What is the relationship between hiatal hernia, gastroesophageal reflux, and reflux esophagitis on barium studies?
D.J. Ott, M.Y.M. Chen (Winston-Salem)
The relationship between hiatal hernia, gastroesophageal reflux, and reflux esophagitis remains controversial. In the past, the demonstration of hiatal hernia was usually equated with the presence of reflux esophagitis. This association often led to surgical management directed at correcting the hiatal hernia rather than at preventing gastroesophageal reflux. However, the pathogenesis of gastroesophageal reflux disease (GERD) is more complex and important factors in its development include:
1) inadequate antireflux barrier;
2) volume and potency of reflux material;
3) esophageal mucosal resistance;
Barium studies of the esophagus can assess several of these pathogenetic factors and the resultant changes of reflux esophagitis. We will address the radiographic examination and its efficacy for evaluating hiatal hernia, gastroesophageal reflux, and reflux esophagitis.
The sliding hiatal hernia is the most common diaphragmatic hernia in which the esophagogastric junction forms the most orad portion of the herniated stomach. Proper radiographic evaluation for hiatal hernia requires an understanding of the anatomy and function of the esophagogastric region and the use of appropriate techniques. A sliding hiatal hernia is present when the esophagogastric junction and a portion of the adjacent stomach extend above the esophageal hiatus of the diaphragm (Figure 1). Radiographic landmarks useful for delineating the esophagogastric junction include the lower esophageal mucosal ring (i.e. Schatzki ring), the notch from the gastric sling fibers, orad level of the areae gastricae of the stomach, identification of the squamocolumnar Z line (rare), and the termination site of primary esophageal peristalsis (Figure 2). The level of the diaphragmatic hiatus is estimated indirectly and is seen as a "pinched-cock effect," which is best recognized at fluoroscopy as a transient narrowing of the esophagogastric region as the patient inspires deeply.
The relationship of hiatal hernia to gastroesophageal reflux and its possible inflammatory sequelae is debated [2-10]. A common notion is that gastroesophageal reflux is caused primarily by lower esophageal sphincter (LES) dysfunction and that the presence of hiatal hernia has little effect on the antireflux barrier. More recent studies, however, have questioned whether the LES is the sole component of the antireflux barrier [9, 10]. The crural diaphragm and phrenoesophageal ligament are anatomic structures that likely play a role in preventing reflux. Hiatal hernia has also been shown to delay esophageal clearance, which may promote esophagitis .
Figure 1. A. Normal esophagogastric region. Tubular esophagus (T) extends to the tubulovestibular junction (arrows). Vestibule (V) is saccular termination of the esophagus. B. Tubular esophagus (T) and vestibule (V) join at the tubulovestibular junction (arrow). Lower end of the vestibule demarcates the esophagogastric junction (arrowhead) below which is a small hiatal hernia (hh).
Figure 2. A. Widely patent mucosal ring projects 3 cm above pinchcock effect of the diaphragmatic hiatus (arrowheads). B. Double-contrast view of the esophagogastric region in another patient with a mucosal ring at the esophagogastric junction. Arrows = tubulovestibular junction; V = vestibule;
hh = hiatal hernia.
Hiatal hernia is the most common diagnosis made during the radiographic examination of the upper gastrointestinal tract with a 40% to 60% prevalence noted in adults [2, 3, 7]. Most individuals with hiatal hernia do not have endoscopic evidence of reflux esophagitis. Conversely, about 90% of patients with reflux disease can be shown to have a concomitant hiatal hernia if appropriate radiographic techniques are used [2, 5]. Hiatal hernia is therefore a common but non specific radiographic finding because it poorly predicts the status of GERD. The presence of hiatal hernia likely affects other causative or anatomic factors that promote excessive gastroesophageal reflux, thus playing a permissive role in the development or exacerbation of this disease.
The frequency and severity of gastroesophageal reflux are important determinants in the pathogenesis of GERD [1, 2]. Gastroesophageal reflux is detected on radiographic examination when barium is seen to enter the esophagus from the stomach. Infrequent reflux of small amounts of barium that are readily cleared from the lower esophagus are likely unimportant. Gastroesophageal reflux of barium may occur spontaneously (i.e. free reflux) or during various provocative maneuvers (i.e. stress reflux) that enhance its occurrence. Reflux also may be observed while the patient drinks water, the so-called water siphon test. When detected fluoroscopically, the type, extent, and frequency of reflux as well as the effectiveness of the esophagus to clear itself should be noted.
The value of the barium esophagram for demonstrating gastroesophageal reflux has been argued. Detection of barium reflux in patients with symptomatic GERD has varied from 20% to 73% and has averaged only 39% [2, 6].
The wide discrepancy in demonstrating reflux during fluoroscopy is in part related to the use of provocative tests, such as the Valsalva maneuver or the water siphon test. These results suggested that the radiologic evaluation of reflux was generally insensitive and that the use of provocative maneuvers increased sensitivity but lessened the specificity of the observation.
In more recent reports, however, the use of the water siphon test has been reevaluated and has shown both good sensitivity and specificity in detecting symptomatic gastroesophageal reflux [11, 12]. The water siphon test is considered positive when barium refluxes into the esophagus while the patient is drinking water. More symptomatic patients have shown reflux with this method than during the search for spontaneous reflux. Sellar et al.  studied the sensitivity of barium radiology using the combined detection of gastroesophageal reflux and morphologic signs of esophagitis and showed a sensitivity of over 80% in patients with symptomatic GERD, which was higher than endoscopic detection when both were compared to pH monitoring.
Patients with GERD may show a variety of appearances in the esophagus, ranging from normal esophageal mucosa to the gross morphologic changes of reflux esophagitis [2, 13, 14]. About 60% of patients with GERD will have endoscopic changes of reflux esophagitis and about two-thirds of those will show signs of esophagitis radiographically. Thus, the barium esophagogram will likely demonstrate morphologic abnormalities of reflux esophagitis in only a third of patients with GERD . The radiographic detection of reflux esophagitis depends primarily on the endoscopic severity of disease. Mild endoscopic esophagitis, depending on the criteria used, is detected poorly by the radiographic examination. However, in the moderate and more severe grades of endoscopic esophagitis (i.e. erosions, ulceration, stricture), combined sensitivities of 90% to 96% have been reported using barium radiology with detection rates of 95% to 100% for diagnosing peptic stricture [2, 14].
Figure 3. A. Mucosal relief film showing thickened and irregular esophageal folds due to reflux esophagitis. B. Full-column radiograph in same patient demonstrates no stricture; however, the mucosal abnormality is obscurred by the nature of the technique.
Figure 4. A. Mucosal irregularity and ulceration of the lower esophagus with hiatal hernia. Reflux esophagitis was present at endoscopy showing ulcerations. B. Double-contrast film of reflux esophagitis showing markedly irregular surface with multiple erosions and ulcerations.
Radiographic detection of reflux esophagitis depends also on the thoroughness of the examination and is optimized by the combined use of the full-column, mucosal relief, and double-contrast techniques . Mild esophagitis is best detected on mucosal relief films as fold thickening and irregularity and on double-contrast views as surface granularity (Figures 3 and 4). All three techniques may contribute to diagnosing moderate esophagitis, with fold thickening shown on mucosal relief techniques; surface irregularity, erosions, and ulceration on double-contrast films; and serration of the esophageal contour and limited distensibility on full-column examination. The full-column technique is most useful in detecting peptic stricture and has shown sensitivities of 95% or better as compared to detection of 79% to 85% for the double-contrast technique [2, 14] (Figures 5 and 6). The reported radiographic specificity for diagnosing reflux esophagitis has been 86% to 98% [2, 14]. Borderline esophageal fold thickening, transient irregularity of the esophageal margin due to tertiary contractions are the most common causes of false positive error. Finally, a lower esophageal mucosal ring may mimic an annular peptic stricture.
Figure 5. Two views of a peptic stricture (arrows) located at the tubulovestibular junction. Esophageal vestibule (V) and hiatal hernia below the level of the stricture suggesting the presence of Barrett's esophagus, which was seen at endoscopy.
Figure 6. A. Normal upright double-contrast film of the lower esophagus in patient with dysphagia. B. Prone full-column radiograph in same patient showing an 8 mm annular narrowing not seen on the double-contrast technique.
The role of the barium esophagogram for evaluation of patients with suspected GERD has been clarified in recent years. The radiographic examination can assess for hiatal hernia, abnormal esophageal motility, gastroesophageal reflux, and the gross morphologic changes of reflux esophagitis. Hiatal hernia is a common radiographic finding but most of these patients will not be shown to have gastroesophageal reflux nor have signs of reflux esophagitis. Gastroesophageal reflux is detected poorly during the brief fluoroscopic observation time used for the radiologic evaluation of the esophagus; the water siphon test may be more effective in detecting abnormal gastroesophageal reflux but further investigations are needed to reassess its efficacy. The barium examination is a reliable screening test for diagnosing the more severe grades of endoscopic reflux esophagitis and is highly effective in showing peptic strictures.
7. Ott DJ, Glauser SJ, Ledbetter MS, Chen MYM, Koufman JA, Gelfand DW. Association of hiatal hernia and gastroesophageal reflux: correlation between presence and size of hiatal hernia and 24-hour pH monitoring of the esophagus. AJR 1995;165:557-559.