What is eventration of the diaphragm?

Eventration of the Diaphragm

Eventration of the diaphragm is defined as an abnormal elevation of an intact diaphragmatic leaf that is attenuated and lacks normal muscular fibers while maintaining its normal anatomical attachments to the sternum, ribs, and dorsolumbar spine. This condition differs from a diaphragmatic hernia, which involves an actual defect or discontinuity in the diaphragm.

Etiology and Classification

Eventration can be classified as:

• Congenital: Results from abnormal myoblast migration to the septum transversum during embryonic development 1
• Acquired: Can occur following phrenic nerve injury, trauma, or certain infections

Eventration can be further categorized as:

• Complete or partial
• Unilateral or bilateral (unilateral is more common)
• Left-sided (more common) or right-sided 2, 1

Clinical Presentation

The clinical presentation varies depending on the extent of the eventration and the patient's age:

In Children:

• Respiratory symptoms including cough, respiratory distress, and fever
• Newborns may present with severe respiratory distress
• Recurrent pulmonary infections
• Failure to thrive 2

In Adults:

• Many adults are asymptomatic and diagnosed incidentally on chest radiography
• Dyspnea is the most common symptom
• Other symptoms may include:
  • Orthopnea
  • Mild hypoxemia
  • Tachypnea
  • Respiratory alkalosis
  • Palpitations
  • Non-specific gastrointestinal symptoms 3, 4

Diagnosis

Diagnosis of diaphragmatic eventration relies primarily on imaging studies:

• Chest X-ray: Initial diagnostic tool showing elevated hemidiaphragm
• Fluoroscopy: Demonstrates paradoxical or reduced diaphragmatic movement
• CT scan: Helps differentiate eventration from other conditions
• Ultrasonography: Useful for confirming diagnosis, especially in children
• Contrast studies of upper GI system: May be needed in some cases 2

Management

Treatment approach depends on the presence and severity of symptoms:

• Asymptomatic patients: Conservative management with observation
• Symptomatic patients: Surgical intervention is indicated 1, 4

Surgical Management:

The standard surgical treatment is diaphragmatic plication, which involves folding and suturing the redundant diaphragm to restore normal position and tension. Approaches include:

1. Thoracotomy: Traditional approach
2. Video-assisted thoracoscopic surgery (VATS): Less invasive option with good outcomes
3. Laparotomy: Alternative approach, especially in children
4. Thoracoabdominal approach: Used in complex cases 2, 3

Outcomes and Prognosis

Surgical outcomes are generally favorable:

• Immediate symptomatic improvement in most patients
• Significant improvement in respiratory function parameters (FEV1 and FVC)
• Reduction in dyspnea grade
• Low mortality rate with proper perioperative management 4

Potential Complications

• Respiratory complications
• Recurrence of elevation (rare)
• Mortality risk is higher in neonates with severe respiratory compromise 2, 5

Important Considerations

• Eventration may mimic diaphragmatic hernia clinically and radiologically, requiring careful evaluation 5
• Postoperative ventilatory support may be necessary, especially in neonates
• Follow-up should include assessment of diaphragm position and respiratory function

Differential Diagnosis

• Diaphragmatic hernia (actual defect in the diaphragm)
• Phrenic nerve paralysis
• Subpulmonic effusion
• Subphrenic abscess
• Atelectasis of lower lobe

Eventration of the diaphragm, while rare, can significantly impact respiratory function and quality of life when symptomatic. Surgical plication offers excellent outcomes for symptomatic patients, with significant improvements in respiratory parameters and symptoms.