How is eventration of the diaphragm diagnosed and managed in an otherwise healthy adult presenting with mild dyspnea?

Diaphragmatic Eventration: Diagnosis and Management

In an otherwise healthy adult with mild dyspnea and suspected diaphragmatic eventration, begin with chest X-ray (PA and lateral views) to identify hemidiaphragm elevation, followed by CT chest without contrast to confirm the diagnosis and rule out true diaphragmatic hernia, then proceed to fluoroscopy or dynamic ultrasound to assess for paradoxical motion—if symptomatic despite conservative management, surgical plication is indicated.

Understanding the Condition

Diaphragmatic eventration is a congenital developmental defect where the diaphragm muscle is abnormally thin and elevated but maintains its anatomical continuity and attachments to the costal margins 1, 2. This differs critically from diaphragmatic hernia, where there is an actual defect allowing herniation of abdominal contents into the thorax. Most adults with eventration are asymptomatic, with the condition discovered incidentally on imaging 3.

Diagnostic Approach

Initial Imaging

• Start with chest X-ray (PA and lateral): This is the appropriate first-line study for chronic dyspnea 4. Look specifically for:
  • Unilateral hemidiaphragm elevation (left side more common in 80% of cases)
  • Smooth, continuous diaphragmatic contour (unlike the irregular appearance of hernias)
  • No bowel gas pattern or air-fluid levels in the chest (which would suggest true hernia)

Confirmatory Imaging

• CT chest without IV contrast: This is the gold standard for differentiating eventration from true diaphragmatic hernia 5. CT will show:
  • An intact, thin, elevated hemidiaphragm
  • No diaphragmatic discontinuity or defect
  • Absence of herniated abdominal organs (though organs may be displaced upward by the elevated diaphragm)
  • No "collar sign" or "dependent viscera sign" that characterize true hernias

Critical distinction: In eventration, the diaphragm is intact but abnormally thin and elevated. In hernia, there is an actual defect with herniation of abdominal contents 6.

Functional Assessment

• Fluoroscopy or dynamic ultrasound: These assess diaphragmatic motion 4, 1
  • Eventration: Shows normal or reduced excursion but NO paradoxical motion
  • Paralysis: Shows paradoxical upward motion during inspiration
  • This distinction is important because both conditions may appear similar on static imaging but have different pathophysiology

Management Algorithm

For Asymptomatic Patients

• No intervention required 2, 3
• Routine follow-up with chest X-ray if clinically indicated
• Reassurance that this is typically a benign condition

For Symptomatic Patients (Dyspnea, Orthopnea, Exercise Intolerance)

Surgery is indicated only when symptoms are present 1, 2, 3

Surgical Approach: Diaphragmatic Plication

Preferred technique: Video-assisted thoracoscopic surgery (VATS) plication 1, 7, 3

• 3-port thoracoscopic approach
• Use horizontal or vertical mattress sutures to plicate the redundant diaphragm
• Pull the diaphragm down to the level of the cardiac base
• Reinforce by suturing to the chest wall

Goals of plication:

• Reduce paradoxical cephalad movement during inspiration
• Improve lung volumes and ventilation
• Decrease compression of lung parenchyma
• Alleviate dyspnea and improve exercise tolerance

Outcomes: Plication is safe with excellent symptomatic improvement in properly selected patients 1, 2

Common Pitfalls to Avoid

1. Misdiagnosing as traumatic diaphragmatic rupture: Eventration maintains diaphragmatic continuity; rupture does not. CT is essential to differentiate 6

2. Operating on asymptomatic patients: Surgery is indicated ONLY for symptomatic patients. Many adults live their entire lives with asymptomatic eventration 3

3. Confusing eventration with paralysis: Use fluoroscopy or dynamic ultrasound to assess motion. Eventration shows no paradoxical motion; paralysis does 1

4. Missing associated gastrointestinal pathology: Rarely, eventration coexists with conditions like megacolon. If gastrointestinal symptoms are prominent, consider additional abdominal workup 8

5. Assuming cardiac pathology: Severe eventration can cause transient cardiac dextroposition, especially postprandially. This is reversible and related to mass effect, not primary cardiac disease 9

Key Differences from Diaphragmatic Hernia

Unlike the complicated diaphragmatic hernias described in the WSES guidelines [5-5], eventration:

• Has NO diaphragmatic defect or discontinuity
• Does NOT involve herniation of abdominal organs through a defect
• Is NOT a surgical emergency
• Does NOT require mesh repair
• Has a much more benign natural history

The WSES guidelines focus on acute, complicated hernias requiring emergency intervention, which is a completely different clinical scenario from the typically benign, chronic presentation of eventration in adults.