What are the differential diagnoses for B lines (B-lines) on lung ultrasound?

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Last updated: February 27, 2025View editorial policy

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B Lines Differential Diagnosis

B lines are a type of artifact seen on lung ultrasound, characterized by hyperechoic, vertical lines that extend from the pleural line to the edge of the screen. They are indicative of lung interstitial syndrome, which can be caused by various conditions. Here is a differential diagnosis for B lines:

  • Single Most Likely Diagnosis

    • Pulmonary edema: This is the most common cause of B lines, resulting from fluid accumulation in the lungs due to heart failure, high altitude, or other conditions.
  • Other Likely Diagnoses

    • Pneumonia: Interstitial pneumonia can cause B lines due to inflammation and fluid accumulation in the lung interstitium.
    • Acute Respiratory Distress Syndrome (ARDS): A life-threatening condition characterized by inflammation and fluid buildup in the lungs, often causing B lines on ultrasound.
    • Interstitial lung disease: Conditions such as pulmonary fibrosis can lead to B lines due to scarring and inflammation in the lung tissue.
  • Do Not Miss Diagnoses

    • Pulmonary embolism: Although less common, pulmonary embolism can cause B lines, especially if there is associated pulmonary infarction or edema.
    • Tension pneumothorax: A life-threatening condition that can cause B lines due to lung compression and fluid shift.
  • Rare Diagnoses

    • Lymphangitic carcinomatosis: A rare condition characterized by cancer spread to the lymphatic vessels in the lungs, which can cause B lines.
    • Sarcoidosis: A condition that causes inflammation and scarring in various organs, including the lungs, which can lead to B lines in some cases.
    • Eosinophilic pneumonia: A rare condition characterized by eosinophilic infiltration of the lungs, which can cause B lines due to inflammation and fluid accumulation.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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