What is the recommended initial diagnostic scan for a concern of hiatal (hiatus) hernia?

Recommended Initial Diagnostic Scan for Hiatal Hernia

A double-contrast upper GI series is the most useful initial diagnostic test for evaluating suspected hiatal hernia. 1

Diagnostic Options for Hiatal Hernia

First-Line Imaging: Fluoroscopic Studies

• Double-contrast upper GI series:

  • Provides the most comprehensive evaluation of hiatal hernias
  • Offers both anatomic and functional information 1
  • Detects presence and size of hiatal hernia
  • Provides information on esophageal length, strictures, and reflux esophagitis
  • Sensitivity of 80% for detecting reflux esophagitis 1
  • Helps differentiate sliding hiatal hernias from paraesophageal hernias 1

• Biphasic esophagram:

  • Combines benefits of both single and double-contrast studies
  • Double-contrast phase optimizes detection of inflammatory changes
  • Single-contrast phase better detects hiatal hernias and strictures
  • Combined technique achieves highest sensitivity (88%) 1
  • Recommended by the American College of Surgeons for all patients being considered for antireflux surgery 1

• Single-contrast esophagram:

  • May be considered in some instances
  • Can delineate the hernia, reveal reflux, and identify rings or strictures
  • Lower sensitivity (77%) compared to double-contrast studies 1
  • If hiatal hernia is large, should be supplemented with upper GI series 1

Clinical Considerations

Type of Hiatal Hernia

• Different imaging approaches may be needed based on suspected hernia type:
  • For sliding hiatal hernias (Type I): Upper GI series or esophagram
  • For paraesophageal hernias (Types II-IV): Double-contrast upper GI series is particularly important 2
  • Distinguishing between sliding and paraesophageal hernias is crucial as surgical approaches differ 1, 2

Diagnostic Accuracy Considerations

• Barium studies are better than endoscopy for differentiating sliding hiatal hernias from paraesophageal hernias 1
• CT scan is the gold standard for diagnosing diaphragmatic hernias (sensitivity 14-82%, specificity 87%) but is not typically the initial test 2
• Chest X-ray has limited sensitivity (2-60% for left-sided hernias) and should not be used as the primary diagnostic tool 2

Potential Pitfalls and Caveats

• Diagnostic discordance: Significant discordance exists between diagnostic modalities; negative results from one test may warrant additional testing 2, 3
• False negatives: Both endoscopy and manometry have high false negative rates (>45%) for hiatal hernia detection 3
• Mobility of the esophagogastric junction: Can make subtle hernias difficult to detect with standard imaging 4
• Size considerations: Small hernias (<2cm) may be missed by standard imaging techniques 4, 3
• Obesity impact: In obese patients, barium X-ray studies have been shown to be superior to endoscopy in diagnosing sliding hiatal hernias 5

Diagnostic Algorithm

1. Initial evaluation: Double-contrast upper GI series
2. If large hernia suspected: Complete upper GI series to fully assess the stomach
3. If results are equivocal or negative but clinical suspicion remains high: Consider additional testing with endoscopy or high-resolution manometry
4. For surgical planning: Biphasic esophagram is recommended by the American College of Surgeons 1

The American College of Radiology Appropriateness Criteria specifically states that fluoroscopy biphasic esophagram, single-contrast esophagram, or upper GI series are all usually appropriate as initial imaging for epigastric pain with clinical suspicion for hiatal hernia 1.