Under normal physiological conditions, these septa are too thin to be visualized on a standard chest X-ray. However, when pathological processes cause these septa to thicken—due to fluid accumulation, cellular infiltration, or fibrosis—they become radiopaque.
Kerley lines represent a critical radiographic finding in the evaluation of cardiopulmonary disease. Originally described by Peter James Kerley in 1933, these distinct linear opacities visible on chest radiographs signify the thickening of the interlobular septa within the lung. While most commonly associated with pulmonary edema resulting from left heart failure, their presence can also indicate malignant pathologies such as lymphangitis carcinomatosa. This paper delineates the classification of Kerley lines (A, B, and C), explores the underlying pathophysiology, and discusses their diagnostic relevance in modern medicine.
The chest radiograph remains a cornerstone diagnostic tool in the assessment of respiratory and cardiac distress. Among the various signs utilized to diagnose pulmonary pathology, Kerley lines are a specific indicator of interlobular septal thickening. These lines are not primary disease entities but rather a radiographic symptom of underlying physiological disruptions, primarily involving the pulmonary lymphatic system and interstitial fluid dynamics. Understanding the distinction between the three types of Kerley lines (A, B, and C) is essential for clinicians in differentiating between cardiogenic pulmonary edema, viral pneumonia, and neoplastic infiltration. kerley lines
: In heart failure, Kerley B lines appear when pulmonary capillary wedge pressure rises above 20–25 mmHg, reflecting chronic or subacute interstitial edema.
However, the diagnostic paradigm has shifted with the widespread use of and Lung Ultrasound . Under normal physiological conditions, these septa are too
Kerley lines serve as a vital window into the interstitial health of the lung. Whether caused by the hydrostatic pressure of heart failure or the infiltrative burden of malignancy, these lines signal a disruption in the delicate balance of pulmonary fluid dynamics. While medical technology has evolved, the ability to recognize Kerley A, B, and C lines on a standard chest radiograph remains a fundamental skill for physicians, enabling prompt diagnosis and management of potentially life-threatening cardiopulmonary conditions.
Kerley lines are a manifestation of interstitial lung disease, which can result from various conditions, such as: Originally described by Peter James Kerley in 1933,
Kerley lines can be detected on:
When interpreting Kerley lines, consider the following differential diagnoses: