Glomerulonephritis is a much unloved issue among medical students. It is a whole group of different diseases, which have common one thing – damage of glomeruli. In this text, the issue is going to be described very easily to make it well understandable even for laymen.
Glomerulus is the basic filtration unit of kidney. It is a thin coiled arteriole with very thin wall. The pressure within the little artery is strong enough to cause filtration of fluid through the arterial wall forming the primary urine.
Glomerulonephritis is usually a condition caused by abnormal immune response. In most cases, the immune system causes development of the so-called immune complexes in the bloodstream. Such immune complex is a molecule (antigen) with attached antibody. Immune complexes accumulate in different parts of glomeruli and disrupt their functions. In addition, the glomeruli may be damaged by immune cells in the ongoing inflammatory reaction. In some rare cases, the glomerulonephritis causes production of antibodies that directly target the glomeruli and damage them.
Types of glomerulonephritis
Glomerulonephritis can be divided into groups according to several aspects; the most understandable seems to be the division according to the speed of progression and duration of clinical symptoms.
This group of glomerulonephritis occurs relatively quickly and can cause acute kidney failure within a few days after the onset of the disease. This group includes for example the so-called Goodpasture syndrome.
This group of glomerulonephritis can cause a relatively rapid renal failure within few months after the onset.
This type of glomerulonephritis progresses quite inconspicuously and can be found as a random deterioration of renal functions. They can be diagnosed even in relatively late stages as chronic kidney failure.
The basic symptoms of glomerulonephritis are nephritic syndrome and nephrotic syndrome. They may be present simultaneously, but usually one manifests much more than the other. With a great inaccuracy we can say that acute glomerulonephritis often expresses symptoms of nephritic syndrome and chronic glomerulonephritis is more typical by symptoms of nephrotic syndrome.
Violation of filtering ability of the kidneys can lead leakage of red blood cells through the damaged glomeruli, which is followed by blood in urine presence (visible to the naked eye or only by urinalysis). The glomeruli damage is also related to elevated blood pressure. The urine may contain higher amount of proteins but this does not reach the amount lost in the nephrotic syndrome (see below).
The syndrome is dominated by protein loss in urine because of damage of the glomeruli membranes. The daily protein loss usually exceeds three grams. This is enough to cause signs of lack of proteins in the organism and symptoms such as swelling, high cholesterol and higher risk of blood clots occurrence (thrombophilia). Glomerulonephritis can progress into acute or chronic kidney failure, whose manifestations and complications can be found in relevant texts.
It is necessary to comprehensively examine the kidneys and their function. It is important to perform urinalysis to evaluate presence of blood and protein in urine. Serologically we can look for certain autoantibodies and presence of immune complexes. The most accurate testing method is, however, the kidney biopsy. This invasive examination method allows us to get a sample of tissue with a special needle. The sample can be investigated histologically and imunohistochemically to detect the above-mentioned deposits of immune complexes.
Treatment depends on particular type of glomerulonephritis. Some types of glomerulonephritis is only regularly monitored or treated with medications. We usually use drugs decreasing the immune response (e.g. corticosteroids) as the disease is of an immunopathological origin. However, given the numerous adverse effects of these drugs, it is necessary to indicate and dose them correctly. In acute kidney failure or last stages of chronic kidney failure, temporary or life-long dialysis is necessary.