What disease state causes Kerley B lines on chest X-ray (Chest Radiograph)?

From the Guidelines

Kerley B lines on chest X-ray are primarily caused by pulmonary edema, most commonly due to congestive heart failure, as evidenced by the 2015 ESC/ERS guidelines 1.

Causes of Kerley B Lines

The primary cause of Kerley B lines is increased hydrostatic pressure in the pulmonary circulation or lymphatic obstruction, leading to fluid accumulation in the interlobular septa. This is often seen in conditions such as:

• Congestive heart failure
• Mitral stenosis
• Lymphangitic carcinomatosis
• Pulmonary fibrosis
• Pulmonary veno-occlusive disease

Clinical Implications

Kerley B lines are valuable early indicators of cardiac decompensation or other interstitial lung processes, as they often appear before more obvious signs of pulmonary edema become visible. The presence of Kerley B lines, along with other clinical features such as symptoms of left heart failure, structural left heart abnormality, and Doppler indices of increased filling pressures, should raise suspicion for pulmonary hypertension due to left heart disease (PH-LHD) 1.

Diagnosis

The diagnosis of the underlying cause of Kerley B lines involves a stepwise approach, combining clinical presentation, specific echocardiographic features, and other modalities such as ECG and other imaging techniques. The 2015 ESC/ERS guidelines provide a comprehensive approach to the diagnosis of PH-LHD, including the use of Kerley B lines as a diagnostic criterion 1.

Key Findings

Key findings that support the diagnosis of Kerley B lines include:

• Thin, horizontal, linear opacities in the peripheral lung fields
• Representation of thickened interlobular septa due to fluid accumulation or lymphatic engorgement
• Typically 1-2 cm in length, extending to the pleural surface, and most visible at the lung bases
• Often appear before more obvious signs of pulmonary edema become visible The 2008 ESC guidelines for the diagnosis and treatment of acute and chronic heart failure also support the use of Kerley B lines as a diagnostic criterion for heart failure, stating that they are indicative of increased lymphatic pressures and are often seen in mitral stenosis or chronic heart failure 1.

From the Research

Disease State Causing Kerley B Lines

Kerley B lines on a chest X-ray are associated with several disease states, including:

• Cardiac insufficiency 2
• Renal insufficiency 2
• Pulmonary congestion 2
• Interstitial lung disease (ILD) 2

Characteristics of Kerley B Lines in Different Disease States

The study found that:

• Kerley B lines in the lung apex were present in 81% of patients with cardiac insufficiency and 76% of patients with renal insufficiency 2
• The lines were distributed more homogenously throughout the lungs in patients with insufficiency compared to those with ILD 2
• The septal lines were thinner in ILD patients compared to those with insufficiency 2

Differentiation Between Disease States

The combination of Kerley B lines, peribronchial cuffing, and increased cardiothoracic ratio can help differentiate between:

• Cardiac/renal insufficiency and pulmonary ILD 2