Age Associated Changes In Renal Function

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Contents 1 Introduction 2 More General Terms 3 Additional Terms 4 References

Introduction

• Renal function declines with age (variable)
• decreased kidney mass & volume

• decreased synthesis of calcitriol

• increased thickness of glomerular basement membrane
• loss of renal glomeruli

• hyaliniization & collapse of glomerular tufts occurs in renal cortex
• increased number of sclerotic glomeruli occurs in juxtaglomerular region

• sclerosis of pre- & postglomerular arterioles

• decreased number & length of tubules

• diminished tubular secretion & reabsorption parallels decline in glomerular filtration rate [12]

• decreased renal blood flow & glomerular filtration rate

• cortical blood flow decreases
• medullary blood flow is maintained [12]
• 1/3 of elderly show no decrease in GFR [12]
• decreased NO production
• increased dependence on prostaglandins to maintain perfusion

• diverticula appear in the distal nephron

• may become retention cysts, common in elderly
• significant unknowm

• decreased creatinine clearance

• decreased serum creatinine (if renal function is unchanged)

• decreased maximum urine osmolality
• decreased responsiveness to volume depletion
• Na+ homeostasis

• decreased basal & stress-induced renin & aldosterone
• blunted response to Na+ restriction
• increase in basal & stimulated ANP levels
• decreased renal response to ANP ( cGMP)
• decreased distal tubular Na+ reabsorption

• susceptibility to hyponatremia

• K+ homeostasis

• decrease in total body K+
• increased frequency of hyporeninemic hypoaldosteronism
• increased use of pharmaceuticals that impair K+ excretion
• increased risk of hyperkalemia [12]

• impaired secretion of H+

• susceptibility to metabolic acidosis

• water regulation

• increased basal & osmolality-stimulated vasopressin
• diminished renal response to vasopressin

• normal renal tubule response to vasopressin [12]

• maximum urine concentration decreases [12]
• diminished thirst to hyperosmolality

More General Terms

• age-related physiological changes

Additional Terms

• kidney
• kidney disease; renal disease
• renal disorders in the elderly
• renal function; kidney function

References

1. Essentials of Clinical Geriatrics, 4th ed, Kane RL et al (eds) McGraw Hill, NY, 1999
2. UCLA Intensive Course in Geriatric Medicine & Board Review, Marina Del Ray, CA, Sept 29-Oct 2, 2004
3. The Merck Manual of Geriatrics, 3rdh ed, Merck & Co, Rahway NJ, 2000
4. Taffet GE, Physiology of Aging, In: Geriatric Medicine: An Evidence-Based Approach, 4th ed, Cassel CK et al (eds), Springer-Verlag, New York, 2003
5. Geriatric Review Syllabus, 7th edition Parada JT et al (eds) American Geriatrics Society, 2010

age-associated changes in renal function