Hiatal hernia

A hiatal (or hiatus) hernia is the abnormal protrusion of any abdominal structure/organ, most often a portion of the stomach, into the thoracic cavity through a lax diaphragmatic esophageal hiatus. It may be congenital or secondary to aging, obesity, and/or smoking. There are four types of hiatal hernia: sliding, paraesophageal, mixed, and complex. Sliding hiatal hernias, where the gastroesophageal junction (GEJ) and the gastric cardia migrate into the thorax, account for 95% of hiatal hernias. In paraesophageal hernias (PEH), only the gastric fundus herniates into the thorax, whereas in mixed hiatal hernias, the GEJ as well as the gastric fundus herniate. Complex hiatal hernias are rare and characterized by protrusion of any abdominal organ other than the stomach. Nearly half of all patients with hiatal hernia are asymptomatic and require no medical or surgical intervention. Symptomatic patients with sliding hiatal hernia present with features of gastroesophageal reflux disease (GERD), which are usually managed with lifestyle modification and proton pump inhibitors. Patients with PEH or mixed hiatal hernias typically present with intermittent dysphagia, substernal discomfort, or abdominal pain, and in rare cases present acutely with gastric volvulus and strangulation. All symptomatic PEH, mixed, and complex hiatal hernias require operative intervention to avoid life-threatening complications. Also see our article “Congenital diaphragmatic hernias”.

Protrusion of any abdominal structure/organ into the thorax through a lax diaphragmatic esophageal hiatus. (In 95% of cases, a portion of the stomach is herniated.)

• Incidence increases with:
  • Age: affects ∼ 70% of people > 70 years
  • ↑ BMI
• Prevalence
  • More prevalent in females and Western populations ^[1]
  • Most commonly occur on the left side, as the liver protects the right diaphragm.

Epidemiological data refers to the US, unless otherwise specified.

The etiology is multifactorial.

• Lax diaphragmatic esophageal hiatus
  • Advanced age
  • Smoking
  • Obesity
  • Genetic predisposition (rare) ^[2]
• Prolonged periods of increased intra-abdominal pressure
  • Pregnancy
  • Ascites
  • Chronic cough
  • Chronic constipation ^[1]
• Defects of the pleuroperitoneal membrane (see “Congenital diaphragmatic hernias”)

Types of hiatal hernias ^[2]

Type I: sliding hiatal hernia

• Most common type (95% of cases)
• The GEJ and the gastric cardia slide up into the posterior mediastinum.
• The gastric fundus remains below the diaphragm (hourglass stomach)

Type II: paraesophageal hiatal hernia

• Part of the gastric fundus herniates into the thorax.
• The GEJ remains in its anatomical position below the diaphragm.

Type III: mixed hiatal hernia

• Mix of types I and II
• The GEJ and a portion of the gastric fundus prolapse through the hiatus.

Type IV: complex hiatal hernia

• Herniation of any abdominal structure other than the stomach (e.g., spleen, omentum, or colon)
• Rarest type

Anatomy

• Esophageal hiatus
  • Central opening of the diaphragm, which allows the esophagus to pass through into the peritoneal cavity; forms the upper part of the esophageal sphincter and the reflux barrier
  • Formed by:
    • Left and right paravertebral tendinous crura
    • Median arcuate ligament
• Gastroesophageal junction (GEJ)
  • Normally lies at the level of the esophageal hiatus
  • Phrenoesophageal ligament (PEL) attaches to the esophagus at the GEJ
    • Peritoneal fold that encircles the distal portion of the esophagus and gastroesophageal junction and connects them to the peritoneal surface of the diaphragm
    • Closes the esophageal hiatus and helps maintain the intra-abdominal position of the GEJ

Changes in the presence of a hiatal hernia

• Predisposing factors lead to laxity of the esophageal hiatus, e.g.:
  • Advanced age → phrenoesophageal ligament weakens
  • Smoking → loss of elastin fibres in the diaphragmatic crura
  • Obesity → deposition of fat in and around the crura → widened hiatus
• Relative negative intrathoracic pressure and the lax hiatus → herniation of the abdominal contents into the thorax → loss of reflux barrier + compromised fluid emptying of distal esophagus → gastroesophageal reflux disease (GERD) ^[3]

• Most patients are asymptomatic
• Type I: symptoms of GERD
• Type II, III, and IV
  • Epigastric/substernal pain
  • Early satiety
  • Retching
  • Symptoms of GERD can occur.
• Saint triad: a combination of cholelithiasis, diverticulosis, and hiatal hernia may occur in ∼ 1.5% of patients. ^[4][5][6]

• Barium swallow: most sensitive test
  • Assesses type and size of a hernia (including location of the stomach and the GEJ) (see “Classification” above)
• Endoscopy: used to diagnose hiatal hernia and evaluate for possible complications (see “Complications” below)
  • Z-line: squamocolumnar junction, which represents the transition from the squamous epithelium-lined esophageal mucosa to the columnar epithelium-lined gastric mucosa; corresponds to the GEJ
    • Types I and III: Z-line lies above the diaphragmatic hiatus
    • Types II and IV: Z-line remains undisplaced (below the diaphragmatic hiatus)
• Other tests that can detect hiatal hernias include ^[2]
  • Chest x-ray
    • Usually incidental finding
    • Types I, II, III: retrocardiac soft tissue opacity with/without an air-fluid level
    • Type IV: retrocardiac visceral gas (small bowel/colon) or soft tissue shadows (spleen/omentum)
  • CT Thorax: recommended for urgent preoperative evaluation of complicated type II, III, and IV hernias
  • Esophageal manometry: helps calculate the size of a sliding hiatal hernia by accurately identifying the level of the diaphragmatic hiatus
  • Esophageal pH monitoring: not a diagnostic test; useful for determining the extent of gastroesophageal reflux

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Management of patients with sliding hiatal hernia

• Conservative management
  • Lifestyle modifications
  • Proton pump inhibitors (PPIs) or histamine H2-receptor antagonists if symptoms of GERD occur
• Surgery: laparoscopic/open fundoplication and hiatoplasty ; ^[2]
  • Indications
    • Persistence of symptoms despite conservative management
    • Refusal or inability to take long-term PPIs
    • Severe symptoms/complications of gastroesophageal reflux disease: bleeding, strictures, ulcerations

Management of patients with types II, III, IV hiatal hernias ^[2]

• Conservative management: older patients or those with other comorbidities ^[7]
• Surgery: laparoscopic/open herniotomy + fundoplication, hiatoplasty, and gastropexy/fundopexy
  • Indications
    • Asymptomatic, small hernias in patients < 50 years of age
    • Symptomatic type II, III, IV hernias

Complications of type I

• Arise from long-standing gastroesophageal reflux (see "Complications” in “Gastroesophageal reflux disease”)

Complications of type II, III, IV

• Upper gastrointestinal bleeding (occult/massive) → iron deficiency anemia ^[8]
• Gastric ulcers
• Gastric perforation
• Gastric volvulus ^[2]
  • A rare condition characterized by abnormal rotation of the stomach
  • Can occur in the abdomen or chest (upside-down stomach)
  • Classified according to the rotational axis: organoaxial (around the long axis of the stomach) and mesenteroaxial (between the lesser and greater curvature)
• Total gastric obstruction

The complications of types II, III, and IV are often medical emergencies.

We list the most important complications. The selection is not exhaustive.