A 70-year-old man is brought to the hospital by his son for evaluation of worsening fatigue. The patient has not seen a physician in the past 15 years. He takes naproxen occasionally for knee arthritis. Physical examination of the prostate shows no abnormalities. Laboratory results are as follows: Urine sediment is unremarkable. Ultrasound examination shows bilateral small kidneys and no hydronephrosis. Kidney biopsy shows intimal thickening and luminal narrowing of the renal arterioles with evidence of glomerular sclerosis. Which of the following is most likely responsible for this patient's kidney disease?

Question

A 70-year-old man is brought to the hospital by his son for evaluation of worsening fatigue.  The patient has not seen a physician in the past 15 years.  He takes naproxen occasionally for knee arthritis.  Physical examination of the prostate shows no abnormalities.  Laboratory results are as follows:  Urine sediment is unremarkable.  Ultrasound examination shows bilateral small kidneys and no hydronephrosis.  Kidney biopsy shows intimal thickening and luminal narrowing of the renal arterioles with evidence of glomerular sclerosis.  Which of the following is most likely responsible for this patient's kidney disease?

Quizplus · Accepted Answer

This patient's biopsy findings are consistent with hypertensive nephrosclerosis (HN), a complication of chronic hypertension that is most common in elderly patients. Prolonged elevation of systemic blood pressure causes the renal arterioles to undergo compensatory medial hypertrophy and fibrointimal proliferation. Endothelial damage leads to deposition of plasma proteins and basement membrane material in the arteriolar walls (hyaline arteriolosclerosis). The resultant lumenal narrowing restricts renal blood flow, resulting in glomerular ischemia and fibrosis (glomerulosclerosis) with collapse of the capillary loops and thickening of the Bowman capsule. Gross examination of affected kidneys shows mild renal atrophy with a finely granular surface. HN generally progresses slowly, and most patients with mild to moderate disease do not develop renal insufficiency. However, advanced disease occurs more commonly in patients of African American descent and in those with severe hypertension or comorbid diabetes. Proteinuria is common in advanced disease, but urinalysis is otherwise typically bland (eg, no casts, red or white blood cells). Like all chronic kidney diseases, advanced HN can cause anemia due to a reduction in renal erythropoietin production. (Choice A) Analgesic nephropathy can occur with prolonged, excessive nonsteroidal anti-inflammatory use. However, pathologic findings typically include papillary necrosis and tubulointerstitial nephritis. (Choice B) Fibromuscular dysplasia causes renal artery stenosis, resulting in refractory hypertension. However, it typically occurs in younger women (age <50), and histology characteristically shows fibromuscular ridges alternating with areas of aneurysmal dilation affecting the main renal artery. (Choice C) Hepatitis C infection can cause membranous nephropathy, which presents with nephrotic syndrome (eg, proteinuria, edema). Histology demonstrates diffuse thickening of the glomerular basement membrane without glomerular hypercellularity. (Choice E) Multiple myeloma can cause anemia and renal disease, but histology typically demonstrates a light chain cast nephropathy; eosinophilic casts obstruct the renal tubules, resulting in tubular inflammation and fibrosis. Patients typically also have fatigue, constipation (hypercalcemia), and bone pain (lytic lesions). Educational objective: Chronic hypertension can result in hypertensive nephrosclerosis, which is characterized by compensatory medial hypertrophy and fibrointimal proliferation; endothelial damage from elevated systemic pressure also leads to hyaline arteriolosclerosis. The narrowed arteriolar lumens cause a progressive decrease in renal blood flow, resulting in glomerular ischemia and fibrosis (glomerulosclerosis).

A 70-Year-Old Man Is Brought to the Hospital by His