The glomeruli are the filtering heads of the kidney. Joined to each glomerulus is a tiny tube (tubule). Each of these glomeruli-and-tubule unit is called a nephron. Glomerulonephritis is an inflammatory condition that affects predominantly the glomeruli. Long standing (chronic) disease will usually lead to End-Stage Renal Disease (ESRD).
There are a number of different conditions that may cause Glomerulonephritis. One common example is IgA nephropathy. In this particular condition, a normally existing antibody (Immunoglobulin A) is deposited in the glomeruli and incites inflammation. It is not certain why this occurs in some people. IgA kidney disease is usually a chronic disease with variable outcome. There is a high likelihood in some that they may progress to End-Stage Renal Disease (ESRD) while others remain with relatively preserved kidney functions even after a long period of time.
In many underprivileged communities, infection with a bacteria (Streptococcus) is still common. It can cause post-Streptococcal Glomerulonephritis. This usually occurs in children below age 10 but can affect all age groups. Although most cases will recover, there are some that will lead to permanent damage. Many other forms of infection such as HIV, Hepatitis and bacterial endocarditis (infection of the tissues of the heart) can lead to Glomerulonephritis. Autoimmune diseases can also give rise to Glomerulonephritis.
In autoimmune disease, the immune system of the patient does not differentiate self and ‘foreign’ and creates (auto)antibodies that attack the body itself. This is usually a disease that is not just confined to the kidneys but many organs of the body (systemic). One example is lupus nephritis (as part of systemic lupus erythematosus or SLE).
Glomerulosclerosis refers to scarring of the glomeruli. It may be caused by the diseases mentioned earlier such as diabetic nephropathy, IgA disease, or lupus nephritis. Focal segmental glomerulosclerosis (FSGS) is one such condition. Sometimes a cause can be found, other times it is not known (idiopathic).
A common glomerular disease without Glomerulonephritis or Glomerulosclerosis is minimal change disease. Patients usually present heavy proteinuria and leg swelling. Outlook for this condition is good.