weakening may be associated with normal aging or may be secondary to esophageal carcinoma, kyphoscoliosis, trauma, or surgery. A sliding hernia may also result from congenital weakness due to certain diaphragmatic malformations.

The exact cause of paraesophageal hiatal hernias isn’t fully understood. One theory maintains that these hernias occur when the stomach isn’t properly anchored below the diaphragm, permitting the upper portion of the stomach to slide through the esophageal hiatus when intra–abdominal pressure increases.

Increased intra–abdominal pressure can be caused by such conditions as ascites, pregnancy, obesity, constrictive clothing, bending, straining, coughing, Valsalva’s maneuver, and extreme physical exertion.

If the hiatal hernia is associated with gastroesophageal reflux, the esophageal mucosa may become irritated, leading to esophagitis, esophageal ulceration, hemorrhage, peritonitis, and mediastinitis. Aspiration of refluxed fluids may lead to respiratory distress, aspiration pneumonia, or cardiac dysfunction from pressure on the heart and lungs.

Other complications include esophageal stricture and incarceration, in which a large portion of the stomach is caught above the diaphragm. Incarceration may lead to perforation, gastric ulcer, and strangulation and gangrene of the herniated stomach portion.

When a sliding hernia causes symptoms, the patient typically complains of heartburn, indicating an incompetent LES and gastroesophageal reflux. The patient history usually reveals that heartburn occurs from 1 to 4 hours after eating and is aggravated by reclining, belching, or conditions that increase intra–abdominal pressure. Heartburn may be accompanied by regurgitation or vomiting. The patient may complain of retrosternal or substernal chest pain (typically after meals or at bedtime), reflecting reflux of gastric contents, distention of the stomach, and spasm.

Keep in mind that the patient with a paraesophageal hernia is usually asymptomatic. Because this type of hernia doesn’t disturb the closing mechanism of the LES, it doesn’t usually cause gastric reflux and reflux esophagitis. Symptoms, when present, usually stem from incarceration of a stomach portion above the diaphragmatic opening. The symptomatic patient may report a feeling of fullness after eating or, if the hernia interferes with breathing, a feeling of breathlessness or suffocation. He may also complain of chest pain resembling angina pectoris.