A 62-year-old woman comes to the office for medical evaluation. The patient states her 26-year-old son has developed renal failure from chronic glomerulonephritis and is undergoing dialysis therapy. She has the same blood group as her son and she wants to donate one of her kidneys to him. The patient has no chronic medical conditions and takes no medications. Vital signs are within normal limits, and physical examination shows no abnormalities. The patient understands that she may not be a compatible donor based on human leukocyte antigen (HLA) testing. In addition, which of the following age-related renal changes should be taken into consideration when assessing donor suitability?

Question

A 62-year-old woman comes to the office for medical evaluation.  The patient states her 26-year-old son has developed renal failure from chronic glomerulonephritis and is undergoing dialysis therapy.  She has the same blood group as her son and she wants to donate one of her kidneys to him.  The patient has no chronic medical conditions and takes no medications.  Vital signs are within normal limits, and physical examination shows no abnormalities.  The patient understands that she may not be a compatible donor based on human leukocyte antigen (HLA) testing.  In addition, which of the following age-related renal changes should be taken into consideration when assessing donor suitability?

Quizplus · Accepted Answer

Normal aging results in multiple physiologic and structural alterations that lead to a slow decline in renal function, even in the absence of renal disease. These alterations typically begin around age 30, with a more marked decline occurs in those >50 years, resulting in the predisposition of elderly patients to develop acute kidney injury or chronic kidney disease. These alterations include: Reduced renal mass and functional glomeruli: There is a 50% reduction in functional glomeruli by age 75 associated with a reduction in renal mass due to atrophy and fibrotic replacement. This results in reduced glomerular filtration rate and creatinine clearance, as well as a reduced ability to concentrate urine, which may predispose patients to hypovolemia during periods of stress (Choice C). Reduced renal blood flow (RBF): Loss of renal microvasculature results in a reduction in renal blood flow with age, increasing the susceptibility to ischemic injury (Choice D). Furthermore, RBF becomes more dependent upon prostaglandins to maintain adequate blood flow, leading to increased susceptibility to renal injury with nonsteroidal anti-inflammatory drugs (due to reduced prostaglandin formation). Reduced hormonal responsiveness: There is reduced secretion of renin (blunts the renin-angiotensin-aldosterone system response) and reduced hydroxylation of vitamin D in response to parathyroid hormone (Choice E). However, unlike chronic renal disease, the production of erythropoietin in response to anemia or hypoxemia is unchanged. Older kidneys also have a higher proportion of cells that undergo apoptosis after a given insult (eg, ischemia) and are less capable of regeneration. (Choice B) The ability to excrete solutes is relatively preserved in the aging kidney. Educational objective: Normal aging results in multiple physiologic and structural alterations that lead to a slow decline in renal function. These include reductions in renal mass and functional glomeruli (ie, reduced glomerular filtration rate and creatinine clearance), decreased renal blood flow, and limited hormonal responsiveness (eg, renin, parathyroid hormone).

A 62-Year-Old Woman Comes to the Office for Medical Evaluation