A 67-year-old man comes to the office due to generalized weakness, easy fatigability, anorexia, and intermittent nausea for the past several months. He also says that he is "itching and scratching a lot." Physical examination shows bilateral lower extremity pitting edema and skin excoriations. Laboratory results show a serum creatinine level of 3.4 mg/dL and a blood urea nitrogen level of 48 mg/dL. A renal biopsy is performed. Light microscopy of the tissue sample shows widespread narrowing of the renal arterioles with deposition of homogeneous, glassy material in the vessel walls that stains pink with periodic acid-Schiff (PAS) stain. This patient most likely has which of the following underlying conditions?

Question

A 67-year-old man comes to the office due to generalized weakness, easy fatigability, anorexia, and intermittent nausea for the past several months.  He also says that he is "itching and scratching a lot."  Physical examination shows bilateral lower extremity pitting edema and skin excoriations.  Laboratory results show a serum creatinine level of 3.4 mg/dL and a blood urea nitrogen level of 48 mg/dL.  A renal biopsy is performed.  Light microscopy of the tissue sample shows widespread narrowing of the renal arterioles with deposition of homogeneous, glassy material in the vessel walls that stains pink with periodic acid-Schiff (PAS) stain.  This patient most likely has which of the following underlying conditions?

Quizplus · Accepted Answer

This patient's symptoms (eg, fatigue, weakness, itching) are most likely due to accumulation of uremia toxins secondary to progressive chronic kidney disease. His renal biopsy shows deposition of eosinophilic hyaline material in the intima and media of small arteries and arterioles, which is characteristic of hyaline arteriolosclerosis. It is typically seen in patients with untreated or poorly controlled hypertension (HTN) or diabetes mellitus. Chronic/repetitive endothelial injury caused by hemodynamic stress or hyperglycemia causes leakage of plasma constituents across the vascular endothelium and stimulates smooth muscle cell (SMC) proliferation and excessive extracellular matrix production. (Choice A) Atheroembolic renal disease typically occurs after manipulation of the aorta (eg, abdominal aortic aneurysm repair) in adults with widespread atherosclerosis. Atheroemboli with cholesterol clefts would be seen within the arterial lumen. (Choice C) Malignant hypertension (extreme or rapidly developing hypertension) causes fibrinoid necrosis and hyperplastic arteriolosclerosis. Fibrinoid necrosis is characterized by localized destruction of the vascular wall with a circumferential ring of pink, amorphous material surrounding the lumen. Hyperplastic arteriolosclerosis consists of onion-like, concentric thickening of the walls of arterioles due to laminated layers of SMCs with intervening basement membrane reduplication (onion skinning). This patient's lack of concentric SMC thickening and absence of vascular necrosis are more suggestive of hyaline arteriolosclerosis. (Choice D) Nephropathy in multiple myeloma is most often due to excess excretion of free light chains (Bence Jones proteins) that precipitate with Tamm-Horsfall protein to form obstructing tubular casts (cast nephropathy). These casts are seen as amorphous hyaline material in the tubular lumen. (Choice E) Rapidly progressive glomerulonephritis (RPGN) is characterized by the formation of glomerular crescents composed of proliferating parietal cells, lymphocytes, macrophages, and fibrin. RPGN may occur in the absence of a systemic vasculitic syndrome; therefore, renal arteriolar lesions are not a defining feature. Educational objective: Homogeneous deposition of eosinophilic hyaline material in the intima and media of small arteries and arterioles characterizes hyaline arteriolosclerosis. This is typically produced by untreated or poorly controlled hypertension and/or diabetes.

A 67-Year-Old Man Comes to the Office Due to Generalized