glomerular disease
TRANSCRIPT
RENAL SYSTEM
The kidneys:An Excretory organ or a Regulatory organ?!!!
The main purpose of the kidney is to separate urea, mineral salts, toxins, and other waste products from the blood.
They also do the job of conserving water, salts, and electrolytes.
At least one kidney must function properly for life to be maintained.
The Kidneys- function
The Kidney Diagram
The Kidney Nephron Diagram
GLOMERULUS:
Glomerular capillary wall:1. Fenestrated endothelium –70 – 100 nm,2. Glomerular Basement Membrane
.. Lamina rara interna,
.. Lamina densa,
.. Lamina rara externa3. Visceral epithelial cells (podocytes)4. Mesangial cells – contract, proliferate, collagen & matrix, secretion;
THE KIDNEY
Three-dimensional schematic drawing of the glomerulus
Afferent arteriole
Efferent arteriole
Bowman’s Capsule
Basement membrane
Visceral Epithelium(Podocyte)
Parietal Epithelium
Capillary loops
Bowman’s Space
Endothelial cells
Stucture of renal
glomerulus
Mesangial matrix and cell
Ultramicroscopic Stucture of glomerullar Capillaries
Filtration Mem
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Light microphotograph of glomerulus
•Normal celluarity
;•Patent capillary lumens
RENAL PATHOLOGY
DISEASES OF GLOMERULI
DISEASES OF TUBULES
DISEASES OF INTERSTITIUM
DISEASES OF BLOOD VESSELS
DISEASES OF THE KIDNEY
AZOTEMIA – BUN, Creatinine --- GFR
UREMIA – Azotemia + Clinical signs and
symptoms + Biochemical abnormalities
+ Involvement of G I tract, Peripheral
nerves
.. and heart;
Clinical manifestations of renal diseases
Glomerular disease
DEFINITION Abnormalites of glomerular funtion can be
caused by damage to the major components of the glomerulus: Epithelium (podocytes), Basement membrane, capillary endothelium, mesangium.
Damage manifested by an inflammatory process.
GLOMERULAR DISEASES
Clinical manifestation of glomerular injury
Histologic alterations
a) hypercellularity: i) cell proliferation of mesangial cells or
endothelial cellsii) leukocyte infiltration (neutrophils,
monocytes and sometimes lymphocytes)iii) formation of crescents
- epithelial cell proliferation (from immune/inflammatory injury)- fibrin thought to elicit this injury (TNF, IL-1, IFN- are others)
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b) basement membrane thickening - thickening of capillary wall
c) hyalinization (hyalinosis) and sclerosis
-accumulation of material that is
eosinophilic and homogeneous
- obliterates capillary lumen of
glomerulus (sclerotic feature)
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classification is based on histology. Subdivided:
a) diffuse (all glomeruli)b) global (entire glomerulus)c) focal (portion of glomeruli)d) segmental (part of each glomerulus)e) mesangial (affecting mesangial
region)
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What causesglomerular disease ?
Most are of immunologic origin, and
caused by immune complexes !
• metabolic stress: DN• mechanical stress:• hypertension
Antibody mediated injury In situ immune complex deposition Fixed intrinsic tissue antigens collagen type4 antigen [anti GBM-nephritis] Heymann antigen [membranous nephropaty Mesangial antigens Circulating immune complex deposition Endogenous antigen[DNA,Nuclear
proteins,immunoglobulins,igA] Exogenous antigen [infectiousagents,drugs]Cytotoxic antibodiesCell mediated immune injuryActivation of alternative complement
pathway
Pathogenesis of glomerular injury
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Pathogenesis of Glomerular Disease
Immune mechanisms underlie most cases of primary GN and many of the secondary cases
a) 2 forms of Ab-associated injuryi) injury resulting from soluble Ag-
Ab deposits in glomerulusii) injury from Ab reacting in-situ
with glomerulus
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• In Situ Immune Complex Depositiona) Ab act directly with intrinsic tissue
Ag “planted” in the glomerulus from
the circulationb) 2 forms of Ab-mediated glomerular injury
i) anti-GBM Ab-induced nephritis- Ab directed against fixed Ag
in ii) Heymann nephritis- a form of membranous GN- Ab bind along GBM in
“granular pattern”
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Antibody mediated GN - Circulating Immune complex
Location: Mesangial and sub-endothelial
Antibody mediated GN -
In-situ Immune complex
Location: GBM sub-epithelial
• circulating auto antibodies with intrinsic autoantigens (component of normal parenchyma)
Antibody mediated GN - In-situ Immune complex (trapped Ag)
Location: GBM sub-epithelial
Extrinsic antigens planted within the glomerulus
Pathogenesis
In situ immune complex
Circulating immune complex
Activation of T lymphocytes
Acitvation of complements
cytokines
C5b-9 C5a,C3a
Epithelial, mesangial,Endothelial cells
Macrophagepolynuclear leucocyte, platelets
Mesangial cells
oxidative stress, protease, matrix accumulations
Glomerular Disease
Glomerular DiseasesPRIMARY GLOMERULOPATHIES Acute proliferative glomerulonephritis Post-infectious Rapidly progressive (crescentic) glomerulonephritis Membranous glomerulopathy Minimal-change disease Focal segmental glomerulosclerosis Membranoproliferative glomerulonephritis IgA nephropathy Chronic glomerulonephritis SYSTEMIC DISEASES WITH GLOMERULAR INVOLVEMENT Systemic lupus erythematosus Diabetes mellitus Amyloidosis Goodpasture syndrome Microscopic polyarteritis/polyangiitis Wegener granulomatosis Henoch-Schönlein purpura Bacterial endocarditis HEREDITARY DISORDERS Alport syndrome Thin basement membrane disease Fabry disease
TABLE 20-2 -- Glomerular DiseasesPRIMARY GLOMERULOPATHIES Acute proliferative glomerulonephritis Post-infectious Other Rapidly progressive (crescentic) glomerulonephritis Membranous glomerulopathy Minimal-change disease Focal segmental glomerulosclerosis Membranoproliferative glomerulonephritis IgA nephropathy Chronic glomerulonephritis SYSTEMIC DISEASES WITH GLOMERULAR INVOLVEMENT Systemic lupus erythematosus Diabetes mellitus Amyloidosis Goodpasture syndrome Microscopic polyarteritis/polyangiitis Wegener granulomatosis Henoch-Schönlein purpura Bacterial endocarditis HEREDITARY DISORDERS Alport syndrome Thin basement membrane disease Fabry disease
TABLE 20-2 -- Glomerular DiseasesPRIMARY GLOMERULOPATHIES Acute proliferative glomerulonephritis Post-infectious Other Rapidly progressive (crescentic) glomerulonephritis Membranous glomerulopathy Minimal-change disease Focal segmental glomerulosclerosis Membranoproliferative glomerulonephritis IgA nephropathy Chronic glomerulonephritis SYSTEMIC DISEASES WITH GLOMERULAR INVOLVEMENT Systemic lupus erythematosus Diabetes mellitus Amyloidosis Goodpasture syndrome Microscopic polyarteritis/polyangiitis Wegener granulomatosis Henoch-Schönlein purpura Bacterial endocarditis HEREDITARY DISORDERS Alport syndrome Thin basement membrane disease Fabry disease
TABLE 20-2 -- Glomerular DiseasesPRIMARY GLOMERULOPATHIES Acute proliferative glomerulonephritis Post-infectious Other Rapidly progressive (crescentic) glomerulonephritis Membranous glomerulopathy Minimal-change disease Focal segmental glomerulosclerosis Membranoproliferative glomerulonephritis IgA nephropathy Chronic glomerulonephritis SYSTEMIC DISEASES WITH GLOMERULAR INVOLVEMENT Systemic lupus erythematosus Diabetes mellitus Amyloidosis Goodpasture syndrome Microscopic polyarteritis/polyangiitis Wegener granulomatosis Henoch-Schönlein purpura Bacterial endocarditis HEREDITARY DISORDERS Alport syndrome Thin basement membrane disease Fabry disease
TABLE 20-2 -- Glomerular DiseasesPRIMARY GLOMERULOPATHIES Acute proliferative glomerulonephritis Post-infectious Other Rapidly progressive (crescentic) glomerulonephritis Membranous glomerulopathy Minimal-change disease Focal segmental glomerulosclerosis Membranoproliferative glomerulonephritis IgA nephropathy Chronic glomerulonephritis SYSTEMIC DISEASES WITH GLOMERULAR INVOLVEMENT Systemic lupus erythematosus Diabetes mellitus Amyloidosis Goodpasture syndrome Microscopic polyarteritis/polyangiitis Wegener granulomatosis Henoch-Schönlein purpura Bacterial endocarditis HEREDITARY DISORDERS Alport syndrome Thin basement membrane disease Fabry disease
Various types of glomerulopathies are characterized by one or more of four basic tissue reactions:
1. Hypercellularity
2. Basement membrane thickening
3. Hyalinosis
4. Sclerosis
HISTOLOGIC ALTERATIONS
ACUTE PROLIFERATIVE (Poststreptococcal,
Postinfectious)GLOMERULONEPHRITIS
Common form of GN in developing countries. 6 to 10yrs of age 1 - 4 weeks after a streptococcal infection of pharynx
or skin (Impetigo) Group A β-haemolytic streptococci - types 12, 4, 1 Immunologically mediated disease Immune Complex mediated Anti - endostreptosin & other cationic antigens . Serum – C
Poststreptococcal Glomerulonephritis
Glomeruli- Enlarged , hypercellular glomeruli - infiltration by leukocytes - proliferation of endothelial &
mesangial cells, - crescent formation (severe cases)
- obliteration of capillary lumen
Fibrin deposition in capillary lumen &
mesangium.
Interstitial edema and leucocytic infiltration
Tubules contain red cell cast.
Microscopy
Diffuse
Normal glomerulus
Acute Proliferative GN
AcuteProliferative GN
Immunofluorescence:
- granular deposits of IgG , IgM , C3 in
mesangium , along BM
Electron microscopy: Discrete , amorphous , electron dense
deposits on epithelial side of BM often having the appearance of “humps
Sudden onset in a young child - malaise, fever , nausea , oliguria , hematuria,
Edema , mild - moderate hypertension , elevation of BUN
Urine - RBC casts, proteinuria Lab - antistreptococcal antibody titre , C3
Clinical Course
95% -- children recover,< 1% - rapidly progressive GN1-2% - slow progression to chronic GN,
Persistent proteinuria, Abnormal GFRAdults
Prognosis
Poorprognosis
CRESCENTIC GLOMERULONEPHRITIS
CRESCENTIC GLOMERULONEPHRITIS
(Rapidly Progressive Glomerulonephritis)[RPGN]
Severe glomerular injury Does not denote a specific etiologic form of
GN Clinically - rapid & progressive loss of renal
function & death within weeks to months Crescents in most glomeruli – parietal
epithelial cells proliferation;
RPGN(Crescentic Glomerulonephritis)
Type - I RPGN ( Anti-GBM antibody induced disease)
.. Idiopathic,
.. Goodpasture syndrome; Type - II RPGN (immune Complex)
.. Idiopathic, postinfecious, SLE, Henoch-Schonlein purpura (IgA), others;
Type - III RPGN ( Pauci-immune ) .. ANCA associated, Idiopathic,
Wagener granulomatosis, PAN;
Classification & Pathogenesis
Linear deposits of IgG , C3 in GBM Cross reaction with pulmonary alveolar BM
Good - Pasture’s antigen located in
noncollagenous portion of α3
domain of collagen type - IV
Type I - RPGN ( Crescentic GN )
Immune complex mediated disease
Complication of immune complex
nephritides - Post infectious GN , SLE ,
IgA nephropathy
Granular deposit of immune complexess of
IgG and C3 along glomerular capillary walls.
IF - lumpy bumpy granular pattern
Type - II RPGN
Lack of anti GBM antibody , immune complexes by IF , EM
ANCA present- defect in humoral immunity. Usually a component of systemic vasculitis
- Wegeners Granulomatosis , Polyarteritis Idiopathic
Type III RPGN( Pauci - immune )
Gross : Kidneys enlarged , pale ,smooth outer surface.
C/S petechial hemorrhages on cortical surface
Morphology
Crescentsproliferation of parietal cells migration of monocytes ,macrophages into Bowmans space Crescents obliterate Bowman’s space ,
compress glomerular tuft Fibrin strands are prominent between cellular
layers in the cresents.
Microscopy
Crescents Sclerosis EM : subepithelial deposits ruptures in GBM IF : Postinfectious cases - granular Good Pastures syndrome - linear
Idiopathic - granular / linear
Microscopy of RPGN (cont. )
Electron micrograph showing characteristic wrinkling of GBM with focal disruptions (arrows).
Hematuria , RBC casts , proteinuria Hypertension , Edema Good - Pastures syndrome -
Hemoptysis Anti - GBM , antinuclear , ANCA Renal involvement - progressive
Clinical Course
a) massive proteinuria (> 3.5 g/day) b) hypoalbuminemia c) generalized edema d) hyperlipidemia and lipiduria
Nephrotic Syndrome
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Clinical syndromes and presentation
Latent GN(asymptomatic
urinary abnormalities)
Nephrotic syndrome
Acute GN RPGN Chronic GN
microscopic or Macroscopic hematuriaProteinuria
Dysmorphic Glomerular erythrocytes
Proteinuria>3.5g/dHypoalbuminemiaHyperlipidemiaEdema
HematuriaProteinuria(1-3g/d)ARFEdemaHypertensionRed cell casts
•Rapidly deterioration of renal function•Hematuria, Proteinuria• oliguria or anuriaRed cell casts•With or without systemic symptom
•Hematuria, Proteinuria•Hypertension•Reduced GFR