Kerley B lines are due to-
Carcinoma bronchus
Pulmonary edema
Lung abscess
Pulmonary embolism
In pulmonary oedema,chest X ray shows increased vascularity of the lung fields,and the right and left pulmonary aeries dilate.Subsequently,interstitial oedema causes thickened interlobular septa and dilated lymphatics.These are evident as horizontal lines in the costophrenic angles(septal or Kerley B lines). Reference:Davidson's medicine-22nd edition,page no:550.
Respiratory system