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PATHOPHYSIOLOGY. Acute Poststreptococcal Glomerulonephritis (APSGN). PATHOPHYSIOLOGY. Acute Nephritic Syndrome glomerular syndrome characterized by acute onset of usually grossly visible hematuria , mild to moderate proteinuria and hypertension . Two Types of Acute Nephritic Syndrome :
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PATHOPHYSIOLOGY Acute Poststreptococcal Glomerulonephritis (APSGN)
PATHOPHYSIOLOGY • Acute Nephritic Syndrome • glomerularsyndrome characterized by acute onset of usually grossly visible hematuria, mild to moderate proteinuria and hypertension. • Two Types of Acute Nephritic Syndrome: • Acute Glomerulonephritis– the diagnosis of the patient • Rapidly Progressive (Crescentic) Glomerulonephritis
PATHOPHYSIOLOGY • Acute Glomerulonephritis • characterized anatomically by inflammatory alterations in the glomeruli • Light microscopy – enlarged hypercellularglomeruli with leucocytic infiltration • IF – granular IgG and C3 in GBM and mesangium • EM – subepithelial humps • clinically by the syndrome of acute nephritis: • Hematuria • Red blood cell casts in the urine • Pyuria • Mild to moderate proteinuria • Hypertension • Edema
PATHOPHYSIOLOGY • Two Types of Acute Glomerulonephritis: • Acute Proliferative/PoststreptococcalGlomerulonephritis • Non-Streptococcal Acute Glomerulonephritis • Bacterial infections • Viral disease • Parasitic Infections
PATHOPHYSIOLOGY DISEASE PROGRESSION Sore Throat and Severe Cough After about 2 weeks Cola – Colored Urine and Bipedal Edema PE and Lab Workups: Clinical Signs of Nephritic Syndrome Acute PoststreptococcalGlomerulonephritis
PATHOPHYSIOLOGY • Acute Poststreptococcalglomerulonephritisfollows infection with only certain strains of streptococci designated as nephritogenic. • Group A Beta Hemolytic streptococci • Pyodermatitis with streptococci M types 47, 49, 55, 2, 60, and 57 • APSGN develops 2-6 weeks • Throat infection with streptococci M types 1, 2, 4, 3, 25, 49, and 12 • APSGN develops 1-3 weeks
PATHOPHYSIOLOGY • ASPGN is an immune-mediated disease • immune complex containing a streptococcal antigen is deposited in the affected glomeruli • The 3 antigens isolated from nephritogenicstreprococci are: • Cysteine protease streptococcal pyrogenicexotoxin B • Nephritis associated streptococcal plasmin receptor which is a plasmin-binding protein with glyceraldehyde phosphate dehydrogenase (also known as presorbing antigen or PA-Ag) • Streptokinase
PATHOPHYSIOLOGY • The size of glomerular basement membrane (GBM) pores and the molecular size of the streptococcus-Ig complex are also important determinants. • Streptococcus-Igcomplex = 15 nm • 10 nm = streptococcus group A • 5 nm = immunoglobulin • Children = 2-3 nm • Adults = 4-4.5 nm
PATHOPHYSIOLOGY • Elevated titers of antibodies • Serum complements are low • Granular immune deposits in glomeruli and electron dense deposits • Rheumatoid factor • Cryoglobulins • Antineutrophilcytoplasmic serum antibodies • Host susceptibility factors(HLA-DRB1*03011)