Renal Flashcards
(80 cards)
GFR
the volume of fluid filtered from the kidney’s into Bowman’s space/ unit time.
filtration rate of all functioning nephrons- gives an estimation of number of working nephrons
Can be calculated by measuring the renal clearance of any stubstance that has a steady level in the blood, is freely filtered or is not reabsorbed or secreted by renal tubules.
Renal clearance
volume of plasma completely cleared of the substance/ unit time
Creatinine clearance (CrCl)
UCr/Pcr x volume/ time
creatinine is freely filtered, it is not reabsorbed by the secreted tubules. it overestimates the GFR by 15%
can be inaccurate, under collection will have a false low CrCl and over collection will have a false high
Serum Creatinine
a poor marker for renal function as it is influenced by muscle mass
Creatinine
comes from muscular creatine and phosphocreatine converted at steady rate 2% of total creatine/day to creatinine.
creatinine is released into bloodstream and excreted exclusively by the kidney’s only
Daily creatine demand meet by diatary and de novo syntheiss, plasma level is a funciton of muscle mass
Renal disease
Etiology- Rnal- Primary kidney diseases- congenital, aquired, (glomeular/ tubulointerstitial)
- Pre-Renal- inadequte blood supply- heartfailure or low cardiac output, low renal perfusion, volume depletion, Sepsis, severe bleeding
- Post Renal( Bilateral urinary obstruction
- tumors, BPH (Prostate)
Clinical manifestations- Acute nephritic syndrome- hematuria, proteinuria,
- nephrotic syndrome- proteinuria, edema, lipiduria, hypoalbuminemia, hyperlipidemia
- asymptomatic- proteinuria, anuria, azotemia
- chronic renal failure- prolonged symptoms of urema
- UTI- bacteruria, pyuria
- Nephrolithiasis- colic, hematuria
- Renal tubular defects- With polyuria, nocturia, electrolyte disorders
Nephrotic Glomerular disease
Clinical manifestations:Heavy proteinuria, oval fat bodies, free fat droplets, few cellular elements, fatty casts, edema, lipiduria
Nephritic Glomerular disease
Clinical manifestations- Red cells, Red cell casts, Granular casts, Variable proteinuria, White blood cells., hematuria, hypertension
Primary Glomerular Diseases
Morphology- neutrophils and macrophages,
Etiology- immune mediated- unkown except for infectious agents
Pathogenesis- Immune mechanisms- antibody, cell, complement. Most are immune. Antibodies may be formed in response to endogenous antigens such as from tumor antigens or kidney antigens. they can also be formed in response to exogenous antigens such as drugs or organisms (viral or fungal). antibodies combine with antigen in periphery or insitu forming an immune complex. the immune complex formed is localized in various parts of glomerulus, this can activate the compliment and inflammatory cells. This causes injury to glomerular filtration membrane(AND)
- Non immune mechanisms- reduction of renal mass
Immune mechanisms for primary Glomerular disase
Insitu immune complex- Ag-Ab formation, fixed antigens for anti GBM (nephritis. Planted antigens(exogenous or endogenous
Circulating immune complex- endogenous antigens for DNA or exogenous antigens for infectious protein
Cytotoxic antibodies-
direct cell injury, without immune complex deposits.
cell mediated- Sensitized T cells will cause Glomeruluar injury
Activation of alternative complement- polysaccharide, endotoxin, IgA aggregates activates C3 which activates C3bBb
Non- immune mechanisms for Primary Glomerular disease
this is caused by Focal Glomeruloscerosis which. It will lead to systemic hypertension, intraglomerular hypertension, glomerular hypertorphy, these lead to mesangial cell hyperplasia/ECM deposition, intraglomerular coagulation and epithelila injury, this causes Proteinuria and Focal glomeruloscerosis.
Histological alterations of the glomeruli
diffuse- all glomeruli,
Focal- some glomeruli
global- entire glomerulus
Segmental- part of the glomerulus.
Immunofluorescence : stais for IgG IgA IgM C3 Kappa, Lambda
distribution can be along the GBM, Mesangium or both and can be patchy or diffuse, with a fine or courase grnular or lienar pattern.
Reasons not to perfomr a Kidney Biopsy
Advanced renal disase with small, echogenic kidneys or ultrasound, patient is a young child with nephrotic syndrome, clinical picture and associated systmeic findings are fairly definitive. Orthostatic proteinuria, Normal complement, normal creatinine, normal blood pressure and limited proteinuria.
Nephrotic Syndrome
Lab findings:Heavy proteinuria, hypoalbuminemia, edema, hyperlipidemia and lipiduria, NORMAL complement
Etiology: Glomerular damage causes increased permeability of glmerular capillaries to protein, this causes albumin to leave and other proteins. This will decrease the plasma oncotic pressure which causes edema, it also decreases PLASMA VOLUME, GFR, ALODSTERONE SECRETION, this causes fluid retention and edema
- hypoalbuminemia also causes compensatory synthesis of proteins by the liver which also includes lipoprotien which will cause hyperlipidemia
Pathogenesis- Immunoglobulin deposition causes membranous nephropathy
- non immunoglobulin deposition causes minimal change, FSGS, diabetic nephropathy, amyloidosis
Minimal Change disases
Epidemiology: most common disorder in children, in 15% of adults
morphology: LM- normal glomeruli, tubules, vessels
IF- no deposits
EM**** Fusion of foot processes and efacement, detachment of basement membrane
Etiology- Idoiopathic usually, may be lymphoma or renal cell carcinoma
Pathogenesis: Primary target is glomerular epithelial cells (Podocyte) results in increased glomerular permeability and subsequent massive proteinuria. NO IC deposition, non inflammotry. it is unclear but may involve ciculating glomerular permeability factors. This is because people who have transplant have recurrence of FGSG or minimal change disease
clincal features
Course:90% will have complete remission of proteinuria within 8 weeks of steroids but with frequent relapses, children 1/3 no relapse, 1/3 relapse few times, 1/3 relapse frequently
-in adults, remission and relpases
-renal failure and mortality rates are low but higher in adults.
- die to complications of Nephrotic Syndrome or therapy
Complications: tendency to progress into CRF/ESRD
Lab diagnositcs: low serum albumin, normal serum creatinine,
- Urine: proteinuria, bland urine sediment,
- normal BP, Edema (periorbital and pedal)
FSGS
Epidemiology- 10-15% idiopathic nephrotic syndrome in children, higher in adults
MorphologyLM- FSGS
IF- negative or non specific granular deposits of IgM or C3
EM- patchy fusion of the foot processes and effacement
Etiology: often idiopathic
-secondary to HIV, Morbid obesity, chronic reflux renal ablation nephropathy, heroin use, malignancies(lymphoma), glomerulonephritis, Congenital unilateral renal agenesis or aplasia
Pathogenesis- secondary- reduction in renal mass due to any renal disease, glomerular or other causes compensatory hypertrophy and hyperfiltration of remaining glomeruli to maintain FGR, intraglomerular hypertension, Hyperfiltration injury this causes Gllomerulosclerosis
Clincal features:- Present with nrephrotic syndrome: insidious onset of asymptomatic proteinuria
Course: degree of proteinuria is improtant for prognosis. persistent proteinuria and progressive decline in renal function. ESRD -5-20 years. with 50% recurrence post transplant. IgA nephropathy
Associations:Hypertension, renal insufficiency
complications:Progression to nephrotic syndrome, massive proteinuria, microscopic hematuria,
Membranous nephropathy
Morphology-LM: diffuse thickening of GBM, little increases in cellularity
- IF: fine granular deposits of IgG, C3 along the basement membrane-subepithelial
- EM- subepithelial immune complex deposits and proliferation and growth of new GBM spikes formation
Pathogenesis: localization of IC in sub epithelial zone as a result of formation IN SITU or CIRCULATIONG IC, Resembles Heymann Nephritis. (subepithelial localization) C5b-C9 insertion into podocyte cell membrane causes damaged GFM, increased permeability massive protein uria
Clinical features- Nephrotic syndrome, Microscopic hematuria (50%), Hypertension, Renal insufficiency(late), renal vein thrombosis
Associations(antigens and disorders) Idiopathic, endogenous antigens (DNA SLE/tumors) exogenous antigens,
-hep B, syphilis, malaria, captopril, mercury, gold, penicillamine
Course: 20 year follow up 25% have remission, 50% persistent proteinuria and stable or only loss of renal function 25% develop ESRD, poor prognosis for male, over 50, and greater than 10gm of proteinuria.
Heymann nephritis
animal model of human membranous nephropathy
-mice immunized with a renal apithelial antigen that develop autoantibodies IgG cross GBMs and bind to antigens on visceral epithelial cells (podocytes. the HNAC (resultant immune complex is shed into adjacent subepithelial space and produce pathological features
Diabetic nephropathy
epidemiology: leading cause of end stage renal diseases in USA 25-40% of type 1 and type 2 diabetics
Morphology- early lesions- expansion of mesangial matrix and thickening of GBM
- later lesions- diffuse glomerulosclerosis with diffuse increase in measangial matrix and diffuse thickening of GBM
- Kimmelstiel Wilson nodules. (contain lipids and fibrin
- fibrin cap and capsular drop(plasma proteins
- ischemia: causes tubular atrophy, interstitial fibrosis and hyaline ateriolsclerosis.
Etiology: adverse effects of systemic hyperglycemia
pathogenesis: hyperglycemia causes non-enzymatic glycosalation, advanced glycosylation products, increased growth factors (TGFbeta), activation of cytokines and formation of reactive O2 species. These leads to
- increased matrix formation and mesangium expansion
- increased type IV collagen, fibronectin and decreased proteoglycan heparin sulfate with thickening of GBM,
- hemodynamic changes- hyperfiltration, increased glomerular cappilary pressure, glomerular hypertrophy
- these all lead to glomerulosclerosis.
clinical presenation: nephrotic syndrome:
course: increased glomerular hydrostatic pressure, after 7-13 years, incipient nephropathy, after 10-20 years, macroalbuminuria, overt nephropathy
20+ years, presistent and progressive HTN, highly variable decline in FGR from 1-24 ml/min/year
Amyloidosis
Morphology: LM: nodular, amorphous hyaline material in the mesangiu and capillary loops, with resultant narrowing or closing of capillary lumens. IM: Congo red stain positive with apple green birefringence
EM:subendothelial and mesangial fibrils.
Etiology: deposition of amyloid fibrils that are composed of soluble proteins that have undergone misfolding resulting in formation of b-pleated sheet structrues,
-no immune or inflammatory response, damage and dysfucntion due to infilatration by amyloid fibrils and replacement of normal organ architecture with consequent loss of cellularity.
Pathogenesis: beta pleated sheets autoaggregate to from aggregates which are sistant to catabolism and removal.
- AL primary- light chain or fragment of light chain produced by abnormal plasma cells (fibrils compsoed of light chains)
- AA secondary amyloid, amyloid precursor protein is an apolipoproteind produced by the liver as an acute phase reactant in response to LONG STANDING INFECTION OR INFLAMMATION>
Clinical features- proteinurai, edema, nephrotic syndrome. Renal insufficiency , fanconi’s synrome(electrolyte abnormal)
- CVS: CM/CHF, arrythmias, heart block,
- GIT: hepatomegaly, malabsorption, bleeding,
- Neuro: ischemic stroke, neuropathy, orthostatic hypotension,
- skin: easy bruising and purpura.
Diagonsis- biopsy of organ involved
Course-Very poor, many die of end organ failure
Association- multiple myeloma(primary)
- rheumatoid arthritis, Behcet syndrome, crohn’s disease, Osteomyelitis, Tuberculosis, renal Cell carcinoma, Hodgkin’s disease. congestive heart failure
Nephtritic Syndrome
Morphology- Urine Sediment- Red blood cells and Red blood cell casts.
- granular casts
- variable proteinuria
-possibly WBC
Normal complement levels
- IgA nephropathy- Henoch-Chnolein Purpura, Alport’s syndrome (hereditary nephtritis, SLE- Class I, II, B, Benign Hematuray
IgA nephropathy
epidemiology: Most common type of glomerulonephritis, any age, peak in 2nd and 3rd decades, Asians, caucasians, rare in blacks
Morphology- LM segmental areas of increased mesangial matrix and hypercellularity
IF: Mesangial and subendothelial deposits of IgA and C3( +/- IgG, IgM
EM: mesangial and subendothelial deposits
Pathogenesis- Production of IgA class Ic mainly from mucosal immune system. supported by clinical hematuria worsens during URI or GI infections, has a predilection for mesangium. (depositions.
clinical- eipsodes of gross hematuria, persistent microscopic hematuria between episodes. non nephrotic proteinuria normal C3C4
Course- generally prolonged benign, 20% wil progres to ESRD. most restricted to kidney but can be assocated ith others
Associations- viral respiratory illness or GI illness, arthritis, vasculitis, non-thrombocytopenic purpura (HSP), hepatic Cirrrhosis, Gluten enteropathy, HIV infection. Minimal change, Membranous wegener’s, ankylosing spondylitis, small cell Carcinoma.
Post streptococcal Glomerulonephritis
Epidemiology- More common in children 6-10 years old
Morphology: LM- hypercellular glomeruli,(neutrophils and monocytes. Proliferation of mesnagial and endothelial, epithelal cells, profess is Diffuse, closure of capillary loops due to proliferationand swelling of endothelial cells and leukocytes infiltration.
IF- granular deposits of IgG and C3 in mesangium and along capillary walls
EM- electron dense deposits in sub epithelial space humps
Etiology- nephritogenic strain of b-hemolytic streptococci
Pathogenesis- usually 10 days folloing pharyngitis or 3 weeks following impetigo. due to late period of antibody formation. intially subendothelial IC depositis that causes activation of complement and influx of inflammatory cells with resultant prolifererative GN decline in GFR, Depsoits are rapidaly cleared accounting for resolution of hematuria and renal faiulre.
- later- characterisitc subepithelial HUMPS responsible for epithelial cell damage and proteinuria
- IC deposits cleared slowly and are separated from circulation by GMP limiting their clearance. This accounts for the slow rate of resolution of proteinuria.
Clinical features- Proteinuria more than 2gm/ day. Complement levels always low. .
Course: lesions begin to resolve after a month or two and usually completley rsolved over 9 months to several years. in children almost always renal function recovered (less than 1% irrevirseble renal faiulre
- long term prognosis, some develop renal insufficiency after 10-4 years after initial illnees.
- some glomeruli irreversibly damaged, results in compensatory hypefiltration in remaining glomeruli to maintain normal fGR
- Long standing increased glomerular capillary pressure eventualy results in hemodynamic mediated injury and glomerulosclerosis
diagnosis: history, clinical presentation. elevated titers for antisterptolysinO Ab or anti DNAase B, in assocation with low complement, no renal biopsy because usually gone
Membranoproliferative glomerulonephritis (MPGN)
Morphology- thickening of the basement membrane, mesangial proliferation, infiltration of inflammatory cells.
-LM- mesangial expansion and hypercellularity, thickening of capillary loops due to double countour formation “tram track” which is duplication of GBM
-EM Type 1: Subendothelial deposits( C3+ IgG)
Type 2 deposition of dense material along GBM- unknown composition (C3)
Type 3: Subendothelial, mesangial, subepithelial deposits. C3-IgG
Etiology- primary is idiopathic, secondary is underlying systemic disorder
-Type 1 most common, idiopathic is rare, secondary forms more common- Lupus, hep C, cryoglobuilnemia, endocarditis, parasitic infection.
Pathogenesis- Type 1 complement classical activation.
Type 2 alternate complement pathway. C4 levels may be nomal but C3 remains depressed for prolonge periods due to C3 nephritic factor. (IgG binds to and stabilizes C3bBb convertase which casues continuous degradation of C3
clinical- usually before age 30 shows, hematuria or proteinuria in urinalysis, acute nephritic syndrome with hematuria, hypertension and edema, recurrent episodes of gross heamturis, insideious onset of edema and nephrotic syndrome.
course: most progress towards ESRD within 10-15 years.