Renal Pathophysiology Flashcards
Kidney structure
Physiological Function of Kidneys
-endocrine functions
-excretion
-control solutes/fluids
-control BP
-acid/base balance
Glomular Filtration depends on
-GFR
-size of drug
-extent of plasma protein binding (only unbound is unfiltered)
Renal drug excretion
-slide 8 structure
-major route of elimination for 25-30% of drugs
renal anatomy
-Bowman’s capsule
-Proximal Tubule
-Loop of Henle
-Distal Tubule
-Collecting Tubule
-most H20 and solutes reabsorbed
-concentrate waste
Bowman’s capsule
-100% filtrate produced
Proximal Tubule
-80% reabsorbed
-active and passive absorption
-secretion and reabsorption of organic acids and bases (**uric acid and most diuretics)
Loop of Henle
-6% reabsorbed
-H2O (descending) and salt conservation (ascending)
-active reabsorption of Na, K, Cl
-2’ reabsorption of Ca and Mg
Distal tubule
-9% reabsorbed
-variable reabsorption
-active secretion
-parathyroid hormone control
Collecting Tubule
-4% reabsorbed
-variable salt and H20 reabsorption
-water reabsorption under vasopressin
Key physiolofical flow values??
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Anatomical Solute and Water Flux in nephron
Measures of Kidney Function
-Serum Creatinine
-Blood Urea Nitrogen (BUN)
-Creatinine Clearance
-GFR
Serum Creatinine
-mostly removed by filtration
-increase is bad
Blood Urea Nitrogen (BUN)
-measure of waste from liver breakdown of AAs
-increase is bad
Creatinine Clearance
-predicts secretion and drug clearance
Markers of Kidney Damage
-urinary abnormalities (protein, RBC suggestive of membrane malfunctions)
-imaging abnormalities (MRI/CT scans)
Aging Kidney
-decline in kidney mass = decline in function
-prob gotta lower the dose slide 14
Compensatory response to renal injury
- injury
- decrease of nephrons
- compensatory inc in size and function of remaining nephrons
- glomerular/tubular lesions
- Loss of nephrons greater than compensatory capacity
- progressive decrease in GFR
- Azotemia
- Uremic Syndrome
9.Death
Sources of kidney injury/failure
-HTN and Diabetes >60%
-glomerulonephritis
-cystic kidney
-other urologic diseases (stones)
impact of acute kidney failure
-300,000 deaths per year in US (more than breast cancer, prostate. cancer, heart failure, and diabetes combined)
Pathophysiology of Acute Kidney Failure
-inc in SCr 0.3mg/dL or more within 48hours
OR
-50% inc in SCr within the last 7 days
OR
-reduction in urine output
Classification of Major causes of acture kidney injury
-prerenal
-intrinsic
-postrenal
Prerenal causes of AKI
-hypovolemia
-dec cardiac output
-dec circulation
-impaired renal autoregulation (NSAIDs, ACE-I/ARB, cyclosporine)
Intrinsic sources of AKI
-acute glomerulonephritis
-ischemia, sepsis/infection, nephrotoxins in tubules
-vasculitis, HTN, TTP-HUS (vascular)
Postrenal sources of AKI
-bladder outlet obstruction
-bilateral pelvoreteral obstruction
Normal perfusion pressure
-normal glomerular capillary pressure is maintained by afferent vasodilation and efferent vasoconstriction