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44 Cards in this Set
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- Back
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What are the definitions of the following: neprhitis, nephritic, nephrotic, focal, diffuse, segmental global, end-stage renal disease
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Nephritis - inflammation of the kidney
Nephritic - kidney (glomerular) disease with inflammation Nephrotic - glomerular disease with heavy proteinuria Focal - < 50% nephron involvement Diffuse - >50% nephron involvement Segmental - only parts of the glomerulus involved Global - entire glomerulus involved End-stage renal disease - patients need dialysis or transplant to live |
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What are the normal physiological functions of the kidney? (5)
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Filter blood to remove nitrogeneous waste
Retain desired blood products Regulate body fluid components Synthesize and process hormones Excrete drugs |
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How do you measure GFR? (2 ways)
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1. 24 hour urine collection for urine [Cr] + plasma [Cr]
2. plug plasma [Cr] into a formula: Cockcroft-Gault formula, MDRD formula |
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What is the Cockroft-Gault formula?
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GFR (ml/min) = (140-age) x (weight (kg)/plasma[Cr]) x 1.2 for men
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What is the relationship between GFR and serum[Cr]?
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Reciprocal:
Plasma [Cr] = Cr production/GFR |
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How do you measure proteinuria? (2)
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1. 24 hour urine collection (N=<0.15g/day, nephrotic=>3.5g/day)
2. Urine dipstick (albumin:creatinine x9 = daily protein excretion) |
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Why do you use albumin:creatinine ratio rather than albumin directly for urine protein measurement?
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Corrects for how dilute or concentrated the urine is
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How do you measure hematuria? (2)
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1. urine dipstick - hemoglobin
2. urine microscopy - red cells and RBC casts |
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What are the stages of chronic kidney disease?
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1. GFR>90, albuminuria
2. GFR 60-90, albuminuria 3. GFR 30-60 4. GFR 15-29 5. GFR <15, end-stage |
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What are the most common forms of Chronic Kidney Disease and which compartment of the kidney do they affect? (4)
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Diabetic nephropathy: glomerulus
Glomerulonephritis: glomerulus Hypertensive/Vascular: vascular Polycystic kidney disease: tubulointerstitial |
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What are syndromes caused by renal parenchymal diseases? (4)
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Glomerular leakage: proteinuria = nephrotic syndrome, hematuria = nephritic syndrome
Renal failure: AKI, CKD, reduced GFR Hypertension Imparied composition of body fluids (retention or overexcretion) |
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What are mechanisms that lead to proteinuria (aka-types of proteinuria)? (5)
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Glomerular capillary wall injury
Tubular disease: protein not reabsorbed Overflow proteinuria: too much protein to handle (ex-multiple myeloma) Associated with acute illness: Heart failure, febrile illnesses leading RAAS activation and increased glomerular capillary pressure Orthostatic proteinurea: excrete when upright |
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What is the pathogenesis of neprhotic syndrome?
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Injury to glomerulus -> heavy proteinuria -> hypoalbuminemia + Renal tubular Na+ reabsorption
Hypalbuminemia -> decreased oncotoic pressure -> liver synthesis of LDL + Edema + decreased intravascular volume Decreased intravascular volume -> activation of RAAS and SNS -> increased renal tubular Na+ reabsorption -> edema |
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How does proteinuria increase renal tubular Na+ reabsorption?
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Aldosterone causes transcription of a regulatory protein in CCD
Regulatory protein inserts Na+ channel into epithelium in CCD Na+ is reabsorbed Plasmin is filtered into tubule and removes regulatory fragment from Na+ channel causing it to be stuck in membrane and increasing Na+ reabsorption |
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How does nephrotic syndrome lead to DVT?
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Loss of antithrombin-III causes thrombophilic state
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Compare and contrast nephritic and nephrotic syndrome
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Nephritic = proliferative = injury to mesangial and/or endothelial cell (gets exposed to immune cells) = glomerulonephritis
Nephrotic = non-proliferative = injury to podocyte (not exposed to blood so no inflammation) = glomerulonephropathy (aka nephropathy) |
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What are typical findings in nephritic syndrome? (5)
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Hematuria
RBC casts HTN Edema Reduced GFR |
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What is the pathogenesis of nephritic syndrome?
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Injury to mesangial and/or endothelial cells -> glomerular inflammation -> proliferation of glomerular cells + reduced surface area for filtration + tubular dysfunction + break in glomerular capillary wall
Proliferation of glomerular cells-> reduced surface area for filtration -> reduced GFR -> reduced Na+ + H20 excretion -> hypertension + edema Tubular dysfunction -> over reabsorption of Na+ -> reduced Na+ + H20 excretion Break in glomerular capillary wall -> Hematuria + RBC casts |
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What pathogenic mechanisms can lead to reduced GFR? (4)
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Glomerular disease - reduced surface area for filtration
Vascular disease - ischemia/thrombosis of multiple nephrons Tubulointerstitial disease - backleak, sloughing, tubuloglomerular feedback Scarring - replacement of nephrons with fibrosis |
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What are risk factors for progressive chronic kidney disease? (4)
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Ongoing activity of underlying disease: DM, SLE, etc
Significant initial injury with loss of nephrons: remaining nephrons hypertrophy and at risk for exhaustion (glomerulosclerosis) Proteinuria: proteins that are toxic to tubules get filtered through Hypertension: enhances scarring injury |
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How are K+, PO4, HCO3- and Na+ affected by renal parenchymal disease?
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K+ and PO4 retained (increased)
HCO3- reduced due to reduced production Na+ balance up or down depending on disease |
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Why does HTN occur in renal parenchymal disease?
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Na+ retention and/or reduced GFR
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What are 3 major categories of parenchymal renal disease?
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Glomerular
Vascular Tubulointerstitial |
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What are examples of glomerular diseases? (2)
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Proliferative
Non-proliferative |
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What are examples of vascular causes of renal parenchymal disease?
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Thrombotic microangiopathy
Cholesterol emboli Nephroangiosclerosis/hypertensive neprhosclerosis/renal artery stenosis |
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What are examples of tubulointerstitial diseases?(4)
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Acute tubular necrosis
Polycystic kidney disease Chronic pyelonephritis Myeloma kidney |
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What is the differential diagnosis of generalized edema?
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Congestive heart failure
Renal failure Cirrhosis Nephrotic syndrome |
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What are major morphologic patterns of nephrotic syndrome?
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1. Minimal change disease
2. Focal segmental glomerulosclerosis (FSGS) 3. Membranous 4. Nodular |
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What are secondary causes of MCD, FSGS, membranous and nodular nephrotic syndrome?
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MCD - Hodgkin's lymphoma, NSAIDs
FSGS - Heroin, HIV Membranous - SLE, Drugs (gold,etc), Cancers(adenocarcinoma), Infection(HBV, syphilis,malaria) Nodular - DM, amyloidosis |
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What blood tests do you order for a nephrotic syndrome workup?
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Serology for SLE
Studies for infectious disease Tests for amyloidosis Blood glucose |
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What are indications for doing a kidney biopsy? (3)
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Nephrotic syndrome (except if severely diabetic)
Renal failure of uncertain etiology and normal kidney size To aide in diagnosing systemic disease in absence of renal syndrome/failure |
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What are risks associated with kidney biopsy? (2)
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Bleeding (10%)
Infection |
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What studies do pathologists use to examine kidney biopsy tissue?
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Electron microscopy
Immunofluorescence Electron microscopy |
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What are primary and secondary causes of MCD?
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Primary - mutation of podocyte membrane protein
Secondary - NSAIDs, lymphoma, hypersensitivity reacion - |
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What is the pathogenesis of MCD?
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T-cell cytokine disrupts glomerular filtration barrier
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What are primary and secondary causes of FSGS?
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Primary - idiopathic (resembles MCD)
Secondary - viruses/drugs (resembles MCD), hyperfiltration-associated causing gradually increasing proteinuria (due to nephron loss or obesity + hypertension) |
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What is the pathogenesis of FSGS?
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Can be a progression of MCD
Mutations in podocyte membrane proteins like in MCD |
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What are primary and secondary causes of membranous nephrotic syndrome?
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Primary - idiopathic
Secondary - Lupus, HBV, epithelial malignancy |
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What is the pathogenesis of membranous nephrotic syndrome?
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Immune complex deposition at the capillary glomerular junction (subendothelial)
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What are non-specific treatments for neprhotic syndrome? (5)
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Control BP (target 130/80)
ACEi or ARB Diuretics with care Treat dyslipidemia Consider prophylaxis against DVT |
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Why do ACEi/ARBs help prevent progression of kidney disease? (2)
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Cause efferent arteriolar dilation which decreases glomerular capillary pressure
Reduces production of TGF-beta |
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How do you treat MCD nephropathy?
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Prednisone - usually resolves fully
Cyclophophamide for refractory |
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How do you treat FSGS?
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Prednisone first and cyclophosphamide if refractory - prognosis worse than MCD
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What is the prognosis of membranous nephropathy? (3)
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1/3 resolve spontaneously
1/3 stable renal function with chronic moderate proteinuria 1/3 progressive chronic kidney disease |
