Pulmonary interstitial edema

Last revised by Daniel J Bell on 16 Nov 2020

Pulmonary interstitial edema represents a form of pulmonary edema resulting from pathological fluid buildup in the interstitial spaces due to increased hydrostatic driving pressure.


Interstitial lung edema arises almost exclusively due to an increase of the pulmonary capillary hydrostatic pressure (Pcap), which occurs most commonly in left sided heart failure, hence it is a key element of cardiogenic lung edema. The increased Pcap leads to an excess filtrate filling the bronchovascular interstitium (causing the imaging appearance of peribronchial cuffing and septal thickening), and lymphatic distension (manifesting as the eponymous Kerley B lines on plain film). Interstitial edema can quickly progress into an alveolar pattern, where the alveolar spaces became flooded too 1

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Cases and figures

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