Kidney nontumor
Blood vessel disorders
Malignant hypertension and accelerated nephrosclerosis

Author: Nikhil Sangle, M.D. (see Authors page)

Revised: 23 March 2018, last major update December 2012

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Malignant hypertension and accelerated nephrosclerosis

Cite this page: Sangle, N. Malignant hypertension and accelerated nephrosclerosis. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/kidneymalignanthyper.html. Accessed August 18th, 2018.
Definition / general
  • Also called hypertensive emergency, malignant nephrosclerosis
  • Severe hypertension with acute impairment of one or more organ systems (especially CNS, cardiovascular, renal) that may cause irreversible organ damage
Pathophysiology
  • Vascular damage (due to chronic hypertension, arteritis, coagulopathy) increases permeability of small vessels to fibrinogen and other plasma proteins
  • This causes endothelial injury and platelet deposition, which causes fibrinoid necrosis
  • Kidneys become ischemic, which stimulates renin-angiotensin system to produce angiotensin II, which causes renal vasoconstriction, as well as increased aldosterone secretion and salt retention, which elevate blood pressure even further
  • May be related to increased TRPC3 expression in vascular endothelium (Dtsch Med Wochenschr 2009;134:2224)
Clinical features
  • Usually associated with pre-existing hypertension, glomerulonephritis or reflux nephropathy
  • Rarely caused by juxtaglomerular cell tumor (J Med Assoc Thai 2012;95 Suppl 2:S251, J Hypertens 2012;30:974)
  • 1 - 5% of patients with hypertension; higher frequency in young men, African-Americans
  • Symptoms: diastolic blood pressure 130 mm or more, cardiac symptoms, encephalopathy, headache, nausea, vomiting, loss of consciousness, proteinuria and renal failure
  • Treatment: antihypertensive therapy before irreversible renal lesions develop
  • Renal survival has improved; mean proteinuria is important prognostic factor (Nephrol Dial Transplant 2010;25:3266)
Gross description
  • "Flea bitten" appearance of kidney due to pinpoint petechiae on cortical surface
Gross images

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Various images

Microscopic (histologic) description
  • Fibrinoid necrosis of arterioles, hyperplastic arteriolitis (onion skinning) due to concentric layering of collagen
  • May see necrotizing glomerulitis, wrinkling and collapse of capillary walls and small crescents
  • Myointimal hyperplasia and hypertropy is associated with acute or persistent severe high blood pressure
  • Necrotizing arteriolitis: fibrinoid necrosis of afferent arteriole, often superimposed on hyperplastic or hyaline lesions; media has deposits of deeply eosinophilic and fibrillar material containing fibrin and fibrinogen
  • Early changes: profound intimal thickening by myxoid connective tissue, reducing lumen
  • Late changes: scarring and concentric thickening of vessel wall by myointimal cells and deposition of basement membrane type material (onion skinning)
Microscopic (histologic) images

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Various images

Immunofluorescence
  • Occasional fibrin, fibrinogen, IgM and complement
Electron microscopy description
  • Swollen endothelium
  • May be focally disrupted from glomerular basement membrane by accumulation of electron-dense material