45-year-old man has had headaches, nausea, and vomiting that have worsened over the past 5 days. He has started “seeing spots” before his eyes. On physical examination, his blood pressure is 268/150 mm Hg. Urinalysis shows1+ proteinuria; 2+ hematuria; and no glucose, ketones, or leukocytes. The serum urea nitrogen and creatinine levels are elevated. Which of the following histologic findings is most likely to be seen in this patient’s kidneys?
Segmental tubular necrosis
Mesangial IgA deposition
Answer:C Hyperplastic arteriolosclerosis
This patient has malignant hypertension, which may follow long-standing benign hypertension. Two types of vascular lesions are found in malignant hypertension.
Fibrinoid necrosis of the arterioles may be present; in addition, there
is intimal thickening in interlobular arteries and arterioles, caused by proliferation of smooth muscle cells and collagen deposition.
The proliferating smooth muscle cells are concentrically arranged, and these lesions, called hyperplastic arteriolosclerosis, cause severe narrowing of the lumen. The resultant ischemia elevates the renin level, which further promotes vasoconstriction to potentiate the injury. Nodular glomerulosclerosis is a feature of diabetes mellitus that slowly
progresses over many years.
Segmental tubular necrosis occurs in ischemic forms of acute tubular necrosis. IgA nephropathy involves glomeruli, but not typically the interstitium or vasculature.