Overview

• Hiatal herniation – when abdominal contents (most commonly the stomach), herniate cranial to the diaphragm into the thorax through the esophageal hiatus. Four types of hernia have been described:
  • Type I (sliding hiatal hernia; most common)
  • Type II (paraesophageal hiatal hernia)
  • Type III (includes elements of both type I and II)
  • Type IV (herniation of organs other than the stomach)
• Congenital and acquired hiatal hernias have been reported. Acquired most commonly associated with severe upper respiratory disease (brachycephalic syndrome, laryngeal paralysis).

Signalment

• Dogs and less commonly cats
• Prevalence-higher in English bulldogs, Shar-Peis and other brachycephalic breeds. Type I more commonly congenital and therefore seen in younger animals.

Signs

Typically recognized in young animals 2–6 months of age. Signs can coincide with weaning. Most signs secondary to GER and esophagitis.

• Regurgitation
• Dysphagia
• Hypersalivation
• Lip smacking
• Inability to gain weight
• Vomiting
• Respiratory distress
• Anorexia
• Weight loss

Causes & Risk Factors

Congenital. Acquired-traumatic event ± severe upper respiratory disease; brachycephalic airway syndrome.

Differential Diagnosis

• Physical examination findings are generally unremarkable unless aspiration pneumonia or chronic weight loss are present.
• Distinguish from other causes of weight loss or regurgitation.

CBC/Biochemistry/Urinalysis

No specific abnormalities. May find inflammatory leukogram secondary to associated pneumonia.

Other Laboratory Tests

N/A

Imaging

Thoracic Radiographic Findings-Cranial displacement of stomach. Soft tissue mass in the caudal thorax adjacent to diaphragm. Gas-filled viscera in thorax. Hiatal hernia is infrequently diagnosed on survey thoracic radiographs alone.

Positive Contrast Esophagram-Preferably performed using videofluoroscopy. Helps to confirm the diagnosis and differentiate between types I and II hiatal hernias. Can also diagnose associated gastroesophageal reflux and esophageal dysmotility. False-negative studies are common due to the highly intermittent and dynamic nature of hiatal herniation.

Diagnostic Procedures

Upper gastrointestinal endoscopy-can document gastroesophageal reflux, esophageal strictures, esophagitis and hiatal hernia in some cases. Secondary evidence may only be detectable if herniation does not occur during the study.

Medical Management

• Can often be managed as an outpatient unless animal has severe aspiration pneumonia.
• Reduce gastric acid secretion (proton pump inhibitors are superior to H2 receptor antagonists).
• Increase rate of gastric emptying and increase LES sphincter tone (prokinetic agents such as cisapride).
• Provide esophageal mucosal protection (sucralfate).
• Feed a low-fat diet in an elevated position.
• 30-day trial of medical management before surgery often recommended; not all patients require surgery.

Surgical Management

• Patients nonresponsive to medical therapy
• Treat with antacids and prokinetics prior to surgery
• Surgical procedures (used alone or in combination)
  • Phrenoplasty
  • Esophagopexy
  • Left-sided gastropexy

Drug(s)

• H2 receptor antagonists/antacids-help to neutralize gastric pH and therefore reduce esophagitis secondary to GER
  • Famotidine 0.5–1 mg/kg PO, IV q12h
  • Ranitidine 1–2 mg/kg PO, IV, IM q8–12h
• Proton pump inhibitors-are more potent than H₂ receptor antagonists
  • Omeprazole 0.7–1.5 mg/kg q24h PO
  • Pantoprazole 0.7–1.5 mg/kg q24h IV
• Prokinetics-increase gastric emptying
  • Metoclopramide 0.2–0.5 mg/kg q6–8h PO or 1–2 mg/kg/24h as a CRI
  • Cisapride 0.5 mg/kg q8–12h PO
• Mucosal protectants
  • Misoprostol 2–5 µg/kg q8h PO 1 h before or 2 h after food or other medications.

Patient Monitoring

• Long-term medical therapy may be indicated in both surgically and conservatively managed patients.
• Postoperative-monitor for dyspnea, worsening regurgitation (may require second surgery), abdominal distension that could result from overtightening of the hiatus resulting in an inability to eructate.

Possible Complications

Continuation of clinical signs, bloat episodes

Expected Course and Prognosis

• Overall prognosis is good.
• Not all patients will necessarily need surgical intervention.
• When medical management fails, surgical intervention leads to a positive outcome in the majority of cases.

Associated Conditions

Often found in dogs with brachycephalic airway disease or other forms of upper airway obstructive diseases. Hypothesized that profound decreases in intrathoracic pressures generated in dogs with upper airway obstruction may act to pull the stomach into the thorax through the hiatus. Some evidence that gastroesophageal reflux can also worsen clinical signs of upper respiratory disease due to irritation of upper respiratory area with irritant gastric contents or associated bronchospasm of the lower airway.

Abbreviations

• GER = Gastroesophageal reflux
• LES = Lower esophageal sphincter

Internet Resources

N/A