Tuesday, November 18, 2008

Hypertensive Emergency: end organ damage


1. End organ damage:
eyes
: retinal hemmorhages, exudates, and papilledema (see picture below for details)
brain: cerebral edema, ischemia, hemmorhage, seizure, altered mental status
heart: angina, flash pulmonary edema from LV failure
kidney: proteinurea, hematurea
blood and vessels: aortic dissection, hemolytic anemia

2. Mechanism of action:
Normally our arterioles will constrict with increasing blood pressure in order to protect the fragile capillary beds beyond. This autoregulatory process fails with blood pressures well above normal (usually >180 -190 systolic, 110 diastolic), and the resulting high pressure damages distal blood vessels/capillaries. High pressures damage the endothelial wall, causing localized edema - which may obliterate perfusion to that region. This mechanisms accounts for many items on our "end organ damage" list seen above.

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