What is right diaphragmatic eventration?

Right Diaphragmatic Eventration

Right diaphragmatic eventration is a condition characterized by abnormal elevation of the right hemidiaphragm due to thinning or weakness of the diaphragmatic muscle, maintaining its normal attachments and anatomical continuity, which can lead to respiratory compromise and gastrointestinal symptoms if severe. 1, 2

Definition and Pathophysiology

• Eventration is a developmental defect of the muscular portion of the diaphragm where the diaphragm appears attenuated and membranous
• It differs from a diaphragmatic hernia as there is no actual defect or discontinuity in the diaphragm
• The abnormally elevated diaphragm may compress the ipsilateral lung and cause mediastinal shift toward the normal side 3
• Can be congenital (due to abnormal myoblast migration to the septum transversum) or acquired (from phrenic nerve injury, trauma, or infection) 4

Epidemiology

• More common in males
• Left-sided eventration is generally more common than right-sided (81.5% left-sided in one study) 5
• Right-sided eventration is less common but may be more frequently misdiagnosed due to liver obscuration 2
• Can be partial or complete, unilateral or bilateral 4

Clinical Presentation

• Many adults are asymptomatic, with diagnosis made incidentally on chest radiography
• When symptomatic, common presentations include:
  • Dyspnea (most common symptom in adults)
  • Orthopnea
  • Recurrent respiratory infections
  • Mild hypoxemia
  • Tachypnea
  • Respiratory alkalosis
  • Palpitations
  • Non-specific gastrointestinal symptoms
  • Failure to thrive (in children) 4, 3, 6

Diagnosis

• Chest X-ray: Shows elevated right hemidiaphragm (sensitivity is lower for right-sided eventration at 17-33% compared to left-sided at 2-60%) 1, 2
• Fluoroscopy/Sniff test: Essential for diagnosis, shows paradoxical or decreased movement of the affected hemidiaphragm during respiration 2, 3
• CT scan: Gold standard for confirming diagnosis and ruling out other pathologies like diaphragmatic hernia 1
• Differential diagnosis includes:
  • Diaphragmatic hernia
  • Subpulmonic effusion
  • Subphrenic abscess
  • Atelectasis of lower lobe
  • Phrenic nerve palsy 2

Management

Conservative Management

• Asymptomatic patients generally require no intervention
• Respiratory therapy and pulmonary rehabilitation for mild symptoms 2

Surgical Management

• Surgery is indicated only in symptomatic patients 4
• Diaphragmatic plication is the established surgical treatment:
  • Restores normal pulmonary volume by replacing the diaphragm in its normal position
  • Can be performed via thoracotomy or minimally invasive approaches (VATS or laparoscopic) 4, 7

Surgical Approaches

• Video-assisted thoracoscopic surgery (VATS): 3-port approach is effective with reduced postoperative pain and faster recovery 4, 7
• Thoracotomy: Traditional approach, may be necessary for complex cases
• Laparoscopic plication: Alternative minimally invasive approach 7

Outcomes and Prognosis

• Most patients show immediate improvement in symptoms after plication
• Studies show significant improvement in dyspnea scores, FEV1, and FVC values after surgical correction 5
• Postoperative fluoroscopy typically shows the diaphragm in normal position with no paradoxical movement 3
• Potential complications include:
  • Pneumothorax
  • Diaphragm rupture
  • Recurrence of eventration (rare) 7

Important Considerations

• Right-sided eventration is more commonly missed or misdiagnosed due to liver obscuration 2
• Untreated symptomatic eventration can lead to recurrent respiratory infections and progressive respiratory compromise 6
• Prompt diagnosis and appropriate surgical intervention in symptomatic cases is crucial for optimal outcomes 6