Hiatus hernia

INTRODUCTION — 

Hiatus hernia is a frequent finding by both radiologists and gastroenterologists. This topic will review the classification, pathogenesis, clinical manifestations, diagnosis, and management of a hiatus hernia. The surgical management of paraesophageal hernia and the management of gastroesophageal reflux disease (GERD) are discussed separately. (See "Surgical management of paraesophageal hernia" and "Initial management of gastroesophageal reflux disease in adults" and "Approach to refractory gastroesophageal reflux disease in adults".)

CLASSIFICATION — 

Hiatus hernia refers to herniation of elements of the abdominal cavity through the esophageal hiatus of the diaphragm. Hiatus hernias are broadly divided into sliding and paraesophageal hernias (figure 1). The most comprehensive classification scheme recognizes four types of hiatus hernia.

Type I: Sliding hernia — A type I or sliding hiatus hernia is characterized by the displacement of the esophagogastric junction (EGJ) above the diaphragm. The stomach remains in its usual longitudinal alignment, and the fundus remains below the EGJ.

Type II, III, IV: Paraesophageal hernias — A paraesophageal hernia is a true hernia with a hernia sac composed of peritoneum. It is characterized by an upward dislocation of the gastric fundus through a focal defect in the phrenoesophageal membrane [1].

●Type II hernias result from a localized defect in the phrenoesophageal membrane, where the gastric fundus serves as a lead point of herniation while the EGJ remains fixed to the preaortic fascia and the median arcuate ligament (figure 1) [2].

●Type III hernias have elements of both types I and II hernias and are characterized by both the EGJ and the fundus herniating through the hiatus. The fundus lies above the EGJ (image 1).

●Type IV hiatus hernias are associated with a large defect in the phrenoesophageal membrane and characterized by the inclusion of organs other than the stomach in the hernia sac (eg, colon, spleen, pancreas, or small intestine) (image 2).

EPIDEMIOLOGY

●Type I (sliding) – It is estimated that greater than 95 percent of hiatus hernias are type I (sliding). Estimates of prevalence of a type I hiatus hernia in the adult population in North America vary widely due to inconsistencies in the definition of small sliding hiatus hernias and the methodology used to detect them. Prevalence estimates for hiatus hernias are higher when diagnosed with endoscopy or a barium esophagram, compared with computed tomography (CT). Additionally, it can be difficult to distinguish a small sliding hiatus hernia from "physiological herniation" that occurs with swallowing.

●Types II, III, and IV (paraesophageal) – Approximately 5 percent are type II, III, or IV (paraesophageal) hernias. Of the paraesophageal hernias, more than 90 percent are type III. The least prevalent is type II.

●Relation to age – The prevalence of hiatus hernia increases with age [3]. In a population-based cohort in the United States, the prevalence of hiatus hernia as identified by CT increased from 2.4 percent in the sixth decade to 16.6 percent in the ninth decade [4]. Similarly, in an endoscopic series of 1260 patients, the reported prevalence was 14 percent in patients ages 18 to 39, 17 percent in those ages 40 to 49, 23 percent in those ages 50 to 59, 28 percent in those ages 60 to 69, 31 percent in those ages 70 to 79, and 42 percent in those ages >80 [5].

PATHOGENESIS — 

Although the etiology of most hiatus hernias is speculative, proposed mechanisms include age-related degeneration, obesity, trauma, congenital malformation, and iatrogenic factors [6].

Anatomy and physiology of swallowing

●Normal anatomy – With normal esophagogastric junction anatomy, the esophagus inserts tangentially into the stomach approximately 2 cm distal to the diaphragmatic hiatus. The esophagus is held in that position by the phrenoesophageal membrane, an elastic structure formed by the fused endothoracic and endoabdominal fascia. The phrenoesophageal membrane inserts into the esophageal musculature close to the squamocolumnar junction, also known as the z-line.

●Effects of swallowing – During swallow-initiated peristalsis, the esophagus shortens, the phrenoesophageal membrane is stretched, and the squamocolumnar junction moves proximally. This is, in effect, "physiologic herniation" since the gastric cardia tents through the diaphragmatic hiatus with each swallow. Following each swallow, the elastic recoil of the phrenoesophageal membrane pulls the squamocolumnar junction back to its normal position. The globular structure seen radiographically that forms above the diaphragm and beneath the tubular esophagus during peristalsis is termed the phrenic ampulla. It is bounded from above by the distal esophagus and from below by the crural diaphragm (figure 2) [7]. Physiologically, the phrenic ampullas is the relaxed, effaced, and elongated lower esophageal sphincter (LES) [8].

●Age-related degeneration – The repetitive stress of swallowing, coupled with the episodic stresses of abdominal straining, vomiting, and belching, subject the phrenoesophageal membrane to substantial wear and tear and make it a plausible target of age-related degeneration.

Type I: Sliding hernia — Type I hiatus hernia results from progressive disruption of the esophagogastric junction (EGJ), first with proximal migration of the intra-abdominal length of the esophagus and progressive widening of the hiatus (figure 3) [9]. Widening of the muscular hiatus and circumferential laxity of the phrenoesophageal membrane allows a portion of the gastric cardia to herniate upward [9]. A sliding hernia does not have a hernia sac and slides into the chest since the EGJ is not fixed inside the abdomen. The phrenoesophageal membrane remains intact, albeit stretched, and the hernia is contained within the posterior mediastinum (figure 1 and image 3).

Type II, III, and IV: Paraesophageal hernias — Paraesophageal hernias are associated with abnormal laxity of the gastrosplenic and gastrocolic ligaments. These ligaments normally prevent displacement of the stomach. However, it is unclear whether their laxity causes or is an effect of the paraesophageal hernia. Type II, III, and IV (paraesophageal) hernias are also a recognized complication of surgical dissection of the hiatus as occurs during antireflux surgery, esophagomyotomy, or partial gastrectomy.  

CLINICAL MANIFESTATIONS

Type I: Sliding hernia

●Gastroesophageal reflux disease – Type I hiatus hernias are often associated with reflux esophagitis [10] and/or symptoms of gastroesophageal reflux disease (GERD), the most common of which are heartburn, regurgitation, and dysphagia (see "Clinical manifestations and diagnosis of gastroesophageal reflux in adults", section on 'Clinical manifestations'). Endoscopic and radiographic studies suggest that 50 to 94 percent of patients with GERD have a type I hiatus hernia [11].

The likelihood of GERD increases with anatomic compromise of the esophagogastric junction (EGJ) and hernia size. Normally, the EGJ limits the reflux of gastric contents, including gastric acid, into the esophagus. Type I hiatus hernias degrade the competence of the EGJ in preventing reflux and compromise esophageal acid clearance once reflux has occurred. (See "Pathophysiology of gastroesophageal reflux disease".)

●Other complications – Other complications rarely occur in patients with type I hiatus hernia and are usually related to reflux esophagitis (see "Complications of gastroesophageal reflux in adults"). However, large type I hernias can be associated with Cameron lesions, which are linear erosions at the level of the hiatus that can cause iron deficiency anemia [12].

Type II, III, and IV: Paraesophageal hernias

●Common symptoms – Patients with type II, III, and IV (paraesophageal) hernias can be asymptomatic or have only vague, intermittent symptoms [1]. The most common symptoms are epigastric or substernal pain, postprandial fullness, nausea, and retching. GERD symptoms are less prevalent than in individuals with a type I hernia.

●Volvulus – Gastric volvulus can occur with large paraesophageal hernias, causing dysphagia, postprandial pain, ischemia and, rarely, strangulation. As the hernia enlarges, the greater curvature of the stomach rolls up into the thorax. Because the stomach is fixed at the EGJ, the herniated stomach tends to rotate around its longitudinal axis, resulting in an organoaxial volvulus (figure 4) [13]. Infrequently, rotation occurs around the transverse axis, resulting in a mesenteroaxial volvulus. Over time, the entire stomach can eventually herniate, with the pylorus juxtaposed to the gastric cardia, forming an upside-down, intrathoracic stomach.

●Bleeding – Bleeding, although infrequent, occurs from gastric ulceration, gastritis, or erosions within the incarcerated hernia pouch.

●Dyspnea – Dyspnea can result from limited lung expansion when a large part of the stomach or other organs herniate through the hiatus.  

Radiographic findings — In patients with paraesophageal hernias, an upright radiograph, computed tomography (CT) scan, or magnetic resonance imaging (MRI) of the chest may reveal a retrocardiac air-fluid level within a paraesophageal hernia or intrathoracic stomach (image 4). In type IV paraesophageal hernia, other organs within the hernia sac can be identified on CT or MRI of the chest (image 2).

DIAGNOSIS

When to suspect the diagnosis — Because hiatus hernias are often asymptomatic or present with nonspecific symptoms, they are usually diagnosed incidentally on upper endoscopy, imaging studies, or manometry done for other reasons. Additionally, we suspect a paraesophageal hernia in individuals with symptoms of epigastric or substernal pain or fullness, nausea, or vomiting and a history of surgical dissection of the hiatus (eg, antireflux procedures, esophagomyotomy, or partial gastrectomy). (See 'Radiographic findings' above and "Approach to the evaluation of dysphagia in adults", section on 'Symptom-based differential diagnosis' and "Clinical manifestations and diagnosis of gastroesophageal reflux in adults", section on 'Differential diagnosis'.)

Establishing the diagnosis — The diagnosis of hiatus hernia is typically established radiographically or by upper gastrointestinal endoscopy. However, small sliding hiatus hernias (<2 cm in axial span) can only be diagnosed with certainty during surgery [14].

Diagnostic approach

●Initial diagnosis – Most hiatus hernias are diagnosed incidentally as part of the diagnostic evaluation of upper gastrointestinal symptoms, such as heartburn, reflux, nausea and vomiting, or dysphagia. In these patients, hiatus hernias are typically not the "end diagnosis," and specific management is targeted to the symptoms that initiated the diagnostic evaluation. (See 'Management' below.)

Diagnostic tests that may reveal hiatus hernias include barium swallow, upper gastrointestinal endoscopy, and imaging of the chest or abdomen with computed tomography (CT), magnetic resonance imaging (MRI) or plain radiography. Specific features of these tests as they pertain to the diagnosis of hiatus hernia are discussed below. (See 'Specific tests' below.)

●Patients with known paraesophageal hernia and new symptoms – Individuals with known paraesophageal hernias may require additional work-up if they develop symptoms that suggest worsening herniation (eg, dyspnea) or hernia complications (eg, volvulus or strangulation). In this clinical scenario, we typically use barium swallow for initial testing, if available. In settings where barium swallow is not available, CT is an appropriate modality. In individuals with known paraesophageal hernia who develop symptoms or signs of upper gastrointestinal bleeding, we perform upper endoscopy.

Specific tests

Barium swallow — Barium swallow can diagnose sliding and paraesophageal hiatus hernias and determine the anatomy and size of the hernia, orientation of the stomach, and location of the esophagogastric junction (EGJ) (image 3).

●Sliding hiatus hernia – A barium swallow can diagnose sliding hiatus hernias that are larger than 2 cm in axial span. A sliding hiatus hernia is characterized by a greater than 2 cm separation between the mucosal B ring at the site of the squamocolumnar junction and the diaphragmatic hiatus (figure 2). If a B ring is not evident, demonstration of at least three rugal folds traversing the diaphragm is diagnostic of a sliding hiatus hernia (image 5). Barium swallow is unreliable for defining smaller sliding hiatus hernias because the EGJ is highly mobile, and a lack of standardization exists regarding the timing of hernia measurement during peristalsis.

●Paraesophageal hernia – A barium swallow is the most sensitive diagnostic test for types II and III paraesophageal hernias. Visualization of a portion of the gastric fundus herniating along the distal esophagus on barium swallow is diagnostic of a paraesophageal hernia (image 6).

Upper endoscopy — Upper endoscopy can diagnose sliding and paraesophageal hiatus hernias.

●Sliding hiatus hernia – To diagnose a sliding hiatus hernia, the endoscopist measures the hernia's axial length calculated as the degree of separation between the squamocolumnar junction and the diaphragmatic impression, from a retroflexed view (picture 1) [9].

●Paraesophageal hernia – In patients with a type II paraesophageal hernia, a retroflexed view shows a portion of the stomach herniating upward through the diaphragm adjacent to the endoscope. In patients with a type III paraesophageal hernia, a retroflexed view shows the EGJ above the diaphragm with a portion of the stomach herniating upward, adjacent to the esophagus.

Computed tomography — Large paraesophageal hernias are evident on CT scan as an intrathoracic stomach (image 4). With type IV paraesophageal hernia, CT images may also reveal additional organs, most commonly colon, within a hernia sac in the thoracic cavity (image 2).

High-resolution manometry — Esophageal manometry may be the most accurate modality for diagnosing hiatus hernia. On high-resolution manometry (HRM), spatial separation between the crural diaphragm (CD) contraction and lower esophageal sphincter (LES) indicates a sliding hiatus hernia [14,15]. HRM allows for prolonged observation that enables the identification of intermittent herniation (figure 5). Small sliding hiatus hernias with less than 2 cm separation between the LES and CD often reduce spontaneously during prolonged manometric recordings. (See "High resolution manometry", section on 'Anatomic sphincters'.)

An analysis comparing the accuracy of HRM, endoscopy, and barium radiography to surgery for detecting and sizing hiatus hernia [16] concluded that HRM, using the LES-CD separation metric, outperformed the other modalities with a sensitivity of 94 percent, specificity of 92 percent, and kappa (measure of interrater reliability) of 0.85. HRM attained both optimal sensitivity and specificity for detecting hiatus hernia, with a threshold LES–CD separation of 1.2 cm.

DIFFERENTIAL DIAGNOSIS — 

The differential diagnosis of hiatus hernia includes other etiologies of epigastric or substernal pain, dysphagia, heartburn, or regurgitation. These etiologies include esophagitis, esophageal motility disorders, functional dyspepsia, and coronary artery disease. Although an evaluation to exclude these diagnoses is not required to diagnose a hiatus hernia, it may be necessary in patients with refractory symptoms and is discussed separately. (See "Clinical manifestations and diagnosis of gastroesophageal reflux in adults", section on 'Evaluation in selected patients'.)

MANAGEMENT

Sliding hiatus hernia

●Asymptomatic – Asymptomatic type 1 hiatus hernias do not require surgical repair.

●Symptomatic – The initial management of patients with a symptomatic sliding hiatus hernia consists of medical treatment of reflux esophagitis and/or reflux-like symptoms (see "Initial management of gastroesophageal reflux disease in adults"). Antireflux surgery is typically reserved for individuals with objectively documented gastroesophageal reflux disease (GERD) (ie, reflux esophagitis or abnormal pH monitoring) who have refractory symptoms despite maximal medical therapy. (See "Surgical treatment of gastroesophageal reflux in adults", section on 'Indications'.)

Paraesophageal hernia

●Asymptomatic – The optimal management of patients with asymptomatic paraesophageal hernias is controversial. Some experts suggest elective surgical repair in healthy individuals with asymptomatic paraesophageal hernias based, in part, on a decision analysis that found improved life expectancy with surgical repair, compared with watchful waiting [17] (see "Surgical management of paraesophageal hernia", section on 'Elective presentation'). Other experts [18], including these authors, prefer watchful waiting for most asymptomatic patients based on a lack of high-quality evidence that demonstrates the superiority of early surgical intervention [19].

●Symptomatic – Surgical repair is indicated in patients with a symptomatic paraesophageal hernia [20]. Emergent repair is required in patients with a gastric volvulus, uncontrolled bleeding, obstruction, strangulation, perforation, or respiratory compromise secondary to a paraesophageal hernia [1,20]. The indications for surgical repair, preoperative evaluation, and the technical aspects of surgical repair of paraesophageal hernias are discussed separately. (See "Surgical management of paraesophageal hernia".)

SOCIETY GUIDELINE LINKS — 

Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Hiatal hernia".)

INFORMATION FOR PATIENTS — 

UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topic (see "Patient education: Hiatal hernia (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Classification – Hiatus hernia refers to herniation of elements of the abdominal cavity through the esophageal hiatus of the diaphragm. Hiatus hernias are broadly divided into sliding and paraesophageal hernias (figure 1). (See 'Classification' above.)

•Types I (sliding) – A type I or sliding hiatus hernia is characterized by the displacement of the esophagogastric junction (EGJ) above the diaphragm. The stomach remains in its usual longitudinal alignment, and the fundus remains below the EGJ.

•Types II, III, and IV (paraesophageal) – Type II, III, and IV hiatus hernias (paraesophageal hernias) are characterized by an upward dislocation of the gastric fundus.

●Epidemiology – Approximately 95 percent of all hiatus hernias are sliding, and 5 percent are paraesophageal. (See 'Epidemiology' above.)

●Pathogenesis – Although the pathogenesis of most hiatus hernias is speculative, age-related degeneration, obesity, trauma, congenital malformation, and iatrogenic factors have been implicated. A sliding hiatus hernia results from progressive disruption of the EGJ that allows a portion of the gastric cardia to herniate upward (figure 3). Paraesophageal hernias are a recognized complication of prior surgical dissection of the hiatus. (See 'Pathogenesis' above.)

●Clinical features – Type I hiatus hernias are often associated with symptoms of gastroesophageal reflux disease (GERD). Many individuals with paraesophageal hernias are asymptomatic or have vague upper gastrointestinal symptoms, such as epigastric pain or fullness, nausea, or vomiting. However, gastric volvulus can occur with large paraesophageal hernias, causing dysphagia, postprandial pain, ischemia and, rarely, strangulation. (See 'Clinical manifestations' above.)

●Diagnosis – Because hiatus hernias are often asymptomatic or present with nonspecific symptoms, they are usually diagnosed incidentally on upper endoscopy, manometry, or imaging studies done for other reasons. Sliding hiatus hernias larger than 2 cm in axial span can be diagnosed by barium swallow, endoscopy, computed tomography (CT), or esophageal manometry, but smaller sliding hernias are often only detected during surgery.

Barium swallow is the most sensitive diagnostic test to detect type II or III paraesophageal hernias. With large paraesophageal hernias, CT scan or magnetic resonance imaging (MRI) of the chest may reveal an intrathoracic stomach (image 4 and image 2). (See 'Diagnosis' above.)

●Management

•Type I (sliding) – Asymptomatic sliding hiatus hernias do not require repair. Management of patients with a symptomatic sliding hiatus hernia consists of management of GERD, which is detailed elsewhere. (See 'Sliding hiatus hernia' above and "Initial management of gastroesophageal reflux disease in adults".)

•Types II, III, and IV (paraesophageal) – We typically reserve surgical repair for paraesophageal hernias for symptomatic patients. Emergent repair is required in patients with a gastric volvulus, uncontrolled bleeding, obstruction, strangulation, perforation, or respiratory compromise. The optimal management of patients with asymptomatic paraesophageal hernias is controversial, with some experts advocating for surgical intervention and others preferring watchful waiting. (See 'Paraesophageal hernia' above and "Surgical management of paraesophageal hernia".)