UMEM Educational Pearls

Title: Non-Cardiogenic Pulmonary Edema

Posted: 9/11/2012 by Haney Mallemat, MD
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Question

40 year-old male with severe uncontrolled hypertension presents with altered mental status (head CT below). The CXR is from the same patient. What's the connection?

Answer

Answer: Neurogenic pulmonary edema (NPE)

NPE is defined as acute pulmonary edema following central nervous system (CNS) insult; NPE has been recognized for over 100 years, but its incidence is underreported due to a lack objective clinical criteria.

The pathophysiology of NPE is poorly understood but it is generally believed that both cardiogenic and non-cardiogenic pulmonary edema play a role. CXR (see above) demonstrates a pattern similar to acute respiratory distress syndrome (i.e., bilateral interstitial infiltrates).

CNS insults that are abrupt, rapidly progressive, and increase intracranial pressure (e.g., subarachnoid hemorrhage, intraparenchymal hemorrhage, traumatic brain injury, subdural, etc.) have the highest risk for NPE. Neural injury leads to sympathetic activation, the release of catecholamines, and one or all of the following:

Direct myocardial injury and cardiac dysfunction
Increased systemic afterload causing left ventricular dysfunction
Increased pulmonary vascular permeability and leak

Treatment of NPE includes:

Reversing and treating the underlying disorder
Supplemental oxygen with positive pressure ventilation as necessary
Low-tidal volume ventilation (if mechanically ventilated) with appropriate PEEP
Cautious use of diuretics, as adequate intravascular volume is needed for cerebral perfusion
Specific pharmacologic measures (eg. alpha blockers) have been studied but their efficacy is unclear and are not recommended as symptoms typically resolve within 72 hours

References

Davidson, D. et al. Neurogenic pulmonary edema. Crit Care. 2012 Mar 20;16(2):212.

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