How should I evaluate and manage a slight elevation of the right hemidiaphragm on imaging in an adult patient with no prior diaphragmatic disease?

Evaluation and Management of Slight Right Hemidiaphragm Elevation

For an adult with incidental slight elevation of the right hemidiaphragm, obtain a chest X-ray (both PA and lateral views) to characterize the elevation, followed by fluoroscopic sniff test to differentiate paralysis from eventration, and proceed to contrast-enhanced CT of chest and abdomen if diaphragmatic hernia is suspected based on clinical context or imaging findings.

Initial Diagnostic Workup

Chest Radiography Assessment

• Obtain both PA and lateral chest radiographs as the first-line diagnostic study to characterize the diaphragmatic elevation and assess for associated findings 1.
• Evaluate the shape and contour of the elevated hemidiaphragm on lateral view, as the radius of curvature is the most important factor for detecting paralysis versus eventration 2.
• A ratio of hemidiaphragm height to anteroposterior chest diameter (HH/APD) >0.28 on lateral radiograph suggests against paralysis 2.
• Look for suspicious findings including abnormal bowel gas pattern, air-fluid levels, abnormal lucency, or soft tissue opacity that might indicate diaphragmatic hernia 1.

Fluoroscopic Sniff Test

• Perform fluoroscopic evaluation to differentiate paralysis (paradoxical upward motion during inspiration) from eventration (no paradoxical motion) 3, 4.
• This distinction is critical because both conditions present with elevation but have different underlying pathophysiology 5, 2.

Advanced Imaging When Indicated

• Proceed to contrast-enhanced CT scan of chest and abdomen if diaphragmatic hernia is suspected based on clinical symptoms (dyspnea, abdominal pain, GI symptoms) or concerning radiographic findings 1, 6.
• CT has 14-82% sensitivity and 87% specificity for diaphragmatic hernia and can identify diaphragmatic discontinuity, herniated organs, defect size, and complications 1, 6.
• Key CT findings to assess include: diaphragmatic discontinuity, "dangling diaphragm" sign, herniated abdominal contents, and signs of visceral obstruction or ischemia 1, 7.

Clinical Context Assessment

History and Symptoms

• Inquire specifically about dyspnea (particularly on exertion), orthopnea, rapid shallow breathing, and paradoxical inward abdominal motion during inspiration as these suggest diaphragmatic weakness or paralysis 5.
• Ask about GI symptoms (nausea, vomiting, abdominal pain, dysphagia) that may indicate diaphragmatic hernia with visceral herniation 1.
• Obtain history of trauma (even remote), prior thoracic or cardiac surgery, mediastinal irradiation, or conditions affecting the phrenic nerve 1, 5.

Physical Examination

• Observe for paradoxical inward motion of the abdomen during inspiration, which indicates diaphragmatic paralysis 5.
• Assess for signs of respiratory compromise including tachypnea and use of accessory muscles 3, 4.

Management Algorithm

For Asymptomatic Patients

• If fluoroscopy confirms eventration or paralysis without symptoms, conservative management with observation is appropriate 3, 4.
• Schedule follow-up imaging in 6-12 months to ensure stability 3.

For Symptomatic Patients

• Diaphragmatic plication is indicated for all symptomatic patients with confirmed elevation (either paralysis or eventration) regardless of etiology 3, 4.
• Symptoms warranting surgical intervention include: dyspnea on exertion, orthopnea, recurrent pneumonia, tachypnea, or failure to thrive 3, 4.
• Minimally invasive thoracoscopic plication is the preferred approach, with goals of improving lung volumes and decreasing paradoxical elevation 3.
• Plication has excellent outcomes with immediate symptom remission in most patients and sustained improvement during follow-up 4.

For Suspected Diaphragmatic Hernia

• If CT confirms diaphragmatic hernia, surgical repair is generally indicated to prevent progression to visceral obstruction, strangulation, or ischemia 1.
• The timing and approach depend on clinical stability and presence of complications 1.

Common Pitfalls to Avoid

• Do not assume chest X-ray alone is adequate—while it can suggest paralysis versus eventration based on diaphragm shape, fluoroscopy provides definitive functional assessment 2.
• Do not dismiss mild elevation as benign without functional assessment, as up to 62% of diaphragmatic injuries may have normal or near-normal initial chest radiographs 1.
• Do not delay CT imaging if clinical suspicion for hernia is high, even with normal chest X-ray, as 25% of cases can be misinterpreted on plain films 1.
• Right-sided elevation is more commonly due to eventration or paralysis than left-sided, but diaphragmatic hernia must still be excluded as right-sided hernias are more difficult to diagnose (sensitivity only 17-33% on chest X-ray) 1.