Uncommon occurs in 1-5% of hypertensive patients: can develop in previously healthy patients but is more often superimposed on preexisting benign hypertension or chronic renal disease.
Usually affects young males and in African Americans.
Initial insult suggested being vascular damage in kidney, leading to fibrinoid necrosis of small vessels and hyperplastic arteriolosclerosis, renal ischemia, renin-angiotensin system stimulated (markedly elevated renin).
Etiology is variable, but clinical course is severe and if left untreated has a rapidly downhill progression.
Full blown syndrome characterized by diastolic hypertension >130 mmHg, papilledema retinopathy, encephalopathy, cardiovascular abnormality, and renal failure.
Image C (click on the image above)
Image D (click on the image above)
May have "hypertensive crises" such as loss of consciousness or convulsion.
Gross: dependent on duration and severity of hypertensive disease; small petechial hemorrhages on the cortical surface give a "flea-bitten" appearance to the kidneys (image A).
Interlobular arteries and arterioles demonstrate densely eosinophilic material representing fibrinoid necrosis of the vessel walls (image B).
Intimal thickening or "onion-skin" appearance of the vessels (hyperplastic arteriolitis) (image C) & (image D).
Microthrombi may be present.
With anti-hypertensive drugs, 75% of patients survive in 5 years; fatal without treatment with 90% mortality within a year.