Q: 46 year old female with no history of tobacco smoking presented to ER with shortness of breath, fever and hypoxia requiring BiPAP mask. CXR showed right sided pleural effusion. Patient is admitted to ICU. You performed bedside ultrasound. Which features may alert you that this may be a malignant pleural effusion?

Answer: Ultrasound of pleural effusion can have a specificity of 100% at diagnosing malignant pleural effusions, if following features can be identified.

• visible pleural metastases
• pleural thickening greater than 1 cm
• pleural nodularity
• diaphragmatic thickening measuring greater than 7mm and 
• an echogenic swirling pattern visible in the pleural fluid

References:

1. Qureshi NR, Rahman NM, Gleeson FV (February 2009). "Thoracic ultrasound in the diagnosis of malignant pleural effusion". Thorax 64 (2): 139–43.

2. Chian CF, Su WL, Soh LH, Yan HC, Perng WC, Wu CP (July 2004). "Echogenic swirling pattern as a predictor of malignant pleural effusions in patients with malignancies". Chest 126 (1): 129–34