Glomerulonephritis is an inflammation of the glomerulus caused by a reaction to a foreign substance within the nephron. Inflammation is the body trying to protect itself by removing anything that harms the body whether it is damaged cells or disease-causing agents called pathogens. This process leads to glomerular damage because of the amount of stress occurring in the area. When the glomeruli are inflamed, the small blood vessels swell and allow protein and red blood cells that circulate through the body to pass through as urine. This causes a decrease in the amount of cells and proteins in the body, as important material is released as waste.
There are many types of glomerulonephritis grouped either as primary or secondary with no known cause. In primary glomerulonephritis, only the kidneys are affected. In secondary glomerulonephritis, the kidneys are damaged as part of a more generalized disease that can affect other parts of the body leading to strep throat.
While most kinds of the disease recover with or without medications there are some types of glomerulonephritis that cannot be successfully treated and progress to chronic kidney disease.