mediastinal shift
Displacement of mediastinal structures away from midline, indicating volume changes in thoracic cavity.
Full Definition
Mediastinal shift refers to the displacement of the mediastinum (central compartment of the thoracic cavity containing the heart, great vessels, trachea, and esophagus) away from its normal midline position. In thoracic oncology, mediastinal shift can occur due to various causes including large pleural effusions, pneumothorax, pulmonary collapse, or space-occupying lesions. The direction of shift provides important diagnostic information: shift away from a lesion suggests volume loss (atelectasis), while shift toward a lesion may indicate volume gain (effusion, pneumothorax). Significant mediastinal shift can cause cardiovascular compromise and requires urgent intervention.
Usage
Usage note: Direction of shift provides diagnostic clues about underlying pathology; specify direction in reports.
In Context
- "Chest radiograph demonstrated mediastinal shift to the right consistent with left-sided volume loss." — Radiology report
- "The large pleural effusion caused significant mediastinal shift requiring urgent thoracentesis." — Emergency department note