Home Education AUAUniversity Education Products & Resources Pathology for Urologists Renovascular Diseases Malignant Hypertension

Malignant Hypertension

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  • 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.

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  • 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).
  • Histology:
    • 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.