الفهرس 
Epidemiology of IgANOnly 14 pages are availabe for public view
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Abstract
IgAN is a renal disease with different frequency throughout the world which is influenced by different causes as: (1) ancestral factors and geographical situations; (2) different social and regional attitude to the management of renal disease in different countries; for example the high incidence of IgAN in Singapore is due to a high selection of patients with asymptomatic microscopic hematuria or occasional mild proteinuria, discovered during the regular medical examination of army recruits. In Japan school children receive a yearly urinalysis, and the persistence of microhematuria and/or proteinuria leads to a renal biopsy; (3) there are differences in the interest and judgment of clinicians on the diagnostic value of renal biopsy; (4) differences in the indications for and background to renal biopsy.
IgAN is an autoimmune renal disease arising from consequences of increased circulating levels of IgA1 with galactose deficient hinge-region O-glycans. However, this glycosylation aberrancy alone is not sufficient to induce nephritis. For the clinical manifestation of renal injury, several additional hits are required, including synthesis of circulating antibodies directed against the aberrantly glycosylated O-linked hinge-region glycans to form immune complexes, accumulation of the complexes in the mesangium, and activation of mesangial cells. Genetic factors apparently influence the expression of these mechanisms. Elucidation of the pathogenesis of IgAN provides an opportunity to develop a disease-specific therapy that heretofore has been missing.
IgA nephropathy is characterized pathologically by prominent, globular deposits of IgA in the mesangium on immunofluorescence microscopy. Light microscopy shows diffuse mesangial proliferation and matrix expansion with proliferative glomerulonephritis and crescents in more advanced disease. Electron microscopy shows dense deposits primarily in the mesangium.
Manifestations of IgA nephropathy are restricted to the kidney. Mesangial IgA deposition, which is often clinically silent, may also be seen with cirrhosis, celiac disease and HIV infection.
Most patients with IgA nephropathy present with either visible hematuria (single or recurrent), usually following an upper respiratory infection, or invisible hematuria with or without mild proteinuria incidentally detected on a routine examination. Rarely, patients may develop acute kidney injury with or without oliguria, due either to crescentic IgA nephropathy, or to gross hematuria causing tubular occlusion and/or damage by red cells.
The diagnosis of IgA nephropathy is often suspected on the basis of the clinical history, but can be confirmed only by kidney biopsy.
A kidney biopsy is usually performed for the evaluation of suspected IgA nephropathy only if there are signs suggestive of more severe or progressive disease such as protein excretion above 0.5 to 1 g/day, elevated serum creatinine concentration, or hypertension.
The Oxford classification identifies variables that are correlated with renal outcomes independent of the clinical features at baseline, the proteinuria level and blood-pressure control. The prognostic utility of this scoring system needs to be validated before it is used in determining treatment.
Clinical predictors of progression of IgA nephropathy include elevated serum creatinine, hypertension, and persistent protein excretion above 1000 mg/day.
The optimal approach to the treatment of IgA nephropathy is uncertain since definitive randomized trials have not been performed. Most trials recommend not treating patients with isolated hematuria, no or minimal proteinuria, and a normal glomerular filtration rate.
For patients with persistent proteinuria greater than 1000 mg/day, they recommend ACE inhibitor or ARB with a goal below 1000 mg/day. Fish oil can be tried in addition to an ACE inhibitor or ARB in patients with protein excretion above 1000 mg/day. They recommend the addition of immunosuppressive therapy with glucocorticoids to angiotensin inhibition in patients with an elevated or increasing serum creatinine and/or protein excretion above 1.0 to 1.5 g/day despite maximum antiproteinuric therapy.
For patients with severe disease at baseline (serum creatinine>1.5 mg/dL) or progressive disease with glucocorticoids alone who do not have significant chronic damage on kidney biopsy, therapy with oral prednisone and cyclophosphamide is suggested.
For patients with crescentic glomerulonephritis and a rapidly progressive clinical course, therapy with intravenous pulse glucocorticoids and cyclophosphamide is recommended.
For patients with acute onset of nephrotic syndrome and minimal change disease as well as mesangial IgA deposits on renal biopsy, glucocorticoid therapy is recommended.
Acute renal failure can occur in patients during episodes of gross hematuria. This is usually due to acute tubular necrosis, and the serum creatinine concentration typically returns to baseline levels within several weeks to months. However, acute renal failure can also represent transformation to crescentic disease, which requires immediate therapy.
Chronic kidney disease from any cause is associated with a marked increase in cardiovascular risk. Statin therapy may lower cardiovascular risk but there is no evidence that it slows the rate of progression of renal disease.