Hiatus hernia

The term hiatus hernia refers to the herniation of a part of the abdominal viscera through the oesophageal aperture of the diaphragm. The vast majority of hiatus hernias involve only the herniation of a part of the gastric cardia through the muscular hiatal aperture of the diaphragm; however, rarely, hernias with a large defect can allow other organs to enter the thoracic cavity, such as the spleen and pancreas.

Epidemiology¹

The precise incidence of hiatus hernia is not known, as most studies have looked only at individuals who presented with symptoms of dyspepsia. Over half of people with reflux oesophagitis diagnosed either endoscopically or radiologically are found to have a hiatus hernia². Estimates for the general population vary enormously - from 10-80% of the adult population in North America, for example. It is more common amongst men³. The incidence increases with age and with obesity.

Risk factors

• Obesity⁴.

• Pregnancy².

• Ascites⁵.

• Advanced age³.

• Genetic predisposition².

• Conditions causing shortening of the oesophagus, such as chronic oesophagitis. Shortening is thought to occur by virtue of reflex contraction of oesophageal longitudinal muscle, evoked by intraluminal acid².

• Previous gastro-oesophageal surgery such as partial gastrectomy (para-oesophageal hernia).

• Trauma to the chest and abdomen.

• Skeletal deformities, such as scoliosis, kyphosis and pectus excavatum (predisposes to para-oesophageal hernia).

Aetiology¹⁶

A hiatus hernia may be caused by one or more of three possible mechanisms:

• Widening of the diaphragmatic hiatus.

• Pulling up of the stomach, due to oesophageal shortening.

• Pushing up of the stomach by increased intra-abdominal pressure.

The anti-reflux barrier is lost, and the larger the hernia, the more impaired the clearance of acid which has refluxed into the oesophagus. The hernia thereby exacerbates gastro-oesophageal reflux disease (GORD).

Classification

Hiatus hernias are broadly subdivided into two types:

Sliding hiatus hernia - the gastro-oesophageal junction slides up into the thoracic cavity (85-95% of cases).

Diagram of sliding hiatus hernia

Para-oesophageal (rolling) hiatus hernia - the gastro-oesophageal junction remains in place but a part of the stomach (or colon, spleen, pancreas or small intestine) herniates into the chest next to the oesophagus (5-15% of cases). Many are mixed, with a sliding component also.

Diagram of rolling hiatus hernia

An alternative classification according to anatomical features is increasingly being used⁷:

• Type I: sliding hiatal hernias, where the gastro-oesophageal junction migrates above the diaphragm. The stomach remains in its usual longitudinal alignment and the fundus remains below the gastro-oesophageal junction.

• Type II: pure para-oesophageal hernias, where the gastro-oesophageal junction remains in its normal anatomical position but a portion of the fundus herniates through the diaphragmatic hiatus adjacent to the oesophagus.

• Type III: a combination of types I and II, where both the gastro-oesophageal junction and the fundus herniate through the hiatus. The fundus lies superior to the gastro-oesophageal junction.

• Type IV: structures other than stomach, such as the omentum, colon or small bowel, lie within the hernia sac.

Presentation

The clinical significance of sliding hiatus hernias is their contribution to GORD; the concern with para-oesophageal hernias is the potential for obstruction, volvulus or ischaemia.

Many individuals with a sliding hiatus hernia will be totally asymptomatic; others may present with any of the following:

• Retrosternal burning sensation or 'heartburn', especially on bending or lying.

• Gastro-oesophageal reflux.

• Difficulty in swallowing.

Para-oesophageal hernias may also be asymptomatic, or may present with chest pain, epigastric pain or fullness, or nausea - potentially symptoms of obstruction.

Examination is usually normal unless an underlying risk factor is present, or presentation is with complications of a para-oesophageal hernia such as obstruction.

Investigations¹²

Hiatus hernias are often intermittent, so investigation may be unreliable. Investigation is needed to rule out sinister causes of symptoms and to exclude complications.

• CXR. Hiatus hernias may be seen on plain X-rays as a soft tissue opacity with or without an air-fluid level. A retrocardiac air-fluid level on CXR is diagnostic of a para-oesophageal hiatus hernia⁸.

• Barium studies (useful for diagnosis of hiatus hernia but not for mucosal complications).

• Endoscopy.

• Oesophageal manometry (mostly used when surgery is being considered).

Associated diseases

• Reflux symptoms and reflux oesophagitis.

• Barrett's oesophagus - there is a strong link with hiatus hernia⁹. Hiatus hernia is present in the vast majority of people with Barrett's oesophagus².

• Oesophageal adenocarcinoma - presence of a hiatus hernia is associated with at least twice the risk, which has been shown to increase to eight-fold if reflux is also present².

• Reflux laryngitis¹⁰.

Differential diagnosis

• Other causes of reflux

• Rumination syndrome - self-induced regurgitation from the stomach to the mouth, caused by a voluntary rise in intra-abdominal and intragastric pressure, leading to the reflux of the gastric content into the oesophagus¹¹.

• Other causes of chest pain.

• More sinister causes or complications of GORD, such as Barrett's oesophagus and malignancy of the stomach or oesophagus.

Management¹²⁸¹²

Treatment is not needed in the absence of symptoms, other than in para-oesophageal hiatus hernias where the potential risks are greater and surgery may be considered even in the absence of symptoms.

Lifestyle

Lifestyle measures to minimise symptoms are the same as those advocated to minimise GORD, although the evidence is weak:

• People with hiatus hernia should be advised to avoid any factors likely to increase intra-abdominal pressure - eg, tight clothing, corsets.

• Nocturnal symptoms may be helped by elevating the head of the bed to reduce postural reflux. Avoidance of eating late in the evening may also be helpful; advise eating at least three hours before going to bed.

• Weight loss should be advised in obese patients; patients who smoke and/or drink alcohol should be encouraged to stop.

• Smaller meals may be helpful, along with avoidance of foods which trigger symptoms.

Pharmacological

Symptomatic relief may be gained by the use of proton pump inhibitors (PPIs), although patients with hiatus hernia may require larger doses for symptom control. Long-term treatment is usually required. PPIs are more effective than antacids or H₂-receptor antagonists, although these may be used as alternatives. The minimum dose needed to control symptoms should be used, and in some intermittent use may be sufficient.

Medical treatment is generally considered preferable to surgery.

Surgical

Asymptomatic patients with type 1 hernias do not need surgery. Indications for surgery in patients with severe GORD include:

• People who are unable to comply with, or who are intolerant to, therapeutic regimes.

• People who require high doses of medication, or in whom high doses are not working - eg, for intractable cough or oesophagitis due to reflux.

• People who wish to avoid lifelong medical treatment.

• People with respiratory complications of reflux, such as asthma.

• People with symptomatic para-oesophageal hernia - elective surgery may be recommended due to the high incidence of strangulation. Asymptomatic para-oesophageal hernias do not necessarily need surgical repair. Age and any comorbidities should be taken into account.

• People having bariatric surgery in whom a hiatus hernia is noted.

Currently the usual surgical procedure is a laparoscopic fundoplication. Open surgery may also be used. A laparoscopic approach is preferable, as it is equally effective and associated with reduced morbidity and mortality, especially in the case of large para-oesophageal hernias¹³. The procedure involves mobilisation of the distal oesophagus, reduction of the associated hiatus hernia, and either complete (Nissen's) or partial (modified) wrapping of the fundus of the stomach around the oesophagus (fundoplication).

Risks include:

• Side-effects of bloating and dysphagia.

• 1-2% risk of major complications or death.

• High recurrence rate which increases with obesity and larger-sized hernias.

Gastropexy (suturing of the stomach to the abdominal wall) is sometimes used in addition to hiatus hernia repair or may be used as the sole procedure in high-risk patients. Trials using endoscopic techniques used in the treatment of GORD with or without hiatus hernia have reported a high rate of complications and are not currently advocated¹⁴.

Prognosis¹⁵

The majority of patients will gain symptomatic relief from medical or surgical intervention, although a few will continue to have symptoms. Morbidity and mortality in patients undergoing laparoscopic hernia repair has been quoted as being higher in patients over the age of 70, but a more recent study of laparoscopic surgery in the elderly did not duplicate this. The study suggested that carefully selected patients over 70 should not be denied the benefits of laparoscopic surgery by reason of age alone¹⁶.