Acute Glomerulonephritis

1. Acute Glomerulonephritis

2. Definition and Incidence • Acute Glomerulonephritis (acute nephritic syndrome) is the sudden onset of: • Haematuria (macroscopic/microscopic) with red cell casts or dysmorphic RBCs and • Proteinuria in the non-nephrotic range • It is often accompanied by: • Hypertension • Oedema (peri orbital, leg or sacral) • Temporary oliguria and uraemia. • Acute glomerulonephritis comprises of a specific set of renal diseases where an immune mechanism triggers inflammation causing damage to the basement membrane, mesangium or capillary endothelium of the glomerulus. • Glomerulonephritis represents 10-15% of glomerular diseases • M:F → 2:1

3. Clinical presentation • Symptoms • Dark, scanty urine. • Non-specific symptoms including weakness, fever, abdominal pain and malaise. • Haematuria • Oliguria • Oedema (peripheral or peri orbital) • Headache secondary to hypertension • SOB on exertion and dyspnoea secondary to heart failure or pulmonary oedema • Possible flank pain due to stretching of the renal capsule.

4. Causes – Berger’s disease • Also known as IgA nephropathy • Commonest form of GN world-wide • Pathophys • Focal and segmental proliferative GN with mesangial deposits of IgA • Superimposed crescent formation is frequent • Tends to occur in children and young males • Clinical pres • Present with asymptomatic microscopic haematuria, proteinuria (5% can be nephrotic). • Can get episodic recurrent haematuria following and URTI or GI viral infection • Ix • Normal complement levels • Increased serum IgA (in 50% of cases) • Under immunofluorescence stain: C3, IgM and IgG can be seen in the mesangium • Rx • Steroids • All patients should receive a combination of ACEi and ARBs

5. IgA nephropathy

6. Causes - Post-infectious GN • Commonly Post-strep GN • Occurs 1-3 weeks after a streptococcal infection usually throat, otitis media or cellulitis • Pathophysiology • Infecting organism is a group A β-haemolytic streptococcus • The organism is of a nephritogenic type • Ix • Biopsy shows diffuse, florid, acute inflammation in the glomerulus (without necrosis but occasionally crescents), with neutrophils and IgG deposition • Rx • Acute phase should be treated with antihypertensives, diuretics, salt restriction and possible dialysis • Treat underlying infection if still present

7. Post-strep GN

8. Causes – Henoch-Schonlein syndrome • A type of systemic vasculitis deposition of immune complexes in the skin and kidney • Clinical presentation • Characteristic skin rash, joint pain, abdo colic and GN • Pathophysiology • The lesion is a focal segmental proliferative GN, sometimes with mesangial hypercellularity • Immunoglobulin deposition of IgA is seen in the glomerular mesangium • Rx • Oral steroids and steroid-sparing agents

9. Causes – Anti-GBM GN • 2/3 of patients with this have Goodpasture’s syndrome with associated lung haemorrhage • Pathophys • Characterised by linear capillary loop staining with IgG and C3 • Also has extensive crescent formation • Anti-GBM antibodies are present in serum and are directed against the non-collagenous component of alpha3 collagen in the basement membrane • When anti-GBM antibody binds basement membrane, it activates complement and proteases and results in disruption of the filtration barrier and Bowman’s capsule, causing proteinuria and crescents • Rx • Plasma exchange is used to remove circulating antibodies • Steroids • Cyclophosphamide to suppress further antibody synthesis

10. Other causes • ANCA-positive vasculitides • Wegener’s granulomatosis • Microscopic polyangiitis • Churg-Strauss syndrome • Characteristic skin rash, joint pain, abdo colic and GN • SLE • Infective endocarditis • Visceral abscess • Cryoglobulinaemias • Non-strep post-infectious GN • Alport’s syndrome

11. Rapidly Progressive GN (RPGN) • RPGN is defined clinically as nephritic syndrome progressing rapidly to renal failure within weeks to months • Histologically defined by the formation of crescents between the Bowman’s capsule and glomerular tuft Classification