Glomerulonephritis can develop in an acute (sudden, rapid onset) or a chronic (slow) form, and is caused by a painless inflammation of the glomerulus (the kidney filter). It can occur by itself or as part of a more general problem such as systemic lupus erythematosus (SLE). Testing of the urine shows the presence of blood and protein. It is associated with high blood pressure and progressive decline of kidney function. It is diagnosed by blood tests and a kidney biopsy. High blood pressure and the presence of protein in the urine may predict the tendency towards progression. Many patients with glomerulonephritis will simply need to be followed-up each year in an outpatient setting. Others may need treatment with specific drugs to reduce inflammation, such as steroids, azathioprine, cyclosporin A, and cyclophosphamide.