Introduction
Background
Hiatal hernia (also called hiatus hernia and paraesophageal hernia) occurs when part of the stomach protrudes into the thoracic cavity through the esophageal hiatus of the diaphragm. Embryologic development of the diaphragm is a complex process; a number of defects result in a variety of possible congenital hernias through the diaphragm. A hernia may occur through a congenitally large esophageal hiatus; however, acquired hernias through the esophageal hiatus are more common. These hiatus hernias are classified either as sliding hernias or paraesophageal hernias (see Images below). Approximately 99% of hiatal hernias are sliding, and the remaining 1% are paraesophageal.1,2
A diagram depicting a sliding hiatal hernia. The gastroesophageal junction (Jn) is located above the diaphragmatic hiatus.
This diagram of a paraesophageal hiatal hernia shows the normal infradiaphragmatic location of the gastroesophageal junction.
Although paraesophageal hernias (see Image above) are uncommon, they are potentially life-threatening because of the risk of volvulus and incarceration. The incidence of a hiatal hernia increases with age. When the lower esophageal sphincter is located within the thorax, its reinforcement of the diaphragmatic crus is loosened and allows gastroesophageal reflux of acid contents; such reflux may be symptomatic of hiatal hernia in one quarter of patients because of reflux esophagitis.3,4
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Related eMedicine topics:
Hiatal Hernia (Gastroenterology)
Congenital Diaphragmatic Hernia
Gastroesophageal Reflux
Gastroenterology Resource Center
Related Medscape topics:
Clinical Significance of Hiatal Hernia in Gastroesophageal Reflux Following Distal Gastrectomy
Barrett Esophagus CME: Prevalence of Central Adiposity, Metabolic Syndrome, and a Proinflammatory State
Hernia Resource Center
Pathophysiology
The phrenicoesophageal membrane normally surrounds the lower esophagus and fixes it to the diaphragm, thereby preventing gastric herniation through the esophageal hiatus into the thorax. When the phrenicoesophageal membrane is deficient, an axial gastric herniation may develop in the thoracic cavity.2
In patients with hiatal hernia, the stomach may be totally intrathoracic. This condition is usually related to a defect in the central tendon of the diaphragm rather than to herniation through the esophageal hiatus. The stomach acquires a position behind the heart as a result of a slight volvulus in its transverse axis. The cardia of the stomach is usually within the thorax, but occasionally, it may lie below the diaphragm. The gastric curvature may lie on the right or the left.2
With a paraesophageal hernia, part of the stomach herniates through a defect in the phrenicoesophageal membrane into the thorax, while the gastric cardia remains in the normal intra-abdominal position. The herniated portion of the stomach is usually anterior to the esophagus; the hernia is frequently nonreducible. In such cases, epigastric discomfort and, occasionally, dysphagia may occur; however, no reflux symptoms are evident because the cardiac mechanism is not disturbed. Occasionally, a gastric ulcer on the lesser curve may be associated at the level of the diaphragmatic hiatus.
A distinct subgroup of paraesophageal hernias occurs in a younger age group and appears to be secondary to a congenital defect. These hernias are characteristically situated to the right of the lower thoracic esophagus, where a part of the gastric fundus herniates into the thorax. A congenitally short esophagus, which is not a true hernia and is exceptionally rare, may mimic a hiatal hernia. Gastric ectopy is responsible for this condition, in which the esophagus is short and straight and a segment of the stomach is intrathoracic; the segment may be round or cylindrical, with large sinuous folds. The gastric intrathoracic segment is nonreducible and remains in the thorax with the patient in both the erect and the supine positions. Often, a circular narrowing occurs at the intrathoracic junction; this finding is commonly associated with gastroesophageal ulcer.5,6
When the lower esophageal sphincter is located within the thorax, its reinforcement of the diaphragmatic crus is loosened. On its own, the lower esophageal sphincter is not sufficiently strong to prevent the reflux of gastric contents into the lower esophagus. Gastroesophageal reflux disease is a common finding in patients with hiatal hernia; however, most patients with hiatal hernia do not have gastroesophageal reflux disease. Occasionally, differentiating a normal ampulla of the distal esophagus from a small hiatal hernia may be difficult. The most ideal way of localizing the lower esophageal sphincter is by manometry, which is performed by monitoring pressure changes between the abdominal and thoracic cavities during breathing.2,6
Hiatal hernia is associated with esophagitis in 20% of patients; it is associated with duodenal ulcer in another 20%, with diverticulosis in 25%, and with gallstones in 18% of cases. In a small series, an association between asplenia syndrome and a hiatal hernia has been described.4,7
Symptoms in patients with hiatal hernia may be multifactorial. Barrett esophagus consists of columnar epithelium lining the esophagus. It is an acquired condition related to chronic gastroesophageal reflux. These patients can develop an ulcer, stricture, or malignancy. An associated hiatal hernia is common. Adenocarcinoma represents the most serious complication of Barrett esophagus. In patients with Barrett esophagus, the risk of esophageal carcinoma is 30-40 times higher than that of the general population.8,9
Frequency
United States
Hiatal hernias occur in 10% of the adult population, and the incidence of hiatal hernia increases significantly with age. Sliding hiatal hernias are common. Paraesophageal hernias are rare.9
International
The international frequency is the same as that found in the United States.
Mortality/Morbidity
- Paraesophageal hernias, while rare, can be potentially life-threatening because of the risk of volvulus and incarceration.9
- Morbidity can also occur as a result of diagnostic procedures, such as endoscopy. Generally, in the setting of hiatal hernia, the mucosa may be lacerated close to the gastroesophageal junction. Such Mallory-Weiss tears can result in massive gastrointestinal (GI) tract hemorrhage. An upper GI barium series may result in aspiration of barium into the lungs.10
- Some of the treatments offered for a hiatal hernia, such as fundoplication, may have risks of morbidity and mortality.9
Race
No racial predilection is recognized.
Sex
Women are affected more frequently than men.9
Age
Most hiatal hernias occur in patients older than 40 years of age. The incidence increases with age.9
Anatomy
The diaphragm is a dome-shaped septum that divides the thoracic cavity from the abdominal cavity. The diaphragm is composed of 2 parts: a peripheral muscular part, and the central fibrous tendinous aponeurosis to which it attaches. The central aponeurosis is trefoil-shaped, and it is partially attached to the undersurface of the pericardium. The peripheral muscular part is arranged into 3 groups of muscle fibers, as follows:
- The vertebral fibers arise from the crura and the arcuate ligaments.
- The costal fibers arise from the inner aspects of the lower 6 ribs and the costal cartilages.
- The sternal fibers arise from the deep surface of the sternum.
The right crus of the diaphragm arises from the anterior aspects of the bodies of the first 3 lumbar vertebral bodies and the associated intervertebral discs. The left crus is attached to the first 2 lumbar vertebral bodies and the intervertebral disks. The arcuate ligaments comprise a series of fibrous arches. The medial arch is formed by thickening of the fascia covering the major psoas muscle, while the lateral arch represents the fascia covering the quadratus lumborum muscle. The median arcuate ligament is formed by the medial fibrous borders of the 2 crura and is found on the anterior surface of the aorta.
In the diaphragm, 3 main openings are identified, as follows (see Image below):
- The aortic opening transmits the aorta, the thoracic duct and, often, the azygos vein.
- The esophageal opening is located between the muscular fibers of the right diaphragmatic crus and transmits the esophagus, the vagi, and the branches of the left gastric artery and vein.
- The opening of the inferior vena cava (IVC) is located within the central aponeurosis, which transmits the IVC and the right phrenic nerve.
A diagram showing the 3 major orifices at the inferior aspect of the diaphragm (inferior vena cava [IVC], esophagus, aorta).
Embryologic development of the diaphragm is complex, and as a result, several defects may occur, giving rise to a variety of congenital hernias. These hernias include the following: herniation of the upper abdominal contents through the canal of Morgagni, which is positioned anteriorly between the xiphoid and the costal margins; herniation through the posteriorly located pleuroperitoneal canal (Bochdalek foramen); herniation through a deficient central tendon; and herniation through a congenitally large esophageal hiatus. Herniation through the central tendon may occasionally be traumatic. In particular, it may be caused by steering-column injuries sustained in motor vehicle accidents.1
Presentation
Most hiatal hernias are found incidentally, and they are usually discovered on routine chest radiographs or computed tomography (CT) scans performed for unrelated symptoms. When symptomatic, patients may experience heartburn, dyspepsia, or epigastric pain. Rarely, the patient may present with recurrent chest infections resulting from aspiration of gastric contents. A paraesophageal or, rarely, a sliding hiatal hernia may present acutely because of a volvulus or strangulation. Paraesophageal hernias are particularly likely to incarcerate and cause symptoms of intermittent epigastric pain. Barrett esophagus is commonly associated with hiatal hernia; patients with Barrett esophagus may present with reflux symptoms or dysphagia.8
Sliding hiatal hernias are common. The clinical significance of a sliding hiatal hernia is uncertain. Most patients with a sliding hiatal hernia do not have gastroesophageal reflux, but reflux esophagitis is found more commonly in patients who have a hiatal hernia than in those who do not.2
Paraesophageal hernias are rare but can be potentially life-threatening because of the risk of volvulus and incarceration. Strangulation of the stomach may occur, but it is a rare finding. Symptoms associated with hiatal hernia may be multifactorial and may be related to gallstone disease, peptic ulcer disease, esophagitis, or, rarely, a carcinoma developing within a hiatal hernia. Recurrent chest infections may be result from aspiration of gastric contents from esophageal reflux; this rarely occurs in elderly patients.3,9
Preferred Examination
Plain chest radiographs may demonstrate a retrocardiac gas-filled structure. An upper GI barium series is the preferred examination in the investigation of suggested hiatal hernia and its sequelae. CT scans are useful when more precise cross-sectional anatomic localization is desired. The use of magnetic resonance imaging (MRI) and radionuclide studies is anecdotal. Ultrasonography is a sensitive means of diagnosing gastroesophageal reflux, and it is particularly attractive for use in young patients because it is noninvasive and does not require the use of ionizing radiation.2,11,12,13,14,15,16,17
Limitations of Techniques
The findings in an upper GI barium series may be specific, although the images may fail to demonstrate a small sliding hiatal hernia. Since gastroesophageal reflux may be intermittent, its presence may be overlooked. When no gas is present within the hernia, differentiating hernias from other retrocardiac masses may be difficult at times.
Making the diagnosis of hiatal hernia using sonography is not always straightforward, and an intermittent hernia is likely to be missed; however, some physicians regard sonography as the examination of choice in infants because the findings may differentiate duodenal causes of vomiting from esophageal causes.
Differential Diagnoses
Other Problems to Be Considered
Diaphragmatic hernia
Morgagni hernia
Bochdalek hernia
Duplication cysts
Neuroenteric cysts
Neurogenic tumors
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References
Ogunyemi D. Serial sonographic findings in a fetus with congenital hiatal hernia. Ultrasound Obstet Gynecol. Apr 2001;17(4):350-3. [Medline].
Kahrilas PJ, Kim HC, Pandolfino JE. Approaches to the diagnosis and grading of hiatal hernia. Best Pract Res Clin Gastroenterol. 2008;22(4):601-16. [Medline].
Huang X, Zhu HM, Deng CZ, et al. Gastroesophageal reflux: the features in elderly patients. World J Gastroenterol. Oct 1999;5(5):421-423. [Medline].
Savas N, Dagli U, Sahin B. The Effect of Hiatal Hernia on Gastroesophageal Reflux Disease and Influence on Proximal and Distal Esophageal Reflux. Dig Dis Sci. Jan 17 2008;[Medline].
Csendes A, Smok G, Quiroz J, Burdiles P, Rojas J, Castro C, et al. Clinical, endoscopic, and functional studies in 408 patients with Barrett's esophagus, compared to 174 cases of intestinal metaplasia of the cardia. Am J Gastroenterol. Mar 2002;97(3):554-60. [Medline].
Ouatu-Lascar R, Lin OS, Fitzgerald RC, Triadafilopoulos G. Upright versus supine reflux in gastroesophageal reflux disease. J Gastroenterol Hepatol. Nov 2001;16(11):1184-90. [Medline].
Wang JK, Chang MH, Li YW, Chen WJ, Lue HC. Association of hiatus hernia with asplenia syndrome. Eur J Pediatr. May 1993;152(5):418-20. [Medline].
Avidan B, Sonnenberg A, Schnell TG, Sontag SJ. Hiatal hernia and acid reflux frequency predict presence and length of Barrett's esophagus. Dig Dis Sci. Feb 2002;47(2):256-64. [Medline].
Qureshi WA. Hiatal Hernia. eMedicine. Available at http://emedicine.medscape.com/article/178393-overview.
Penston JG, Boyd EJ, Wormsley KG. Mallory-Weiss tears occurring during endoscopy: a report of seven cases. Endoscopy. May 1992;24(4):262-5. [Medline].
Gürgün C, Yavuzgil O, Akín M. Images in cardiology. Paraoesophageal hiatal hernia as a rare cause of dyspnoea. Heart. Mar 2002;87(3):275. [Medline].
Halkiewicz F, Kasner J, Karczewska K, Rusek-Zychma M. Ultrasound picture of gastroesophageal junction in children with reflux disease. Med Sci Monit. Jan-Feb 2000;6(1):96-9. [Medline].
Bisset RAL, Khan AN. Differential Diagnosis in Abdominal Ultrasound. 2nd ed. London: W. B. Saunders;1992:235-7.
Yamashita K, Tsunoda T. Three-dimensional computer images of stomach diseases. Am J Surg. Jan 2002;183(1):87-8. [Medline].
Khouzam RN, Akhtar A, Minderman D, Kaiser J, D'Cruz IA. Echocardiographic aspects of hiatal hernia: A review. J Clin Ultrasound. May 2007;35(4):196-203. [Medline].
Gupta M, Nanda NC, Inamdar V. Two- and three-dimensional transthoracic echocardiographic assessment of hiatal hernia. Echocardiography. Aug 2008;25(7):790-3. [Medline].
Barone M, Di Lernia P, Carbonara M, Ladisa R, Donno A, Amoruso A, et al. Sliding gastric hiatal hernia diagnosis by transabdominal ultrasonography: an easy, reliable and non-invasive procedure. Scand J Gastroenterol. Jul 2006;41(7):851-5. [Medline].
Shih WJ, Shih GL, Huang WS, Milan P. Duodenogastric reflux in a hiatal hernia seen as retrocardiac activity on 99mTc-tetrofosmin cardiac SPECT raw-data images. J Nucl Med Technol. Dec 2007;35(4):252-4. [Medline].
Scheidler MG, Keenan RJ, Maley RH, et al. "True" parahiatal hernia: a rare entity radiologic presentation and clinical management. Ann Thorac Surg. Feb 2002;73(2):416-9. [Medline].
Spechler SJ, Goyal RK. Barrett's esophagus. N Engl J Med. Aug 7 1986;315(6):362-71. [Medline].
Thorpe JA, Foroulis CN, Shah S. A rare complication of pneumonectomy: hiatal hernia associated with gastric volvulus. Asian Cardiovasc Thorac Ann. Dec 2007;15(6):518-20. [Medline].
Further Reading
Esophageal dilation.
American Society for Gastrointestinal Endoscopy. 2006 May. 6 pages. NGC:004974
Vomiting in infants up to 3 months of age.
American College of Radiology. 1995 (revised 2005). 7 pages. NGC:004792
Keywords
hernia, hiatal, hiatal hernia, hiatal hernias, hiatus hernia, paraesophageal hernia, sliding hernia, acid reflux, gastroesophageal reflux, sliding hiatal hernia, esophageal hernia, esophagus hernia, paraesophageal hiatal hernia, axial hernia, concentric hernia, rolling hiatal hernia, parahiatal hernia, congenital hernia, acquired hernia, congenital hernia, volvulus, diaphragmatic hernia, Barrett esophagus
